Enhanced wear resistance of pure tin by addition of bronze and Fe-C reinforcing particles

Wear resistance enhancement of tin by composite production through powder metallurgy was investigated in the present study. To this end, 10 vol% bronze or cast iron (Fe-C) particles were incorporated within a tin matrix via pressing and extrusion. The produced materials were evaluated by comparing their density, microstructure, hardness and wear resistance. Relative densities of extruded samples were more than 99% of the theoretical value. Homogeneous distribution of reinforcing particles in the matrix was revealed by optical microscopy. The introduction of bronze and Fe-C powders within the tin matrix were accompanied by 8 and 15% increase in hardness value together with 51 and 40% decrease in wear loss, respectively. On the other hand, the least friction coefficient (0.37) obtained from the sample containing Fe-C particles worn under 3 N applied load. In addition, the frictional behavior of pure tin showed a more stable trace with the addition of reinforcing particles. While an increase in applied load led to an increase in volume loss of both reinforced and unreinforced tin, it only resulted in a reduction in friction coefficient in the composite specimens. This reduction was considerable especially for the tin matrix composites reinforced with cast iron where a higher amount of graphite particles was smeared out on the wear surface due to the increased normal load. Microscopic study of the worn surfaces together with EDS analysis showed that oxidative wear was active during sliding wear of pure tin and its composites.