Microfriction of various phases in a carbon fiber, polytetrafluoroethylene, graphite and polyetheretherketone composite blend as measured by atomic force microscopy

Atomic force microscopy and friction force microscopy have been used to conduct microfriction studies on short carbon fiber reinforced PEEK/PTFE composite blends. The relative micro-scale coefficients of friction of different filler particles (PTFE, CF in normal and anti-plane orientation, and graphite) have been compared with the matrix PEEK. The order of the nanoscopic coefficients of friction was: carbon fiber in normal orientation>carbon fiber in plane orientation>PEEK matrix>graphite flake>carbon fiber in parallel orientation>PTFE particle. Additional microhardness studies resulted in qualitative hardness comparisons of the various phases. Their order of the form: carbon fibers PEEK and graphite>PTFE also reflects the contribution of the various phases to the wear resistance of the composite blend. The latter can be estimated from the AFM-topography traces of the polished composite surfaces.