A bearing is a means for supporting a load between rela-tively moving surfaces with as little friction as possible .' The plain bearings, used in the automobile , aircraft and other engineering industries, consist of
two surfaces, the shaft and the hearing, generally
separated by a film of lubricant. The so-called bear- ing alloys utilised for the purpose have to satisfy
some primary requirements such as suitable chemical
make up giving rise to a hard constituent embedded in
a soft matrix , and a certain range of physical
( melting point , density, thermal conductivity, etc.)
and mechanical (hardness , modulus of elasticity,
tensile strength, impact resistance and age-hardening characteristics) properties. Besides these, certain service properties such as wear, seizure-resistance , conformability , embeddability corrosion-resistance,
etc. are also to be complied with
