Effects of lead and copper particles on corrosion and wear behaviour of Al-Si matrix composites

Matrix composites of Al-Si containing dispersed lead and copper particles were fabricated by hot pressing. The effects of the addition of 5 and 10 wt-% lead and 3 wt-% copper particles on the wear and wear corrosion properties of Al-Si composites have been evaluated. Wear testing was conducted at ambient temperature without lubricant, and wear corrosion testing was executed in 3-5 wt-%NaCl solution (pH 6·7). The results show that the dry wear loss of Al-Si/Pb and Al-Si/ Cu-Pb composites decreased as the lead content increased. The hardness increased and the dry wear loss was reduced with the addition of copper particles. The corrosion potential E_corr decreased with the presence of copper and with an increase of the lead content, for both pressed and heat treated conditions. The corrosion current density l_corr increased with copper and lead incorporation into composites in the as pressed state, and decreased after heat treatment for Al-Si/Cu and Al-Si/Cu-Pb composites. Wear corrosion properties were improved by addition of the lead phase to Al-Si and Al-Si/Cu composites. The Al-Si/Cu-Pb composites exhibited better dry wear and wear corrosion resistance than those of other composites in the present study. The lead containing composites (Al-Si/Pb and Al-Si/Cu-Pb) possessed lower E_corr values compared with other Al-Si composites.