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Zinc and Zinc Alloys

Authors:
  • International Zinc Association

Abstract and Figures

Zinc is a relatively active metal and its compounds are stable. Since it is not found free in nature, it was discovered much later than less-reactive metals such as copper, gold, silver, iron, and lead. In early times, the smelting of copper ores containing zinc resulted in brasses, which were known to the Romans before 200 BC. Later, brasses were made by heating copper with zinc oxide or carbonate and charcoal. The oldest piece of zinc extent is an idol found in a prehistoric Dacian site in Transylvania which analyzed at 87.52% zinc, 11.41% lead, and 1.07% iron. Zinc smelting is thought to have originated in China, where it was known in the seventh century AD how to make malleable zinc. In India, zinc was produced from ore mined at Zawar before 1380. By the seventeenth century, zinc was imported into Europe from Asia and in 1743 a zinc smelter for zinc oxide ore was erected in Bristol, UK. By the early nineteenth century, zinc smelting was well established in Germany and Belgium. Zinc was first produced in the United States at the arsenal in Washington, D.C., in1835, and by 1860 The New Jersey Zinc Company had well-established smelting operations at Bethlehem, Pennsylvania.
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Zinc and Zinc
425
Part B | 16
16. Zinc and Zinc Alloys
Frank E. Goodwin
This chapter presents key facts about zinc’s role
in the world together with technical reasons for
its widespread use. The frequency and occurrence
of zinc resources are compared with present and
forecast demand, showing that more than 
years of future demand will be met by known zinc
resources. An overview of the primary zinc produc-
tion process is then given, including an overview
of the mining, aqueous concentration, roasting,
cementation and electrolytic rening steps. Me-
chanical, thermal and crystallographic properties
of zinc are then provided, especially for the most
widely produced and used grade, :% (special
high grade) zinc. The principal uses of zinc and its
alloys are then described. The most important use
of zinc is the corrosion protection of steel; the
. Naturally Occurring Zinc .................... 
. Properties of Zinc.............................. 
. Uses of Zinc ...................................... 
References................................................... 
usual reactions occurring during corrosion of gal-
vanized steel are given together with corrosion
rates typical of many environments where it is
used. The next most important use is zinc die
casting alloys; the composition of these alloys and
their engineering properties are provided. Com-
positions and technical characteristics of other
applications including rolled and thermal sprayed
zinc, as well as zinc anodes, are also given.
Zinc is an abundant componentof the Earth’s crust. It is
estimated that the amount of zinc in the first mile of the
Earth’s crust, underdry land, is 224 trillion (2:241014)
metric tons. Under the oceans and in the seabed, the
amount of zinc is 15 billion (1:51010) metric tons.
Zinc ore deposits are widely spread throughout the
world, with zinc ores being extracted in more than 15
countries. Zinc is normally associated with lead, gold,
silver and copper in deposits. Available zinc resources,
which include the identified concentration of zinc in the
Earth’s crust in a form for which economic extraction is
currently or potentially feasible, total 1.9 billion tons.
Of this, 480 million tons are, or may become in the
close future, available for production. Of the world’s
zinc reserves known in 2010, 21% were in Australia,
17% in China, 9% in Peru, 7% in Kazakhstan, 6% in
Mexico, 5% in the USA, with the remaining balance in
other countries. Together with primary sources of zinc,
recycling of zinc products is increasing in volume. It is
currently estimated that about 66% of all zinc used in
Europe is recycled [16.1]. In 2011, zinc metal demand
was 13.4 million tons, meaning that given available re-
serves of 250 million tons, 19 years of demand are
available from currently developed reserves. However,
reserve bases and available economically developable
resources will supply over140 years of current demand,
if no recycling sources are available. Given the increas-
ing volume from recycled sources, it is expected that
available zinc resources can serve demand for at least
200 years, based on known deposits.
CE1 Please consider to provide additional headings for (sub)sections.
CE2 Please provide full form for ISO and ASTM
TS3 Please check the content of the last row of Table 16.3. We propose to use J mol1k1
as unit for Cp, please confirm.
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zinc!naturally occurring zinc!properties
Part B | 16.2
426 Part B Metals
16.1 Naturally Occurring Zinc
There are four types of zinc-bearing geologic materials,
each of which contributes about equally to the supply
of zinc for metallurgical smelting:
1. Carbonate-hosted deposits, including limestones
and dolomites
2. Shales of the black marine type, or siltstones or their
metamorphic equivalents – sillimanite, schists and
gneisses
3. Volcanogenic and massive sulfide bodies
4. Skarn and manto types of ore body, mostly of ter-
tiary origin.
