Abstract:

Yttria stabilized zirconia （YSZ） ceramics have emerged as an important material in mechanical and electronic applications owing to their high strength， excellent high-temperature resistance and good biocompatibility. However， the excessively high sintering temperature results in high energy consumption and costs. Therefore， the current research focus on finding ways to lower the sintering temperature while maintaining performance. YSZ ceramics with varying TiO₂ content were prepared by atmospheric pressure sintering at different temperatures. The effect of TiO₂ content on the densification， phase composition and mechanical properties of YSZ ceramics at different sintering temperatures was systematically studied. The results show that the doping of TiO₂ can reduce the sintering temperature of YSZ ceramics， promote grain growth and sintering densification， and is beneficial to stabilize tetragonal phase zirconia. At lower sintering temperatures （1 350， 1 400 ℃）， the flexural strength of YSZ ceramics decreases first and then increases with increasing TiO₂ content （0.5%~7.0%， mole fraction）. The flexural strength of YSZ ceramics with 7.0% TiO₂ is the highest， reaching 530.4 and 576.3 MPa， respectively. At higher sintering temperatures （1 450， 1 500 ℃）， flexural strength generally declines with increasing TiO₂ content， and only trace content （0.5%~1.0%） exhibiting a strengthening effect. Specifically， the flexural strength of YSZ ceramics doping with 1.0% TiO₂ at 1 450 ℃ is 660.7 MPa， and that of YSZ ceramics doping with 0.5% TiO₂ at 1 500 ℃ is 633.1 MPa.

Key words: TiO₂, YSZ, relative density, flexural strength, phase composition, grain size