A study on tribological properties of textured Co-Cr-Mo alloy for artificial hip joints

Abstract Co-Cr-Mo alloys are widely applied in the field of artificial hip joints. However, the service life of artificial hip joints is limited to 10–15 years due to its poor wear resistance. Thus, more and more patients have to replace the damaged artificial hip joints by revision surgery, which leaves the patient in pain. The surface micro-textures manufactured on the surfaces of artificial joints is an established method to improve its tribological behaviors such as coefficient of friction (COF), wear and scratches etc. However, most of researches about textured Co-Cr-Mo were limited to simple dimple shaped micro-textures. In this study, innovative patterned surface micro-textures, i.e., arrays of groove, hexagon and concentric circles were manufactured on Co-Cr-Mo alloy by laser surface texturing (LST). Results showed that the hardness and wettability of Co-Cr-Mo alloy were improved. The rotating friction tests were carried out under bovine serum albumin (BSA) lubricants by a ball-on-disc type friction machine. Frictional experiments showed that the tribological properties of concentric circles micro-textures were best. And, under the 10 N loading conditions, the COF and weight loss of PEEK ball of concentric circles sliding against concentric circles micro-textured sample with 20% density (C-20) were reduced by 49.22% and 52.3% compared to untextured sample, respectively. Meanwhile, the relationship between surface wettability and COF of the textured Co-Cr-Mo alloy was discussed and the mechanism for the effects of the surface micro-textures was revealed.