Most mining operations are conducted underground,
although there are several large open-pit mines. Con-
centration of ores is carried out by flotation, followed
by grinding. Roasting to zinc oxide is then typically the
next step, followed by leaching in sulfuric acid to pre-
pare a solution for electrolytic zinc production. Iron is
then precipitated as jarosite, goethite or hematite. These
iron- and zinc-bearing residues can be further treated to
recover between 10% and 15% of the extra zinc pre-
viously lost. All elements to be removed from the zinc
feed lie below zinc in the electrochemical series and can
be precipitated by cementation. This is done by adding
zinc dust to the solution. In the electrolytic refining pro-
cess, a solution of zinc sulfate is electrolyzed between
anodes typically made of lead alloys and aluminum
cathodes. Zinc is deposited on the cathodes and period-
ically removed.The cathodes are stripped and then sent
to a casting house where alloying and ingot casting are
conducted. A small fraction of world zinc production
continues to be produced by thermal reduction, includ-
ing blast furnace reduction of sintered zinc-rich feeds.
Thermal reduction accounted for 90% of zinc produc-
tion in the early 1900sbut is now less than 15% of world
production [16.2]. CE1
Compositions of pure zinc are shown in Table 16.1.
These show the several grades according to ISO 752
and ASTM B6 CE2 that are the most widely used stan-
dards for pure zinc. The most widely produced and used
grade is the 99:99% (special high grade) zinc.
Tab l e 1 6.1 Composition of unalloyed zinc (ingots or slabs)
Standard Zn
min (%)
Pb
max (%)
Cd
max (%)
Sn
max (%)
Fe
max (%)
Tot a l P b CCd CSn CFe CCu
max (%)
ISO 752
Zn99.995 99.995 0.003 0.003 0.001 0.002 0.0050
Zn99.99 99.99 0.003 0.003 0.001 0.003 0.010
Zn99.95 99.95 0.03 0.02 0.001 0.02 0.050
Zn98.5 98.5 1.4 0.20 0.05 1.50
Zn98 98 1.8 – – 0.08 2.0
ANSI/ASTM B6
LME grade 99.995 0.003 0.003 0.001 0.002 0.01
Special high grade 99.990 0.003 0.003 0.001 0.003 0.01
High grade 99.90 0.03 0.02 0.02 0.063
Intermediate grade 99.5 0.45 0.01 0.05 0.71
Prime western 98.0 1.4 0.20 0.05 1.85
16.2 Properties of Zinc
The mechanical properties of pure zinc are shown in
Table 16.2. The tensile strength and elongation figures
are not usually of practical interest, but the informa-
tion shown indicates the sensitivity of these properties
to zinc purity.
The thermal properties of zinc are shown in Ta-
ble 16.3. Zinc is not combustible and does not spark
when struck by steel tools, which makes it valuable for
use in environments where explosives and combustibles
are present. The boiling point of zinc is among the
lowest of the engineering metals. The US Bureau of
Standards indicated that at 53 atmospheres the boiling
point was raised to 1510 ıC [16.3]. The vapor pressure
of zinc is dependent upon temperature by the formula
shown in (16.1)
log10 Pmm D8:888 6888
T;(.)
where Pmm Dvapor pressure measured in millimeters
of mercury and TDtemperature in K.
