The role of hardness and roughness on the wear of different CoCrMo counterfaces on UHMWPE for artificial joints

Abstract

Wear tests were carried out to study the effect of various counterface materials in the wear behaviour of Ultra High Molecular Weight Polyethylene (UHMWPE). The materials used as counterfaces were based on varieties of CoCrMo: 1) forged (hand- pol-ished) CoCrMo; 2) forged (mass-finished) Co- CrMo; 3) cast (mass-finished) CoCrMo. Additionally, two coatings were proposed: 1) a CoCrMo coating applied to the forged CoCrMo alloy by means of physical vapour deposition (PVD); 2) a ZrO2 coating applied to the forged CoCrMo alloy by means of plasma-assisted chemical vapour deposition (PACVD). The reciprocating pin-on-flat (RPOF) device for pin-on-disk wear testing was used for this study. The worn surfaces were observed using optical, atomic force and scanning electron microscopes.