Materials Handbook 15th ed - G. Brady_ H. Clauser_ J. Vaccari (McGraw-Hill_ 2002) Episode 14 pptx

have made these alloys obsolete. The bearing alloy known in England
as motor bronze is a babbitt with about twice the copper of a stan-
dard babbitt. One analysis gives tin, 84%; antimony, 7.5; copper, 7.5;
and bismuth 1. An old alloy, used in India for utensils and known as
bidery metal, contained 31 parts zinc, 1 lead, and 2 copper, fluxed
with resins. It was finished with a velvety-black color by treating
with a solution of copper sulfate. A white metal sheet now much
used for making stamped and formed parts for costume jewelry and
electronic parts is zinc with up to 1.5% copper and up to 0.5 titanium.
The titanium with the copper prevents coarse-grain formation, rais-
ing the recrystallization temperature. The alloy weighs 2% less than
copper, and it plates and solders easily. Zilloy-20 is pure zinc with no
more than 1% of other elements. In rolled strip it has a tensile
strength up to 27,000 lb/in
2
(186 MPa) and elongation of 35%.
WILLOW. The wood of the trees Salix coerulea and S. alba, native to
Europe, but grown in many other places. It is best known as a mater-
ial for cricket bats made in England. The American willows are
known as black willow, from the tree S. nigra, and western black
willow, from the tree S. lasiandra. The wood is also employed for
making artificial limbs and for articles where toughness and non-
shrinking qualities are valued. The wood is brownish yellow; has a
fine, open grain; and has a density of about 30 lb/ft
3
(481 kg/m
3
). It is
of the approximate hardness of cherry and birch. Japanese willow
is from the tree S. urbaniana. It has a closer and finer texture and a
browner color. Black willow has a maximum crushing strength paral-

lel to the grain of about 1,500 lb/in
2
(10 MPa). Salicin, also called
salicoside and saligenin, is a glucoside extracted from several
species of willow bark of England and also from the American aspen.
It is a colorless, crystalline material of composition (OH)
4
C
6
H
7
и OO и
C
6
H
4
CH
2
OH, decomposing at 394°F (201°C) and soluble in water and
in alcohol. It is used in medicine as an antipyretic and tonic, and as a
reagent for nitric acid. It hydrolyzes to glucose and salicyl alcohol,
and the latter is oxidized to salicylic acid, C
6
H
4
(OH)COOH.
Aspirin, acetyl salicylic acid, is used as an antipyretic and anal-
gesic.
WIRE CLOTH. Stiff fabrics made of fine wire woven with plain, loose
weave, used for screens to protect windows, for guards, and for sieves

and filters. Steel and iron wire may be used—plain, painted, galva-
nized, or rustproofed—or various nonferrous metal wires are
employed. It is usually put up in rolls in widths from 18 to 48 in (46
to 122 cm). Screen cloth is usually 12, 14, 16, and 18 mesh, but wire
cloth in copper, brass, or Monel metal is made regularly in meshes
1040 WILLOW
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
from 4 to 100. The size of wire is usually from 0.009 to 0.065 in (0.023
to 0.165 cm) in diameter. Wire cloth for fine filtering is made in very
fine meshes. Mesh indicates the number of openings per inch and has
no reference to the diameter of wire. A 200-mesh cloth has 200 open-
ings each way on a square inch, or 40,000 openings per square inch
(6.4 cm
2
). Wire cloth as fine as 400 mesh, or having 160,000 openings
per square inch (6.4 cm
2
), is made by wedge-shaped weaving,
although 250 wires of the size of 0.004 in (0.010 cm) when placed par-
allel and in contact will fill the space of 1 in (2.5 cm). Very fine-mesh
wire cloth must be woven at an angle since the globular nature of
most liquids will not permit passage of the liquid through microscopic
square openings. One wire screen cloth, for filtering and screening,
has elongated openings. One way the 0.0055-in (0.0140-cm) wire
count is 200 per inch (2.5 cm), while the other way the 0.007-in
(0.018-cm) warp wire count is 40 per inch (2.5 cm).
Wire fabrics for reentry parachutes are made of heat-resistant

nickel-chromium alloys, and the wire is not larger than 0.005 in
(0.013 cm) in diameter to give flexibility to the cloth. Wire fabrics for
ion engines to operate in cesium vapor at temperatures to 2400°F
(1316°C) are made with tantalum, molybdenum, or tungsten wire,
0.003 to 0.006 in (0.008 to 0.015 cm) in diameter, with a twill weave.
Meshes to a fineness of 350 by 2,300 can be obtained. Porosity unifor-
mity is controlled by pressure calendaring of the woven cloth, but for
extremely fine meshes in wire cloth it is difficult to obtain the unifor-
mity that can be obtained with porous sintered metals.
Where accuracy of sizing is not important, as in gravel or ore
screening, wire fabric is made with oblong or rectangular openings
instead of squares to give faster screening. High-manganese steel
wire is used for rock screens. For window screening in tropical cli-
mates or in corrosive atmospheres, plastic filaments are sometimes
substituted for the standard copper or steel wire. Lumite screen
cloth is woven of vinylidene chloride monofilament 0.015 in (0.038
cm) in diameter in 18 and 20 mesh. The impact strength of the plastic
cloth is higher than that of metal wire cloth, but it cannot be used for
screening very hot materials. Lektromesh is copper or nickel screen
cloth of 40 to 200 mesh made in one piece by electrodeposition. It can
be drawn or formed more readily than wire screen, and circular or
other shapes can be made with an integral selvage edge.
WIRE GLASS. A sheet glass used in building construction for windows,
doors, floors, and skylights, having woven wire mesh embedded in the
center of the plate. It does not splinter or fly apart as common glass
when subjected to fire or shock, and it has higher strength than com-
mon glass. It is made in standard thicknesses from 0.125 to 0.375 in
WIRE GLASS 1041
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
(0.318 to 0.953 cm) and in plates 60 by 110 in (1.5 by 2.8 m) and 61 by
140 in (1.5 by 3.6 m). Underwriters’ specifications call for a minimum
thickness of 0.25 in (0.635 cm). Wire glass is made with plain, rough,
or polished surfaces, or with ribbed or cobweb surface on one side for
diffusing the light and for decorative purposes. It is also obtainable in
corrugated sheets, usually 27.75 in (70.5 cm) wide. Wire glass 0.25 in
(0.635 cm) thick weighs 2.25 lb/ft
2
(11 kg/m
2
). Plastic-coated wire mesh
may be used to replace wire glass for hothouses or skylights where less
weight and fuller penetration of light rays are desired. Cel-O-Glass, of
Du Pont, is a plastic-coated wire mesh in sheet form.
WOLLASTON WIRE. Any wire made by the Wollaston process of fine-
wire drawing. It consists of inserting a length of bare drawn wire into
a close-fitting tube of another metal, the tube and core then being
treated as a single rod and drawn through dies down to the required
size. The outside jacket of metal is then dissolved away by an acid
that does not affect the core metal. Platinum wire as fine as 0.00005
in (0.00013 cm) in diameter is made commercially by this method,
and gold wire as fine as 0.00001 in (0.00002 cm) in diameter is also
drawn. Wires of this fineness are employed only in instruments. They
are marketed as composite wires, the user dissolving off the jacket.
Taylor process wire is a very fine wire made by the process of
drawing in a glass tube. The process is used chiefly for obtaining fine
wire from a material lacking ductility, such as antimony, or extremely
fine wire from a ductile metal. The procedure is to melt the metal or

alloy into a glass or quartz tube, and then draw down this tube with
its contained material. Wire as fine as 0.00004 in (0.00012 cm) in
diameter is made, but only in short lengths.
WOOD. A general name applied to the cut material derived from
trees. A tree, as distinguished from a bush, is designated by the U.S.
Forest Service as a woody plant with a single erect stem 3 in (7.6 cm)
or more in diameter at 4.5 ft (1.4 m) above the ground, and at least 12
ft (3.7 m) high. But this definition is merely empirical since in the
cold climate of northern Canada, perfect, full-grown trees 10 to 15
years old may be only 6 in (15 cm) high. Timber, in general, refers to
standing trees, while lumber is the sawed wood used for construction
purposes. In construction work the word timber is often applied to
large pieces of lumber used as beams.
Wood is an organic chemical compound composed of approximately
49% carbon, 44 oxygen, 6 hydrogen, and 1 ash. It is largely cellulose
and lignin. The wood of white pine is about 50% cellulose, 25 lignin,
and the remainder sugars, resin, acetic acid, and other materials.
Wood is produced in most trees by a progressive growth from the out-
1042 WOLLASTON WIRE
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
side. In the spring, when sap flows rapidly, a rapid formation of large
cells takes place, followed by a slower growth of hard and close cells in
summer. In some woods, such as oak, there is a considerable difference
in quality and appearance between the spring and summer woods. In
some long-lived trees, such as Douglas fir, there is a decrease in
strength between the outside wood with narrow rings and the wide-
ringed wood of the interior. Heartwood is the dark center of the tree

