摘要

Zirconia powders Co-doped with multiple rare earths were prepared by coating Y(NO3)3, Ce(NO3)3 and La(NO3)3 on the surface of ZrO2 by a novel coating method, and then 1.5Y-5.5Ce-0.3La-TZP tetragonal zirconia bulk materials were prepared by pressureless sintering. The effects of sintering temperature, holding time and heating rate on the relative density, apparent porosity, linear shrinkage, phase transformation, mechanical properties and microstructures of zirconia ceramics were studied. The results show that the content of monoclinic phase decreases with the increase of sintering temperature. When the sintering temperature is 1 550 ℃, the content of monoclinic phase is almost zero, and the degree of tetragonal phase stabilization reaches the maximum. At the sintering temperature of 1 200-1 450 ℃, decreasing the heating rate is beneficial to the densification of ceramics. The relative density, bending strength, hardness (HV10) and fracture toughness of ZrO2 ceramics reach the maximum at 1 550 ℃ for 90 min, which are 98.8%, 1 001.3 MPa, 1 124.3 and 10.81 MPa?m1/2, respectively. ? 2021, Editorial Office of Materials Science and Engineering of Powder Metallurgy. All right reserved.