阴离子掺杂稳定c-ZrO2的第一性原理研究

利用密度泛函(DFT)中的PW91PW91方法计算了碳和氮阴离子掺杂稳定c-ZrO2的机制.热力学计算表明碳元素和氮元素取代氧化锆晶格氧反应的吉布斯自由能均小于零,这表明两种取代反应都是可以进行的.结合阴离子掺杂稳定作用能计算和结晶学理论分析认为氮元素主要以替代晶格氧引入空位的方式稳定四方或立方氧化锆,而碳元素则是首先扩散进入氧化锆的八面体空隙,随八面体体积收缩和热处理温度的升高,转变为替代晶格氧引入空位的方式稳定四方或立方氧化锆.同时,分析认为不同氮源和初始氧化锆相成份也影响着立方或四方氧化锆的稳定作用.

First-principles Study on the Anion-doped Stable c-ZrO2

Mechanisms of anion-doped c -ZrO_2 was calculated by PW91PW91 method of Density-Functional Theory (DFT). Thermodynamic calculation shows that the Gibbs free energy of carbon and nitrogen substituting the crystal lattice oxygen is lower than zero, which shows the two substitution reactions are all feasible. Theoretical calculation of stable effect and crystallography analysis for anion-doped c -ZrO_2 show that the nitrogen mainly substitutes oxygen so as to attain the stable t -ZrO_2 and c -ZrO_2. However, for carbon-doped c -ZrO_2, it first diffuses into the octahedral space, and then becomes the substitution mode with the decrease of the octahedral space and the increase of heat treatment temperature. Meanwhile, our analysis demonstrates the different nitrogen materials and zirconia phase content also affect the stable process of t -ZrO_2 and c -ZrO_2.