which has become set, and through which the sap has ceased to flow.
Sapwood is the outer, live wood of the tree; unless treated, it has low
decay resistance. The grain of sawed lumber results from sawing
across the annual growth rings, varied to produce different grains.
Wood is seasoned either by exposing it to the air to dry or by kiln
drying. The former method is considered to give superior quality, but
it requires more time, is expensive, and is indefinite. Numerous tests
made at the U.S. Forest Products Laboratory did not reveal any supe-
riority in air-dried wood when kiln drying was well done. Solvent sea-
soning is a rapid process consisting of circulating a hot solvent
through the wood in a closed chamber. California redwood, when sea-
soned with acetone at 130°F (54°C), yields tannin and some other
chemicals as by-products. Seasoned wood, when dry, is always
stronger than unseasoned wood. Tank woods are selected for resis-
tance to the liquids to be contained. Tanks for vinegar and foodstuffs
containing vinegar, such as pickles, are of white oak, cypress, or west-
ern red cedar. Beer tanks are of white oak or cypress. Tanks for aging
wine are of redwood, oak, or fir. The traditional violin woods are
spruce and curly maple, although sugar maple is also used.
The term log designates the tree trunk with the branches removed.
Balk is a roughly squared log; plank is a piece cut to rectangular sec-
tion 11 in (28 cm) wide; deal is a piece 9 in (23 cm) wide; and batten
is a piece 7 in (18 cm) wide. Board is a thin piece of any width less
than 2 in (5 cm). Flitch is half a balk, cut in two lengthwise.
Scantling is a piece sawed on all sides. Shakes are longitudinal
splits or cracks in the wood due to shrinkage or decay.
All woods are divided into two major classes on the basis of the type
of tree from which they are cut. Hardwoods are from broad-leaved,
deciduous trees. Softwoods are from conifers, which have needle- or
scalelike leaves and are, with few exceptions, evergreens. These terms

do not refer to the relative hardnesses of the woods in these two
classes. Hardwood lumber is available in three basic categories: fac-
tory lumber; dimension lumber, or dimension parts; and fin-
ished market products. The important difference between factory
lumber and dimension parts is that factory lumber grades reflect the
proportion of the pieces that can be cut into useful smaller pieces,
while the dimension grades are based on use of the entire piece.
WOOD 1043
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
Finished market products are graded for their end use with little or no
remanufacturing. Examples of finished market products are flooring,
siding, ties, timbers, trim, molding, stair treads, and risers. The rules
adopted by the National Hardwood Lumber Association are considered
standard in grading factory lumber. The grades from the highest to the
lowest quality are as follows: firsts, the top quality, and seconds, both
of which are usually marketed as one grade called firsts and seconds
(FAS); selects; and common grades No. 1, No. 2, No. 3A, and No. 3B.
Sometimes a grade is further specified, such as FAS one face, which
means that only one face is of the FAS quality. Another designation,
WHND, sometimes used, means that wormholes are not considered
defects in determining the grade. Dimension lumber, generally graded
under the rules of the Hardware Dimension Manufacturers
Association, are of three classes: solid dimension flat stock, kiln-dried
dimension flat stock, and solid dimension squares. Each class may be
rough, semifabricated, or fabricated. Rough dimension blanks are usu-
ally kiln-dried and are supplied sawn and ripped to size. Surfaced or
semifabricated stock has been further processed by gluing, surfacing,

etc. Fabricated stock has been completely processed for the end use.
Solid dimension flat stock has five grades: clear—two faces, clear—one
face, paint, core, and sound. Squares have three grades if rough (clear,
select, sound) and four if surfaced (clear, select, paint, sound).
There are two major categories of softwood lumber: construction
and remanufacture. Construction lumber is of three general types:
stress-graded; non-stress-graded, also referred to as yard lumber;
and appearance lumber. Stress-graded lumber is structural lum-
ber never less than 2 in (5 cm) thick, intended for use where definite
strength requirements are specified. The allowable stresses specified
for stress-graded lumber depend on the size, number, and placement
of defects. Because the location of defects is important, the piece must
be used in its entirety for the specified strength to be realized. Stress-
graded products include timbers, posts, stringers, beams, decking,
and some boards.
Typical non-stress-graded lumber items include boards, lath,
battens, cross-arms, planks, and foundation stock. Boards, some-
times referred to as commons, are one of the more important
non-stress-graded products. They are separated into three to five dif-
ferent grades, depending upon the species and lumber manufacturing
association involved. Grades may be described by number (No. 1, No.
2) or by descriptive terms (construction, standard). First-grade boards
are usually graded primarily for serviceability, but appearance is also
considered. Second- and third-grade boards are often used together
for such purposes as subfloors and sheeting. Fourth-grade boards are
selected not for appearance but for adequate strength. The appear-
1044 WOOD
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.

Materials, Their Properties and Uses
ance category of construction lumber includes trim, siding, flooring,
ceiling, paneling, casing, and finish boards. Most appearance lumber
grades are designated by letters and combinations of letters, and are
also often known as select grades. Typical grades of lumber remanu-
facture are the factory grades and industrial clears. Factory select
and select shop are typical high grades of factory lumber, followed by
No. 1, No. 2, and No. 3 shop. Industrial clears are used for cabinet
stock, door stock, and other products where excellent appearance,
mechanical and physical properties, and finishing characteristics are
important. The principal grades are B&BTR, C, and D.
Metallized wood is wood treated with molten metal so that the
cells of the wood are filled with the metal. Fusible alloys, with melt-
ing points below the scorching point of the wood, are used. The wood
is immersed in molten metal in a closed container under pressure.
The hardness, compressive strength, and flexural strength of the
wood are increased, and the wood becomes an electric conductor
lengthwise of the grain. Woods are also metallized with a surface
coating of metal by vacuum deposition.
Sugar pine is one of the most widely used pattern woods for
foundry patterns. It replaces eastern white pine, which is scarcer and
now usually more costly. Poplar is used for patterns where a firmer
wood is desired; cherry or maple is employed where the pattern is to
be used frequently or will be subject to severe treatment. Densified
wood is also used for patterns required to be very wear-resistant.
Mahogany is used for small and intricate patterns where a firm tex-
ture and freedom from warpage are needed. However, for small cast-
ings made in quantities on gates, aluminum or brass is more
frequently used.
Excelsior is an old trade name, still used, for continuous, curly,

fine wood shavings employed as a packing material for breakable
articles. It is light and elastic, and it is also used as a cushioning and
stuffing material. It is usually made from poplar, aspen, basswood, or
cottonwood. A cord of wood produces about 1,500 lb (680 kg), but it
may be made as a by-product from other woodworking. It is also
called wood fiber and wood wool, but these terms more properly
refer to fibers of controlled size and length used with a resin binder
for molding into handles, knobs, and other imitation wood parts.
Several plastics are suitable for imitation wood, also called synthetic
wood and plastic lumber. And environmental concerns regarding
global deforestation have increased prices of certain woods, making
plastics more cost-competitive.
Some wood for special purposes comes from roots or from bushes.
The briar used for tobacco pipes is from the roots of the white
heath, Erica arborea, of north Africa. Substitutes for briar are the
WOOD 1045
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
burls of the laurel and rhododendron. Yareta, used for fuel in the cop-
per region of Chile, is a mosslike, woody plant which grows on the
sunny northern mountain slopes at altitudes above 12,000 ft (3,658
m) and requires several hundred years to reach a useful size.
WOOD FLOUR. Finely ground dried wood employed as a filler and as
reinforcing material in molding plastics and in linoleum, and as an
absorbent for nitroglycerin. It is made largely from light-colored soft-
woods, chiefly pine and spruce, but maple and ash flours are pre-
ferred where no resin content is desired. Woods containing essential
oils, such as cedar, are not suitable. Wood flour is produced from saw-

