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Ullmann's Encyclopedia of Industrial Chemistry

ULLMANN'S Encyclopedia of Industrial Chemistry

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Abrasives

1

Abrasives
Jean-Claude Menard, Federation of European Producers of Abrasives, 75041 Paris, France
Newman W. Thibault, Norton Co., Worcester, Massachusetts 01606, United States
1.
2.
2.1.
2.2.
2.3.
2.4.
3.
3.1.
3.1.1.
3.1.2.
3.1.3.
3.2.
3.3.
3.4.
3.5.
3.6.
3.7.
4.

Introduction . . . . . . . . . . . . . . .
Natural Abrasives . . . . . . . . . . . .
Quartz . . . . . . . . . . . . . . . . . . .
Garnet . . . . . . . . . . . . . . . . . . .
Corundum and Emery . . . . . . . .
Diamond . . . . . . . . . . . . . . . . . .
Manufactured Abrasives . . . . . . .
Fused Aluminum Oxides . . . . . . .
Raw Materials . . . . . . . . . . . . . . .
Furnace Designs . . . . . . . . . . . . .
Fused Alumina Types . . . . . . . . . .
Fused Zirconia – Aluminas . . . . . .
Sintered Aluminas . . . . . . . . . . .
Silicon Carbide . . . . . . . . . . . . .
Boron Carbide . . . . . . . . . . . . . .
Diamond . . . . . . . . . . . . . . . . . .
Cubic Boron Nitride . . . . . . . . . .
Manufacture and Testing of Sized
Grains . . . . . . . . . . . . . . . . . . .

1
1
1
2
2
2
3
3
3
3
3
5
5
6
6
7
7
8

1. Introduction
An abrasive has been defined as “any of a wide
variety of natural or manufactured substances
used to grind, wear down, rub away, smooth,
scour, clean or polish, often combined with a
binder to make grinding wheels or affixed with
glue to the surface of paper or cloth” [1].
Although this broad definition could include
such products as plastic pads, metal wool,
pumice, and various tools employing large single diamonds, as in bits for oil-well drilling, this
article is limited to granular abrasives as hard
as, or harder than, quartz (crystalline silicon dioxide) with grit sizes from about 5 mm average
diameter down to 1 µm or smaller. The abrasives can be used in their loose, bonded (grinding
wheel), or coated (sandpaper) forms.
Abrasives have applications that are so extensive and varied that only the major ones are
mentioned in this article. For further information see [2–12]. In addition major manufacturers of abrasives, bonded and coated products,
and related trade organizations have their own
brochures, reprints of published articles, etc.,
c 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

10.1002/14356007.a01 001

5.
5.1.
5.2.
5.3.
6.
7.
7.1.
7.2.
7.3.
8.
8.1.
8.2.
8.3.
9.
10.
11.

Physical and Chemical Properties .
Hardness . . . . . . . . . . . . . . . . . .
Grain Strength or Fracture Toughness . . . . . . . . . . . . . . . . . . . . .
Resistance to Attrition or Plastic
Flow . . . . . . . . . . . . . . . . . . . . .
Loose-Grain Applications . . . . . .
Bonded Abrasive Products . . . . . .
Vitrified Bonds . . . . . . . . . . . . . .
Organic Bonds . . . . . . . . . . . . . .
Metal Bonds . . . . . . . . . . . . . . .
Coated Abrasive Products . . . . . .
Components . . . . . . . . . . . . . . .
Production . . . . . . . . . . . . . . . .
Applications . . . . . . . . . . . . . . .
International Quality Specifications
Safety . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . .

11
11
11
12
12
13
13
14
15
15
15
16
16
16
16
18

available on almost any aspect of the application of their products. Most of them, as well as
some universities and miscellaneous organizations, also have Internet sites.

2. Natural Abrasives
2.1. Quartz
Quartz [14808-60-7] is found worldwide. Major applications include the abrasive for common
flint sandpaper used industrially for the finishing of nonmetallic substances, such as leather
and felt, and also for miscellaneous household
applications. Other uses are in sandblasting, in
lapping of soft materials, as the cutting medium
in wire sawing of soft stone, such as marble, and
in scouring compounds. The use of this abrasive
has declined greatly because inhalation of free
silica dust may lead to silicosis. Quartz has been
replaced to a considerable extent by manufactured abrasives, such as fused aluminum oxide
and silicon carbide, as well as by garnet, glass,
and slags.

2

Abrasives

2.2. Garnet
Mineralogically, the term garnet refers to a group
of minerals with similar crystal structure but
varying considerably in chemical composition.
Most abrasive garnet is almandite [1302-62-1],
an iron aluminum silicate, Fe3 Al2 (SiO4 )3 .
Almost all of the garnet used for highperformance coated abrasives is mined in the
Adirondack area of New York State. The ore is
crushed and beneficiated and the resulting garnet is separated into various grit sizes and heat
treated. This particular garnet is unique, as the
mineral fractures to produce grains having sharp,
continuous edges that are optimum for use as a
coated abrasive. Also its hardness is at the upper
end of the range for garnets. The coated product
is used for finish sanding of wood in furniture
and woodworking plants.
Other U.S. operations in New York, Idaho,
and Maine, and those elsewhere in the world,
produce garnet of inferior quality for coated
applications, but which is used extensively for
sandblasting, metal lapping, and the fine grinding of glass.
Estimated 1996 world production in 103 t/a
are [49]:
United States
India
Australia
China
Others
Total

68.2
15
40
15
16.8
155

Approximately 30 % of U.S. production was
used for water-filtration applications.

2.3. Corundum and Emery
Corundum [1302-74-5] is a naturally occurring
aluminum oxide mineral of high purity. Estimated production in 1990 in 103 t/a was [50]:
South America
Europe + CIS
Africa
Asia (India)
World total

0.25
10
20
2
32.25

The major use of corundum is for the loosegrain grinding and polishing of optical components.
Emery [12415-34-8] consists predominantly of corundum but also contains varying

amounts of other minerals, particularly magnetite [1309-38-2] and hematite [1317-60-8].
High-quality emery has been produced on the
Greek island of Naxos for at least 2000 years
and also is mined in Turkey. Major uses include
polishing metals with the coated products and
incorporation of the abrasive in nonslip floors,
pavements, and stair treads.
The term “emery” has also been applied to
a rock mined near Peekskill in New York State.
Also known as spinel emery, it contains little or
no corundum. However, because of its content
of spinel [1302-67-6], a mineral with hardness
between quartz and corundum, this “emery” has
utility in less demanding applications. Very little, however, is used for coated abrasives.
Estimated world emery production in 1990
was 20 000 t/a and has decreased sharply since
1983.

2.4. Diamond
Diamonds [7782-40-3] apparently were found
first in India and Borneo over 2000 years ago,
but the discovery of them in South Africa in 1866
began an era of great expansion that is still continuing (→ Carbon).
Diamonds may be classified as gem quality,
high-grade industrial, and bort, the borderlines
between grades overlapping and varying with
demand. Bort contains inclusions, microcracks,
and other flaws, giving rise to translucency or
opacity, off-color, etc. The material therefore
is used almost exclusively in grain and powder
forms. Most natural diamonds are single crystals, but carbonado [12414-51-6], a type found
in Brazil, and ballas, found in Brazil and Africa,
are polycrystalline in structure. They are especially tough because of the absence of welldeveloped cleavage planes, and are particularly
useful for heavy-duty applications, such as truing and dressing grinding wheels.
World production of natural industrial diamonds in 1996 in 106 carats, including bort,
which accounts for over 85 %, was:
Congo (Kinshasa)
Russia
Botswana
Republic of South Africa
Australia
All others
Total

15
9.2
5
6
23.1
3.3
61.6

Abrasives

3

Australia is the worlds largest producer since
the startup of the Argyle alluvial operation in
Western Australia in January 1983.
Major uses of diamonds are discussed in Section 3.6.

The alumina from the indirect Bayer process
contains about 99 % Al2 O3 . The type commonly
used for fused alumina production contains approximately 0.4 – 0.5 % Na2 O, the remainder
being small amounts of SiO2 , Fe2 O3 , and water.

3. Manufactured Abrasives

3.1.2. Furnace Designs

3.1. Fused Aluminum Oxides
Differences in the composition of natural corundum and emery gave rise to variability in grinding wheel manufacture and in end-use performance. Therefore attempts were made to produce more consistent synthetic corundum abrasives.
Although some early work was carried out
in Europe, the first commercially successful
product resulted from the experiments of C. B.
Jacobs, C. M. Hall, and A. C. Higgins in the
United States at the end of the 19th century
and the beginning of the 20th [13]. This technology was the foundation for a variety of
fused aluminum oxide [1344-28-1] abrasives
(→ Aluminum Oxide).

3.1.1. Raw Materials
Bauxite [1318-16-7] is used directly for the production of some fused alumina types, and indirectly, through the Bayer process, for other
varieties. Largely for economic reasons, bauxites used for the production of fused aluminum
oxide abrasives are of relatively high Al2 O3 content. Materials from various sources are usually
blended, a typical specification being:
Al2 O3 ∗ = 82 % minimum
SiO2 = 8 % maximum
Fe2 O3 = 8 % maximum
TiO2 = 4 % maximum
∗ determined by subtracting total SiO2 ,
Fe2 O3 , and TiO2 from 100 %.
Abrasive-grade bauxite consumption in the
United States and Canada was quoted as
197 × 103 t in 1994 and 133 × 103 t in 1995,
both on a dry basis. This is less than 2 % of
the total consumption of bauxite, 90 % of which
was used for the production of aluminum.

Two general types of furnace are employed, one
resulting in a batch process and the other in a
continuous one.
The first, generally known as the Higgins furnace, consists of an open-ended, slightly tapered
cylinder of sheet steel, smaller diameter up, resting on a hearth protected by a carbon coating
[14]. Fusion of the bauxite is accomplished using
an electric arc. Water continuously flows down
the outside of the shell, keeping it from melting during the process. After fusion is complete,
the product is cooled for several days, resulting
in a coarsely crystalline material. This is sorted
and rough crushed to yield crude abrasive about
50 mm in size.
Continuous furnaces are patterned after the
batch type except that they are generally much
larger and arranged for tilting and tapping the
molten products into suitable containers [15],
[16]. For economic reasons most fused aluminas
being produced in similar large-capacity casting
furnaces where fusion may continue uninterruptedly for many days or even months.

3.1.3. Fused Alumina Types
The fused alumina produced in largest tonnage
is known as regular aluminum oxide. The raw
materials are calcined bauxite, carbon usually
in the form of coke, and iron borings, a typical mass ratio being 80 : 15 : 5. Because the
relative ease of reduction of the bauxite feed
to metal in the fusion process with carbon is
Fe2 O3 > SiO2 > TiO2 > Al2 O3 , an abrasive of
considerably higher Al2 O3 content than that of
the furnace feed can be attained. During fusion
two immiscible liquids exist. The upper one becomes the abrasive on crystallization, and the
lower one becomes a byproduct, ferrosilicon.
Regular aluminum oxide is brown and has a
chemical composition of approximately 95 %

