Lithography-based manufacturing of advanced ceramics for orthopaedic applications: A comparative tribological study

Ceramics long history in biomedical field is related to their high biocompatibility and mechanical properties. Precisely, for joint replacements, wear resistance is fundamental, so advanced ceramics as alumina and zirconia are preferred. Developments in ceramic additive manufacturing allow for dense ceramic parts with improved mechanical properties and shape accuracy. This paper focuses on the tribological analysis of stereolithography-manufactured components for orthopaedics. Alumina, yttria-stabilised zirconia, 10 and 20 wt% zirconia toughened alumina (ZTA) samples were analysed. The effect of surface finishing, microstructure and microhardness on wear was considered. Printing orientation does not significantly impact microhardness, wettability, and microporosity. However, some printing artefacts as the staircase effect were observed on spherical surfaces. Zirconia system presented high wear rates and friction coefficient, while alumina system showed more acceptable and stable values, with the formation of a self-mated tribofilm. ZTA composites presented the lowest wear volume and better mechanical and surface properties in general.