Abstract In this paper, a comparative study between conventional and microwave sintering of pure spinel MgAl2O4 is presented. The goal is to clarify and identify the possible microwave effects on densification and microstructure of the pure spinel. Sintering trajectories obtained for microwave and conventional sintering are similar and converge into a unique trajectory. Therefore, microwave processing does not refine the grain size of pure spinel. The dominant mechanism of initial and intermediate stages of sintering was determined from the shrinkage curves and sintering trajectory. It was shown that densification is mostly controlled by grain boundary diffusion for both processes. Porosity of microwave and conventionally sintered samples was also characterized by mercury porosimetry and BET analysis. The evolution of the open porosity and pore size distribution is the same whatsoever the process used. This work shows that microwave sintering does not differ that much from conventional sintering on pure MgAl2O4 material.

中文翻译：

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纯MgAl2O4常规和微波烧结的烧结路径和机理

摘要 本文对纯尖晶石MgAl2O4 的常规烧结和微波烧结进行了对比研究。目标是澄清和确定微波对纯尖晶石致密化和微观结构的可能影响。微波和传统烧结获得的烧结轨迹是相似的，并会聚成一个独特的轨迹。因此，微波处理不会细化纯尖晶石的晶粒尺寸。从收缩曲线和烧结轨迹确定了烧结初期和中期的主导机制。结果表明，两种工艺的致密化主要受晶界扩散控制。微波和常规烧结样品的孔隙率也通过汞孔隙率测定法和 BET 分析进行表征。无论使用何种工艺，开孔率和孔径分布的演变都是相同的。这项工作表明，微波烧结与传统的纯 MgAl2O4 材料烧结没有太大区别。