In this work, we investigate the effects of powder chemistry on the sintering of MgO‐doped specialty alumina. The stages at which MgO influences densification of Al₂O₃ were identified by comparing dilatometry measurements and the sintering kinetics of MgO‐free and MgO‐doped specialty alumina powders. MgO is observed to reduce the grain boundary thickness during densification using TEM. We show that MgO increases the solubility of SiO₂ in alumina grains near the boundaries using EDS. First‐principles DFT calculations demonstrate that the co‐dissolution of MgO and SiO₂ in alumina is thermodynamically favored over the dissolution of MgO or SiO₂ individually in alumina. This study experimentally demonstrates for the first time that removal of SiO₂ from the grain boundaries is a key process by which MgO enhances the sintering of alumina.

中文翻译：

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粉末化学性质对掺MgO的特种Al2O3烧结的影响

在这项工作中，我们研究了粉末化学对MgO掺杂特种氧化铝烧结的影响。通过比较膨胀测量和不含MgO和掺杂MgO的特种氧化铝粉末的烧结动力学，可以确定MgO影响Al ₂ O ₃致密化的阶段。观察到MgO在使用TEM致密化期间减小了晶界厚度。我们表明，使用EDS ，MgO会增加边界附近氧化铝颗粒中SiO ₂的溶解度。第一性原理DFT计算表明，MgO和SiO ₂在氧化铝中的共溶解在热力学上优于MgO或SiO ₂的溶解分别在氧化铝中。该研究首次通过实验证明，从晶界去除SiO ₂是MgO增强氧化铝烧结的关键过程。