Frictional Characteristics of Cobalt, Nickel, and Iron as Influenced by Their Surface Oxide Films

Abstract

Friction-temperature-time curves were obtained with the pure metals cobalt, nickel and iron sliding against themselves in various gases at temperatures to 1400 F. In general, the frictional behavior confirmed that of earlier work where the atmosphere was not as rigidly controlled. The friction of cobalt appears to be controlled by two processes; at high temperatures it is oxidation controlled; at low temperatures the friction is low. This is attributed to absorption of gases on cobalt or cobalt oxide or the inherent effective sliding of the cobalt-cobalt combination. Iron oxide films were found to be very durable at the temperature at which they were formed.