Chapter 21: Metals and Ceramics

Abstract

and nickel show large µ values (between 4 and 5), which means adhesion is stronger in the inert gases than in air. The high friction of pure metals shown in Abrasive wear resistance of such pure metals linearly increases with hardness as shown in Soft Metals and Soft Bearing Alloys When hard metals such as steels slide on themselves without lubricants, high friction, gross seizure, and severe wear take place in air or vacuum. A soft-metal thin film at the sliding interface between hard materials can reduce friction to the level of µ = 0.1 to 0.2. Gold, silver, lead, and indium are representative soft metals whose hardness values vary from about 0.3 GPa to about 0.5 GPa. In practical cases of soft metal-lubricated tribosystems, sliding velocities are relatively small and soft metals are not expected to work in the molten state