4

Abrasives

Al2 O3 , 1.5 % SiO2 , less than 0.5 % Fe2 O3 ,
and 3 % TiO2 . Because of very slow cooling
in the Higgins furnace, the crystals of alumina
are coarse, averaging 10 – 15 mm in diameter. If
the fused material is cast, the upper liquid must
be poured into very large molds holding at least
5 t of product to insure similar slow cooling and
coarse crystallization.
A second brown type is semifriable fused alumina. It is purer than regular, containing approximately 97 % Al2 O3 , 0.5 % SiO2 , less than 0.5 %
Fe2 O3 , and 2 % TiO2 . Both batch and continuous processes are used to produce this variety.
Because the regular and semifriable types are
close in composition, the present trend is toward a single brown fused alumina of intermediate composition, produced in casting furnaces.
The relative friabilities are adjusted by crushing and processing methods to give different
grain shapes, the more equidimensional being
the regular and the sharper, less blocky being
the semifriable.
In general, the major use of fused alumina
abrasives is for processing high-tensile-strength
ferrous metals, such as carbon steels. The regular kind is employed in loose-grain form in
blasting, lapping, and barrel finishing, in bonded
form mostly in nonprecision operations, such
as cutting off and rough grinding in organicbonded products. Semifriable alumina is more
commonly used in vitrified-bonded products for
precision grinding operations, and on coated
belts and discs.
A third type, similar in composition and fusion method to the above, is known as microcrystalline. In order to produce an abrasive with very
small alumina crystals, rapid cooling of the melt
is required. This is effected by pouring it into
small molds or onto pans to produce slabs. The
resulting abrasive has higher intrinsic strength
than the others. It formerly was used extensively
in heat-treated form for very heavy duty grinding
wheel applications, such as the conditioning of
steel slabs and billets using resin-bonded products. For the most part this abrasive has been superseded by fused zirconia – alumina of the ZS
type (Section 3.2), or by sintered alumina of the
76 Alundum type (Section 3.3).
White fused alumina is produced by direct
fusion of Bayer process alumina [14]. Either
the batch or the continuous casting process may
be employed. Because the raw material is of

high purity, only fusion and crystallization take
place. The resulting abrasive has about the same
chemical composition as the alumina. However,
a small amount of the soda is volatilized, giving
rise to pores in the resulting product. Sometimes
small amounts of chromium oxide [1308-38-9]
are added to the furnace feed, producing a pink
or ruby-colored abrasive. Similarly, a small addition of vanadium oxide [1314-34-7] results in
an emerald green color. Although claims have
been made for the value of such additions, controlled grinding tests have failed to detect positively any advantages. The major use for the
white abrasive is in vitrified-bonded wheels for
toolroom grinding or precision grinding of heatsensitive steels.
Monocrystalline aluminum oxide is a very
high purity abrasive, produced directly from
bauxite in a single-stage fusion [17]. The preferred method employs a furnace feed consisting of bauxite, pyrite (FeS2 ) [1309-36-0] or sulfur [7704-34-9], carbon, and iron borings. When
subjected to fusion in the Higgins batch furnace,
two immiscible liquids are formed as with regular aluminum oxide. However, in the present
case very slow cooling of the upper liquid results
in essentially pure, individual crystals of Al2 O3
in a matrix of sulfides. After the pig has cooled
and been crushed, the matrix is removed chemically and mechanically. This treatment releases
alumina crystals in the range of sizes required
by the industry.
Little or no crushing is needed, so in this respect this abrasive is entirely different from all
the other types of fused aluminas in use today.
Chemical analysis approximates 99.2 % Al2 O3 ,
0.6 % TiO2 , 0.2 % impurities. This abrasive also
may be produced in a casting furnace provided
that the fusion is poured into a large receptable
capable of holding many tons of product to permit slow cooling of the melt. The size distribution of the resulting abrasive crystals can be
varied by changes in manufacturing parameters.
Surprisingly the monocrystalline type also may
be produced from a mixture of Bayer process
alumina, elemental sulfur, and carbon [18]. In
this process only one liquid is present in the furnace during fusion, but otherwise the sequence
of operations is similar, and the resulting product is the same as that produced directly from
bauxite. This premium-priced abrasive is found
to be more cost efficient than others, such as the

Abrasives
semifriable type, in many precision operations
using vitrified-bonded wheels.
Production. World production capacity for
fused aluminum oxide is listed in Table 1.
Table 1. World production capacity (103 t/a) for fused aluminum
oxide in 1996 and 1997 (estimated) [49]
1996
USA and Canada
Australia
Austria
Brazil
China
France
Germany
India
Japan
Others
World total (rounded)

220
75
60
100
450
45
150
20
55
125
1300

1997
220
50
60
100
500
45
150
20
55
100
1300

Trade Names: Alundum, Aloxite, etc.

3.2. Fused Zirconia – Aluminas
The most outstanding commercial development
in the area of alumina-containing abrasives in
the last two decades was the invention of fused
zirconia – alumina products. For the applications in which they are most useful, they result in substantially greater efficiencies (lower
total grinding costs) than the fused aluminas previously employed. United States and Canadian
production for 1980 was 17.2 × 103 t, amounting to 11 % of all fused aluminas, including the
zirconia – aluminas. No production data were
available for 1981 or 1983; however, 1982 production was quoted as 7.3 × 103 t or 6 % on the
same basis as the 11 % for 1980. This reduction
was caused by the severe depression in those segments of the metal-working industry in which
zirconia – alumina abrasives are most applicable.
These abrasives also are produced in Japan,
France, Austria, Federal Republic of Germany,
and possibly other countries. However, production data are not available for them.
Zirconia Content 25 wt %. Although the basic patent specified an abrasive alloy consisting
essentially of zirconium oxide [1314-23-4] and
aluminum oxide, with the content of the former between 10 and 60 wt %, the resulting commercial product typically contains about 25 %

5

[19]. The alumina may be derived from bauxite or from the Bayer process, and the zirconia
from the mineral zircon (a zirconium silicate)
[14940-68-2], baddeleyite (a naturally occurring
mineral high in ZrO2 ) [12036-23-6], or fused
zirconium oxide. Zirconia and alumina are fused
by electric-arc casting furnaces to give primary
crystals of alumina with diameters no greater
than about 300 µm but typically less than 30 µm
in a matrix of a eutectic of alumina and zirconia.
The resulting abrasive is dense and very tough.
The grains dull slowly during heavy-duty grinding operations, as with resin-bonded wheels
on floorstand machines in foundries. They also
have a longer life on high-speed, high-pressure
grinders used for conditioning billets and slabs,
particularly those made of alloy steels or of stainless steel, where better surface finish is required
than produced by the sintered alumina of the 76
Alundum type (Chap. 3.3.).
Trade Names: ZF-ZS Alundum, BX, BZ,
etc.
Zirconia Content 40 wt %. The raw materials and fusion methods are similar to those discussed above; however, in this case the melt must
be solidified very rapidly in order to produce extremely small crystals [20]. In addition to a relatively slow dulling rate, these grains tend to fracture to a greater extent than the 25 % analogue
and do so in such a manner as to provide new
cutting edges rather than being shed from the
grinding wheel or coated abrasive product. Major applications include resin-bonded portable
wheels, cones and plugs, cloth-backed resinbonded belts, and fiber-backed discs for grinding
castings of steel, gray and ductile iron, and stainless steel alloys. In some cases mixtures of this
abrasive with the less expensive fused aluminas or with silicon carbide are used for specific
purposes; for example, the latter blend can efficiently clean and grind castings having burnedon sand.
Trade Names: NZ Alundum, etc.

3.3. Sintered Aluminas
From Bauxite. Calcined bauxites are ground
to a fine powder, mixed with an organic binder,
such as grease, extruded through an orifice, cut,
and fired statically or in a rotary furnace to temperatures between 1400 and 1600 ◦ C [21]. This

6

Abrasives

results in limited recrystallization of the alumina, increased density, and great strength of the
particles, which have the desired grain size without being crushed. The major use of this abrasive
is the conditioning of stainless steel billets and
slabs using hot-pressed resin-bonded wheels.
Trade Names: 76 Alundum, SO 200, etc.
From Alumina Gels. A colloidal dispersion
of alumina monohydrate [12252-67-4] and of
modifying oxides, such as zirconia and/or magnesia [1309-48-4], is formed, and the resulting
gel dried to produce chunks. These are crushed
and air fired (sintered) to above 1250 ◦ C, resulting in considerable shrinkage and formation of a dense, sharp, and extremely tough
abrasive [22], [23]. These expensive abrasives
are now widely used in industry as they significantly outperform fused alumina grains for
high-precision grinding and creep-feed grinding. They are mostly used in vitrified wheels,
but specific operations requiring organic-bonded
wheels, such as flute grinding, surfacing, and
calibrating with disk grinders, also use sol – gel
aluminas. Coated abrasives are also produced
with these grains for foundry snagging with belts
and fiber disks and for other work on stainless
steel and high-resistance alloys. As new types of
sol – gel aluminas are developed and production
volume grows, they are progressively replacing
fused aluminas in many operations.
Trade Names: Cubitron, SG, TG, etc. Often
referred to with the generic name “ceramic abrasives”.

3.4. Silicon Carbide
The discovery of silicon carbide [409-21-2]
by Edward G. Acheson in 1891 was indeed
epoch-making because it was the first synthetic
abrasive invented and commercialized, and signaled the gradual decline in the use of natural
abrasives (→ Silicon Carbide). In an attempt to
make diamonds by an electric-arc heating process, Acheson produced a very few hard crystals. Knowing that they were not diamond but
thinking that they were a combination of carbon
and corundum, he called them “carborundum,”
a term that remained even after the crystals were
determined to be silicon carbide. Carborundum
became the name of the company he organized to
exploit the discovery. Abrasive SiC is produced

today in furnaces similar to the one he patented
in 1893 [24]. Silica sand plus carbon in the form
of coke, or low-ash coal in the approximate mass
ratio of 60 : 40 is heated in a troughlike electric
resistance furnace to produce SiC according to
the equation:
SiO2 + 3 C −→ SiC + 2 CO

Several grades of this abrasive are produced.
The most common black or gray type is used
in bonded and coated form for grinding lowtensile, nonferrous metals such as aluminum,
brass, copper; some cast irons; and nonmetallics,
such as glass, stone, concrete, ceramics, and refractories. A higher purity green variety is employed for those operations, such as rough grinding of cemented carbide tools with vitrifiedbonded wheels, in which this abrasive’s more
friable characteristic and the light green color are
helpful. A type lower in purity than that used for
bonded and coated products has utility in loosegrain applications, such as wiresawing and lapping.
World production capacity for silicon carbide
abrasives is listed in Table 2.
Table 2. World production capacity (103 t/a) for silicon carbide abrasives in 1996 and 1997 (estimated) [49]

USA and Canada
Argentina
Brazil
China
France
Germany
India
Japan
Mexico
Norway
Venezuela
Others
World total (rounded)

1996

1997

90
5
43
450
16
36
5
90
60
80
40
185
1100

90
5
43
450
16
36
5
90
60
80
40
185
1100

Trade Names: Carborundum, Crystolon, etc.

3.5. Boron Carbide
Abrasive boron carbide, B4 C [12069-32-8], is
produced in electric resistance furnaces from
a charge of high-purity boron oxide glass and
high-purity coke according to the equation [25]:

Abrasives
2 B2 O3 + 7 C −→ B4 C + 6 CO

As explained in Section 5.3, this abrasive is
unsuited for use in bonded or coated products.
However, for loose-grain applications, such as
the lapping of cemented carbides and other hard
materials, it is used alone or mixed with silicon
carbide.
Trade Names: Norbide, etc.

3.6. Diamond
Commercial availability of manufactured diamond [7782-40-3] is the most important abrasive development in the 20th century (→ Carbon). Not only did it eliminate occasional shortages of natural diamond grain, but also it made
possible a great variety of diamonds with vastly
different characteristics, thereby increasing diamond efficiency and consequent use.
Commercial manufacture of diamond requires high pressure (5.0 – 6.5 GPa) and high
temperature (> 1400 ◦ C) [26]. Depending upon
manufacturing parameters, a wide range of properties may be obtained, from very friable composite structures of small diamond crystals to
stronger single crystals containing various defects and inclusions, to very strong, almost flawless crystals, equidimensional in shape, with
well-developed crystal faces. One leading producer offers no fewer than seven different basic
types. Over the years the major manufacturers
have gradually been able to produce economically high-quality single diamonds of larger and
larger size, now up to 20 – 25 mesh (approximately 700 – 850 µm in diameter). No doubt
they will continue to extend availability further
in the coarse direction.
The two major producers further improved
the efficiency of diamonds for use in resinbonded products by introducing metal-clad varieties in 1966 [27]. These coatings are believed
to improve wheel efficiency by controlling abrasive breakdown, and by acting as a heat sink between the abrasive and the bond, retarding deterioration of the latter from heat generated during
grinding. The most commonly employed coatings are nickel-based (30, 55, or 60 wt %) or
copper (50 wt %). Although used mostly with
manufactured diamonds, the 55 % nickel coating is also available on natural diamonds.

7

World production of synthetic diamond is
listed in Table 3.
In general, diamonds, both natural and manufactured, are used for lapping carbides and other
hard materials, and for grinding, drilling, and
sawing cemented carbides and a wide variety
of nonmetallics, such as plastics, glass, stone,
concrete, ceramics, refractories, and such electronic materials as silicon and quartz. Silicon
carbide also can be used for these same materials. However, bonded diamond products, in
spite of their higher cost, often are more efficient, resulting in lower total costs per unit of
work performed. This is particularly true in cemented carbide grinding, where diamond, now
nearly always one of the manufactured types,
is used almost exclusively except for offhand
roughing with vitrified-bonded green silicon carbide wheels. Because of the affinity between diamond (carbon) and iron, diamonds are not economical for grinding ferrous metals except those
containing relatively large amounts of hard constituents, such as certain vanadium steels.
The cost of synthetic diamond has greatly
decreased since the mid-1980s, and this has allowed it to be used in nonprecision applications
such as cutting masonry materials, stones and
bricks with steel disks on hand-held grinders.
The disks have laser-welded, metal-bonded diamond segments, and their low cost and long life
have allowed them to replace most conventional
silicon carbide cutting-off disks.

