Friction and wear behavior of polyetherimide composites in various wear modes

A high performance engineering polymer, polyetherimide (PEI) and its two composites, one containing only short glass fibers (GF) 20% and the other, commercially established bearing material containing 25% GF and three solid lubricants were selected for studying the wear behavior in four types of wear modes. These included, adhesive (continuous sliding against metal); abrasive (abrading in single pass and multi pass against silicon carbide abrasive paper), and three-body abrasion (abrading against rubber wheel), fretting, and erosive wear modes. A bearing grade material proved to be extremely good in adhesive and fretting wear modes. The same composite, however, proved very poor in abrasive and erosive wear modes. Neat polymer performed best in these two modes. Thus, performance rankings of three materials in adhesive and fretting wear modes were identical while for abrasive and erosive wear modes, exactly the reverse trend was observed. SEM studies proved helpful in understanding the wear mechanism.