The Tribological Behavior of Polycrystalline Cobalt as Related to Crystallographic Texture and Structure

Abstract

The friction and wear behavior of polycrystalline hexagonal cobalt was determined under normal atmospheric conditions, using heavy loads and sliding speeds ranging from 0.92 cm/sec to 36.8 cm/sec. Very uniform wear was observed for most conditions together with a low coefficient of friction. X-ray diffraction measurements showed that this desirable behavior is caused by the formation of a preferred orientation during sliding. Under high-load high-speed conditions a different mode of wear was observed, best described as brittle disintegration. When cobalt was alloyed with 8 percent iron and thus rendered face-centered cubic, a deeply torn wear track, an increased initial wear rate and a high coefficient of friction were obtained.