3.7. Cubic Boron Nitride
The second, and eventually possibly the most
important development in the abrasive area this
century, was the invention [28] of cubic boron nitride (CBN) [10043-11-5], first introduced commercially in 1969 (→ Boron Carbide, Boron Nitride, and Metal Borides).
This abrasive may be made in any of the highpressure, high-temperature apparatuses used for
diamond production. By using different raw materials and manufacturing conditions, a variety
of products having a range of friabilities may be
produced. Color ranges from almost colorless
through shades of yellow, red, and black. As with
diamonds, the producers supply CBN in sized
grains and flours. Metal cladding of this abrasive
also has improved its efficiency in resin-bonded

8

Abrasives

Table 3. Estimated world production of synthetic diamond (103 carat)

Belarus
China
Czech Republic
France
Greece
Ireland
Japan
Poland
Romania
Russia
Slovakia
South Africa
Sweden
Ukraine
USA
Total

1992

1993

1994

1995

1996

30 000
15 000
10 000 ∗
3 500
750
60 000
30 000
320
3 000
80 000

30 000
15 000
5 000
3 500
1 000
65 000
32 000
98
5 000
80 000
5 000
60 000
25 000
10 000
103 000
440 000

25 000
15 000
5 000
3 500
1 000
65 000
32 000
271
5 000
80 000
5 000
60 000
25 000
8 000
104 000
434 000

25 000
15 000
5 000
3 000
1 000
60 000
32 000
256
5 000
80 000
5 000
60 000
25 000
8 000
115 000
440 000

25 000
15 000
5 000
3 000
750
60 000
32 000
250
5 000
80 000
5 000
60 000
25 000
8 000
114 000
439 000

60 000
25 000
10 000
90 000
418 000

∗ Czechoslovakia

products [29]. A 60 % nickel-based coating is
used commonly.
Initial successful applications of CBN were
for high-performance grinding of difficult to
grind ferrous metals where use of fused alumina
abrasives results in high rates of wheel wear per
unit of material removed from the workpiece and
in rapid dulling of the abrasive grains. Therefore
machine productivity is low and grinding costs
high, as is the liability of metallurgical damage
to the work. Because of its hardness (inferior
only to diamond), strength, low coefficient of
friction during operation, and thermal and chemical stability to well over 1000 ◦ C, CBN wheels,
although expensive, increase productivity. This
is because of much lower wheel wear, improved
workpiece integrity, and fewer rejections and reworks. Now, with the development of computercontrolled, high-production systems especially
designed for use with this abrasive, its application is being extended to more common, less difficult to grind ferrous metals. This has resulted
in increased productivity for such operations as
camshaft grinding in the automobile industry.
In 1981 one producer introduced a CBN family (trade names: Borazon 550, 560, 570) with
sized grain that is polycrystalline and extremely
tough. In certain applications resinoid- and
vitrified-bonded wheels containing this abrasive
have shown lower wheel wear than similar products containing the usual monocrystalline CBN.
However, the expense of the abrasive has been
a problem in establishing lower overall grinding
costs in many cases.

Production of CBN by region is summarized
in Table 4.
Table 4. Production of CBN by region (106 carat) [51]

Pacific Rim
United States
Europe
Total

1992

1993

1998

12.5
10.9
9.9
33.3

13.2
13.1
10.9
37.2

18.8
37.7
19.5
76.1

Trade Names: Borazon, Amber Boron Nitride, etc.

4. Manufacture and Testing of Sized
Grains
As mentioned in Chapter 3, some abrasive types
are produced directly to size for use in bonded or
on coated products. Other abrasives, such as the
fused aluminum oxides, must be crushed, sized,
and otherwise treated before use.
Crushing is accomplished by a variety of
means, depending on the shape and other characteristics of the desired product. Jaw crushers,
hammer mills, roll mills (in which precrushed
crude is passed through sets of alloy steel rolls),
and ball or rod mills commonly are employed. If
exceptionally equidimensional particles are desired, the grain may be mulled by the use of
heavy steel rollers working the grain in a revolving pan.
To produce specific grit sizes, screening is
used for the coarser ones (macrogrits; >50 µm

Abrasives

9

Table 5. Standards for sizing of abrasive grains
Type of abrasive
All except diamond and CBN for :
Grinding wheel and
general industrial usage
Coated Applications

Diamond, CBN, all uses

Screen sizes (macrogrits)

Subsieve sizes (microgrits)

ANSI B74.12−1992 [30]
FEPA 42/93
ISO 8486, part 1 (1996)
ANSI B74.18−1996
FEPA 43/93
ISO 6344, parts 1 and 2 (1998)
ANSI B74.16−1995
FEPA 61/97

ANSI B74.10−1977 (R1992)
FEPA 42/93
ISO 8486, part 2 (1996)
ANSI B74.18−1996
FEPA 43/93
ISO 6344, part 3 (1998)
ANSI B74.20−1997
FEPA 60/77 (under revision)

in diameter). Finer sizes (micogrits) are separated by various elutriation methods. Centrifuging often is employed for the finest grains.
For checking the sizing of abrasive grits, the
standards shown in Table 5 are used.
Conventional (i.e., non-diamond and nonCBN) abrasive grits are sized according to standards that assign each size a number and define the mean size and the proportion and dimensions of coarser and finer sizes that can be
present. The standards usually differ for bonded
and coated abrasives, as the optimum performance of the products requires different grain
shapes and a different size distribution for each
grit number. For example, FEPA (Federation of
European Producers of Abrasive Products) has
issued two standards: FEPA 42/93, which defines the F series for bonded abrasives, and FEPA
43/93, which defines the P series for coated abrasives. Similarly, ISO has issued ISO 8486 for
bonded and ISO 6344 for coated abrasives. The
grit numbers and the mean particle sizes in micrometers in the F series (aluminum oxide and
silicon carbide grains for grinding wheels and
other bonded abrasives are as follows:
Macrogrits
F4
F5
F6
F7
F8
F10
F12
F14
F16
F20
F22
F24
F30
F36
F40
F46
F54
F60
F70
F80

4890
4125
3460
2900
2460
2085
1765
1470
1230
1040
885
745
625
525
438
370
310
260
218
185

F90
F100
F120
F150
F180
F200
Microgrits
F230
F240
F280
F320
F360
F400
F500
F600
F800
F1000
F1200

154
129
109
82
69
58
55.7 ± 3
47.5 ± 2
39.9 ± 1.5
32.8 ± 1.5
26.7 ± 1.5
21.4 ± 1
17.1 ± 1
13.7 ± 1
11 ± 1
9.1 ± 0.8
7.6 ± 0.5

The grit numbers and the mean particle sizes
in micrometers in the P series (aluminum oxide
and silicon carbide grains for coated abrasives
are as follows:
Macrogrits
P12
P16
P20
P24
P30
P36
P40
P50
P60
P80
P100
P120
P150
P180
P220
Microgrits
P240
P280
P320
P360
P400
P500
P600
P800
P1000
P1200
P1500
P2000
P2500

1815
1324
1000
764
642
538
425
336
269
201
162
125
100
82
68
58.5 ± 2
52.2 ± 2
46.2 ± 1.5
40.5 ± 1.5
35 ± 1.5
30.2 ± 1.5
25.8 ± 1
21.8 ± 1
18.3 ± 1
15.3 ± 1
12.6 ± 1
10.3 ± 0.8
8.4 ± 0.5

10

Abrasives

Figure 1. Example of size gradations of the FEPA standard F series for bonded abrasive grits

The approximate relationship between the
FEPA and other national diamond and CBN grit
size designations is summarized in Table 6.
Table 6. Approximate relationship between the FEPA and other national diamond and CBN grit size designations
FEPA grit designation ∗
(approx. mean size, µm)
Narrow-range grades
1181
1001
851
711
601
501
426
356
301
251
213
181
151
126
107
91
76
64
54
46
Wide-range grades
1182
852
602
502
427
252

ASTM 11

BS 1987

16/18
18/20
20/25
25/30
30/35
35/40
40/45
45/50
50/60
60/70
70/80
80/100
100/120
120/140
140/170
170/200
200/230
230/270
270/325
325/400

14/16
16/18
18/22
22/25
25/30
30/36
36/444
44/52
52/60
60/72
72/85
85/100
100/120
120/150
150/170
170/200
200/240
240/300
300/350
350/400

16/20
20/30
30/40
35/45
40/50
60/80

14/18
18/25
25/36
30/44
36/52
60/85

∗ The grit designation is prefixed with a “D” to denote diamond
and a “B” to denote CBN.

Figure 1 shows the relationship between grit
size designations, sieve numbers, aperture size
of sieves, and micrometer dimensions of particles for both screen-size and subscreen-size
grains according to FEPA standards [31].
In practice various manufacturers use other
equipment for checking abrasive sizing, such as
the Coulter counter.
The major suppliers of subsieve diamond and
cubic boron nitride products offer their own series, many items of which are extremely well
classified into the very narrow ranges demanded
by the trade. One supplier, for example, offers
17 sizes from 40 – 80 µm down to 0 – 0.5 µm.
After sizing, grits are washed, processed further, and tested using the methods in Table 7.
Instrumental techniques such as atomic absorption, emission spectroscopy, and X-ray fluorescence are used in practice for chemical analyses. Eventually new standards based on such
methods will be forthcoming.
Strength of abrasive grains containing glass
as a minor impurity, as in regular fused alumina,
can be increased significantly by heat treatment
in air to 1250 – 1350 ◦ C. The glass migrates to
the surface, sealing microcracks, and thus repairing damage caused by the crushing operation. Alternatively, the grain may be coated with
a glass frit that matures at 800 – 1000 ◦ C. Such
treatments increase abrasive efficiency in heavy-

Abrasives

11

Table 7. Test methods for abrasive grain properties
Application

Test method

Presence of magnetic particles
Measure of coating weight for diamond
and CBN grains
Relative strength of saw diamond grits
Degree of capillarity

ANSI B74.19−1990 (R1995)
FEPA 62/93

Grain shape

Bulk density
Grain strength (friability)
Chemical analysis (classical wet methods)

Sampling and splitting
Test-sieving machines

Comments

FEPA 63/93
ANSI B74.5−1964 (revised 1995)
ISO 9137 (1990)
FEPA 44/93, part 3
ANSI B74.4−1992 (R1997)
ANSI B74.17−1973 (revised 1993)
ISO 9136, parts 1 and 2 (1989)
FEPA 46/93, part 2
ANSI B74.8−1987
FEPA 46/93
ISO 9285 (1995)
ANSI B74.14−1992
ISO 9286 (1995)
FEPA 45/93
ANSI B74.15−1992
ISO 9138 (1993)
FEPA 44/93, part 1
ISO 9284 (1992)

capillarity is increased by heating to 500 – 600 ◦ C
used for conventional abrasives
used for conventional abrasives
equidimensional shapes pack to a higher bulk
density than flat or slivery ones
this method is used for testing diamond and CBN
used for conventional abrasives
ball mill test (see Section 5.2 for interpretation of
strength data)
used for fused aluminum oxides
used for fused aluminum oxides
used for fused aluminum oxides
used for silicon carbides
used for silicon carbides
used for silicon carbides
used for conventional abrasives
used for conventional abrasives
used for conventional abrasives

duty applications, such as in the conditioning of
steel slabs and billets with resinoid wheels.
Sometimes grits are treated with a liquid silicone resin before being incorporated into resinbonded products. Silicon carbide grain may be
subjected to froth flotation to remove free carbon and/or treated with a sodium hydroxide solution to remove free silicon. In order to insure
vitrified-bonded products free from iron spotting, fused alumina grains, especially the white
variety, may be acid-treated to remove ferrosilicon or tramp steel not eliminated by magnetic
separation.

number. Values of K100 for common abrasives
compared with the Mohs’ hardness scale generally used by mineralogists are:

5. Physical and Chemical Properties

5.2. Grain Strength or Fracture
Toughness

5.1. Hardness
The hardness level required of an abrasive obviously depends upon the specific use. However,
the vast majority of industrial applications necessitates abrasives at least as hard as quartz.
A common means for determining hardness
is by use of the Knoop indenter, a gem-quality
diamond carefully lapped to the shape of an
elongated pyramid. This device indents the material to be tested under controlled-load conditions [32]. The applied gram load must be specified, e.g., K100 , because it can cause considerable variation in the resulting Knoop hardness

Knoop, K100

Mohs’

Quartz (silica)
820
Spinel (magnesium aluminate)
1270
Garnet (almandite from Adirondacks, U.S.)
1360
Fused zirconia-alumina (NZ Alundum type)
1600
Fused alumina (white type)
2050
Silicon carbide
2480
Boron carbide
2800
Cubic boron nitride
4700
Diamond
7000 – 8000

7
8
9

10

Strengths resulting from three different properties are important and usually act together during
an abrasive operation. First is the grain shape, the
blocky or equidimensional one being referred
to as a strong shape, that with many flakes and
slivers as a weak shape. Second, grains containing microcracks and other flaws produced by
crushing tend to be weaker than those produced
directly to size without subsequent comminution, assuming that the grains are otherwise of
about the same overall shape. Third, is the intrinsic strength of the body of the abrasive itself.