dust and shavings by grinding in burr mills. It has the appearance of
wheat flour. The sizes commonly used are 40, 60, and 80 mesh; the
finest is 140 mesh. Grade 1, used as a filler in rubber and plastics,
has a particle size of 60 mesh and a specific gravity of 1.25, but 80
and 100 mesh are also used for plastic filler. Since wood flour absorbs
the resin or gums when mixed in molding plastics and sets hard, it is
sometimes mixed with mineral powders to vary the hardness and
toughness of the molded product.
Vast quantities of sawdust are obtained in the sawmill areas.
Besides being used as a fuel, it is employed for packing, for finishing
metal parts in tumbling machines, for making particleboard, and for
distilling to obtain resins, alcohols, sugars, and other chemicals.
Some sawdust is pulped, and as much as 20% of such pulp can be
used in kraft paper without loss of strength. Hickory, walnut, and
oak sawdusts are used for meat smoking, or for the making of liq-
uid smoke, which is produced by burning the sawdust and absorb-
ing the smoke into water. For the rapid production of bacon and
other meats, immersion in liquid smoke imitates the flavor of
smoked meat. Some sawdust is used for agricultural mulch and fer-
tilizer by chemical treatment to accelerate decay. Bark fuel is
shredded bark, flash-dried and pelletized with powdered coal.
Particleboard, made by compressing sawdust or wood particles
with a resin binder into sheets, has uniform strength in all direc-
tions, and a smooth, grainless surface. When used as a core for
veneer panels, it requires no cross-laminating. Mechanical pulp for
newsprint can be made from sawdust but the quantity available is
usually not sufficient. The material known as ground wood, of
fine-mesh fibers, is made from cord wood, about 1 ton of fibers being
produced from one cord of pulpwood. Plastic wood, usually mar-
keted as a paste in tubes for filling cavities or seams in wood prod-

ucts, is wood flour or wood cellulose compounded with a synthetic
resin of high molecular weight that will give good adhesion but not
penetrate the wood particles to destroy their nature. The solvent is
1046 WOOD FLOUR
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
kept low to reduce shrinkage. When cured in place, the material can
be machined, polished, and painted.
WOOD PRESERVATIVES. These fall into two general classes: oils, such
as creosote and petroleum solutions of pentachlorophenol; and
waterborne salts that are applied as water solutions. Coal tar cre-
osote, a black or brownish oil made by distilling coal tar, is the oldest
and still one of the more important and useful wood preservatives.
Because it has recently been classified as a carcinogen, its use is
expected to decrease. Its advantages are high toxicity to
wood-destroying organisms; relative insolubility in water and low
volatility, which impart to it a great degree of permanence under the
most varied use conditions; ease of application; ease with which its
depth of penetration can be determined; general availability and rela-
tively low cost; and long record of satisfactory use.
Creosotes distilled from tars other than coal tar are used to some
extent for wood preservation. For many years, either cold tar or
petroleum oil has been mixed with cold tar creosote in various pro-
portions to lower preservative costs.
Water-repellent solutions containing chlorinate phenols, principally
pentachlorophenol, in solvents of the mineral spirit type have been
used in commercial treatment of wood by the millwork industry since
about 1931. Pentachlorophenol solutions for wood preservation gener-

ally contain 5% (by weight) of this chemical, although solutions with
volatile solvents may contain lower or higher concentrations.
Preservative systems containing water-repellent components are sold
under various trade names, principally for the dip or equivalent treat-
ment of window sash and other millwork. According to federal specifi-
cations the preservative chemicals may not contain less than 5%
pentachlorophenol.
Standard wood preservatives used in water solution include acid
copper chromate, ammoniacal copper arsenite, chromated cop-
per arsenate, zinc naphthenate, chromated zinc chloride, and
fluor chrome arsenate phenol. These preservatives are often
employed when cleanliness and paintability of the treated wood are
required. The chromated zinc chloride and fluor chrome arsenate phenol
formulations resist leaching less than preservative oils, and are seldom
used where a high degree of protection is required for wood in ground
contact or for other wet installations. Several formulations involving
combinations of copper, chromium, and arsenic have shown high resis-
tance to leaching and very good performance in service. The ammonia-
cal copper arsenite and chromated copper arsenate are included in
specifications for such items as building foundations, building poles,
utility poles, marine piling, and piling for land and freshwater use.
WOOD PRESERVATIVES 1047
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
Organic sulfones are another class of wood preservatives offering high
degrees of protection. One such product is diiodomethyl p-tolyl sul-
fone, with trade name Amical, from Angus Chemical Co.
WOOL. The fine, soft, curly hair or fleece of the sheep, alpaca, vicuña,

certain goats, and a few other animals. The specific designation wool
always means the wool of sheep. Sheep’s wool is one of the most
important commercial fibers because of its good physical qualities and
its insulating value, especially for clothing, but it now constitutes only
about 10% of the textile fiber market. It is best known for its use in
clothing fabrics, called woolens. These are designated under a variety
of very old general trade names such as a loosely woven fabric called
flannel, or the fine, smooth fabric known as broadcloth. Cheviot is a
close-napped, twill-woven fabric, and tweed is a woolen fabric with a
coarse surface, usually with a herringbone-twill weave. Serge is a
twill-woven worsted fabric. Worsteds are wool fabrics made from
combed-wool yarn, usually from long, smooth wool. Wool is also
employed for packings and for insulation, either loose or felted, and for
making felts. The average amount of wool shorn from sheep in the
United States is 8.1 lb (3.7 kg) per animal.
Wool differs from hair in fineness and its felting and spinning prop-
erties. The latter are due to the fine scales of the wool fibers. The
finest short-staple wool has as many as 4,000 scales to the inch (2.5
cm), and the average long-staple wool has about 2,000 scales per inch
(2.5 cm). These scales give wool its cohesive qualities. Some animals
have both wool and hair, while others have wool only when young.
There is no sharp dividing line between wool and hair.
Wool quality is by fineness, softness, length, and scaliness. Fiber
diameters vary from 0.0025 to 0.005 in (0.0064 to 0.013 cm). Long
wools are generally heavy. Fibers below 3 in (7.6 cm) in length are
known as clothing wool, and those from 3 to 7 in (7.6 to 17.8 cm) are
called combing wools. Long wools are fibers longer than 7 in (17.8
cm). The term apparel wool generally means clothing wool of fine
weaving quality from known sources. Fleece wool is the unscoured
fiber. It may contain as much as 65% grease and dirt, but this is the

form in which wool is normally shipped because it then has the pro-
tection of the wool fat until it is manufactured. Wool is very absorbent
to moisture and will take up about 33% of its weight of water, and in
some areas moisture and dirty grease are added to fleece wool to
increase weight. Carpet wools are usually long, nonresilient fibers
from sheep bred in severe climates, such as the Mongolian wool.
The only breed of sheep developed for wool alone is the merino. In
Australia the corriedale and the polworth sheep are dual-purpose
animals for wool and meat.
1048 WOOL
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
The finest of sheep wools come from the merino sheep, but these
vary according to the age of breeding of the animal. The Lincoln
sheep produces the longest fiber. It is lustrous but very coarse.
Luster of wool depends upon the size and smoothness of the scales,
but the chemical composition is important. The molecular chains are
linked with sulfur, and when sulfur is fed to the sheep, in some defi-
cient areas the quality of the wool is improved. Crimpiness in wool is
due to the open formation of the scales. A fine merino will have 24
crimps per inch (2.5 cm), whereas a coarse crossbreed will have only 6
per inch (2.5 cm). Strength of wool fibers often depends upon the
health of the animal and the feeding.
One-quarter of the world production of wool is in Australia.
Argentina ranks second in production, with the United States third.
But the United States is a lamb-eating nation, and a large proportion
of the animals are slaughtered when 4 to 8 months old, and most of
the others are kept only one season for one crop of wool. New Zealand,