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Zinc and Zinc Alloys 16.2 Properties of Zinc 427
Part B | 16.2
Tab l e 1 6.2 Mechanical and physical properties of pure zinc
Tensile strength (cast) 28 MN m2(4000 psi)
(rolled – with grain)
99:95% zinc soft temper 126 MN m2(18 000 psi)
98:0% zinc hard temper 246 MN m2(35 000 psi)
Elongation (rolled – with grain)
99:95% zinc soft temper 65%
98:0% zinc hard temper 5%
Modulus of elasticity 7104MN m2(1 107psi)
Brinell hardness , 500 kg load for 30 s 30
Impact resistance
(pressed zinc, elongation D30%)
6:59Jcm
2(2635 ft lbs in2)
Surface tens ion – liquid (450 ıC) 0:755 N m1
Surface tension – liquid (419:5ıC) 0:782 N m1
Viscosity – liquid (419:5ıC) 0:00385 N m1
Velocity of sound (20 ıC) 3:67 km s1
Coefficient of friction
(rolled zinc versus rolled zinc)
0.21
Hardness 2:5 Mohs
Tab l e 1 6.3 Thermal properties of pure zinc TS3
Melting point 419:5ıC (692:7K)
Boiling point (760 mm Hg) 907 ıC (1180 K)
Combustion temperature 1800 ıC (approximately)
Vapor pressure (419:5ıC) 1:39 101mm Hg
Thermal conductivity
Solid (18 ıC) 113 W m 1K1
Solid (410:5ıC) 96 W m1K1
Liquid (419 ıC) 61 W m1K1
Liquid (750 ıC) 57 W m1K1
Linear coefficient of thermal expansion:
Single crystal along aaxis 0100 ıC15 mm
1K1
Single crystal along caxis 0100 ıC61 mm
1K1
Polycrystalline 20250 ıC39:7mm
1K1
Volume coefficient of thermal expansion
20400 ıC 0:89 106K1
120360 ıC 0:85 106K1
Contraction on freezing at 419:5ıC 4:48%
Volume change on freezing 469 ıC!0ıC 7:28%
Specific heat (20 ıC) 0:382 kJ kg1K1
Latent heat of fusion (419:5ıC) 100:9kJkg
1
Latent heat of vaporization (906 ıC) 1:782 MJ kg1
Heat capacity
Solid (298692:7K) CpD22:40 C103TJmol
1
Liquid CpD31:40 J mol1
Gas CpD20:80 J mol1
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Part B | 16.2
428 Part B Metals
Tab l e 1 6.4 Electrical, magnetic and electrochemical properties of pure zinc
Electrical resistivity:
Polycrystalline at 20 ıC 5:9 m
Liquid at 419:5ıC37:4 m
Single crystal along aaxis at 20 ıC 5:83  m
Single crystal along caxis at 20 ıC 6:16  m
Temperature coefficient of electrical resistivity:
Between 0 and 100 ıC 0:0419 nmK
1
Between 170 and 25 ıC 0:0406 nmK
1
Pressure coefficient at 20 ıC
At 100300 kPa 25 nmTPa
1
Superconductive at 0:84 ˙0:05 K
Magnetic susceptibility
Polycrystalline at 20 ıC0:123 106mks
Single crystal along caxis at 20 ıC0:169 106mks
Single crystal along aaxis at 20 ıC0:124 106mks
Electrochemical properties:
Standard electrode potential
Against H2electrode 0:762 V
Hydrogen overvoltage 0:75 V at 108 A=m2for metal rubbed with fine emery
Temperature coefficient of overvoltage 0:002 V=ıC
Electrochemical equivalent 1:2195 kg/1000 A hr
140
120
100
80
60
40
20 800600400+2000–200
Tem per at u r e (° C)
Thermal conductivity (W m–1 K–1)
Melting point
Fig. 16.1 Thermal conductivity of zinc (after [16.4])
The thermal conductivity of zinc decreases with in-
creasing temperature, while the specific heat increases
0.60
0.55
0.50
0.45
0.40
0.35 10008006004002000
Tem per at u r e (° C)
Specific heat (kJ kg–1 K–1)
Melting point
Fig. 16.2 Effect of temperature on the specific heat of zinc
(after [16.4])
as shown in Figs. 16.1 and 16.2. Single crystals of zinc
have a higher thermal conductivity than polycrystalline
zinc. The thermal conductivity also varies with crys-
tallographic direction. Electrical, magnetic and electro-
chemical properties are shown in Table 16.4. Electrical
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Zinc and Zinc Alloys 16.2 Properties of Zinc 429
Part B | 16.2
Tab l e 1 6.5 Atomic and crystallographic properties
Atomic number 30
Atomic weight 65.37
Metallic radius 1:38 Å
Isotope abundance
Mass number 64 66 67 68 70
Terrestrial % 50.9 27.3 3.9 17.4 0.5
Radioactive isotopes
Mass number 62 63 65 69 72 73
Half life 9:5h 38:3m 250 d 57 m 2:1d <2m
Decay particles or process K, ˇCˇC,K K, ˇCˇˇˇ
Tetrahedral covalent radius 1:31 Å
Ionic radius Zn2C0:74 Å
Valency 2
