Y_2O_3和纳米AlN协同作用对氮化铝陶瓷烧结性能及热传导的影响

Influence of Y_2O_3 and Nano-AlN Powders on the Sintering and Thermal Conductivity of AlN Ceramics

在微米氮化铝粉体中添加含量为4%的Y2O3和不同含量的纳米AlN粉体制备氮化铝陶瓷,研究了Y2O3和纳米AlN协同作用对微米氮化铝陶瓷烧结性能和热传导性能的影响。结果表明,Y2O3优先与纳米AlN粉体表面的Al2O3反应生成活性较高的第二相Al5Y3O12,相比于Y2O3与微米AlN粉体表面Al2O3反应生成的Al5Y3O12,具有更低的熔化温度及更好的流动性;同时,纳米AlN粉体的高比表面能也促进氮化铝陶瓷的致密化进程。二者的协同作用有效地促进氮化铝陶瓷的致密烧结,改善第二相的微观分布,从而能在较低的烧结温度下获得具有较高热导率的氮化铝陶瓷。当Y2O3和纳米AlN粉体的添加量(质量分数)分别为4%和1.5%时,在1800℃烧结得到的氮化铝陶瓷密度为3.26 g·cm-3,第二相以连续相的形式分布于氮化铝晶界处,热导率为151.75 W/(m.K)。

AIN ceramics doped with 4% Y203 and appropriate nano-AIN powders were sintered at 1700-1850℃, the influences of Y203 and nano-AIN powders on the sintering and thermal conductivity of AIN ceramics were investigated. The results show that the AI203 powders distributed in the surface of na- no-AIN took the priority to react with Y203, and second phase of AIsY3012 with higher activity were gotten, which could form liquid at lower temperature. In addition, the nano-AIN powders can also promote the density of AIN ceramics. The two factors have a synergetic action on the sintering of AIN ceramics, and can improve the distribution of second phase in the microstructure of AIN ceramics. Therefore, AIN ceram- ics with higher thermal conductivity can be prepared at lower sintering temperature. The AIN ceramics with 4% Y203 and 1.5% nano-AIN doped, sintered at 1800℃ have a density of 3.26 g·cm-3and a thermal conductivity of 151.75 W/（m·K）, and second phase distributes in the boundaries of AIN grains.