Development of Pb alloy overlay for high rotational gasoline engines

Abstract Rotation speed of some engines is increasing to achieve higher performance. Therefore, engine bearings will be used at higher temperature due to higher rotation. When bearings are operated at higher temperature, the overlay gives different damage from conventional damage mode. This is overlay peeling caused by melting of a low melting point compound near the Ni interlayer. Therefore, a new overlay was developed to form no low melting point compounds. The new overlay consists of Pb, Sn, In and Cu. Addition of Cu suppresses diffusion of Sn and In to inhibit the formation of low melting point compounds.