Porous Surface Layer on Copper for Lubrication in Cold Working

The authors proposed a new lubrication system for cold working using porous surface layer on workpiece formed by oxidation and chemical reduction W. This system was successfully applied only to carbon steels. In this study, the system is applied to oxygen-free high conductivity (OFHC) copper. The copper was oxidized at 623K for 15min, then chemically reduced at 473K in hydrogen gas for 15min. Scanning Electron Microscopy (SEM) revealed that pores 0.2 similar to 0.5 mu m in diameter were fauned on the surface. When grease is used as lubricant in ring compression test, porous rings show slightly lower friction coefficient than normal rings.