Valence electron configuration 3d104s2
Ionization potentials
First 9:39 eV
Second 17:87 eV
Third 40:0eV
Chemical constant 1.136 atmospheres (theoretical)
Density
At 25 ıC 7:14 mg m3
Solid at 419:5ıC 6:83 mg m3
Liquid at 419:5ıC 6:62 mg m3
At 800 ıC 6:25 mg m 3
Structure Close packed hexagonal
a0:2665 nm at 25 ıC(seetext)
or 0:2907 nm
c0:4947 nm at 25 ıC
c=a1.856 at 25 ıC
Twinning plane (10N
12) – pyramidal plane
Slippage plane (0001) – basal plane
Cleavage plane (0001) – basal plane
Glide direction [11N
20]
resistivity measurements were made at 99:993% zinc
[16.5]. The effect of pressure and temperature on elec-
trical resistivity is shown in Figs. 16.3 and 16.4. Zinc
is diamagnetic, therefore it has a magnetic permeabil-
ity less than 1. Zinc is anisotropic with regard to its
diamagnetic susceptibility. Zinc shows a thermoelectric
effect, meaning that when two ends of a zinc speci-
men are maintained at different temperatures, current
will flow through an electrical circuit joining these
ends. Values for a polycrystalline spectrographically
pure zinc against platinum when the cold junction is
maintained at 0 ıC show a voltage of 0:758 mV when
the hot junction is 100 ıC; 1:894 mV at 200 ıCand
5:29 mV at 400 ıC. The atomic and crystallographic
properties of zinc are shown in Table 16.5. The nor-
mal valence states are Zn (I) and Zn (II). Compounds
of zinc (I) do not exist in nature, although ZnH, ZnBr,
and ZnCl are known as spectrographic species. Zinc is
generally divalent and can donate two outer electrons
to form an electrovalent compound; for example, zinc
carbonate (ZnCO3). It may also share those electrons,
such as in ZnCl2, in which the bonds are partly ionic
and partly covalent. Zinc crystallizes in the hexagonal
system, but while the crystal structure is considered
to be of a close packed hexagonal type, the c=aax-
ial ratio is 1.856, much greater than the theoretical
1.633 calculated for this system. As required by the
hexagonal close packed system, each zinc atom has
12 nearest neighbors, but six are one distance apart
at 0:2665 nm, and six are further apart at 0:2907 nm.
It has been reported that the bonds in the hexagonal
basal plane are appreciably stronger than those between
planes [16.6]. This explains much of the behavior of
the metal under deformation and the anisotropy of the
zinc crystal. With a c=aratio greater than 1.633, only
basal slip will occur. At ratios less than 1.633, slip
CE4 In this table, while there are notes for b and c at the bottom of the table, they do not
appear anywhere in the table itself or the caption.
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zinc!uses
Part B | 16.3
430 Part B Metals
59.5
59.4
59.3
59.2
59.1
59.0 120010008006004002000
Pressure (MPa)
Electrical resistivity (nΩ m)
Fig. 16.3 Effect of pressure on electrical resistivity (af-
ter [16.4])
will occur on other planes as well. Because bonding
between basal planes is relatively weak, when accom-
modating stress the lattice first tends to slip along
such planes. In such slip there is movement of part
of the lattice along the basal planes so that the basic
crystal structure is maintained. Above room tempera-
Electrical resistivity (nΩ m)
500
400
300
200
100
040030020010 00500
Tem per at u r e (° C)
Melting point
Composition:
99.993% Zn
0.005% Fe
0.0004% Pb
0.0018% Cd
Traces of As and S
Fig. 16.4 Effect of temperature on electrical resistivity (af-
ter [16.4])
ture, slip may also occur along the prismatic (1010)
plane.
16.3 Uses of Zinc
The largest use of zinc is as a protective coating for
steel, where it provides both barrier and sacrificial pro-
tection. Zinc coating can be applied to steel articles
after they are fabricated, in which case a mainly pure
zinc coating is used. For the coating of steel sheet, wire
and other products in a continuous process, different
zinc alloys are used. The different zinc compositions
used for sheet steel coatings are shown in Table 16.6.
