Friction and wear of cobalt–chromium–nickel–copper alloy in contact with tungsten-carbide-sintered balls

ABSTRACT This paper describes a study of the influence of elemental nickel (Ni) and copper (Cu) elements on the tribological behaviour of a CoCr-based alloy. The tribology of CoCr-based alloys was examined by using a Bruker UMT-TriboLab machine with normal loads of 200 N, a frequency of 3 Hz, and a duration of 10 min. The Co70Cr20Ni5Cu5 alloy with 5wt-% Ni and 5wt-% Cu content showed the best wear property compared with other alloys, with a minimum friction coefficient of 0.147. The large improvement in wear resistance is related to the strongly inhibiting effect of crack initiation and growth in the worn surface, which reduces delamination wear. Because of the Co0.52Cu0.48 plastic deformation layer, hard phases like NiCoCr and CrCo can slip easily on the sliding interface and embed into the matrix, which may decrease delamination wear and reduce the crack growth rate.