Abstract AlN with 0.5–8 wt% CaO was pressureless sintered between 1100 °C and 1800 °C. The results of density, second-phases, microstructure, and weight loss were used to identify the possible mechanisms that may cause a significant delay on the densification of AlN with CaO additive. It was observed that the additive content is the main parameter controlling the densification behavior during liquid phase sintering (LPS) of AlN with CaO. The positive effects of increasing the CaO content were associated with the decrease in the temperature of liquid-phase formation and the increase of the liquid-phase fraction during sintering. The negative effects were associated with the high viscosity of the liquid-phase below 1600 °C, the formation of large pores, and the gas entrapment in closed pores. The balance between positive and negative effects results in an intermediate additive content (around 2 wt% CaO), which is best to promote densification of AlN at a temperature as low as 1650 °C.

中文翻译：

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CaO添加剂对氮化铝陶瓷烧结的作用

摘要 含有 0.5-8 wt% CaO 的 AlN 在 1100 °C 和 1800 °C 之间无压烧结。密度、第二相、微观结构和重量损失的结果用于确定可能导致 AlN 与 CaO 添加剂致密化显着延迟的可能机制。据观察，添加剂含量是控制 AlN 与 CaO 液相烧结 (LPS) 过程中致密化行为的主要参数。增加 CaO 含量的积极影响与液相形成温度的降低和烧结过程中液相分数的增加有关。负面影响与低于 1600 °C 的液相的高粘度、大孔的形成以及封闭孔中的气体截留有关。