3. Non Ferrous Metals and Alloys
•Usually metals and alloys are divided into two
categories.
1. Ferrous
2. Non- Ferrous (All metallic elements other than iron
are referred to as non ferrous).
•Iron occupy special position among alloys owing to
its availability, comparatively low cost and useful
range of alloys.
4. However, they have some distinct limitations, chiefly:
(1) a relatively high density,
(2) a comparatively low electrical conductivity, and
(3) an inherent susceptibility to corrosion in some
common environments.
So there is the need of non- ferrous alloys.
Of all the non ferrous alloys only eight are produced
in relatively large quantities, Al, Cu, Pb, Mg, Ni, Sn, Ti,
and Zn
5. Copper and Its Alloys
•Oldest metal known to man.
•In early civilization Cu along with bronze used for
decorative and utilitarian purposes.
•Extremely useful, but due to high cost, Cu and its
alloys are replaced with other cheap materials, such
as plastic, aluminum in many applications.
Occurrence:
•High affinity for sulphur, so occurs in forms of oxides
and sulphides. Copper Iron Sulphide, Copper Oxide,
and copper silicates.
8. Properties
•High electrical conductivity
•High thermal conductivity
•High corrosion resistance (unaffected by an
oxidation environment)
• Good ductility and malleability.
• Reasonable tensile strength
•Ease of joining (by adding other metals, soldering,
brazing, welding)
•Machinabilty and recyclability.
•Greater affinity for sulphur
9. Physical properties of copper and
copper alloys
Crystal structure FCC
Atomic number 29
Atomic weight 63.546
Density (g.cm-3) 8.933
Melting point (oC) 1084.62
Tensile Strength(MPa) 220
Corrosion Resistance Very Good
10. Application of copper in automotives
Copper: working behind the scenes in automotive
applications
Increasing use of electronic parts in cars raise the
amount of copper used per vehicle.
11. Mineral Ores of Copper
•Bornite (Cu5FeS4 ) ,
•Chalco pyrite (CuFeS2),
•Covellite (CuS),
•Chalco cite ( sulphide ores),
•Malachite (Cu2CO3(OH)2) ,Azurite (Cu3(CO3)2(OH)2,
Cuprite (oxide form)
•Native Cu (100% cu, red in color)
13. Extraction of Copper
Ores of copper are generally complex mixtures of
copper and iron sulphides.
Extraction Process
Mining. By mining, ores containing 1% cu is obtained.
Ore is crushed, ground and separated, as a result of
which the material becomes concentrated containing
40- 60% cu. Grinding is usually done to increase
surface area.
14.
15.
16. Reverberatory furnace
A Reverberatory furnace is a metallurgical or process furnace
that isolates the material being processed from contact with
fuel but not from contact with combustion gases
17. Roasting (Concentration)
In the roaster, the copper concentrate is partially
oxidized to produce iron oxide, copper sulfide
and sulfur dioxide gas.
The stoichiometry of the reaction which occurs is:
2 CuFeS2 + 3 O2 → 2 FeO + 2 CuS + 2 SO2
18. Reverberatory Furnace
The calcine is then mixed with silica and coke and
smelted in an exothermic reaction at 1200 °C (above
the melting point of copper, but below that of the
iron and silica) to form a liquid called "copper
matte". The high temperature allows reactions to
proceed rapidly, and allow the matte and slag to melt.
Iron oxides and sulfides are converted to slag, a less
dense molten mass that is floated off the matte.
19. The reactions for slag formation is
FeO(s) + SiO2(s) → FeSiO3 (l)
In a parallel reaction the iron sulfide is converted to
slag:
2 FeS(l) + 3 O2 + 2 SiO2 (l) →2 FeSiO3(l) + 2 SO2(g)
The slag is discarded or reprocessed to recover any
remaining copper.
20. Copper Convertor
The matte, which is produced in the smelter, contains
around 70% copper primarily as copper sulfide as well
as iron sulfide. The sulfur is removed at high
temperature as sulfur dioxide by blowing air through
molten matte:
2 CuS + 3 O2 → 2 CuO + 2 SO2
CuS + O2 → Cu + SO2
In a parallel reaction the iron sulfide is converted to
slag:
2 FeS + 3 O2 → 2 FeO + 2 SO2
2 FeO + 2 SiO2 → 2 FeSiO3
21. The purity of this product is 98%, it is known
as blister because of the broken surface created by
the escape of sulfur dioxide gas.
22. Refining Furnace
Fire refining of blister copper is an interesting process.
