Mechanical properties and tribological behaviors of yttria-zirconia ceramics with additions of graphene oxide by hot-press sintering for dental implants

Abstract

Yttria-zirconia (3Y-ZrO2) ceramics are widely used in orthopedic implants and carbon nanotubes (CNTs) attract the public attention due to their unique properties. To investigate the effect of graphene oxide (GO) concentrations on the mechanical properties and tribological behaviors of 3Y-ZrO2 for dental implants, 3Y-ZrO2/GO composites were prepared by hot-press sintering. GO was uniformly distributed in 3Y-ZrO2 and the composites showed good mechanical properties and tribological behaviors with suitable GO concentration. A moderate content in ZG3 and ZG2 (the ceramic with 0.15 wt.% and 0.1 wt.% GO) improved the flexural strength and fracture toughness up to 200% and 40.9%, respectively, compared to 3Y-ZrO2. Microstructural surfaces presented crack deflection, crack bridging, and GO put-out in the composites. In addition, a lower or higher proportion of GO destroyed overall structures of ZG1 (the ceramic with 0.05 wt.% GO) and ZG4 (the ceramic with 0.2 wt.% GO). These not only reduced the mechanical performances, but also resulted to an increase in surface roughness. Besides, Worn surfaces showed micro-ploughing and plastic deformation were dominant wear mechanisms in the ZG0 (the ceramic without GO), however, the addition of GO transformed the wear from a severe state to mild owing to self-lubricating property. Thus, friction coefficient, wear rate and surface roughness of ZG3 were reduced to the least among all the composites.