12

Abrasives

Although this is difficult to measure in finished
grain form because of the effect of shape and
crushing, relative intrinsic strengths may be estimated. If the difference between abrasives is
large, this is done by means of data derived from
ball milling (method of ANSI B 74.8−1977) or
by crushing or blasting tests, provided that the
difference in grain shape has at least been minimized and crushing histories are similar.
The fracture strength or toughness of ceramics is determined by studying the cracking
produced by indenting polished sections with
a Vickers indenter. The load is such that fractures are produced at the corners of the indentations. The fracture toughness (K c ) may be calculated by measuring the average crack length and
the diagonals of the indentations when Young’s
modulus and the microhardness are known [33].
This method of measuring intrinsic strength or
toughness of abrasives is destined to replace the
other procedures because it is a direct one.

5.3. Resistance to Attrition or Plastic
Flow
When abrasive boron carbide was first produced
in the early 1930s, its hardness was greater than
that of any known material except diamond. Its
effectiveness as an abrasive in loosegrain lapping operations, such as on cemented carbides,
correlated well with relative hardnesses, being
greatly superior to silicon carbide and fused aluminas, but inferior to diamond. For that reason boron carbide was excepted to have extensive applications in bonded products, replacing
those older, softer abrasives. However, extensive
grinding tests proved boron carbide to be completely unsuitable in any such operation because
the wheels quickly became dull. The major reasons appear to be oxidation of the boron carbide,
and the reaction or diffusion between the abrasive and the material being ground. A similar explanation appears to apply to the relatively poor
performance of diamond when grinding common ferrous metals. Temperatures at the interface may approach the melting point of steel.
Under these conditions both the abrasive and
piece being worked are greatly softened, with
reaction or diffusion between the two greatly accelerated. The result is attritious wear or plastic
flow, leading to the development of polished flats

on the abrasive grains and so the loss of much or
all of their stock-removal capabilities [34–36].
For loose-grain lapping operations, hardness
and strength are the most important abrasive
properties. However, stock removal with fixed
abrasives is a complicated process involving the
interaction of hardness, strength, and chemical
properties of both the abrasive and the workpiece. In addition the conditions of operation
also must be considered.

6. Loose-Grain Applications
Blasting. In this operation, screen-size abrasives, such as quartz sand, garnet, fused alumina,
and silicon carbide, impact the work material by
means of compressed air, centrifugal force, or
pressurized water. Blasting is used to descale
or otherwise clean and deburr metal parts, clean
buildings, and carve letters and designs on stone.
Wire Sawing. Endless, multistrand, twisted
wire under tension is used to carry a slurry of
water and abrasive for sawing blocks or slabs
of stone such as limestone, marble, and granite. Quartz sand may be used to cut the softest
stones, but fused alumina or silicon carbide is
required for the harder granites and sandstones.
This method is used both in the quarrying process itself and to shape and slice blocks removed
from the quarry.
Barrel Finishing. Metal parts requiring
cleaning, deburring, and/or refining of surface
finish are tumbled in a slowly rotating barrel with
water, acid or alkaline cleaning compounds, and
suitable abrasives. Depending upon the work
material and finishing requirements, the abrasives may be natural ones, such as emery or
crushed granite, or, more commonly, manufactured abrasives, such as fused aluminas. The latter may be used as such, or they may be bonded
with vitrified or organic materials into specific
shapes, such as triangles, stars, or pins. A more
efficient finishing method, involves vibrating
the materials in bowls or tubs.
Lapping. Loose abrasives in a vehicle of water, soluble oil, kerosine, greases, etc., can be
used to fine grind flat, cylindrical, or other surfaces. Laps of cast iron and other metals are used,
and the abrasive grains may become embedded
to some degree in these during the operation. The
choice of abrasive depends upon the nature of

Abrasives
the workpiece. Harder abrasives, such as boron
carbide and diamond, are most suitable for lapping cemented carbides, whereas quartz, garnet,
and emery may be used on relatively soft materials. Gear lapping is accomplished by feeding an
abrasive slurry between the parts as they revolve.
Buffing. Abrasives, such as fused aluminas
and silicon carbide of subsieve size, are bonded
with greases or waxes into cakes or sticks. These
are applied dry to the face of rotating resilient
wheels made of such materials as felt and other
cloth types. The bond melts during the buffing
operation so the abrasive is not fixed. A small
amount of material is removed from the work,
usually a metal; but, more importantly, a lustrous, satin, or mirror-like finish is produced.

7. Bonded Abrasive Products
These are rigid or only slightly flexible bodies, such as grinding wheels, which normally
have more than a single layer of abrasive grains
bonded with glass (vitrified bonds), organic materials, or metals. The products are manufactured in a wide variety of shapes and sizes,
including wheels (mounted and unmounted),
segments, bricks, sticks, etc. For details see
ANSI B74.2−1974, Specifications for Shapes
and Sizes of Grinding Wheels. . . . The specifications for diamond and CBN wheels are
given in ANSI B74.3−1974 (revised 1980),
and for marking of abrasive products in ANSI
B 74.13−1977. Considering possible variations
in types of abrasives, grit sizes, bond types,
structure of the bodies (variations in volume percentages of abrasive, bond, and pores), and size
and shape of the bodies themselves, it is understandable that major manufacturers produce
several hundred thousand varieties of grinding
wheels alone.

13

clay, fluxes, or frits, molding the mix to a predetermined mass : volume ratio, drying it, altering
the shape in the green state by shaving, if necessary, and finally maturing the bond by firing in a
kiln, usually at 850 – 1250 ◦ C or above. After it
cools, a wheel may be sided and faced, and the
hole reamed or bushed.
Products are characterized by volume percentages of abrasive, bond, and pores (Fig. 2).
Softer grades contain higher pore volumes, and
lower structure numbers have higher grain volumes. The final product is inspected by measuring mass : volume, modulus of elasticity, and
resistance to penetration by a rotating chisel or
by a blast of a known volume of sand or other
abrasive under known pressure. The pores of the
wheel may be filled with sulfur or waxes to improve grinding action by retarding loading of the
wheel face with swarf during operation. A composite wheel can be made with a stronger center
portion (finer grit abrasive, harder grade) to increase the overall strength of the body. Also the
portion adjacent to the hole can be treated with
a liquid epoxy resin for the same purpose.

7.1. Vitrified Bonds

Figure 2. Relationship of hardness to structure in bonded
abrasives
Bv) Bond volume; Gv) Grain volume; Pv) Pore volume

Abrasives bonded with glass include silicon carbide, diamond, cubic boron nitride, and all of the
fused alumina types.
With fused alumina and silicon carbide, a
typical manufacturing method involves coating
the abrasive grain with premixed temporary and
permanent bonding ingredients such as feldspar,

Because of the high cost of diamond and cubic boron nitride (CBN), only a small portion of
the body contains these abrasives, the remainder being the core or “preform”. A “green” prepressed ceramic body is first formed, placed in

14

Abrasives

a mold, and the abrasive-bond mix packed between preform and mold assembly. Bonds commonly employed are of the borosilicate type
from frits or raw materials of the same general
composition. After pressing and stripping from
the mold, the product is fired to 900 – 1000 ◦ C.
Because diamond oxidizes at such temperatures,
firing is usually in nitrogen; CBN may be fired
in air.
Content of diamond and CBN in bonded
products is based on volume percentages, 100
concentration being 25 vol % and others being proportional. For diamond-containing items,
concentrations are almost always in the range
of 25 – 100, whereas for CBN the range is
50 – 200. Average porosities are lower and the
items more durable than those containing fused
aluminas and silicon carbide.
For the most part, vitrified bonds are used
for precision operations, such as surface, internal, and cylindrical grinding, where close dimensional tolerances are required.

7.2. Organic Bonds
Phenol – Formaldehyde Polymers. Most
organic bonds are of this type. They have gradually replaced vitrified types in rough grinding
applications because the wheels are stronger
and more shock resistant and so can be operated
safely at higher speeds with resulting greater efficiency. Diamond and all of the manufactured
abrasives described in Chapter 3 are available in
this bond type.
For abrasives other than diamond and CBN,
a common cold-pressed manufacturing method
involves wetting the abrasive with furfural
[98-01-1] or liquid phenolic resin followed
by coating it with a premixed blend of powdered phenol – formaldehyde resin and fillers
or grinding aids, such as pyrite (FeS2 ), cryolite [15096-52-3], or potassium tetrafluoroborate [14075-53-7]. Molding is similar to that
for vitrified products. Curing is carried out in
an oven at 140 – 200 ◦ C, or dielectrically. Very
low porosity products may be produced by hot
pressing at 160 – 175 ◦ C followed by oven curing, as with the cold-pressed products.
When a softer grade action is desired, the
phenolic resins may be modified with epoxies,
rubbers, or other thermoplastics. Some resin-

bonded products, such as thin wheels for cuttingoff operations and portable wheels for offhand
grinding, are reinforced by molding sheets of
woven fiberglass onto the sides, within the body,
or both.
Resin-bonded alumina and silicon carbide
products are used for precision-grinding, rollgrinding, centerless-grinding, and, most commonly, for rough-grinding operations where dimensional tolerances and finish are less critical,
as in offhand grinding of rough castings and the
conditioning of steel billets and slabs.
Most diamond and CBN products are hot
pressed, and preforms are employed, as with the
vitrified-bonded analogs. Uses are mentioned in
Sections 3.6 and 3.7.
Rubber. Natural or synthetic rubbers or combinations are milled between rolls to break down
the fibers, after which the abrasive grain, fillers,
and sulfur for vulcanization are added. After being mixed, the batch is calendered to the required thickness, cut to shape, and heated to
150 – 175 ◦ C to vulcanize the rubber. Depending on the amount of sulfur, type of rubber, and
variety and amount of fillers, the product may
range from soft and resilient to hard.
Because of strength and resiliency, rubber
cutoff wheels, particularly thin ones, give accurate cuts with good surface finish and little
burring in wet-grinding operations. Another application is the grinding of ball bearing races and
centerless feed wheels.
Shellac. Shellac is a natural polymer prepared by heating and filtering the secretion of
the lac insect, a parasite found on tress in India
and surrounding countries. A common wheelmaking process involves coating the abrasive
with shellac and hot pressing the mixture in
steel molds. The mix also may be calendered
into thin sheets, from which wheels are cut and
cured at 150 – 175 ◦ C. Another method involves
moistening the abrasive with a shellac solvent,
adding powdered shellac, mixing, cold pressing,
and postcuring. Shellac wheels exhibit a considerable degree of thermoplasticity, giving rise
to a soft grinding action with a distinct polishing characteristic. They are used in some wet,
light grinding operations, particularly for finishing steel rolls.

Abrasives
Polyimide Polymers. For limited, specialized applications, such as the grinding of flutes
on carbide drills, and edge-grinding of carbide
inserts on certain types of machines, diamonds
in a polyimide bond have proved to be advantageous [37]. This particular polymer has considerably higher resistance to thermal degradation
than the phenol – formaldehydes.

