PISTON HAVING IMPROVED WEAR RESISTANCE AND METHOD OF MAKING

摘要

A piston formed from an Al-Si alloy having an average Si composition includes a high wear region having a surface that is Si-rich with respect to the average Si composition of the Al-Si alloy. The surface of the predetermined high wear region is treated, as by etching, to selectively remove Al from the surface to produce the Si- rich region. The Si-rich region has improved resistance to wear. The piston may be treated to produce one or more high wear regions which are Si-rich with respect to the average Si composition of the alloy. High wear regions may include the annular grooves for receiving a piston ring, the piston skirt and the pin bore.