Effect of counter materials on coefficients of friction of TiN coatings with preferred grain orientations

In order to investigate the effect of counter materials on the coefficients of friction of TiN coatings with preferred grain orientations, the coefficients of friction against six counter materials (ball) were measured. The ball materials were aluminum (A1050), stainless steel (SUS304, SUS440C), bearing steel (SUJ2), carburized steel (SWRM10), cemented tungsten carbide (WC-Co) and alumina (Al2O3). After tests, the worn flat surfaces of balls and the wear tracks of TiN coatings were analyzed by the electron probe micro analysis (EPMA) and the auger electron spectroscopy (AES) to observe the Ti oxide film on each ball material and the adhesion of ball materials to the TiN coatings. The Ti oxide film was observed on the worn flat surfaces of the ball materials and the ball materials did not adhere to the TiN coatings in case that the low coefficients of friction were obtained.