Uruguay, Russia, and England are also important producers. England
is the center of wool-sheep breeding, with more varieties than any
other country. In general, warm climates produce fine wools, and hot
climates produce thin, wiry wools, but the fundamental differences
come from the type of animal and the feeding. The reused wool from
old cloth was originally called shoddy, but the name has an opprobri-
ous signification in the United States, and is not used by manufactur-
ers to designate the fabrics made from reclaimed wool. Shoddy is used
in mixtures with new wool for clothing and other fabrics. Extract
wool is shoddy that is recovered by dissolving out the cotton fibers of
the old cloth with sulfuric acid. Short fibers of shoddy, less than 0.5 in
(1.27 cm), are known as mungo fibers. They are used in woolen
blends to obtain a napped effect. Reprocessed wool is fiber obtained
from waste fabric which has not been used. Noils are short fibers pro-
duced in the combining of wool tops for making worsteds. They are
used for woolen goods and felt. Zeset, of Du Pont, a shrinkproofing
agent for wools, is a variant of Surlyn T, a terpolymer of 70% ethyl-
ene, 6 methacryloyl chloride, and 24 vinyl acetate. It prevents shrink-
age and pilling under ordinary laundry methods, does not affect color,
and increases the tensile strength of the fiber. But all resinous addi-
tives tend to harden the fiber and lessen the drape and feel.
Conversely, each dry cleaning of wool fabric decreases the natural oil
content and hardens the fiber.
WOOL GREASE. A brownish, waxy fat of a faint, disagreeable odor,
obtained as a by-product in the scouring of wool. The purified grease
was formerly known as degras and was used for leather dressing, in
lubricating and slushing oils, and in soaps and ointments; but it is now
WOOL GREASE 1049
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
largely employed for the production of lanolin and its derivatives,
chiefly for cosmetics. Wool grease contains lanoceric acid;
lanopalmic acid, C
15
H
30
O
3
; and lanosterol, a high alcohol related to
cholesterol. All of these can be broken down into derivatives.
Lanolin is a purified and hydrated grease, also known as lanain,
and in pharmacy as lanum and adeps lanae. It has a melting point
of about 104°F (40°C) and is soluble in alcohol. Lanolin is basically a
wax consisting of esters of sterol alcohols combined with straight-
chain fatty acids, and with only a small proportion of free alcohols. It
contains about 95% of fatty acid esters, but its direct use as an emol-
lient depends on the 5% of free alcohols and acids. However, more
than 30 derivatives are obtained from lanolin, and these are used in
blends to give specific properties to cosmetics. They are often mar-
keted under trade names, and some of the ingredients may be synthe-
sized from raw materials other than wool grease, or chemically
altered from wool-grease derivatives.
A variety of products used in cosmetics and pharmaceuticals are
made by fractionation or chemical alteration of lanolin. They are also
useful in compounding plastics and industrial coating, but are gener-
ally too scarce and expensive for these purposes. Ethoxylated lano-
lin and ethoxylated lanolin alcohols are used in water-soluble
emulsions and conditioners. Solulan is a general trade name for

these materials. Lanolin oil and lanolin wax are made by solvent
fractionation of lanolin. Viscolan and Waxolan are these products.
Isopropyl lanolates, with trade name Amerlate, are soft,
hydrophylic solids which liquefy easily and are used in cosmetics as
emollients, emulsifiers, and pigment dispersants. Amerlate LFA is
derived from lanolin hydroxy acids containing iso-acids. The high
hydroxyl content produces the emollient and emulsifying qualities.
Barium lanolate, made by saponification, is used as an anticorro-
sion agent. It is antiphobic and is also used as an anticaking agent. In
a 25% barium concentration it is used for hard lubricating grease.
Ethoxylan is an ethylene oxide derivative of lanolin, soluble in
water and in alcohol, and used in shampoos. Ceralan is a waxy solid
melting at 131°F (55°C) to an amber-colored, viscous liquid. It is a
mixture of monohydroxyl alcohols, obtained by splitting lanolin, and
contains 30% sterol, and free cholesterol. It forms water-in-oil emul-
sions and is used in cosmetics as a dispersing and stiffening agent
and as an emollient. Acetylated lanolin is made by reacting lanolin
with polyoxyethylenes. They are clear, nongreasy liquids soluble in
water, oils, and alcohol. The acetylated lanolin is hydrophobic and
oil-soluble, and is used as an odorless, nontacky emollient in cosmet-
ics. Acylan, from Croda Chemicals, is a soft solid with a bland odor
that is employed in baby products, hair grooms, creams, and pharma-
1050 WOOL GREASE
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
ceuticals. Oil-based solutions of Acylan are clear, forming soft, waxy,
hydrophobic films. Satulan of the same firm is a hydrogenated
lanolin useful in products for skin protection.

Veriderm, of Upjohn Co., is a substitute for lanolin as an emol-
lient. It contains about the same percentage of triglycerol esters of
fatty acids, free cholesterol, and saturated and unsaturated hydrocar-
bons as occurs in the natural human skin oils. Cholesterol is one of
the most important of the complex sterols, or zoosterols, from ani-
mal sources. It is produced from lanolin, but also from other sources,
and used in drugs and cosmetics. Amerchol L-101 is a liquid non-
ionic cholesterol containing other sterols. Wool grease from the scour-
ing of wool was originally called Yorkshire grease. Moellon degras
is not wool grease, but is a by-product of chamois leather making. The
sheepskins are impregnated with fish oil, and when the tanning is
complete, they are soaked in warm water and the excess oil is pressed
out to form the moellon degras.
WROUGHT IRON. Commercially pure iron made by melting white cast
iron and passing an oxidizing flame over it, leaving the iron in a
porous condition which is then rolled to unite it into one mass. As
thus made, it has a fibrous structure, with fibers of slag through the
iron in the direction of rolling. It is also made by the Aston process of
shooting Bessemer iron into a ladle of molten slag. Modern wrought
iron has a fine dispersion of silicate inclusions which interrupt the
granular pattern and give it a fibrous nature.
The value of wrought iron is in its corrosion resistance and ductil-
ity. It is used chiefly for rivets, staybolts, water pipes, tank plates,
and forged work. Minimum specifications for ASTM wrought iron
call for a tensile strength of 40,000 lb/in
2
(276 MPa), yield strength of
24,000 lb/in
2
(165 MPa), and elongation of 12%, with carbon not over

0.08%, but the physical properties are usually higher. Wrought iron
4D has only 0.02% carbon with 0.12 phosphorus, and the fine fibers
are of a controlled composition of silicon, manganese, and phospho-
rus. This iron has a tensile strength of 48,000 lb/in
2
(331 MPa), elon-
gation 14%, and Brinell hardness 105. Mn wrought iron has 1%
manganese for higher impact strength.
Ordinary wrought iron with slag may contain frequent slag cracks,
and the quality grades are now made by controlled additions of sili-
cate, and with controlled working to obtain uniformity. But for tanks
and plate work, ingot iron is now usually substituted. Merchant bar
iron is an old name for wrought-iron bars and rods made by faggot-
ing and forging. Iron-fibered steel is soft steel with fine iron wire
worked into it. Staybolt iron may be wrought iron, but was origi-
nally puddled charcoal iron. Lewis iron, for staybolts, is highly
WROUGHT IRON 1051
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
refined, puddled iron with a tensile strength of 52,000 lb/in
2
(359
MPa) and elongation of 30%.
The Norway iron formerly much used for bolts and rivets was a
Swedish charcoal iron brought to America in Norwegian ships.
This iron, with as low as 0.02% carbon, and extremely low silicon, sul-
fur, and phosphorus, was valued for its great ductility and toughness
and for its permeability qualities for transformer cores. Commercial

wrought iron is now usually ingot iron or fibered low-carbon steel.
YARNS. Assemblages or bundles of fibers twisted or laid together to
form continuous strands. They are produced with either filaments or
staple fibers. Single strands of yarns can be twisted together to form ply
or plied yarns, and ply yarns in turn can be twisted together to form
cabled yarn or cord. Important yarn characteristics related to behavior
are fineness (diameter or linear density) and number of twists per unit
length. The measuring of fineness is commonly referred to as yarn
number. Yarn numbering systems are somewhat complex, and they are
different for different types of fibers. Essentially, they provide a mea-
sure of fineness in terms of weight per unit or length per unit weight.
Cotton yarns are designated by numbers, or counts. The stan-
dard count of cotton is 840 yd/lb (1,690 m/kg). Number 10 yarn is
therefore 8,400 yd/lb (16,900 m/kg). A No. 80 sewing cotton is 80ϫ840,
or 67,200 yd/lb (135,500 m/kg).
Linen yarns are designated by the lea of 300 yd (274 m). A
10-count linen yarn is 10 ϫ 300, or 3,000 yd/lb (6,048 m/kg).
The size or count of spun rayon yarns is on the same basis as cot-
ton yarn. The size or count of rayon filament yarn is on the basis of
the denier, the rayon denier being 492 yd (450 m), weighing 0.00011
lb (5 cg). If 492 yd of yarn weighs 0.00011 lb, it has a count of 1
denier. If it weighs 0.0011 lb (10 cg), it is No. 2 denier. Rayon yarns
run from 15 denier, the finest, to 1,200 denier, the coarsest.
Reeled silk yarn counts are designated in deniers. The interna-
tional denier for reeled silk is 547 yd (500 m) of yarn weighing
0.00011 lb. If 547 yd weighs 0.0022 lb (1 g), the denier is No. 20. Spun
silk count under the English system is the same as the cotton count.
Under the French system the count is designated by the number of
skeins weighing 2.205 lb (1 kg). The skein of silk is 1,094 yd (1,000 m).
A ply yarn is one that has two or more yarns twisted together. A

