Tribological and corrosion performance of the plasma-sprayed conformal ceramic coating on selective laser melted CoCrMo alloy.

Abstract

Ceramic implants have superior performance due to the excellent wear resistance and biocompatibility. However, the poor machinability limits their applications. Plasma sprayed ceramic coating on the additively manufactured metal substrate not only provides a 3-dimensional conformal implant coating and but also forms a highly wear-resistant surface layer. In this paper, three types of ceramic coatings of Al₂O_3, ZrO₂, and Al₂O₃-ZrO₂ composite have been fabricated by atmosphere plasma spray on the CoCrMo alloy substrate prepared by selective laser melting (SLM). It has been found that the Al₂O₃-ZrO₂ composite coating has better corrosion and wear resistance compared with the ceramic coating (Al₂O_3, ZrO₂) and the CoCrMo substrate. The adhesion strength between the Al₂O₃-ZrO₂ composite coating and the substrate reaches 238 MPa. In addition, the wear and corrosion resistance increase with wear progression for all the fabricated ceramic coatings. The highly dense microstructure, fewer microcracks, and the amorphous phases are deterministic factors responsible for the superior tribological and corrosion performance of the Al₂O₃-ZrO₂ composite coating. The fabrication route has been proved very promising to manufacture high-performance implants with ceramic coating.