7.3. Metal Bonds
The abrasive most often bonded with metal is
manufactured diamond, but the use of cubic
boron nitride (CBN) in metal bonds is expected
to increase very significantly.
Three types of metal-bonded products are
made:
1) Those in which the abrasive zone is bonded
directly to the core by a heating process;
2) Those in which segments or rims are produced
and then attached to the core or steel blade afterward;
3) Those bonded by electroplating.
For the first type, a core or preform is placed
in a mold, and the abrasive-metal mix added
and then pressed. After being stripped from the
mold, the body usually is sintered to maximum
density, or it may be sintered to controlled porosity followed by infiltration with a liquid metal,
such as a silver solder. Alternatively, the product may be hot pressed in a graphite mold. Bond
compositions vary greatly. Commonly used ones
include bronzes, various cobalt and nickel alloys, steels, and cemented carbides. Maturing
temperatures vary from 500 ◦ C for bronzes to
1200 ◦ C for cemented carbides. Firing is in neutral or reducing atmospheres. In general softer
bonds are used with hard, dense work materials,
whereas harder ones are used to grind relatively
soft but abrasive materials. For example, bronze
bonds commonly are used on dense alumina, cemented carbides, and quartz crystals, whereas
carbide bonds often are used to groove concrete
highways and cut sandstones.
In the case of rims and segments, similar
bonds, manufacturing methods, and firing temperatures are employed. In the production of diamond blades for use in the construction industry,
segments have been attached to the steel center
by brazing. However, laser welding, introduced

15

in 1982, has permitted a much higher bonding
strength, virtually eliminating loss of segments
because of weakening of the joint from the heat
generated during the cutting operations.
Electroplated products normally have a rigid
core, a nickel bond, and a single layer of either diamond or CBN. Examples are: diamondcoated mounted points and discs used by
dentists, relatively inexpensive diamond-coated
wheels for offhand sharpening of carbide tools,
and wheels of complicated shapes coated with
diamond or CBN used for form grinding of
workpieces, where great precision can be attained because of little or no tool wear.

8. Coated Abrasive Products
In coated abrasives a single layer of abrasive
grains is bonded with an adhesive to flexible or
semirigid backings.

8.1. Components
Abrasives include quartz, known in the trade
as flint; garnet; emery, usually the Turkish variety; fused aluminas of the regular, semifriable, white, and pink types; sintered aluminas
made from gels; fused zirconia – alumina of the
NZ Alundum variety; silicon carbide, black and
green types; and diamond and CBN, for very
limited applications.
Backings include Paper of different
weights: A for fine hand sanding with sheets, C
for medium hand operations or machine finishing, E for heavy machine grinding.
Cloth: woven cotton or polyester, stitchbonded polyester. They must be specially treated
before being coated with abrasives on clothfinishing lines to give them the appropriate mechanical characteristics. Different weights are
used, depending on the operation: J for flexible products, X or Y for coarse grits or use on
powerful machines.
Combinations of paper plus cloth: used when
limited backing stretching and high resistance to
tearing are necessary: wide belts for high power
machines, drum sanders.

16

Abrasives

Vulcanized fiber made of several layers of
cotton-based paper gelatinized with zinc chloride and vulcanized together. Different thicknesses are used, from 0.4 to 0.75 mm, depending
upon the required stiffness and strength. Main
use is fiber disks for portable machines for rough
grinding and semi-finishing.
Polyester films for microfinishing and polishing of mechanical, electronic and optic components with very fine P series grits and micron or
sub-micron sizes Abrasive grains are aluminium
oxide, silicon carbide, diamond and special materials such as alumina flour and chromium, iron,
and cerium oxides.
Adhesives used are high-quality hide glue;
phenol – or urea – formaldehyde resins; and
polyurethane or epoxy-based varnishes. These
adhesives may contain mineral fillers to modify
the physical properties of the bond, or to aid the
operations in other ways (see Section 7.2).

8.2. Production
A strip of backing material up to 1.5 m or more
in width is passed into a making machine where
a thin film of bond, known as the maker coat, is
applied. Sized abrasive is fed onto it by gravity, or an electrostatic field is used to orient
the longer dimension of the grain perpendicular to the backing. The coating may be closed,
in which the abrasive entirely covers the adhesive, or open, in which 50 – 75 % of the surface
is covered. The item is dried at about 60 ◦ C after
which another layer of adhesive, known as the
sizing coat, is applied to secure more firmly the
abrasive grains. This second coat may be of the
same composition as the first, or it may be different, e.g., resin used over glue. Then the bond
is dried further and cured at about 150 ◦ C. The
coated abrasive is then coiled into a large roll
known as a jumbo.
For most uses a further operation is required
to improve product flexibility. This involves
breaking the bond in a controlled manner. In
single flexing, cracks are developed at right angles to the length of the strip. In double flexing,
there are two series of cracks at about 45◦ to
the length. Triple flexing is a combination of
the other two types. Because of disturbance to
the abrasive bond layer by such operations, only

the minimum amount needed to satisfy end-use
conditions is employed.

8.3. Applications
The jumbo rolls are cut and converted into many
different shapes: narrow rolls, sheets, disks, endless belts 10 to 3000 mm wide and 250 to
7000 mm long, flap wheels and flap disks, spirally wound cones and pencils. These shapes
are used by hand or on sanding machines in
practically all industries for roughing, finishing, and polishing of wood, sheet and structural metal, mechanical parts, weldings, lacquers, glass, plastic, rubber, plaster, semiconductors, etc.

9. International Quality
Specifications
Because of the mature nature of the abrasive industry and the use of various specifications, truly
international standards have been slow in developing.
However, the International Organization for
Standardization (ISO) has been active in establishing specifications relating to bonded and
coated products, and, to a lesser extent, to the
abrasive grain itself. This organization has issued ISO standards, some 21 of which relate to
those items [38]. Eleven of them cover designations and dimensions of various coated products,
nine of bonded items, including diamond and
CBN, and one relates to grit sizes of diamond
and CBN.
National standards exist in the United States
(ANSI) [30], Japan, Japanese Industrial Standards (JIS) [42], and Europe (FEPA) [31].

10. Safety
Bonded abrasive products are not indestructible.
Strengths vary with such factors as the type of
bond, the grit size of the abrasive, and the structure and grade of the product required to efficiently perform a particular grinding operation.
Therefore, the user must take special precautions
to see that these products are properly handled,

Abrasives
mounted correctly on the machine, and not operated at excessive speed. The latter is the most frequent cause of wheel breakage, leading to damage of equipment and possible personal injury.
Most wheels are marked for maximum operating speeds or instructions are packaged with the
items.
“Safety Requirements for the Use, Care
and Protection of Abrasive Wheels,” ANSI
B 7.1−1988, 106 p., is particularly useful because it includes sections on definitions of the
various types of grinding operations, and on
wheel shapes with their limitations, and handling and storage of abrasive products. General
conditions of machines, safety guards, flanges,
proper methods for mounting, general operating rules, and, most importantly, standard and
special maximum operating speeds are covered
also.
“Safety Requirements for the Construction,
Care and Use of Grinding Machines,” ANSI
B11.9−1975, 71 p., is likewise helpful because
it contains sections on design of machines,
guards and flanges; on operating risks, and on
the responsibilities of manufacturer, employer,
and employee in connection with the care and
use of equipment.
An EC standard concerning the safety of
grinding machines is in preparation (EN 13218).
Japanese Industrial Standards (JIS),
R6240−1972 and R6241−1972 [42], as well
as the European Safety Code, FEPA standard
12/87, are similar to ANSI B7.1 but vary in details. Requirements in Germany (VBG 49) are
more stringent than in most other countries because high-speed wheels must carry a certificate
with certifying that they have been tested by the
manufacturer in accordance with the specifics
of ZH 1/670. Independent tests also are carried
out to assure compliance with ZH 1/670.
EC standards concerning the safety of
bonded, coated, and diamond/CBN abrasives are
in preparation [52].
Another potential risk involves the effect of
breathing dusts generated during abrasive operations, such as grinding and polishing or blasting,
particularly when done in a dry operation.
“Ventilation Control of Grinding, Polishing
and Buffing Operations,” ANSI Z 43.1−1966,
21 p., is of particular interest because it covers
exhaust hoods and enclosures, with minimum
exhaust volumes specified for various opera-

17

tions and wheel dimensions. Drawings of suitable equipment are included. Similarly, “Ventilation and Safe Practices of Abrasive Blasting Operations,” ANSI Z9.4−1979, 12 p., includes sections on dust risks, equipment, and operational procedures. It contains information on
minimum air volumes for blast cleaning rooms
occupied by blasters.
Most abrasive products are inert, producing
dusts classified as inert or nuisance types when
the work material also is inert. When the dust
is not inert, not only must the amount to which
the operator is exposed be known, but also its
composition. Most of the dust generated from
dry grinding and coated-abrasive operations is
from the work material, with lesser amounts
derived from the abrasive products themselves.
Some abrasive products incorporate active fillers
or grinding aids containing sulfur or fluorine
compounds. Use of coated abrasives containing
quartz (free silica) as the abrasive may require
special controls. Only when both the amount and
the composition of the airborne dust are known
can a determination be made as to whether the
requirements of the particular jurisdiction (city,
country, etc.) are being met, and the health of the
operator safeguarded.
For further details see “Fundamentals of Industrial Hygiene” [43], which relates specifically to requirements in the United States but
which should be of interest worldwide. Particularly valuable are the appendices and their
revisions [44–47]. For requirements in Europe
(MAK), see [48].
With respect to disposal of wastes from abrasive products, the major concern is related to the
chemical composition of the swarf because of
its finely divided nature and consequently large
surface area, which accelerates solubility and
chemical reactions. Because most of the grinding debris originates from the work material,
primary interest resides in its composition, solubility, and toxicity, with secondary emphasis on
those properties of the bonded or coated abrasive used in the operation. Knowledge of such
factors is required to determine the method of
disposal that will not have an adverse impact on
the environment.
Disposal of organic-bonded wheels and
coated abrasives is also becoming a problem as
they release phenol when leached by rain water
in open landfills.

18

Abrasives

11. References
1. P. B. Gove (ed.): Webster’s Third New
International Dictionary, Merriam-Webster,
Inc., Springfield, Mass. 1981.
2. T. J. Drozda, C. Wick (eds.): Tool and
Manufacturing Engineers Handbook, 4th ed.,
vol. 1, Machining, Chapter 11, Grinding, 130
pages, Society of Manufacturing Engineers,
Dearborn, Mich.1983, see especially pages
11 – 1 to 11 – 15, 11 – 49 to 11 – 130.
3. Coated Abrasives – Modern Tool of Industry,
1st ed., Coated Abrasives Manufacturers’
Institute, Cleveland, Ohio 1982, esp.
p. 80 – 426.
4. R. Williams (ed.): Machining Hard Materials,
1st ed., Society of Manufacturing Engineers,
Dearborn, Mich. 1982, p. 131 – 243.
5. R. L. McKee: Machining with Abrasives, Van
Nostrand Reinhold Co., New York 1982, esp.
1 – 36, 123 – 304.
6. P. Daniel (ed.): Advances in Ultrahard
Materials Applications Technology, vol. 1,
DeBeers Industrial Diamond Division, Ascot,
England 1982, esp. 16 – 71, 92 – 103.
7. Ultrahard Materials in Industry, Grinding
Metals with Abrasive Boron Nitride, DeBeers
Industrial Diamond Division, Ascot, England
1982, p. 1 – 63.
8. W. Burkart, K. Schmotz: Grinding and
Polishing Theory and Practice, 1st ed.
(English), Portcullis Press, Redhill, England
1981, esp. 47 – 239.
9. F. T. Farago: Abrasive Methods Engineering,
Industrial Press, Inc., New York 1980, vol. 1,
366 p., vol. 2, 508 p.
10. F. Hughes: Diamond Grinding of Metals, 2nd
ed., Industrial Diamond Information Bureau,
Ascot, England 1978, esp. 39 – 290.
11. K. B. Lewis, W. F. Schleicher: The Grinding
Wheel, 3rd ed., Grinding Wheel Institute,
Cleveland, Ohio 1976, esp. 36 – 463.
12. P. Daniel (ed.): Industrial Diamond Review,
DeBeers Industrial Diamond Division, Ascot,
England. (Includes articles on the application
of diamond and CBN as well as a section
devoted to abstracts relating to various aspects
of diamond, cubic boron nitride and other hard
materials), published1940 – present.
13. V. L. Eardley-Wilmot: “Artificial Abrasives
and Manufactured Abrasive Products and
Their Uses,” Abrasives, Canada Dept. Mines,
no. 699, part 4, Ottawa 1929.
14. Ind. Miner. (London) 149 (Feb. 1980) 55 – 57.