two-ply yarn has two separate yarns twisted together. The separate
yarns may be of different materials, such as cotton and rayon. A six-
ply yarn has six separate yarns. A ply yarn may have the different
plies of different twists to give different effects. Ply yarns are stronger
than single yarns of the same diameter. Tightly twisted yarns make
strong, hard fabrics. Linen yarns are not twisted as tightly as cotton
1052 YARNS
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
because the flux fiber is longer, stronger, and not as fuzzy as the cot-
ton. Filament rayon yarn is made from long, continuous rayon
fibers, and it requires only slight twist. Fabrics made from filament
yarn are called twalle. Monofilament is fiber heavy enough to be
used alone as yarn, usually more than 15 denier. Tow consists of mul-
tifilament reject strands suitable for cutting into staple lengths for
spinning. Spun rayon yarn is yarn made from staple fiber, which is
rayon filament cut into standard short lengths.
YUCCA FIBER. The fiber obtained from the leaves of a number of
desert plants of the genus Yucca of the lily family native to the south-
western United States and northern Mexico. The fiber is similar to
fibers from agave plants and is often confused with them and with
istle. The heavier fibers are used for brushes, and the lighter fibers
are employed for cordage and burlap fabrics. In Mexico the word
palma designates yucca fibers and grades of istle as well as palm-leaf
fibers. Palma samandoca is fiber from the plant Samuela carner-
osana, the date yucca. It is also called palma istle. Palmilla fiber
is from Y. elata. Palma pita is a fiber from Y. treculeana. Pita fiber
used for coffee bags in Colombia and Central America is from a differ-

ent plant. Other yucca fibers come from the plants Y. glauca, Y. bac-
cata, and Y. gloriosa. Some varieties of Y. baccata also yield edible
fruits. The roots of species of yucca yield saponin which is also
obtained as a by-product in extracting the yucca fiber.
ZINC. A bluish-white, crystalline metal, symbol Zn, with a specific
gravity of 7.13, melting at 788°F (420°C) and boiling at 1662°F
(906°C). The commercially pure metal has a tensile strength, cast, of
about 9,000 lb/in
2
(62 MPa) with elongation of 1%, and the rolled
metal has a strength of 24,000 lb/in
2
(165 MPa) with elongation of
35%. But small amounts of alloying elements harden and strengthen
the metal, and it is seldom used alone. Zinc is used for galvanizing
and plating; for making brass, bronze, and nickel silver; for electric
batteries; for die castings; and in alloyed sheets for flashings, gutters,
and stamped and formed parts. The metal is harder than tin, and an
electrodeposited plate has a Vickers hardness of about 45. Zinc is also
used for many chemicals.
The old name spelter, often applied to slab zinc, came from the
name spailter used by Dutch traders for the zinc brought from China.
The first zinc produced in the United States in 1838 came from New
Jersey ore. Sterling spelter was 99.5% pure. Special high-grade zinc
is distilled, with a purity of 99.99%, containing no more than 0.006%
lead and 0.004 cadmium. High-grade zinc, used in alloys for die cast-
ing, is 99.9% pure, with 0.07 maximum lead. Brass special zinc is
ZINC 1053
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
99.10% pure, with 0.06 maximum lead and 0.5 maximum cadmium.
Prime western zinc, used for galvanizing, contains 1.60% maxi-
mum lead and 0.08 maximum iron. Zinc crystals produced for elec-
tronic uses are 99.999% pure metal.
On exposure to the air, zinc becomes coated with a film of carbonate
and is then very corrosion-resistant. Zinc foil comes in thicknesses
from 0.001 to 0.006 in (0.003 to 0.015 cm). It is produced by electrode-
position on an aluminum drum cathode and stripping off on a collect-
ing reel. But most of the zinc sheet contains a small amount of
alloying elements to increase the physical properties. Slight amounts
of copper and titanium reduce grain size in sheet zinc. In cast zinc the
hexagonal columnar grain extends from the mold face to the surface
or to other grains growing from another mold face, and even very
slight additions of iron can control this grain growth. Aluminum is
also much used in alloying zinc. In zinc used for galvanizing, a small
addition of aluminum prevents formation of brittle alloy layer,
increases ductility of the coating, and gives a smoother surface. Small
additions of tin give bright, spangled coatings.
Zinc has 12 isotopes, but the natural material consists of 5 stable
isotopes, of which nearly half is zinc 64. The stable isotope zinc 67,
occurring to the extent of about 4% in natural zinc, is sensitive to tiny
variations in transmitted energy, giving off electromagnetic radia-
tions which permit high accuracy in measuring instruments. It mea-
sures gamma-ray vibrations with great sensitivity and is used in the
nuclear clock.
Zinc powder, or zinc dust, is a fine, gray powder of 97% minimum
purity usually in 325-mesh particle size. It is used in pyrotechnics, in
paints, as a reducing agent and catalyst, in rubbers as a secondary dis-

persing agent and to increase flexing, and to produce Sherardized
steel. Sherardizing consists in hot-tumbling steel parts in a closed
drum with the zinc powder. It is a form of galvanizing, and controlled
zinc coatings of 0.1 to 0.4 oz/ft
2
(0.4 to 1.8 g/cm
2
) of surface give good
corrosion protection. In paints, zinc powder is easily wetted by oils. It
keeps the zinc oxide in suspension and hardens the film. Mossy zinc,
used to obtain color effects on face brick, is a spangly zinc powder made
by pouring the molten metal into water. Feathered zinc is a fine grade
of mossy zinc. Photoengraving zinc for printing plates is made from
pure zinc with only a small amount of iron to reduce grain size and
alloyed with not more than 0.2% each of cadmium, manganese, and
magnesium. Cathodic zinc, used in the form of small bars or plates
fastened to the hulls of ships or to underground pipelines to reduce elec-
trolytic corrosion, is zinc of 99.99% purity with iron less than 0.0014 to
prevent polarization. Merrillite is high-purity zinc dust. Zinc serves as
the anode in the zinc-air battery, which, for powering electric vehi-
1054 ZINC
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
cles, has demonstrated much greater storage capacity than the com-
mon lead-acid battery.
ZINC ALLOYS. Alloys of zinc are mostly used for die castings for deco-
rative parts and for functional parts where the load-bearing and
shock requirements are relatively low. Since the zinc alloys can be

cast easily in high-speed machines, producing parts that weigh less
than brass and have high accuracy and smooth surfaces that require
minimum machining and finishing, they are widely used for such
parts as handles, and for gears, levers, pawls, and other small parts.
Zinc alloys for sheet contain only small amounts of alloying elements,
with 92 to 98% zinc, and the sheet is generally referred to simply as
zinc or by a trade name. The modified zinc sheet is used for
stamped, drawn, or spun parts for costume jewelry and electronics,
and it contains up to 1.5% copper and 0.5 titanium. The titanium
raises the recrystallization temperature, permitting heat treatment
without coarse-grain formation.
Hartzink had 5% iron and 2 to 3 lead, but iron forms various
chemical compounds with zinc and the alloy is hard and brittle.
Copper reduces the brittleness. Germania bearing bronze con-
tained 1% iron, 10 tin, about 5 each of copper and lead, and the bal-
ance zinc. Fenton’s alloy had 14% tin, 6 copper, and 80 zinc; and
Ehrhard’s bearing metal contained 2.5% aluminum, 10 copper, 1
lead, and a small amount of tin to form copper-tin crystals. Binding
metal, for wire-rope slings, has about 2.8% tin, 3.7 antimony, and the
balance zinc. Pattern metal, for casting gates of small patterns, was
almost any brass with more zinc and some lead added, but is now
standard die-casting metal.
Zinc alloys are commonly used for die castings, and the zinc used is
high-purity zinc known as special high-grade zinc. ASTM
AG40A (SAE 903) is the most widely used; others include AC41A
(SAE 925), Alloy 7, and ILZRO 16. All typically contain about 4%
aluminum, small amounts of copper and very small amounts of mag-
nesium. AG40A has a density of 0.24 lb/ft
3
(6,643 kg/m