In many atmospheric, aqueous and other environments,
zinc coatings are able to form a protective scale layer
consisting of a mixture of zinc oxide, zinc hydroxide
and various basic salts, depending upon the environ-
ment, providing useful corrosion lives. The formation
of the protective layers is mainly influenced by the
pH of the environment. Zinc forms an amphoteric ox-
ide, and therefore both acid and alkaline conditions can
interfere with the formation of protective layers. Fig-
ure 16.5 shows how the corrosion rate of zinc varies
with pH. Attack is seen to be most severe at pH lev-
els below 6 and above 12.5, whereas within this range
the corrosion rate is slow. In general, zinc corrodes by
a slow general dissolution process. Pitting corrosion
only occurs under special considerations; for example,
in water where a scale may crack, locally exposing
a small anodic area. Intergranular corrosion of cast
zinc was historically a problem until it was found that
this was due to certain impurities, especially lead, tin
and cadmium. The use of high-purity zinc prevents the
occurrence of intergranular corrosion caused by these
elements. The surface corrosion rates of zinc are not
greatly affected by the purity of zinc: 98:0% zinc and
99:99% zinc behave similarly in many conditions. The
aluminum-containing coatings for continuous galvaniz-
ing products greatly improve corrosion resistance and
are widely used in industry. Zinc-iron (galvannealed)
coatings are also widely used, especially in automo-
tive applications. In addition, zinc-iron coatings can be
more than 30% more resistant to corrosion than pure
zinc in mildly acidic conditions. The main reactions of
zinc coatings during the corrosion process are shown in
Table 16.7. Examples of atmospheric corrosion rates of
zinc-coated steels at typical outdoor sites are shown in
Table 16.8.CE4
Zinc is also widely used in casting alloys, mainly
for pressure die casting. The main zinc casting al-
loys are composed of zinc, aluminum and magnesium,
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Zinc and Zinc Alloys 16.3 Uses of Zinc 431
Part B | 16.3
Tab l e 1 6.6 Representative zinc alloy compositions used for coating of sheet steel
Name Al (wt%) Mg (wt%) Other (wt%)
Normal Galvanize (GI) 0.14–0.3 0
Galvanneal (GA) 0.11–0.135 010–14 Fe
Galfan® 5 0 0.03–0.10 Ce CLa
Galvalume® 55 01.5 Si
MagiZinc® 1.5 1.5
Magnelis® 3.5 3
ZAM® 6 3
Super Dyma® 11 3
Galfan is a trademark of Galfan Technology Centre Inc.
Galvalume is a trademark of BIEC International Inc.
MagiZinc is a trademark of Tata Steel Europe
Magnelis is a trademark of ArcelorMittal
ZAM is a trademark of Nisshin Steel
Super Dyma is a trademark of Nippon Steel
with additions of copper to improve strength in several
instances. Table 16.9 shows the compositions of stan-
dard zinc casting alloys. Zinc die casting alloys possess
an attractive combination of properties, including low
melting point, high precision, the ability to be finished
with a wide variety of surface treatments and long tool
life. The physical and mechanical properties of the ma-
jor zinc casting alloys are shown in Tables 16.10 and
16.11.
Rolled zinc alloys can be produced as sheet, strip,
plate, rod and wire. Because of the hexagonal closed-
packed crystallography of zinc, modification is needed
in the rolling techniques commonly employed for other
metals. Unalloyed zinc also recrystallizes at room tem-
perature so that the effects of work hardening are
quickly removed. Therefore, it is not possible to harden
zinc appreciably by mechanical working. Rolled zinc
alloys used in buildings have compositions shown in Ta-
ble 16.12. Their physical and mechanical properties are
shown in Tables 16.13 and 16.14. Rolled zinc may be
formed by many techniques, including bending, spin-
ning, stamping, deep drawing, rollforming, coining and
impact extrusion. A special class of proprietary alloys
is used in deep-drawn conditions for production of dry
cell battery calots.
Zinc wire is also used to produce thermal sprayed
coatings for the protection of steel. Thermal spray al-
loys include pure zincand also a zinc-15% Al alloy that
shows superior performance in marine and other salt-
laden environments. This sprayed coating is produced
by melting zinc powder or wire in a flame or electric
arc and projecting molten droplets by air or gas onto
a grit-blasted steel surface that is to be coated. The cor-
rosion resistance of the pure zinc coating is similar to
that of galvanized coatings discussed earlier.
Zinc anodes are used when it is possible to con-
nect a steel structure to zinc by an electrical connection
1614121086420
pH
Corrosion rate
Acid: film
dissolving Stable film
HCI NaOH Dilute al kali ne:
film dissolving
Fig. 16.5 Variation of corrosion rate with pH (after [16.7])
through the conductive medium of the environment.
This includes the anodic protection of immersed struc-
tures such as ships and pipelines. The compositions
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Part B | 16.3
432 Part B Metals
of zinc anodes used to protect steel in sea water are
shown in Table 16.15. The rate at which zinc anodes
are consumed in sea water is about 12 kg yr1.On
bare steel the current density is about 0:1Am
2,soto
protect 100 m2of bare steel requires about 120 kg yr1
of zinc anodes. In other environments, the life of the
anode depends upon the severity and the conductivity
Tab l e 1 6.7 Zinc corrosion reactions in different atmospheres (schematic). CO2has been included as an attacking substance be-
cause it participates in the formation of corrosion products. However, CO2is also necessary to form stable films (after [16.8])
Type of atmosphere Attacking substances Corrosion products
Composition Relative solubility in water Corrosion rate
Rural O2CH2OCCO2ZnO !Zn.OH/2!2ZnCO33Zn.OH/2Very low Very low
Marine O2CH2OCCO2CCl ZnO !Zn.OH/2!
