烧结助剂对AlN陶瓷制备及性能的影响

EFFECTS OF SINTERING ADDITIVES ON PREPARATION AND PROPERTIES OF AlN CERAMICS

用三组烧结助剂[多壁碳纳米管(multi-wall carbonnanotube,MWNT)、Y2O3-CaF2及MWNT-Y2O3-CaF2]在1600℃低温烧结AlN陶瓷,测试AlN陶瓷烧结密度、热性能和电性能,分析其物相变化和微观结构。结果表明:外添加剂在低温能明显促进AlN陶瓷致密化及晶粒生长发育,并且用合适的埋粉和保护气氛可以防止AlN陶瓷在烧结过程中发生氧化,其中添加质量分数(下同)1%MWNT-3%Y2O3-2%CaF2作烧结助剂,于1600℃保温4h可以制备相对体积密度为97.2%,热导率为138.57W/(m·K),同时具有较低相对相对介电常数的AlN陶瓷,即在低温无压条件下制备性能较高的AlN陶瓷。

Aluminum nitride（AlN） ceramics doped with multi-wall carbon nanotube（MWNT）,Y2O3-CaF2 and MWNT-Y2O3-CaF2 were sintered at 1 600 ℃.Density,thermal properties,electrical properties,phase change,and microstructure of sintered AlN ceramics were tested and analyzed.The results show that composite sintering additives significantly promote AlN ceramic densification and grain growth,and the appropriate powders and protective atmosphere prevent oxidation of AlN ceramics during the sintering process.Especially dense AlN ceramics with a relative density of 97.2% and thermal conductivity of 138.57 W/（m·K） are obtained by sintering at 1 600 ℃ for 4 h with mass freaction（the same below） of 1% MWNT-3% Y2O3-2%CaF2,while the AlN ceramics have a low relative dielectric constant.Higher performance AlN ceramics can be prepared by the pressureless sintering at a lower temperature.