prevention of corrosion

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Hi friends, I want to tell about prevention of corrosion. The rusting of iron can be prevented by painting. oilling Preasi g galvanising. chrome plating anodsing or making alloys. Galvanisation is a method of protecting steel and iron from rustling by coating them with a thin layer of zinc. the galvanised article is protected agianst rusting even if the zinc coating is broken can you reason this out? Alloying is a very good method of improving the properties of a metal. we can get the desired properites by this method. For example. iron is the most widely used metal. But is is never used in its pure state. This is because pure iron is very soft and stretches easily when hot. But If it is mixed with a small amount of carbon It becomes hard and strong. When iron is mixed with nickel and chromium. we get stainless steel. Which is hard and does not rust. Thus if iron is mixed with some other substance added may be a metal or a non-metal. an alloy is a homogeneous mixture of two or more metals or a non-metal. It is prepared by first melting the primary metal, and then disolving the other elements in it in definite proportions. It is then cooled to room temperature. if one of the metals is mercury. then the alloy is known as an amalgam. The electrical conductivity and melting point of an alloy is less than that of pure metals. For example. brass an alloy of copper and zinc (Cu and Zn). and bronze and alloy of copper and tin (Cu and Sn) are electical circuits. solder an alloy of lead and tin (Pb and Sn) has a low melting point and is used for welding electrical wires together. U know friends : The wonder of ancient Indian Metallurgy The iron pillar near the Qutub minar in Delhi was made around 400 BC by the iron workers of india. They had developed a process which prevented wrought iron from rusting. this is likely because of formation of a thin film of magnetic oxide (Fe3O4) on the surface as a result of finishing treatment given to the pillar, painting it with a mixture of different salts. then heating and quenching. The iron pillar is 8 m high and weight 6 tonnes (6000Kg).