The effect of microstructure and chromia content on the properties of zirconia toughened alumina

Variants of zirconia toughened alumina with a composition comparable to a commercial material were produced as to assess the effect on hardness, fracture toughness, Young's modulus, and scratch resistance. Chromia content was adjusted above and below the reference material. Separately, sintering conditions were varied to create grain size and density variations. It is shown that the chromia content within the composition range studied does not impact the mechanical properties but only the color of the final product. Hardness can be increased via sintering variations that impact grain size and density, however, at the potential cost of fracture toughness. From scratch test results, it is anticipated that fracture toughness is the dominating material property for robust performance of the material when used as joint bearing implant components under adverse wear conditions. The high relative hardness of alumina based ceramics is one of the advantages when compared to alternative non ceramic joint bearing implant components, however, the fine tuning of the ZTA hardness via sintering variations herein does not create improved performance of the joint bearing implant component.