2ZnCO33Zn.OH/2!
nZnCl24Zn.OH/2
ZnCl26Zn.OH/2
CnZn3OCl4
Zn4OCl6
Moderate Low
Urban and industrial O2CH2OCCO2CSO2ZnO !Zn.OH/2!2ZnCO3
3Zn.OH/2!ZnS CZnSO3CZnSO4
Good High
Tab l e 1 6.8 Zinc one-year corrosion rates, ratio of steel corrosion to zinc corrosion, and site atmospheric characteristics a(af-
ter [16.9])
Test site Zinc corrosion Steel/zinc ratio, Environmental characteristics
1-yr results (m) mean, 1-yr results (m)
Flat Helix
of wire
Flat Helix Cl, mean
(mg m2)
SO2
(mg m2)
Time of wetness (TOW),
mean (h, per annum)
Iquazu 1.6 4Semiarid, wet, rural 5680
Camet 1.3 28 Subtropical, marine, wet 6088
Buenos Aires 1.0 16 Subtropical, marine, wet 4645
San Juan 0.2 23 Subtropical, dry, rural 855
Yubany Base 1.9 19 Antarctic, desert 2693
Boucherville 1.4 2.0 17 14 59 16 1396
Kasp Hory 1.9 2.2 14 22 Rural 17 3206
Praha-Bachov 2.8 3.3 17 21 Urban 67 2991
Kopisty 3.5 4.8 20 23 Industrial 90 2444
Helsinki 1.3 2.6 26 16 419 3578
Otaniemi 0.9 1.8 28 21 315 3256
Athari 0.7 1.2 18 13 Rural 43105
St.Denis,Paris 1.5 3.6 25 14 28 50 4268
Ponteau Mart 2.6 13.4 28 9241 87 3846
Richerande 0.9 2.2 18 10 7 9 4171
St. Remy 1.5 4.2 29 23 378 30 6310
Salin de Gir 4.6 5.7 16 23 184 20 3311
Ostende (Belgium) 5.1 10.6 19 12 173 24 6083
Paris 3.0 2.8 14 18 Urban 53 3189
Auby 5.6 8.5 19 17 16 188 4571
Biarritz 4.3 8.2 20 8193
Bergisch Glad. 1.6 1.8 23 29 Urban 18 4267
Choshi 1.4 2.8 31 33 56 85704
Tokyo 1.5 1.5 26 26 415 2173
Okinawa 3.4 8.8 22 12 97 11 3852
Judgeford, Wellington 0.7 1.2 29 30 Rural-marine
Oslo 1.3 1.8 19 19 214 2641
Borregaard 3.8 5.7 16 16 944 3339
of the medium. In certain soils, for example, zinc an-
odes used together with protective coatings have lives
up to five years. After this time, the zinc anode can
be replaced and a further period of protection ob-
tained. Soils with a resistivity less than 5 cm are
sufficient to provide galvanic protection by the zinc for
the steel.
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Zinc and Zinc Alloys 16.3 Uses of Zinc 433
Part B | 16.3
Tab l e 1 6.8 (continued)
Test site Zinc corrosion Steel/zinc ratio, Environmental characteristics
1-yr results (m) mean, 1-yr results (m)
Flat Helix
of wire
Flat Helix Cl, mean
(mg m2)
SO2
(mg m2)
Time of wetness (TOW),
mean (h, per annum)
Birkenes 2.3 2.0 914 Acid rain 14138
Tananger 3.0 3.3 20 22 308 44583
Bergen 2.1 2.2 13 15 7 9 4439
Svanvik 0.8 1.4 25 21 117 2605
Murmansk 1.1 2.1 28 25 19 53227
Batum 1.6 2.0 18 14 126 3216
Vladivostok 2.3 3.1 11 22 18 29 3920
Oymyakon 0.4 0.6 2 3 Cold 5381
Madrid 0.6 1.6 46 18 Urban 44 2060
El Prado 0.5 1.2 31 18 Urban 53223
Lagoas-Vigo 1.0 2.5 27 14 29 49 2840
Baracaldo-Vizcaya 1.2 2.6 37 22 25 32 4375
Stockholm Vana 0.6 1.5 41 28 Urban 10
Kattesand 1.5 2.8 23 22 76 5
Kyamyk 1.8 3.5 34 19 650 5
Stratford 1.7 1.5 23 34 Industry 20 5783
Crowthorne 1.1 1.2 34 48 Rural
Rye 2.5 2.0 23 46 Marine 21
Fleet Hall 1.3 2.3 29 25 Urban
Kure Beach 2.0 3.9 19 21 102 10 4289
Newark 2.0 2.2 13 12 Industrial
Panama CZ 17.5 7.6 21 39 619 52 7598
Research Triangle 0.8 28 Urban
Point Reyes 1.7 3.5 23 42 Marine
Los Angeles 1.1 1.8 20 11 Urban, marine 20 4003
aThe zinc corrosion results are normally the mean of 18 determinations (three replicates for six one-year exposures starting in spring and
autumn for three years.
