Microstructure and properties of 6Yb2O3-2Y2O3-ZrO2 composite nanoceramic powders by microwave-assisted co-precipitation method

Abstract

Abstract

The stability and other physicochemical characteristics of zirconia ceramics can be further improved by including stabilizers. In this study, the effect of different microwave calcination temperatures on 6Yb2O3-2Y2O3-ZrO2 composite nanoceramic powders was investigated by using the microwave calcination-assisted co-precipitation method, in which Yb2O3 and Y2O3 were used as stabilizers to co-doped ZrO2. The samples at different microwave calcination temperatures were characterized by XRD, TG-DTG, Raman, SEM, and FT-IR, and the effects of the microwave sintering process on the microstructure and grain growth behavior of the composite nanoceramic powders were further analyzed. The solid solution structure was created by adding Yb3+ and Y3+ with ionic radii larger than Zr4+. This resulted in O-O coupling and an increase in the concentration of oxygen vacancies close to the substitutional ions, which caused Zr4+ to be replaced by Yb3+ and Y3+ and suppressed the tetragonal to monoclinic phase transformation. The experimental results show that the co-doping of ZrO2 with Yb2O3 and Y2O3 has good phase stability, and there is no appearance of a monoclinic phase after microwave calcination. The precursor sample transforms from an amorphous form to a large number of cubic phases and a small number of tetragonal phases. The powder is spherical with a uniform particle size distribution. A calcination temperature of 1000 °C produced the maximum tetragonal phase ZrO2 content of 41.3 %, and a stability rate of 97.4 % made the best stability of the sample. 6Yb2O3-2Y2O3-ZrO2 composite nanoceramic powders' activation energy for grain development was further determined to be 22.03 kJ/mol. This work offers a theoretical and practical foundation for synthesizing zirconia ceramic powders with exceptional qualities.