NEW MEASUREMENTS OF THE COEFFICIENT OF FRICTION FOR THE INTERFACE BETWEEN CERAMIC BALL HEADS AND DIFFERENT METAL TAPER MATERIALS

Introduction Frictional behavior and, therefore, the coefficient of friction (CoF) play an important role in the evolution of fretting wear. Several studies investigated fretting at the ball head-taper junction with a remarkable variation in the CoF (0.15 to 0.55). This may be due to different material couplings, surface topographies or macro-geometries. Since the results of Finite Element (FE) models are strongly dependent on the choice of CoF it is crucial to determine the correct CoF for a speci?c system. Therefore, this study aimed to determine the CoF for the interface between ceramic ball heads and metal tapers. Materials and Methods Three groups of taper-ball head couplings were investigated (n=18 titanium (Ti), n=18 cobalt chromium (CoCr), n=18 steel tapers (SS)). Line profiles of the taper surfaces were measured and tapers and ball heads were assembled using different loads (2, 4, 6 kN). Tapers were disassembled from ball heads by using liquid nitrogen, surface topography was remeasured and the e...