3
), an electrical
conductivity 27% that of copper, a thermal conductivity of 65 Btu/(ft и
h и °F) [113 W/(m и K)], an ultimate tensile strength of 41,000 lb/in
2
(283 MPa), and a Brinell hardness of 82. AC41A is stronger [48,000
lb/in
2
(331 MPa)] and harder (Brinell 91), a trifle less electrically and
heat-conductive, and similar in density. The alloys have much greater
unnotched Charpy impact strength than either die-cast aluminum or
magnesium alloys, but are not especially heat-resistant, losing about
one-third of their strength at temperatures above about 200°F (93°C).
Both alloys have found wide use for auto and appliance parts, espe-
cially chromium-plated parts, as well as for office equipment parts,
ZINC ALLOYS 1055
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
hardware, locks, toys, and novelties. Alloy 7 is noted primarily for its
better castability and the smoother surface finish it provides. It is as
strong as AG40A, though slightly less hard, and more ductile. ILZRO
16 is not nearly as strong [33,000 lb/in
2
(228 MPa)], but more
creep-resistant at room and elevated temperatures.
The most recent casting alloys are three high-aluminum zinc
casting alloys for sand and permanent-mold casting: ZA-8, ZA-12,
and ZA-27, the numerals in the designations indicating approxi-

mate aluminum content. They also contain more copper than
AG40A and AC41A, from 0.5 to 1.2% in ZA-12 to 2 to 2.5 in ZA-27,
and a bit less magnesium. As sand-cast, ultimate tensile strengths
range from 36,000 to 40,000 lb/in
2
(248 to 276 MPa) for ZA-8 and
58,000 to 64,000 lb/in
2
(400 to 441 MPa) for ZA-27. Unlike the com-
mon die-casting alloys, the ZA alloys also exhibit clearly defined
tensile yield strengths: from 28,000 lb/in
2
(193 MPa) minimum for
sand-cast ZA-8 to 53,000 lb/in
2
(365 MPa) for sand-cast ZA-27.
Tensile modulus is roughly 12ϫ10
6
lb/in
2
(83,000 MPa). Also,
because of their greater aluminum content, they are lighter in
weight than the die casting alloys. Zinc-copper-aluminum alloys
developed at General Motors and designated ACuZinc alloys, are
noted for high tensile strength and superior creep resistance.
ACuZinc 5, with 5% copper and 3 aluminum, has a tensile strength
of 59,000 lb/in
2
(407 MPa). ACuZinc 10, with 10% copper and 3.5
aluminum, has a creep strength of 8,000 lb/in

2
(55 MPa) at 120°F
(49°C) for 0.2% creep in 10,000 h.
Manganese-zinc alloys, with up to 25% manganese, for high-
strength extrusions and forgings, are really 60–40 brass with part of
the copper replaced by an equal amount of manganese, and are classi-
fied with manganese bronze. They have a bright white color and are
corrosion-resistant. Zam metal, for zinc-plating anodes, is zinc with
small percentages of aluminum and mercury to stabilize against acid
attack. A zinc-aluminum-oxide coating imparts corrosion resis-
tance to steel underhood and underbody auto parts. Developed by
Metal Coatings International, it consists of zinc and aluminum flakes
in a waterborne, neutral pH solution that complies with regulations
governing emission of volatile organic compounds. It is applied by
dipping or spraying. Baking during curing forms an insoluble matrix
of silicon, aluminum, and zinc oxides between the flakes for corrosion
protection.
CorroBan, of Pure Coatings Inc., is an electrolytically deposited
coating of 82 to 89% zinc, balance nickel, which resists corrosion as
well as cadmium plating. Zinc solders are used for joining alu-
minum. The tin-zinc solders have 70 to 80% tin, about 1.5 alu-
minum, and the balance zinc. The working range is 500 to 590°F
1056 ZINC ALLOYS
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
(260 to 310°C). Zinc-cadmium solder has about 60% zinc and 40
cadmium. The pasty range is between 510 and 599°F (266 and
315°C).

A group of wrought alloys, called superplastic zinc alloys,
have elongations of up to 2,500% in the annealed condition. These
alloys contain about 22% aluminum. One grade can be annealed
and air-cooled to a strength of 71,000 lb/in
2
(490 MPa). Parts made
of these alloys have been produced by vacuum forming and by a
compression molding technique similar to forging but requiring
lower pressures.
ZINC CHEMICALS. With the exception of the oxide, the quantities of
zinc compounds consumed are not large compared with many other
metals, but zinc chemicals have a very wide range of use, being essen-
tial in almost all industries and for the maintenance of animal and
vegetable life. Zinc is a complex element and can provide some
unusual conditions in alloys and chemicals.
Zinc oxide, ZnO, is a white, water-insoluble, refractory powder
melting at about 3587°F (1975°C), having a specific gravity of 5.66. It
is much used as a pigment and accelerator in paints and rubbers. Its
high refractive index, about 2.01, absorption of ultraviolet light, and
fine particle size give high hiding power in paints, and make it also
useful in such products as cosmetic creams to protect against sun-
burn. Commercial zinc oxide is always white, and in the paint indus-
try is also called zinc white and Chinese white. But with a small
excess of zinc atoms in the crystals, obtained by heat treatment, the
color is brown to red.
In paints, zinc oxide is not as whitening as lithopone, but it resists
the action of ultraviolet rays and is not affected by sulfur atmo-
spheres, and is thus valued in outside paints. Leaded zinc oxide,
consisting of zinc oxide and basic lead sulfate, is used in paints, but
for use in rubber the oxide must be free of lead. The lead-free variety

is also called French process zinc oxide. Canfelzo is one such
product, from Pigment & Chemical Corp. In insulating compounds
zinc oxide improves electrical resistance. In paper coatings it gives
opacity and improves the finish. Zinc-white paste for paint mixing
usually has 90% oxide and 10 oil. Zinc oxide stabilizers, composed
of zinc oxides and other chemicals, can be added to plastic molding
compounds to reduce the deteriorating effects of sunlight and other
types of degrading atmospheres.
Zinc oxide crystals are used for transducers and other piezoelec-
tric devices. The crystals are hexagonal and are effective at elevated
temperatures, as the crystal has no phase change up to its disassocia-
tion point. The resistivity range is 0.2 to 3.9 ⍀иin (0.5 to 10 ⍀иcm).
ZINC CHEMICALS 1057
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
Zinc oxide has luminescent and light-sensitive properties which are
utilized in phosphors and ferrites. But the oxygen-dominated zinc
phosphors used for radar and television are modifications of zinc sul-
fide phosphors. The zinc sulfide phosphors which produce lumines-
cence by exposure to light are made with zinc sulfide mixed with
about 2% sodium chloride and 0.005 copper, manganese, or other acti-
vator, and fired in a nonoxidizing atmosphere. The cubic crystal struc-
ture of zinc sulfide changes to a stable hexagonal structure at 1868°F
(1020°C), but both forms have the phosphor properties. Thin films
and crystals of zinc selenide with purities of 99.999% are used for
photo- or electroluminescent devices. Zinc selenide is also used for
optical lenses in CO
2

laser systems. Zinc sulfide is a white powder of
composition ZnS и H
2
O, and is also used as a paint pigment, for
whitening rubber, and for paper coating. Cryptone is zinc sulfide for
pigment use in various grades, some grades containing barium sul-
fate, calcium sulfide, or titanium dioxide. Multilayer coatings of zinc
sulfide and yttria protect zinc sulfide infrared sensor windows of mis-
siles and military aircraft from harsh flight environments.
Zinc is an amphoteric element, having both acid and basic prop-
erties, and it combines with fatty acids to form metallic soaps, or with
the alkali metals or with ammonia to form zincates. Sodium zin-
cate is used for waterproofing asbestos-cement shingles. Zinc
stearate, ZN(C
18
H
35
O
2
)
2
, is a zinc soap in the form of a fine, white
powder used in paints and in rubber. A USP grade of 325 mesh is
used in cosmetics. Aquazinc and Liquizinc, of Rubba, Inc., are zinc
stearate dispersions in water used as an antitack agent in milling
rubber. Zinc acetate, Zn(C
2
H
3
O

