低温烧结AlN陶瓷的微结构和热导率

Microstructure and Thermal Conductivity of AlN Ceramics Sintered at a Low Temperature

采用CaF2,Y2O3和Li2CO3做添加剂,在低温下制备了高热导率的AlN陶瓷,通过SEM,TEM和XRD研究了AlN陶瓷在烧结过程中微结构及晶格常数的变化及其对热导率的影响。研究发现,当使用CaF2和CaF2-Y2O3做添加剂时,液相对晶粒浸润性较差,不利于AlN晶格的纯化。而添加Li2O-CaF2-Y2O3的AlN陶瓷在烧结温度之前已经完成了液相的重新分布,液相与AlN晶粒之间有较好的浸润性,这促进了AlN陶瓷的致密化和AlN晶格的纯化,有利于获得较高的热导率。

Using Li2CO3, CaF2 and Y2O3 as additives, AlN ceramics with high thermal conductivity were achieved at a low sintering temperature The changes occurring on the microstructure and lattice parameters of the sintered AlN ceramics were studied using SEM, TEM and XRD Furthermore, their effects on the thermal conductivity were discussed The results show that the liquid formed in the sintering has a less wetting to the AlN grains, which has no significant benefit to purify the AlN lattice using CaF2 and Y2O3 as additives In AlN ceramics adding Li2CO3CaF2Y2O3, the liquid phase redistributed before the sintering temperature has a good wettability to the AlN grains This promotes the densification of AlN ceramics and the purification of AlN lattice, thus ensuring the high thermal conductivity