Tribological Behavior of Hot-extruded Al-Si-Pb Bearing Alloys

To improve mechanical properties, especially friction and wear characteristics of as cast Al Pb alloys, an attempt was made to study the friction and wear behavior of hot extruded Al Pb alloys under dry sliding conditions. It was found that hot extrusion considerably improved the mechanical properties of as cast Al Pb alloys and greatly decreased the porosity that was caused by powerful stirring. The friction coefficient and wear rate decreased with increasing lead content, especially the anti seizure property of Al Pb alloys containing 20wt.% and 25wt.% lead was improved remarkably. The optical and XPS analysis of worn surface reveal that the reason is attributed to formation of a black compact film of lubricant on almost entire worn surface of specimens at high applied load. This film could be composed of probably is a mixture of Al 2O 3, Fe 2O 3 and a compound containing Pb.