15. Norton Co., US 2 426 643, 1947 (R.
R. Ridgway).
16. Norton Co., US 2 579 885, 1951 (J. A. Upper).
17. Norton Co., US 2 003 867, 1935 (R.
R. Ridgway).
18. Norton Co., US 3 216 794, 1965 (S.
J. Roschuk).
19. Norton Co., US 3 181 939, 1965 (D.
W. Marshall, S. J. Roschuk, N. W. Thibault).
20. Norton Co., US 3 891 408, 1975 (R. A. Rowse,
G. R. Watson).
21. Norton Co., US 3 079 243, 1963 (H. F. G.
Ueltz).
22. 3 M Co., US 4 314 827, 1982 (M.
A. Leitheiser, H. G. Sowman).
23. Kennecott Corp., GB 2 099 012 A, 1982 (R.
J. Seider, A. P. Gerk).
24. Carborundum Co., US 492 767, 1893 (E. G.
Acheson).
25. Norton Co., US 1 897 214, 1933 (R.
R. Ridgway).
26. General Electric Co., US 2 941 241 to 248
inclusive, and 250 to 252 incl., 1960 (various
G. E. Co. personnel). US 2 947 608 to 611
incl., 1960 (H. T. Hall, 608; H. M. Strong, 609;
Hall, Strong, 610; F. P. Bundy, 611).
27. Industrial Distributors (1946) Ltd., US
3 902 873, 1975 (F. H. Hughes). ASEA, US
3 904 391, 1975, US 3 957 461, 1976 (O.
Lindstrom, E. Lundblad).
28. General Electric Co., US 2 947 617, 1960 (R.
H. Wentorf, Jr.).
29. General Electric Co., US 3 645 706, 1972 (H.
P. Bovenkerk, W. A. Berecki).
30. ANSI, standards available from American
National Standards Institute, Inc., 1430
Broadway, New York, NY.
31. FEPA, Fédération Européenne des Fabricants
de Produits Abrasifs, Standards,20, Avenue
Reille, F-75014, Paris, France; Internet:
http://www.fepa-abrasives.org.
32. N. W. Thibault, H. L. Nyquist, Trans. Am. Soc.
Met. 38 (1947) 271 – 330.
33. A. G. Evans, E. A. Charles, J. Am. Ceram. Soc.
59 (1976) 371 – 372.
34. T. N. Loladze, G. V. Bokuchava, G.
E. Davidova in J. H. Westbrook, H. Conrad
(eds.): The Science of Hardness Testing and Its
Research Applications, Am. Soc. for Metals,
Metals Park, Ohio 1973, p. 251 – 257.
35. T. N. Loladze, G. V. Bokuchava, G.
E. Davidova in J. H. Westbrook, H. Conrad
(eds.): The Science of Hardness Testing and Its
Research Applications, Am. Soc. for Metals,
Metals Park, Ohio 1973, p. 495 – 502.

Abrasives
36. L. Coes, Jr.: Abrasives, Springer Verlag, New
York-Wien 1971, p. 154 – 163.
37. E. I. du Pont, US 3 179 631, 1965 (A.
L. Endrey).
38. “Tools”, ISO Standards Handbook 6, 1st ed.,
ISO Central Secretariat, Case postale 56,
CH-1211 Geneva 20, Switzerland 1980,
p. 81 – 86, 121 – 133, 164 – 185, 289 – 292,
330 – 334, 400 – 405, 417, 465, 519 – 521,
589 – 591, 663, 683 – 703.
39. Industry and Trade Summary: Abrasives, U.S.
Dept. Commerce, International Trade
Commission, Washington, D.C.1995, 30
pages.
40. P. Harben, Ind. Miner. (London) 134 (Nov.
1978) 62.
41. T. Dickson, Ind. Miner. (London) 159 (Dec.
1980) 70.
42. JIS Standards, available from ANSI, American
National Standards Institute, Inc., 1430
Broadway, New York, NY.
43. B. A. Plog (ed.): Fundamentals of Industrial
Hygiene, 4th ed., National Safety Council,
Itasca, Ill., 1995, esp. pp. 175 – 182, 456 – 459,
538 – 539, 574 – 576.
44. American Conference of Governmental
Industrial Hygienists. (ACGIH) (ed.):
Threshold Limit Values for Chemical
Substances 1998 – 99, (TLV), Cincinnati, Ohio
1998, esp. pp. 15 – 86.

ABS

→ Polystyrene and Styrene Copolymers

19

45. OSHA Safety & Health Standards (29 CFR
1910), OSHA 2206, U.S. Department of Labor
Occupational Safety & Health Administration,
Washington, D.C., July 1997, esp. Subpart G,
Section 1910.94: Ventilation.
46. RTECS, US Department of Health and Human
Services, Cincinnati, 1997.
47. OSHA hazard communication standard (29
CFR 1910–1200) and material safety data
sheets available from chemical manufacturers.
48. Deutsche Forschungsgemeinschaft (ed.):
Maximum Concentrations at the Workplace
and Biological Tolerance Values for Working
Materials 1995 (MAK), VCH
Verlagsgesellschaft, Weinheim 1995.
49. US Geological Survey, Mineral Commodity
Summaries, Jan. 1988.
50. Mineral Facts and Problems, US Bureau of
Mines Bulletin, 675 (1985)
51. F. J. Kuzler: Hard and Superhard
Materials–World Markets, Applications, and
Opportunities: 1993 –1998 Analysis , World
Information Technologies, Northport, NY
1993.
52. EN 12413: Safety of Bonded Abrasives
(1998); EN 13236: Safety of Diamond/CBN
Abrasives (in preparation); Safety of Coated
Abrasives (in preparation).

Acaricides

1

Acaricides
Franz Müller (formerly Novartis Crop Protection AG, Basel), Allschwil, Switzerland (Chaps. 2, 3, 4)
Hans Peter Streibert, Novartis Crop Protection AG, Basel, Switzerland (Chap. 1; Chaps. 2 and 3 in part)
Saleem Farooq, Novartis Crop Protection AG, Basel, Switzerland (Chap. 1; Chaps. 2 and 3 in part)

1.
1.1.
1.2.
1.3.
1.4.
2.
3.
3.1.
3.2.
3.3.
3.4.
3.5.

Phytophagous Mites and Their Control . . . . . . . . . . . . . . . . . . . . . . .
Possible Reasons for the Mite Problem
Mite Species of Economic Importance
Possibilities for Mite Control . . . . . .
Mite Resistance . . . . . . . . . . . . . . .
Older Acaricides . . . . . . . . . . . . . .
Insecticides with Acaricidal Activity .
Organophosphates
and (Oxime)Carbamates . . . . . . . .
Pyrethroids . . . . . . . . . . . . . . . . .
Formamidines . . . . . . . . . . . . . . .
Nitrophenyl Esters . . . . . . . . . . . . .
Sulfonic Acid Esters . . . . . . . . . . . .

1
1
1
3
3
3
4
4
11
13
13
14

1. Phytophagous Mites and Their
Control
Mites belong to the phylum Arthropoda, the
class Arachnida, and the order Acarina. They
have developed an astonishing variety of feeding
habits. Some mites are predators, while others
feed on detritus in soil or water. The economically important species are parasitic on either animals (e.g., ticks, scab mites) or plants (e.g., spider mites, eriophyid mites). Phytophagous mites
are found in all parts of the world on practically all crop plants and may cause considerable damage. Approximately 8 – 10 % (annually
ca. $ 400×106 ) of the total insecticide-acaricide
market is spent on the control of phytophagous
mites.

1.1. Possible Reasons for the Mite
Problem
In recent decades, attacks by mites on food crops
and fibers have increased so drastically that in
many situations mite control has become an important feature of crop protection. Reasons for
c 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

10.1002/14356007.a01 017

3.6.
3.7.
3.8.
4.
4.1.
4.2.
4.3.
4.4.
4.5.
4.6.
4.7.
4.8.
5.

Halogenated Benzhydrol Derivatives
Organometallic Compounds . . . . .
Other Compounds . . . . . . . . . . . .
Toxicology . . . . . . . . . . . . . . . . .
Organophosphates and
(Oxime)Carbamates . . . . . . . . . .
Pyrethroids . . . . . . . . . . . . . . . .
Formamidines . . . . . . . . . . . . . .
Nitrophenyl Esters . . . . . . . . . . . .
Sulfonic Acid Ester . . . . . . . . . . .
Halogenated Benzhydrol Derivatives
Organometallic Compounds . . . . .
Other Compounds . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . .

.
.
.
.

14
15
15
20

.
.
.
.
.
.
.
.
.

20
30
31
32
32
33
33
34
38

this increase of mites are manifold and not yet
completely understood. Intensified agricultural
production methods, such as monocultures, extensive use of fertilizers, improved irrigation
systems, and cultural practices such as pruning
have improved the vigor and nutritional value
of the plants. However, these conditions also are
beneficial to the development of phytophagous
mites and may result in higher rates of reproduction. Furthermore, the indiscriminate use of
pesticides in the past may have reduced or even
eliminated the populations of natural enemies
of the mites (predatory mites and beneficial insects) thereby encouraging the development of
certain phytophagous mite species. In addition,
some insecticides (e.g., DDT, Carbaryl) used for
the control of insect pests, may promote the reproduction of phytophagous mites [6–8].

1.2. Mite Species of Economic
Importance
The economically important species of the phytophagous mites are as follows:

2

Acaricides

Tetranychidae – Spider mites
Tetranychus urticae (Koch), Two-spotted
mite, widespread on fruit and on grapes, vegetables, cotton, hops, roses, ornamentals, and
greenhouse cultures.
Tetranychus cinnabarinus (Boisduval), carmine
mite, widely spread in the warmer climatic regions on cotton, fruit cultures, ornamentals, and
in greenhouses.
Tetranychus kanzawai (Kishida), tea red spider
mite, found on tea in Asia.
Tetranychus mcdanieli (McGregor), McDaniel
mite, found on fruit on the west coast of the
United States, as are other, different Tetranychus
species.
Panonychus ulmi (Koch), European red mite,
widespread on fruit (apples, peaches, pears,
prunes, plums) and on grapes.
Panonychus citri (McGregor), citrus red mite,
found in citrus cultures worldwide.
Tenuipalpidae – False spider mites
Various Brevipalpus species, flat mites, found
on citrus and different subtropical fruits, tea,
greenhouse cultures.
Tarsonemidae – Soft-bodied mites
Hemitaronemus latus (Banks), citrus silver
mite, found on cotton, citrus, attacks a wide
range of agricultural crops and ornamental and
indigenous plants in tropical and subtropical regions.
Eriophyidae – Gall mites
Phyllocoptruta oleivora (Ashmead), citrus
rust mite, found on citrus.
Aceria sheldoni (Ewing), citrus bud mite, found
on citrus.
Life cycles and behavioral and morphologic
characteristics of mites vary greatly. The description of life history given here concentrates
on the agriculturally important Tetranychidae
family.
The spider mites are 0.3 – 0.5 mm long,
eggshaped, eight-legged animals covered with
hairlike appendages. These hairs (setae) are immobile and are sense organs. Spider mites live
in dense colonies, mainly on the underside of
the leaves. In such colonies, usually all the development stages are present: eggs, larvae, and
nymphs, as well as adults of both sexes.
Many spider mite species produce protective
webbing composed of almost invisible strands
of silk; these webs produce a favorable microclimate on the leaf surface. Characteristic of spi-

der mites is their enormous reproductive potential: a female of the European red mite (Panonychus ulmi) produces 14 – 30 eggs during its lifetime, the female two-spotted mite as many as
70 – 120. The tiny, pale green eggs are usually
deposited on the underside of the leaves within
the webbing [9–11].
The eggs hatch after 3 – 4 days in the case
of Tetranychus species, whereas in the European red mites the first instar larva appears after 6 – 20 days. All the spider mites go through
five stages in their life cycle: egg, six-legged
larva, eight-legged protonymph, deutonymph,
and adult. These stages are separated by resting stages followed by molts. The time for the
whole development depends strongly upon the
temperature, humidity, and the host plant. Under favorable conditions, the postembryonal development in Tetranychidae is completed within
8 – 14 days.
Orchard mites usually develop six to eight
generations per season, depending on the areas
where they occur. In greenhouses and in warm
climates, the two-spotted mite may develop up
to 30 generations per vegetation period, whereas
for Panonychus species only 6 – 20 generations
can be expected.
The climatic conditions during the summer
months have a strong influence on the population build-up during the following spring. Most
spider mites overwinter as bright orange adult
females within bark crevices or in plant debris
on the ground. The European red mite is an exception, overwintering as a winter egg on twigs.
Many weed species are excellent host plants
from which the spider mites may move on to
crop plants, either by crawling or by ballooning (transport by wind). All mites live on the
sap of the plant, piercing the leaf tissue with the
two sharp lances attached to the mouth and thus
puncturing the cells in the leaf epidermis. The
leaves then become speckled, later turn brown,
and, if the attack is severe, may drop. As a consequence, photosynthesis and respiration are impaired and this may affect the number of flower
buds in the following season. A mass attack of
phytophagous mites on deciduous fruit may result in yield losses of up to 40 % [12].
The gall mites (Eriophyidae) are very tiny
rodshaped mites with threadlike appendages.
Gall mites are very host specific and have
high reproductive potential. They destroy buds,

Acaricides
leaves, and fruit, and they also transmit viruses.
They may cause serious economic damage, especially in citrus fruits.
After a heavy attack of citrus rust mites
(Phyllocoptruta oleivora), the fruit turns reddish
brown and shrinks because of the loss of water. The citrus bud mite (Aceria sheldoni) causes
malformation of citrus fruits.