bWhere no atmospheric data are available, a quantitative description of the site is given.
cMarine splash zone.
Tab l e 1 6.9 Typical composition of zinc–aluminum pressure die-casting alloys
Alloy
Element
(wt%)
2 3 5 7 ZA-8
Aluminum 3.5–4.3 3.5–4.3 3.5–4.3 3.5–4.3 8.2–8.8
Copper 2.5–3.5 0.25 max 0.5-1.25 0.25 max 0.8–1.3
Magnesium 0.02–0.06 0.01–0.06 0.03–0.08 0.005 0.02–0.03
Iron (max) 0.10 0.10 0.10 0.075 0.065
Lead (max) 0.005 0.005 0.005 0.0030 0.005
Cadmium (max) 0.004 0.004 0.004 0.0020 0.005
Tin (max) 0.003 0.003 0.003 0.0010 0.002
Tellurium Cindium (max) 0.0015 0.0015 0.0015 0.0010
Nickel –––0.005–0.020
Alloy 2 is best known as the German DIN 1743 Alloy Z430 and ASTM AC43A.
Alloy 3 is also ISO 301 Alloy ZnA14, BSI Alloy A, ASTM AG40A, UNS Z33521, German Alloy Z 400.
Alloy 5 is also ISO 301 Alloy ZnA14Cu1, BSI Ally B, ASTM AC41A, UNS Z33530, German Alloy Z 410.
Alloy 7 is best known as ASTM AC40B.
ID: 10.1007/ 016 Springer Handbook of Materials Data Date: December 19, 2017 Proof number: 1
Part B | 16.3
434 Part B Metals
Tab l e 1 6.1 0 Physical properties of the zinc-aluminum pressure die casting alloys (after [16.10])
Physical Property Alloy
2 3 5 7 ZA-8
Specific gravity (kg m3)6.6 6.6 6.7 6.6 6.3
Solidification temperature range (ıC) 390–379 387–381 386–380 387–381 375–404
Solidification shrinkage (%) 1.25 1.17 1.17 1.17 1.1
Thermal expansion coefficient at 20100 ıC
(106K1)
27.8 27.4 27.4 27.4 23.3
Electrical conductivity (% IACS) 25 27 26 27 27.7
Electrical resistivity at 20 ıC( cm) 6.37 6.54 6.2
Thermal conductivity at 70140 ıC(Wm
1K1)105 113 109 113 114.7
Heat capacity at 20100 ıC(Jkg
1h1)418.7 418.7 418.7 418.7 435.4
Tab l e 1 6.1 1 Typical mechanical properties at 2021 ıC of alloys 2, 3, 5, 7 and 8 (after [16.10])
Property Alloy
23578
As As As As As
Cast Aged Cast Aged Cast Aged Cast Aged Cast Aged
Ultimate tensile strength (MPa) 358 283 328 283 374 331 241 269 241 297
Yield strength
(0:2% offset) (MPa)
220 230 290 225
Elongation (on 51 mm) (%) 810 712 8 2 16 13 18 20
Hardness (Brinell 500 kg ) 100 82 91 80 103 98 72 80 67 91
Shear strength (MPa) 317 214 262 214 275 227
Compressive yield strength
(0:1% offset) (MPa)
641 414 600 414 252 171
Impact energy
(unnotched bar 6:35 6:35 mm2)(J)
47 58 65 58 42 6.8 55.6 54.2 55.6 17
Tab l e 1 6.1 2 Typical chemical compositions of rolled zinc alloys (percent by weight) (after [16.10])
Alloy Family Alloying elements Impurities
Cu Ti Al Mg Cd Pb Fe Pb Fe Cd Cu
Pure zinc <0:003 <0:002 <0:003 <0:001
0.004–0.006 <0:01 <0:002
Zn-Cu 0.7–0.9 0.002 0.005 0.008 <0:02 <0:008 <0:02
Zn-Cu-Ti 0.7–0.9 0.08–0.14 0.005 0.02 0.02 0.01 <0:020 <0:010 <0:020
0.4–0.5 0.15 0.002 <0:003 <0:002 <0:003
0.18 0.08 0.002 <0:003 <0:002 <0:003
