烧结方法对AlN陶瓷微观形貌及热导率的影响

Effect of Sintering Methods on the Microstructure and Thermal Conductivity of AlN Ceramics

采用真空烧结、N2保护无压烧结、放电等离子烧结等方法对AlN粉末进行烧结,研究烧结方法对粉体烧结行为以及产物物相组成、微观形貌及热导率的影响。结果表明:真空烧结会显著降低AlN材料的脱氮分解温度,无法实现其致密化;而通过N2保护无压烧结和放电等离子烧结的方法均能得到结构致密、热导率较高的AlN陶瓷,其中后者的烧结温度更低、制得陶瓷样品的致密度和热导率更高,在1650℃保温10min即可烧结得到热导率为121.5W·m-1·K-1的AlN陶瓷。

Various methods, including vacuum sintering, pressure-less sintering in the N2 atmosphere and spark plasma sintering, were used to densify the AlN ceramics, and effects of sintering methods on the sintering behavior, phase composition, microstructure and thermal conductivity of the sintered AlN samples were investigated. The results show that vacuum sintering can remarkably reduce the decomposition temperature of AlN which makes it impossible to densify the samples, while the other two methods can prepare almost fully dense samples with high thermal conductivity. In particular, spark plasma sintering is a better way to clean the grain boundary and obtain denser samples with a high thermal conductivity of 121.5 W·m-1·K-1 at a lower sintering temperature of 1650 ℃.