1.3. Possibilities for Mite Control
Chemical treatment can be aimed either at overwintering eggs (e.g., those of Panonychus ulmi)
or at the mobile stages of the mites. Winter eggs
often are treated with mineral oils. For the effective control of mites during the vegetative period,
a number of chemicals are available. However,
compounds that are effective against all development stages and have a long-term residual effect
are preferred.
The compounds used should be well tolerated by the plants, and the effects on environment and beneficial insects should be minimal.
The population of these natural enemies, which
could control mite populations effectively, has
been reduced severely or eliminated in most orchards, vineyards, and citrus groves as a result
of the use of broadspectrum pesticides aimed at
targets other than mites.
Biological control of phytophagous mites by
releasing their natural enemies, such as predatory bugs or coccinellids, has been successful
in greenhouses or in plastic tunnels. However,
only limited success has been achieved under
field conditions [13–15].
Integrated pest management, which makes
use of a variety of possible techniques, including chemicals, to keep the pest population below the economic threshold, is far more promising than simple biological control. In integrated
pest management systems, chemicals are used
only when the population density reaches a certain level (economic threshold) and if possible,
selective acaricides are chosen so as not to harm
beneficial insects and predatory mites.

1.4. Mite Resistance
In many areas, mites have developed resistance
to certain chemicals: their control therefore has

3

become problematic. Because of the large number of generations per season, selection may occur very rapidly in a mite population. Resistance
is induced by repeated application of the same
or closely related chemicals. To compensate for
this effect, higher dosages are needed, but this is
not a long-term solution to the resistance problem. New compounds with new modes of action must continue to be developed to replace
the older ones, that have decreased in effectiveness.
New control concepts, such as integrated pest
management, have made it possible to reduce
the number of acaricide treatments in many situations, and this has slowed development of resistance in mite populations.

2. Older Acaricides
Products introduced at the beginning of the pesticide era still find limited use as acaricides in
various parts of the world.
Nitrophenols , in combination with mineral
oil, were used to fight mites in orchards by eliminating their overwintering eggs. However, the
phytotoxicity of these compounds has been a
drawback [16, p. 527]. For a review of nitrophenols with acaricidal activity see [17, p. 2] and
[18, p. 537].
Sulfur [7704-34-9], used mainly as a protective fungicide to control powdery mildews, is
effective against the mobile stages of various
mite species. It is used in combination with other
fungicides and insecticides mainly in vineyards
[17, p. 2].
Azobenzene [103-33-3] has been used as a fumigant in greenhouses against insects and mites,
especially against eggs [17, p. 2].
Binaparcryl [485-31-4] has been used as a
nonsystemic acaricide, mainly against all stages
of spider mites and powdery mildew of apples,
citrus fruits, cotton, etc. [19, p. 73].
Chlorfenson [80-33-1] has been used as a
nonsystemic acaricide with long residual ovicidal activity. It is effective against mites of citrus
and other fruits [19, p. 150].
Tetrasul [2227-13-6] has been used as a nonsystemic acaricide, particularly suitable for the
control of various phytophagous mites which hibernate in winter egg form. It has been used on
vegetables and fruits [19, p. 790].

4

Acaricides

Chlorpropylate [5836-10-2] has been used as
a nonsystemic contact acaricide on cotton, fruits,
and ornamentals [19, p. 169].
Aldoxycarb [1646-88-4] is a systemic insecticide and nematicide, and is a potent
cholinesterase inhibitor. It has been used on tobacco and as a cotton seed dressing [19, p. 9].
Chlorobenzilate [510-15-6] is a nonsystemic
acaricide with little insecticidal activity. It has
been used against phytophagous mites on fruits
and vegetables [19, p. 162].

Chlorfenvinphos [470-90-6], 2-chloro-1(2,4-dichlorophenyl)vinyl diethyl phosphate,
C12 H14 Cl3 O4 P, M r 359.6, mp − 23 to − 29 ◦ C,
bp 167 – 170 ◦ C, is a colorless liquid which is
sparingly soluble in water, and miscible with
most organic solvents [20, p. 211].

3. Insecticides with
Acaricidal Activity

Organophosphates and carbamates, used as
broad-spectrum insecticides but also exhibiting
acaricidal action, were able to contain the mite
problem for some time. However, development
of mite resistance toward these compounds has
made them less and less effective as acaricides.

Chlorfenvinphos is produced by reaction of
2,4-dichloroacetophenone with triethyl phosphite [22].
Chlorfenvinphos (announced in 1952) is used
for soil application to control root flies, root
worms, and insects in vegetables and fruit flies
in maize.
Trade Names. Birlane (Cyanamid); Apachlor
(Rhône-Poulenc).

Aldicarb [116-06-3], 2-methyl-2-(methylthio)propanal
O-methylcarbamoyloxime,
C7 H14 N2 O2 S, M r 190.3, mp 98 – 100 ◦ C, forms
colorless crystals which are practically insoluble
in heptane and mineral oils, moderately soluble
in water, and soluble in most organic solvents
[20, p. 26].

Chlorpyrifos-methyl [5598-13-0],
O,Odimethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate, C7 H7 C13 NO3 PS, M r 322.5, mp
45.5 – 46.5 ◦ C, consists of colorless crystals
which are sparingly soluble in water but soluble in acetone, benzene, chloroform, hexane,
and methanol [20, p. 237].

Aldicarb is produced by reaction of isobutene
with nitrosyl chloride followed by reaction of the
product with sodium methyl sulfide; the resulting oxime is then converted into the carbamate
with methyl isocyanate [21].
Aldicarb (announced in 1965) is a
cholinesterase inhibitor which is metabolically
activated to sulfoxide. It is applied to soil to control chewing and sucking insects, spider mites,
and nematodes in glasshouse and outdoor ornamentals, vegetables, sugar beet, peanuts, fruits,
etc.
Trade Names. Temik (Rhône-Poulenc);
Sanacarb (Sanachem).

Chlorpyrifos-methyl is produced by reaction
of 3,5,6-trichloro-2-pyridinol with dimethylthiophosphoryl chloride [23].
Chlorpyrifos-methyl is used to control aquatic larvae, flies, household pests,
mosquitoes, pests in stored grain, and various
foliar crop pests.
Trade Name. Reldan (DowElanco); Pyriban
(Aimco).

3.1. Organophosphates and
(Oxime)Carbamates

Diazinon [333-41-5], O,O-diethyl O-2isoproyl-6-methylpyrimidine-4-yl phosphorothioate, C12 H21 N2 O3 PS, M r 304.3, bp

Acaricides

5

83 – 84 ◦ C (26.6 mPa), is a clear colorless liquid
which is sparingly soluble in water but completely miscible with common organic solvents
[20, p. 354].

Diazinon is produced by condensation of
isobutyramidine with acetoacetate to yield the
intermediate 2-isopropyl-4-methylpyrimidine,
which is transformed into the final product by
treatment with diethylthiophosphoric acid [24].
Diazinon (announced in 1953) is a nonsystemic insecticide/acaricide with contact, stomach, and respiratory action. It is used to control
sucking and chewing insects and mites on a variety of crops.
Trade Names. Basudin (Novartis); Dianon (Nippon Kayaku); Knox-out (Elf Atochem).
Dicrotophos [141-66-2], dimethyl (E)-2dimethylcarbamoyl-1-methylvinyl phosphate,
C8 H16 NO5 P, M r 237.2, bp 460 ◦ C, is a yellowish liquid which is completely miscible with water and common organic solvents [20, p. 382].

Dicrotophos is produced by reaction of
trimethyl phosphite with 2-chloro-N,N-dimethyl-3-oxobutyramide [25].
Dicrotophos (announced in 1965) is used to
control sucking, chewing, and boring insects and
mites in cotton, coffee, rice, sugar cane, and tobacco.
Trade Names. Bidrin (Cyanamid); Dicron (Hui
Kwang).
Dimethoate [60-51-5], O,O-dimethyl S-(Nmethylcarbamoyl)methyl phosphorodithioate,
C5 H12 NO3 PS2 , M r 229.2, mp 51 – 52 ◦ C, consists of colorless crystals which are moderately soluble in water, soluble in alcohols, benzene, chloroform, dichloromethane, ketones,
and toluene [20, p. 550].

Dimethoate is produced by reaction of the
sodium salt of O,O-dimethyldithiophosphoric
acid with N-methylchloroacetamide [26].
Dimethoate (announced in 1948) is effective
against houseflies and Diptera of medical importance.
Trade Names. Cygon, Roxion (Wilbur-Ellis);
Perfekthion (BASF); Champ (Searle India);
Danadim (Cheminova); Robgor (Ramcides).
Disulfoton [298-04-4],
O,O-diethyl
S-(2-ethylthio)ethyl
phosphorodithioate,
C8 H19 O2 PS3 , M r 274.4, mp < −25, bp 128 ◦ C,
is a colorless oil which is sparingly soluble in
water but readily miscible with common organic
solvents [20, p. 438].

Disulfoton is produced by reaction of the
sodium salt of diethyldithiophosphoric acid with
ethylmercaptoethyl chloride [27].
Disulfoton (announced in 1952) is used to
control aphids, thrips, mealybugs, other sucking
insects, and spider mites in potatoes, vegetables,
cereals and other crops.
Trade Names. Disyston (Bayer); Solvirex,
Fremin AL (Novartis).
EPN [2104-64-5], O-ethyl O-4-nitrophenyl
phenylphosphonothioate, C14 H14 NO4 PS, M r
323.3, mp 34.5 ◦ C, consists of yellow crystals
which are practically insoluble in water but soluble in common organic solvents [20, p. 464].

EPN is produced by reaction of benzene with
phosphorus trichloride in the presence of aluminum chloride and treatment of the resulting

6

Acaricides

product with phosphenyl chloride to give the
thiophosphonic acid, which is converted to ethyl
phenyl thiophosphonate chloride by treatment
with ethanol, followed by condensation of the
product with the sodium salt of p-nitrophenol
[28].
EPN (announced in 1948) is used against a
broad range of Lepidoptera larvae, especially
ballworms and Alabama argillacea in cotton,
Chilo spp. in rice, and other leaf-eating larvae
in fruit and vegetables.
Trade Name. EPN (Nisson).
Ethion [563-12-2],
O,O,O ,O -tetraethyl

S,S -methylene
bis(phosphorodithioate),
C9 H22 O4 P2 S4 , M r 384.5, bp 164 – 165 ◦ C
(40 Pa), is a colorless to amber liquid which is
practically insoluble in water but miscible with
most common organic solvents [20, p. 480].

Ethion is produced by reaction of
diethyldithiophosphoric acid with formaldehyde in the presence of sulfuric acid [29].
Ethion (announced in 1957) is used to control spider mites, aphids, scale insects, thrips,
and lepidopterous larvae in fruits, vegetables,
and turf.
Trade Names. Ethiol, Rhodocide (RhônePoulenc); Tafethion (Rallis); Dhanumix
(Dhanuka).
Fenothiocarb [62850-32-2], S-4-phenoxybutyl dimethylthiocarbamate, C13 H19 NO2 S,
M r 253.4, mp 40 – 41 ◦ C, consists of colorless
crystals which are sparingly soluble in water
but readily soluble in cyclohexanone, acetonitrile, acetone, xylene, methanol, and hexane [20,
p. 517].

Fenothiocarb is produced by reaction of
the sodium salt of N,N-dimethylcarbamothioate
with phenoxybutylchloride, which is obtained

by reaction of an excess of dichlorobutane with
phenol in the presence of potassium hydroxide
[30].
Fenothiocarb (announced in 1985) is a nonsystemic acaricide used to control eggs and
young stages of Panonychus citri, Panonychus
ulmi, and other Panonychus spp.
Trade Name. Panocan (Kumiai).
Formothion [2540-82-1], O,O-dimethyl S[formyl(methyl)carbomylmethyl] phosphorodithioate, C6 H12 NO4 PS2 , M r 257.3, mp
25 – 26 ◦ C, is a pale yellow viscous liquid or
crystalline mass which is moderately soluble
in water but completely miscible with common
organic solvents [20, p. 625].