The bath of oxidized copper is then subjected to
reducing conditions to reduce the oxygen content.
The resulting product being termed as Tough Pitch
Copper with a residual oxygen content of about 0.03
%. Necessary reducing conditions were obtained by
poling the liquid bath.
23. Tough pitch copper is unsuitable for welding owing to
the oxygen contents of the material. Unsuitable for
applications requiring high electrical conductivity.
Arsenical Copper
Some grades of copper contain up to 0.5% of arsenic.
Arsenical copper which has improved tensile
properties and an improved resistance to oxidation at
high temperatures, is made by adding up to 0.5 % of
arsenic to tough pitch.
24. The copper is refined by electrolysis. The anodes cast
from processed blister copper are placed into
an aqueous solution of 3–4% copper sulfate and 10–
16% sulfuric acid. Cathodes are thin rolled sheets of
highly pure copper. A potential of only 0.2–0.4 volts is
required for the process to commence.
At the anode, copper and less noble metals dissolve.
More noble metals such as silver and gold as well
as selenium and tellurium settle to the bottom of the
cell as anode slime, which forms a saleable byproduct.
Electrolytic Refining
25. Copper(II) ions migrate through the electrolyte to the
cathode. At the cathode, copper metal deposit but
less noble constituents such
as arsenic and zinc remain in solution.
The reactions are:
At the anode: Cu(s) → Cu2+
(aq) + 2e–
At the cathode: Cu2+
(aq) + 2e– → Cu(s)
Cu produced in this way is termed as cathode
copper(99.9%)
26.
27.
28. Alloys of Copper
Copper may be alloyed with a number of elements to
provide a range of useful alloys.
1. Copper-Nickel (Cupronickels)
Ni is soluble in solid copper. This alloy is strong and
ductile and excellent resistance to corrosion. It is used for
manufacturing condenser tubing and heat exchanger.
2. Nickel –Silver Alloy (German silver)
Addition of zn to cu and Ni produces this alloy. They are
ductile. Nickel silver is used for silver-plated cutlery,
better-quality keys, costume jewellery, for making musical
instruments (e.g.,cymbals), production of coins. Its
industrial and technical uses include plumbing fixtures
for its corrosion resistance.
29. 3. Beryllium – Copper Alloy
It contains up to 2.7% of Be, having the highest
strength among all copper alloys available. These
alloys may be strengthened by solution heat
treatment and by this process tensile strength up to
1400 MN/m2 can be obtained. Normally Be- Cu
contains 2% of Be.
Applications. Manufacturing of spring pressure
diaphragm and non-sparking tools.
4. Cadmium – Copper alloys
The addition of 1% Cd to copper gives an alloy with a
tensile strength approximately 50% higher than that
of high conductivity copper but it decreases its
electrical conductivity.
30. Application. Major applications are telephone wires,
electrodes, electrodes holders for electrical resistance
welding equipments.
5. Chromium- Copper Alloy
It contains 0.5% cr, and resultant will be formed
having high strength coupled with high electrical and
thermal conductivities.
6. Tellurium- Copper Alloy
This alloy contains 0.3- 0.7% Te and it is alloy of high
electrical conductivity. It is a free machining alloy. Te
is virtually insoluble in cu and appears in the
microstructure as small particles of copper telluride.
These will act as internal chip breakers.
31. Major Alloys of Copper
Brass (peetal)
It is a binary alloy of Cu and Zn. It has low density, low
melting point. Zn can be added from 5-40%. On adding
Zn, it becomes cheaper, it can be used in manufacturing
of pressure vessels. Cu has good thermal, electrical and
corrosion resistance properties but on adding Zn up to
36% , its mechanical properties get improved at the cost
of reduction of thermal, electrical and corrosion
resistance properties.
Some of the common uses for brass alloys include
costume jewelry, cartridge casings, automotive radiators,
musical instruments, electronic packaging, and coins.
32. Bronze (kaansi)
Bronze is a metal alloy consisting primarily of copper,
usually with tin as the main additive, but Al, Si and Ni
can also be used. It is hard and brittle. Bronze is
typically 88% copper and 12% tin. It are used to
make coins, springs, turbines, medal and blades.
Applications of Copper
• About 37% of cu is used in building, construction,
wiring, plumbing, heating, commercial refrigeration,
hard ware and architectural materials.
• 26% of cu is used in electrical and electronic devices.
33. • 15% of cu is used in industrial machinery and
equipments.
• 11% of cu is used in transportation equipment like
marines, vehicles, buses and trucks.
• Remaining 11% is used in cutlery, coins and
ornaments
