Influence of TiO2 content on the mechanical properties, wear performance and hydrothermal aging stability in zirconia-toughened alumina composites

Zirconia-toughened alumina (ZTA) ceramics have become the preferred material for hip joint implants due to their excellent mechanical properties and biocompatibility. However, wear caused by friction and hydrothermal aging remains one of the major challenges. This study investigated the effects of TiO 2 addition (ranging from 0 wt.% to 1.2 wt.%) on phase composition, microstructure, mechanical properties, tribological properties, and hydrothermal aging resistance of zirconia-toughened alumina (ZTA) composites. TiO 2 -ZTA ceramics were fabricated by pressureless sintering and subjected to hydrothermal aging treatment (134 ± 2 °C, 0.2 MPa). The TiO 2 -ZTA composites were characterized before and after hydrothermal aging treatment using XRD, SEM, densitometry, and Vickers indentation techniques. Tribological tests were conducted to evaluate the influences of TiO 2 addition and hydrothermal aging. Results demonstrated that the addition of TiO 2 improved the microstructure of ZTA ceramic composites and enhanced their densification. The 0.6 wt.% TiO 2 -ZTA composite exhibited excellent performance: the hardness of 17.25 GPa, the fracture toughness of 6.08 MPa·m 1/2 , and the wear rate of 3.2×10 -6 mm 3 /Nm, with a decrease by 25.6%. After hydrothermal aging, the hardness of the 0.6 wt.% TiO 2 -ZTA composite was 17.04 GPa, and the fracture toughness was 5.75 MPa·m 1/2 . The wear mechanism of the TiO 2 -ZTA composites mainly consists of abrasive wear and adhesive wear.