Zn-Pb-Cd-Fe 0.002 0.04–0.06 0.06–0.08 0.008 <0:008 <0:002
0.015 0.2–0.3 0.005 <0:001
0.005 0.6–0.7 <0:002 <0:001
Zn-Al
(superplastic
alloy)
0.4–0.6 21–23 0.008–0.012 <0:01 <0:01
ID: 10.1007/ 016 Springer Handbook of Materials Data Date: December 19, 2017 Proof number: 1
Zinc and Zinc Alloys 16.3 Uses of Zinc 435
Part B | 16.3
Tab l e 1 6.1 3 Physical properties of rolled zinc (after [16.10])
Alloy family
Pure zinc Zn-Cu Zn-Cu-Ti Zn-Pb-Cd-Fe Zn-22% Al
Density (g=cm3)7.14 7.17 7.17–7.2 7.14 5.2
Melting point (ıC) 419 422 420 419
Specific heat capacity
(J kg1K1)
393.5 401.9 401.9 393.5
Thermal expansion, with grain
(mmm
1K1)
30 34.7 20.0–24.0 32.6 22.1
Thermal expansion, against grain
(mmm
1K1)
20 21.1 16.0–19.4 23 22.1
Thermal conductivity
(W m1K1)
104.7 104.7 104.7 107.6
Electrical conductivity
(%IACS)
28 27 32
Electrical resistivity
( cm)
6.24 6.06 6
aTypical values
Tab l e 1 6.1 4 Mechanical properties of rolled zinc alloys (after [16.10])
Alloy family
Pure Zinc Zn-Cu Zn-Cu-Ti Zn-Pb-Cd-Fe Zn-22% Ala
Tensile strength (MPa)
With grain 120d160–193d110–140d379.2b
172–207c165–207e124–165e
Against grain 150d200–280d140–180d441.2c
214–262e207–262e152–193e
Elongation (%)
With grain 60–90d35–70d80-90d25b
25–45e25–45e30–65e
Against grain 40–60d15–80d40–80d9c
20–36e20–36e24–52e
Yield strength (MPa) (0:2%)
With grain 125d296.5b
Against grain 177d386.1c
Young’s modulus (MPa)
With grain 63 500d93 000b
Against grain 88 000d68 250c
Vickers hardness 30d51–75d30
Rockwell hardness 55–65e54–66e41–58e79b
85c
Creep rate at 25 ıCandastressof68:95 MPa
(% hr1)
0.00001–0.0004
Stress to produce 1% creep 24.8b
in 11:4yr (0:01% in 1000 hr) (MPa) 55–69c
Shear strength (MPa) 138–152 138–152 124–138
aSuperplastic alloy.
bAs rolled.
cAnnealed at 350 ıC.
dBased on Standard Method of European Zinc Testing Committee CE4 (International Lead Zinc Research Org., Inc. 1982).
eBased on thermomechanical treatment applied.
ID: 10.1007/ 016 Springer Handbook of Materials Data Date: December 19, 2017 Proof number: 1
Part B | 16
436 Part B Metals
Tab l e 1 6.1 5 Zinc anode specifications for use in sea water
ASTM B418-12 2012
MIL-A-18001H 1968 (%) Ty p e 1 ( % ) Ty p e 2 ( %)
Aluminum 0.10–0.50 0.10–0.4 0.005 max.
Cadmium 0.025–0.15 0.03–0.10 0.003 max.
Iron, max. 0.005 0.005 0.0014
Lead, max. 0.006
Copper, max. 0.005
Silicon, max. 0.125
Zinc Remainder Remainder Remainder
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Littreal: Effect of pH on the corrosion rate of zinc in oxygenated aqueous solutions
  • B E Rotheli
  • G L Cox
B.E. Rotheli, G.L. Cox, W.B. Littreal: Effect of pH on the corrosion rate of zinc in oxygenated aqueous solutions, Metals Alloys 3, 73-76 (1932)