2
)
2
, is a white solid partly soluble in
water, used as a mordant, as a wood preservative, in porcelain glazes,
and as a mild antiseptic in pharmaceuticals.
Zinc sulfate, ZnSO
4
и 7H
2
O, is the chief material for supplying zinc
in fertilizers, agricultural sprays, and animal feeds. For these pur-
poses it is used in the form of white vitriol containing 22% zinc, or as
the monohydrate, ZnSO
4
и H
2
O, containing 37% zinc. Zink Gro is a
water-soluble grade for dry-blended fertilizers for correction of zinc
deficiencies. It is from Eagle-Picher Industries, Inc. Zinc chloride, a
white, crystalline, water-soluble powder, ZNCl
2
, was formerly an
important preservative for wood, and railway crossties treated with
the material were called Burnettized wood. But it is highly soluble
and leaches out of the wood, and is now chromated and copperized
with sodium bichromate and cupric chloride. Copperized CZC, of
Koppers Co., Inc., for treating wood against rot and termites, is cop-
perized chromated zinc chloride. zinc chloride is also used for vulcan-
izing fiber, as a mordant, in mercerizing cotton, in dry batteries, in

disinfecting, and in making many chemicals. Spirits of salts and
butter of zinc are old names for the material.
1058 ZINC CHEMICALS
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
Zinc chromate, used chiefly as a pigment and called zinc yellow
and buttercup yellow, is stable to light and in sulfur atmospheres,
but has a lower tinting strength than chrome yellow, although it is
less subject to staining and discoloration. It is a crystalline powder of
specific gravity 3.40. It is only slightly soluble in water, but will
absorb 24 lb (11 kg) of linseed oil per 100 lb (45 kg). Zinc chromates
are made by reacting zinc oxide with chromate solutions, and they
may vary; but the usual composition is 4ZnO и 4CrO
3
и K
2
O и 3H
2
O.
Zinc bichromate, ZnCr
2
O
7
, is an orange-yellow pigment. The zinc
peroxide used in dental pastes and cosmetics as a mild antiseptic is
a white powder, ZnO
2
, containing 8.5% active oxygen. Organic salts of

zinc that have achieved commercial prominence are zinc naphthen-
ate and zinc pyrithione. The former is available in 6 and 8% grades
for prevention of wood rot and decay, in solvent- and water-dispersible
formulations. Nap-All and M-Gards are from Mooney Chemicals,
Inc., and Zinclear is from Standard Tar Products Co. Olin Corp.’s
Zinc Omadine, a zinc pyrithione, is employed as an antidandruff
agent, for preserving cosmetics, in metalworking fluids, and as an
antimicrobial on textiles.
Fluidized zinc titanate (FZT) can serve as a sorbent to remove
99% of the sulfur dioxide in power plants using sulfur-containing coal.
In a process developed at Research Triangle Institute with the U.S.
Department of Energy, the sorbent can be continuously recirculated
and the sulfur absorbed recovered from the regenerator off-gas. Use
of the sorbent is an alternative to cooling the coal gas to remove sul-
fur, then having to reheat it to produce electricity.
ZINC ORES. The metal zinc is obtained from a large number of ores,
but the average zinc content of the ores in the United States is only
about 3%, so that they are concentrated to contain 35 to 65% before
treatment. The sulfide ores are marketed on the basis of 60% zinc
content, and the oxide ores on the basis of 40% zinc content.
Sphalerite, or zinc blende, is the most important ore and is found
in quantities in Missouri and surrounding states and in Europe.
Sphalerite is a zinc sulfide, ZnS, containing theoretically 67% zinc. It
has a massive crystalline or granular structure and a Mohs hardness
of about 4. When pure, its color is white; it colors yellow, brown,
green, to black with impurities. The ores from New York State are
round and concentrated by flotation to an average of 58% zinc and 32
sulfur, which is then concentrated by roasting to 68 zinc and 1 sulfur.
It is then sintered to remove lead and cadmium and finally smelted
with coke, and the zinc vapor condensed. The Silesian zinc blende,

known as wurtzite, contains 15% zinc, 2 lead, and some cadmium.
Calamine is found in New Jersey, Pennsylvania, Missouri, and
Europe. It is the ore that was formerly mixed directly with copper for
ZINC ORES 1059
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
making brass. The ore usually contains only about 3% zinc, and is
concentrated to 35 to 45%, and then roasted and distilled. Calamine
is zinc silicate, 2ZnO и SiO
2
и H
2
O. It is a mineral occurring in crys-
tal groups of a vitreous luster, and it may be white, greenish, yellow,
or brown. The specific gravity is 3.4, and Mohs hardness 4.5 to 5. It
occurs in Arkansas with smithsonite, a zinc carbonate ore, ZnCO
3
.
Franklinite is an ore of both the metals zinc and manganese. Its
approximate composition is (FeZnMo)O и (FeMn)
2
O
3
, but it shows
wide variation in the proportions of the different elements. It is found
in the zinc deposits of New Jersey. The zinc is converted into zinc
white, and the residue is smelted to form spiegeleisen. The mineral
franklinite occurs in massive granular structure with a metallic lus-

ter and an iron-black color.
The ore zincite is used chiefly for the production of the zinc oxide
known as zinc white employed as a pigment. Zincite has the composi-
tion ZnO, containing theoretically 80.3% zinc. The mineral has usually
a massive granular structure with a deep-red to orange streaked color.
It may be translucent or almost opaque. Deep-red specimens from the
workings at Franklin, New Jersey, are cut into gemstones for costume
jewelry. Willemite is an anhydrous silicate, Zn
2
SiO
4
, containing theo-
retically 58.5% zinc. When manganese replaces part of the zinc, the ore
is called troostite. It is in hexagonal prisms of white, yellow, green, or
blue; manganese makes it apple-green, brown, or red. The specific grav-
ity is about 4 and Mohs hardness 5.5. The crushed ore is used in making
fluorescent glass. The ore is widely dispersed in the United States.
ZIRCONIA. A white, crystalline powder which is zirconium oxide,
ZrO
2
, with a specific gravity of 5.7, Mohs hardness 6.5, and refractive
index 2.2. When pure, its melting point is about 5000°F (2760°C), and
it is one of the most refractory of the ceramics. It is produced by react-
ing zircon sand and dolomite at 2500°F (1371°C) and leaching out the
silicates. The material is used as fused or sintered ceramics and for
crucibles and furnace bricks. From 4.5 to 6% of CaO or other oxide is
added to convert the unstable monoclinic crystal to the stable cubic
form with a lowered melting point.
Fused zirconia, used as a refractory ceramic, has a melting point of
4620°F (2549°C) and a usable temperature to 4450°F (2454°C). The

Zinnorite fused zirconia of Norton Co. is a powder that contains less
than 0.8% silica and has a melting point of 4900°F (2704°C). A sintered
zirconia can have a specific gravity of 5.4, a tensile strength of 12,000
lb/in
2
(83 MPa), compressive strength of 200,000 lb/in
2
(1,379 MPa), and
Knoop hardness of 1,100. Zircoa B is stabilized cubic zirconia used for
making ceramics. Zircoa A is the pure monoclinic zirconia used as a
pigment, as a catalyst, in glass, and as an opacifier in ceramic coatings.
1060 ZIRCONIA
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
Zirconia brick for lining electric furnaces has no more than 94%
zirconia, with up to 5 calcium oxide as a stabilizer, and some silica.
It melts at about 4300°F (2371°C), but softens at about 3600°F
(1982°C). The IBC 4200 brick of Ipsen Industries, Inc., is zirconia
with calcium and hafnium oxides for stabilizing. It withstands tem-
peratures to 4200°F (2316°C) in oxidizing atmospheres and to
3000°F (1849°C) in reducing atmospheres. Zirconia foam is mar-
keted in bricks and shapes for thermal insulation. With a porosity
of 75% it has a flexural strength above 500 lb/in
2
(3 MPa) and a
compressive strength above 100 lb/in
2
(0.7 MPa). For use in cru-

cibles, zirconia is insoluble in most metals except the alkali metals
and titanium. It is resistant to most oxides, but with silica it forms
ZrSiO
4
, and with titania it forms ZrTiO
4
. Since structural disinte-
gration of zirconia refractories comes from crystal alteration, the
phase changes are important considerations. The monoclinic mater-
ial, with a specific gravity of 5.7, is stable to 1850°F (1010°C) and
then inverts to the tetragonal crystal with a specific gravity of 6.1
and volume change of 7%. It reverts when the temperature again
drops below 1850°F (1010°C). The cubic material, with a specific
gravity of 5.55, is stable at all temperatures to the melting point,
which is not above 4800°F (2649°C) because of the contained stabi-
lizers. A lime-stabilized zirconia refractory with a tensile strength
of 20,000 lb/in
2
(138 MPa) has a tensile strength of 10,000 lb/in
2
(69
MPa) at 2370°F (1299°C). Stabilized zirconia has a very low coef-
ficient of expansion, and white-hot parts can be plunged into cold
water without breaking. The thermal conductivity is only about
one-third that of magnesia. It is also resistant to acids and alkalies
and is a good electrical insulator. Diamond Z refers to a line of
“unbreakable” buttons made of zirconia, fired at 3200°F (1760°C),
polished and coated to look like ivory. Developed by Adolph Coors
Co., they are sold by ACX Technologies for high-priced shirts.
Toughening mechanisms, by which a crack in a ceramic can be

arrested, complement processing techniques that seek to eliminate
crack-initiating imperfections. Transformation toughening relies on
a change in crystal structure (from tetragonal to monoclinic) that zirco-
nia or zirconium dioxide (ZrO
2
) grains undergo when they are subjected
to stresses at a crack tip. Because the monoclinic grains have a slightly
larger volume, they can “squeeze” a crack shut as they expand in the
course of transformation. Due to ZrO
2
’s transformation-toughening abil-
ities, which impart higher fracture toughness, research interest in
engine applications has been high. In order for ZrO
2
to be used in
high-temperature, structural applications, it must be stabilized or par-
tially stabilized to prevent a monoclinic-tetragonal phase change.
Stabilization involves the addition of calcia, magnesia, or yttria followed
ZIRCONIA 1061
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
by some form of heat treatment. PSZ ceramic, the toughest known
ceramic, is being investigated for diesel-engine applications.
A new zirconia ceramic being developed is tetragonal zirconia
polycrystal (TZP) doped with Y
2
O
3

