ZnO对Mg-PSZ陶瓷细晶化和相组成的影响

Effects of ZnO on the Microstructure and Phase Constitutions of the Mg-PSZ Ceramics

在氧化镁部分稳定的氧化锆基质中加入不同含量的ZnO,研究烧结,热处理过程中Zn,Mg-PSZ显微结构和相组成的变化。结果表明:ZnO的加入使ZrO_2晶格发生畸变,降低了烧结温度,获得了具有细晶结构的更加致密的烧结体,同时降温过程中有大量的四方相析出并保留至室温。另外,ZnO的加入可细化晶粒,其含量可以调控四方析出体的形貌,随着氧化锌加入量的增加,晶粒内析出体粒径增大,其形状也逐渐由球形转变为具有特定晶向的各向异性。

The ternary phase of the partially stabilized zirconia （（Zn, Mg-PSZ） was prepared by doping zinc oxide into the 10 mol% Mg-PSZ ceramics. The microstructure and stability of the t-ZrO2 during sintering and annealing process were investigated. Results showed that the reaction of ZnO and ZrO2 led to the distortion of the lattice space of t-ZrO2. The addition of ZnO lowered the sintering temperature, promoted densification and refined the grain sizes in the ceramics. Differently from that in the traditional Mg-PSZ, the t-ZrO2 phase in this new reaction system precipitated directly from the （Zn, Mg）-ZrO2 matrix, and this occurred during cooling, without the need of a long-time heat-annealing. The content of the added ZnO controlled the shapes of the precipitated grains, which changed from spherical to polyhedron gradually with the increase of ZnO from 0.4 mol% to 3.0 mol%.