Alloy
↪ An alloy is a homogenous mixture of two or more metals or a metal and a non-metal.
↪ It possesses in general the properties of metals as a class and in particular the general properties of the elements of which it is composed but these are not necessarily intermediate.
↪ Alloys may be completely homogenous mixtures or may contain small particles of one phase in the other phase.
↪ Alloys are usually harder than their components but very often less ductile and less malleable.
↪ Thus the hardness of gold and silver is increased by the addition of copper but malleability is considerably decreased.
↪ The melting point of an alloy is always lower than the melting point of the constituent metals.
↪ The chemical properties are altered to a very great extent and an alloy is generally more stable so far as corrosion and solubility in acids is concerned.
↪ Above five thousands alloys have so far been prepared from forty metals and out of these about a hundred are in common use and constant use.
↪ Alloys are broadly classified into two classes:
⇲ Ferrous alloys
⇲ Non-ferrous alloys
↪ Ferrous alloy contains iron as the one of the constituent.
↪ Steel, stainless steel, manganese steel, invar, tungsten steel etc. are some examples of ferrous alloys.
↪ Similarly, brass, bronze, bell metal, duralumin etc. are examples of non-ferrous alloys.
↪ Examples of some common alloys with their exact composition and uses are tabulated below:
| Alloy | Composition | Uses |
| Brass | Cu: 60-80% Zn: 40-20% | For making household utensils |
| Bronze | Cu: 75-90% Sn: 25-10% | For making utensils, statues. |
| Stainless steel | Cr: 12% Ni: 2% and Fe: 86% | For making cycles. |
| Manganese steel | Mn: 12-15% Fe: 88-85% | In making railway tracks. |
| Invar | Ni: 36% Fe: 64% | For making pendulums. |
| Duralumin | Al: 95% Cu: 4% Mg: 0.5% Mn: 0.5% | Used to make bodies of aircraft |
| Type metal | Pb: 82% Sb: 15% Sn: 3% |
For making type words. |
| Pewter | Sn: 80% Pb: 20% | For making fuse |
| Bell metal | Cu: 80% Sn: 20% | For making bells. |
| Rose metal | Bi: 50% Pb: 28% Sn: 22% | For making fire protection |
Amalgams
↪ An alloy of mercury with one or more other metals is known as alloy.