Formothion is produced by reaction of the
sodium salt of O,O-dimethyldithiophosphoric
acid with N-methyl N-formyl carbamoylmethyl
chloride [31].
Formothion (announced in 1960) is used
against a wide range of sucking and mining insects, such as Aphididae, bugs, Cicadellidae,
Cocidae, as well as against some chewing insects and spider mites on a variety of field crops,
fruit trees, citrus and other tropical fruit, cotton,
ornamentals, rice, tobacco, and vegetables.
Trade Name. Anthio (Novartis).
Mecarbam [2595-54-2], O,O-diethyl S-(Nethoxycarbonyl-N-methylcarbamoylmethyl)
phosphorodithioate, C10 H20 NO5 PS2 , M r 329.4,
bp 144 ◦ C (2.7 Pa), is a pale yellow to brown oil
which is sparingly soluble in water, soluble in
aliphatic hydrocarbons, and miscible with alcohols, esters, and ketones [20, p. 774].

Mecarbam is produced by reaction of
the sodium salt of O,O-diethyldithiophosphoric acid with N-ethoxycarbonyl-Nmethylcarbamoylmethyl chloride [32].

Acaricides
Mecarbam (announced in 1961) possesses
slight systemic properties, contact and stomach
action, and long residual activity. It is used to
control aphids, suckers, whitefly, scale insects,
mealybugs and red spider mites on a variety of
crops; and leaf hoppers, plant hoppers, and miners on rice.
Trade Name. Murfatox (Efthymiadis).
Methacrifos [62610-77-9],
(E)-O-2methoxycarbonylprop-1-enyl
O,O-dimethyl
phosphorothioate, C7 H13 O5 PS, M r 240.2, bp
90 ◦ C (1.3 Pa), is a colorless liquid which is
sparingly soluble in water and miscible with
many organic solvents [20, p. 806].

Methacrifos is produced by reaction of 2hydroxymethylenepropionic acid methyl ester
with dimethylthiophosphoryl chloride [33].
Methacrifos (announced in 1977) is an insecticide and acaricide with respiratory, contact,
and stomach action. It is used for control of
arthropod pests in stored products by incorporation or by surface treatment.
Trade Name. Damfin (Novartis).
Methamidophos [10265-92-6],
O,S-dimethylphosporamidothioate, C2 H8 NO2 PS, M r
141.1, mp 44.9 ◦ C, consists of colorless crystals
which are highly soluble in water, isopropanol,
and dichloromethane, and moderately soluble
in hexane and toluene [20, p. 808].

Methamidophos is prepared by isomerization
of O,O-dimethylthiophosphamidate [34].
Methamidophos (announced in 1970) is a
systemic insecticide and acaricide with contact
and stomach action. It is used for control of
chewing and sucking insects and spider mites
on ornamentals, vegetables, and fruits.
Trade Names. Monitor (Bayer, Tomen, Valent);
Tamaron (Bayer); Metaphos (Eftymiadis); Patrole (Pruductos OSA).

7

Methidathion [950-37-8],
O,O-dimethyl S-2,3-dihydro-5-methoxy-2-oxo-1,3,4thiadiazol-yl
methyl
phosphorodithioate,
C6 H11 N2 O4 PS3 , M r 302.3, mp 39 – 40 ◦ C, consists of colorless crystals which are sparingly
soluble in water, moderately soluble in hexane
and n-octanol, and soluble in ethanol, acetone,
and toluene [20, p. 811].

Methidathion is produced by reaction
of 2-methoxy-1,3,4-thiadiazol-5(4H)-one with
dimethyldithiophosphoric acid via the Nchloromethyl derivative or in a one-step reaction
in the presence of formaldehyde [35].
Methidathion (announced in 1965) is a nonsystemic insecticide and acaricide with contact
and stomach action that is used against a wide
range of sucking and chewing insects and spider
mites in many crops.
Trade Names. Supracide (Novartis); Suprathion
(Makhteshim-Agan).
Methiocarb [2032-65-7],
(3,5-dimethyl4-methylthio)phenyl
methylcarbamate,
C11 H25 NO2 S, M r 225.3, mp 119 ◦ C, consists
of colorless crystals which are sparingly soluble
in water, moderately soluble in hexane, and soluble in dichloromethane and isopropanol [20,
p. 813].

Methiocarb is produced by reaction of 4methyl-3,5-dimethylphenol with chloroacetoacetate [36].
Methiocarb (announced in 1962) is used for
control of slugs and snails in a wide range of
agricultural applications: broad-range control of
Lipidoptera, Coleoptera, Piptera, Thysanoptera,
and Homoptera in vegetables, fruits, oilseed
rape, and ornamentals.

8

Acaricides

Trade Names. Draza, Mesurol (Bayer).
Methomyl [16752-77-5],
S-methyl-N(methylcarbamoyloxy)
thioacetimidate,
C5 H10 N2 O2 S, M r 162.2, mp 78 – 79 ◦ C, consists of colorless crystals which are fairly soluble
in water and highly soluble in methanol, ethanol,
acetone, isopropanol [20, p. 815].

Methomyl is produced by chlorination of
acetaldoxime and conversion of the resulting
α-chlorooxime with sodium methylmercaptide
[37].
Methomyl (announced in 1968) controls a
wide range of insects and spider mites in fruits,
vines, olives, hops, vegetables, and ornamentals.
Trade Names. Lannate (Du Pont); Methavin
(Rhône-Poulenc); Methosan (Sanachem);
Nudrin (Cyanamid).
Mevinphos [26718-65-0], 2-methoxycarbonyl1-methylvinyl dimethyl phosphate, C7 H13 O6 P,
M r 224.1, bp 21 ◦ C (E isomer), 6.9 ◦ C (Z isomer), is a colorless liquid which is completely
miscible with water and many organic solvents
[20, p. 844].

Monocrotophos [2157-98-4], dimethyl (E)1-methyl-2-(methylcarbamoyl)vinyl phosphate,
C7 H14 NO5 P, M r 223.2, mp 54 – 55 ◦ C, consists
of colorless, hygroscopic crystals which are soluble in water, methanol, acetone, and n-octanol
[20, p. 849].

Monocrotophos is produced by reaction of
trimethylphosphite with chloroacetoacetic acid
methylamide in the presence of a base [39].
Monocrotophos (announced in 1959) is used
for control of a wide range of pests on cotton,
rice, maize, vegetables, and ornamentals.
Trade Names. Azodrin (Cyanamid); Nuvacron
(Novartis); Apadrin (Rhône-Poulenc); Balwan
(Rallis); Monodhan (Dhanuka).
Omethoate [1113-02-6], O,O-dimethyl Smethylcarbamoylmethyl
phosphorothioate,
C5 H12 NO4 PS, M r 213.2, mp − 28 ◦ C (decomp.), bp ca. 135 ◦ C, is a colorless liquid which
is readily soluble in water, alcohols, acetone, and
many hydrocarbons, slightly soluble in diethyl
ether, and almost insoluble in petroleum ether
[20, p. 896].

Omethoate is produced by reaction of O,Odimethylphosphorylmercaptoacetic acid with
methyl isocyanate [40].
Omethoate (announced in 1959) is used for
control of spider mites, aphids, beetles, caterpillars, scale insects, thrips, and other pests on fruit,
hops, cereal, rice, ornamentals, and other crops.
Trade Name. Folimat (Bayer).
Mevinphos is produced by reaction of
trimethyl phosphite with chloroacetoacetate
[38].
Mevinphos (announced in 1953) is used for
control of chewing and sucking insects and spiter
mites on a wide range of crops.
Trade Names. Phosdrin (Cyanamid, Amvac);
Duraphos (Amvac); Mevindrin (Hui Kwang).

Oxamyl [23135-22-0],
N,N-dimethyl-2methylcarbamoylimino-2-(methylthio)acetamide, C7 H13 N3 O3 S, M r 219.3, mp 100 – 102 ◦ C,
consists of colorless crystals which are readily
soluble in water, methanol, ethanol, acetone,
and fairly soluble in toluene [20, p. 909].

Acaricides

Oxamyl is produced by chlorination of
the oxime of methylglycolate, reaction with
methanethiol and alkali, and conversion to the
carbamate with methyl isocyanate [41].
Oxamyl (announced in 1968) is used for control of chewing and sucking insects, spider mites,
and nematodes in ornamentals, vegetables, potatoes, and other crops.
Trade Name. Vydate (DU Pont).
Phenthoate [2597-03-7],
O,O-dimethyl
S-(α-carboethoxy)phenylmethyl phosphorodithioate, C12 H17 O4 PS2 , M r 320.4, mp
186 – 187 ◦ C, consists of colorless crystals
which are slightly soluble in water but readily
soluble in many organic solvents [20, p. 952].

Phenthoate is produced by reaction of the
sodium salt of O,O-dimethyldithiophosphonic
acid with phenylbromoethyl acetate [42].
Phenthoate (announced in 1955) is used for
control of aphids, scale insects, jassids, lacebugs, etc., in cereals, maize, rice, coffee, sunflowers, sugar cane, and other crops.
Trade Names. Elsan (Nissan); Cidial (Isagro);
Aimsan (Aimco).
Phorate [298-02-2],
O,O-diethyl
S(2-ethylthio)methyl
phosphorodithioate,
C7 H17 O2 PS3 , M r 260.4, mp < − 15 ◦ C, bp
118 – 120 ◦ C (0.1 kPa), is a colorless liquid
which is sparingly soluble in water but miscible with alcohols, ketones, ethers, and esters
[20, p. 959].

9

Phorate is produced by reaction of O,Odiethyldithiophosphoric acid with ethanethiol
and formaldehyde [43].
Phorate (announced in 1948) is a systemic insecticide and acaricide used for control of Agromyzidae, Aleyrodidae, Aphididae,
Chrysomelidae, Noctuidae, Pyralidae, Tetranychidae, and certain nematodes in a variety of
crops.
Trade Names. Thimet (Cyanamid); Ramcides
(Kunurai); Umet (United Phosphorus).
Phosalone [2310-17-0], O,O-diethyl S-(6chloro-2,3-dihydro-2-oxobenzoxazol-3-yl)methyl phosphorodithioate, C12 H15 ClNO4 PS2 , M r
367.8, mp 42 – 48 ◦ C, consists of colorless crystals which are sparingly soluble in water, fairly
soluble in hexane, and readily soluble in many
organic solvents [20, p. 961].

Phosalone is produced by treating
O,O-diethyldithiophosphoric acid with Nchloromethyl-5-chlorobenzoxazolone [44].
Phosalone (announced in 1963) is used as a
nonsystemic acaricide and insecticide, primarly
in pome and stone fruit trees against Coleoptera,
Homoptera, Lepidoptera and Thysanoptera.
Trade Name. Zolone (Rhône-Poulenc).
Phosmet [732-11-6], O,O-dimethyl S(N-phthalimidomethyl)
phosphorodithioate,
C11 H12 NO4 PS2 , M r 317.3, mp 72 – 72.7 ◦ C,
consists of colorless crystals which are sparingly
soluble in water but readily soluble in acetone,
toluene, xylene, and methanol [20, p. 963].

Phosmet is produced by reaction
of N-chloromethylphthalimide with dimethyldithiophosphoric acid [45].
Phosmet (announced in 1961) is used for
control of lepidopterous larvae, aphids, suckers,

10

Acaricides

fruit flies, and spider mites on pome fruit, stone
fruit, citrus fruit, ornamentals, and vines.
Trade Names. Prolate (Gowan); Fosdan (General Quimica); Inovat (Productos OSA).
Phosphamidon [13171-21-6],
O,O-dimethyl
O-(2-chloro-2-diethylcarbamoyl-1methyl)vinyl phosphate, C10 H19 ClNO5 P, M r
299.7, bp 162 ◦ C (2 kPa), is a pale yellow liquid
which is miscible with water and many organic
solvents with the exception of aliphatic hydrocarbons [20, p. 965].

Phosphamidon is produced by reaction of
trimethylphosphite with α,α-dichloroacetic acid
diethylamide [46].
Phosphamidon (announced in 1956) is used
for control of sucking, chewing, and boring insects, and spider mites on a wide range of crops.
Trade Names. Dimecron (Novartis); Rilan (Rallis); Kinadon (United Phosphorus).
Pirimiphos-methyl [29232-93-7], O,O-dimethyl O-2-diethylamino-6-methylpyrimidin4-yl phosphorothioate, C11 H20 N3 O3 PS, M r
305.3, bp 15 – 18 ◦ C, is a straw-colored liquid
which is sparingly soluble in water but miscible
with most organic solvents [20, p. 988].

Pirimiphos-methyl is produced by condensation of diethylguanidine