Explain electrical contact materials.

Electrical contact materials: some elements, in their relatively pure forms as copper, nickel, molybdenum, palladium, silver, tungsten and platinum are acceptable make and break contact materials. All alloys and heterogeneous mixtures that are, generally, combinations of the elements mentioned above are also utilized for electrical contacts. Silver is a significant contact material. Copper (Cu0) added to silver reduces the cost of the contact material, while a combination of tungsten and silver results in a contact material comprising the advantages of the particular metals. A silver tungsten contact material will have electrical conductivity, high thermal and low contact resistance and high resistance to oxidation because of the presence of silver and a high melting point and a high resistance to electrical erosion because of the presence of tungsten.