. Designated Y-TZP, it has the
most impressive room-temperature mechanical properties of any zir-
conia ceramic. The commercial applications of TZP zirconia include
scissors having TZP blades suitable for industrial use for cutting
tough fiber fabrics, e.g., Kevlar, cables, and ceramic scalpels for surgi-
cal applications. One unique application is fish knives. The knife
blades are Y-TZP and can be used when the delicate taste of raw fish
would be tainted by slicing with metal-blade knives. Tungsten-car-
bide-reinforced Y-TZP, developed by Toray Industries and Nippon
Tungsten Co. of Japan, has five times the thermal conductivity of
Y-TZP and high hardness, strength, toughness, and heat resistance.
Magnesia-stabilized PSZ, Mg-PSZ, is fired at a higher tempera-
ture than Y-TZP and, thus, develops a larger grain size: 1,970 to 3,940
␮in (50 to 100 ␮m) versus 11.8 to 31.5 ␮in (0.3 to 0.8 ␮m).
Consequently, Mg-PSZ is slightly porous while Y-TZP is virtually free
of porosity. However, this porosity does not affect its sealing behavior
in valve applications. Mg-PSZ is not as strong as Y-TZP, but it is
slightly tougher and, thus, more resistant to erosion by particle
impingement. Also, Mg-PSZ has not exhibited susceptibility to low-
temperature degradation in warm, moist environments even with just
trace amounts of water vapor, which has limited Y-TZP to moisture-
free valve applications.
Another zirconia ceramic–developed material is zirconia-tough-
ened alumina (ZTA). ZTA zirconia is a composite polycrystalline
ceramic containing ZrO
2
as a dispersed phase (typically about 15 vol-
ume %). Close control of initial starting-powder sizes and sintering
schedules is thus necessary in order to attain the desired ZrO
2

parti-
cle dimensions in the finished ceramic. Hence the mechanical proper-
ties of the composite ZTA ceramics limit current commercial
applications to cutting tools and ceramic scissors.
PSZ is also finding application in the transformation toughening of
metals used in the glass industry as orifices for glass fiber drawing.
This material is being termed zirconia grain-stabilized (ZGS)
platinum.
Zirconia is produced from the zirconium ores known as zircon and
baddeleyite. The latter is a natural zirconium oxide, but is obtain-
able commercially only from Minas Gerais, Brazil. It is also called
zirkite and Brazilite. Zircon is zirconium silicate, ZrO
2
и SiO
2
,
and comes chiefly from beach sands. The commercial sand is found in
Florida, Brazil, India, Sri Lanka, Australia, and western Africa. The
sands are also called zirkelite and zirconite, or merely zircon
1062 ZIRCONIA
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
sand. The white zircon sand from India has a zirconia content of 62%
and contains less than 1% iron. Beach sands of New South Wales are
naturally concentrated to an average of 74% zircon, but Australian
zircon is shipped on a basis of 65% zirconia. Zircon sand may be used
directly for making firebricks, as an opacifier in ceramics, and for
mold facings. Clear zircon crystals are valued as gemstones since

the high refractive index gives great brilliance. The colorless natural
crystals are called Matura diamonds, and the yellow-red are known
as jacinth.
Zirconia fiber, used for high-temperature textiles, is produced
from zirconia with about 5% lime for stabilization. The fiber is
polycrystalline, has a melting point of 4700°F (2593°C), and with-
stands continuous temperatures above 3000°F (1649°C). These
fibers are produced by Union Carbide as small as 118 to 394 ␮in (3
to 10 ␮m) and are made into fabrics for filter and fuel cell use.
Zirconia fabrics are woven, knitted, or felted of short-length
fibers and are flexible. Ultratemp adhesive, of Aremco Products,
for high-heat applications, is zirconia powder in solution. At
1100°F (593°C) it adheres strongly to metals and withstands tem-
peratures to 4400°F (2427°C). Zircar, of Union Carbide, is zirconia
fiber compressed into sheets to a density of 20 lb/ft
3
(320 kg/m
3
). It
withstands temperatures up to 4500°F (2482°C) and has low ther-
mal conductivity. It is used for insulation and for high-temperature
filtering.
ZIRCONIUM. A silvery-white metal, symbol Zr, having a specific
gravity of 6.5 and melting at about 3362°F (1850°C). It is more
abundant than nickel, but is difficult to reduce to metallic form as
it combines easily with oxygen, nitrogen, carbon, and silicon. The
metal is obtained from zircon sand by reacting with carbon and
then converting to the tetrachloride, which is reduced to a sponge
metal for further production of shapes. The ordinary sponge zirco-
nium contains about 2.5% hafnium, which is closely related and

difficult to separate. The commercial metal usually contains
hafnium, but reactor-grade zirconium, for use in atomic work, is
hafnium-free.
Commercially pure zirconium is not a high-strength metal, having
a tensile strength of about 32,000 lb/in
2
(221 MPa), elongation 40%,
and Brinell hardness 30, or about the same physical properties as
pure iron. Because of its low neutron-capture cross section, thermal
stability, and corrosion resistance, it is the standard metal for fuel-rod
cladding and core components in nuclear reactors. It is employed
mostly in the form of alloys but may be had in 99.99% pure
single-crystal rods, sheets, foil, and wire for superconductors, surgical
ZIRCONIUM 1063
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses
implants, and vacuum-tube parts. The neutron cross section of zirco-
nium is 0.18 barn, compared with 2.4 for iron and 4.5 for nickel. The
cold-worked metal, with 50% reduction, has a tensile strength of
about 82,000 lb/in
2
(565 MPa), with elongation of 18% and Brinell
hardness of 95. The unalloyed metal is difficult to roll and is usually
worked at temperatures to 900°F (482°C). Though nontoxic, the metal
is pyrophoric because of its heat-generating reaction with oxygen,
necessitating special precautions in handling powder and fine chips
resulting from machining operations.
The metal has a close-packed hexagonal crystal structure, which

changes at 1583°F (862°C) to a body-centered cubic structure which is
stable to the melting point. At 572 to 752°F (300 to 400°C) the metal
absorbs hydrogen rapidly, and above 392°F (200°C) it picks up oxy-
gen. At about 752°F it picks up nitrogen, and at 1472°F (800°C) the
absorption is rapid, increasing the volume and embrittling the metal.
The metal is not attacked by nitric (except red fuming nitric), sulfu-
ric, or hydrochloric acids, but is dissolved by hydrofluoric acid. It also
resists phosphoric acid, most organic acids including acetic and
formic, strong alkalis, and molten salts. And it is one of the few mate-
rials that works well in alternating contact with strong acids and
basic environments.
Zirconium powder is very reactive, and for making sintered met-
als it is usually marketed as zirconium hydride, ZrH
2
, containing
about 2% hydrogen which is driven off when the powder is heated to
300°C. For making sintered parts, alloyed powders are also used.
Zirconium copper, containing 35% zirconium, zirconium nickel,
with 35 to 50% zirconium, and zirconium cobalt, with 50% zirco-
nium, are marketed as powders of 200 to 300 mesh.
Small amounts of zirconium are used in many steels. It is a pow-
erful deoxidizer, removes the nitrogen, and combines with the sul-
fur, reducing hot-shortness and giving ductility. Zirconium steels
with small amounts of residual zirconium have a fine grain and are
shock-resistant and fatigue-resistant. In amounts above 0.15% the
zirconium forms zirconium sulfide and improves the cutting quality
of the steel. Zirconium alloys generally have only small amounts
of alloying elements to add strength and resist hydrogen pickup.
Zircoloy 2, for reactor structural parts, has 1.5% tin, 0.12 iron,
0.10 chromium, 0.05 nickel, and the balance zirconium. Tensile

strength is 68,000 lb/in
2
(469 MPa), elongation 37%, and Rockwell
B hardness 89; at 600°F (316°C) it retains a strength of 30,000
lb/in
2
(207 MPa).
Small amounts of zirconium in copper give age-hardening and
increase the tensile strength. Copper alloys containing even small
amounts of zirconium are called zirconium bronze. They pour
1064 ZIRCONIUM
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Materials, Their Properties and Uses