以AlN粉末为原料,添加稀土氧化物(Sm2O3、Y2O3),在氮气气氛下,采用SPS烧结方法制备AlN陶瓷,研究稀土氧化物的掺杂对AlN烧结试样相组成、微观结构和电性能的影响。实验表明： Sm2O3、Y2O3与Al2O3反应生成的液相稀土金属铝酸盐会提高AlN陶瓷致密度,且在晶界处形成导电通路降低了AlN陶瓷电阻率。随着Sm2O3掺杂量的增加,晶界相逐渐由Sm4Al2O9过渡到SmAlO3,且Sm4Al2O9对电阻率贡献最大。其中,3wt% Sm2O3掺杂AlN陶瓷电阻率最低,为1.32×1010?·cm,相对密度为99.33%。Y2O3掺杂量的增加会使晶界处钇铝酸盐由富铝酸盐向富钇酸盐转变,三者电阻率相差较小, Y2O3含量高于3wt%的AlN陶瓷电阻率维持在1×1010?·cm左右,其中4wt%Y2O3掺杂AlN相对密度最高为99.08%。
AlN ceramics doped with rare earth oxide (Sm2O3, Y2O3) were prepared bySpark Plasma Sintering (SPS) in nitrogen atmosphere using AlN powder as raw materials. The effect of rare earth oxide on the phase composition, microstructure and electrical resistivity of AlN ceramics were investigated. The results showed that those sintering additives promoted densification through liquid-phase sintering. AlN ceramics with elec-trical resistivity values of 1×1010–1×1012??cm were obtained by precipitating rare earth aluminates as a conducting pathway at the grain boundaries. With the increasing of Sm2O3 doping, the phase of samarium aluminate gradually changed from Sm4Al2O9 to SmAlO3 which had a higher resistivity than Sm4Al2O9. 3wt% Sm2O3 doped AlN ceramics had the minimum resistivity of 1.32×1010??cm with the relative density of 99.33%. The yttrium aluminate phase gradually changed from Y3Al5O12 to Y4Al2O9 with the increase of Y2O3-doping. The electrical resistivity of different yttrium aluminates were about 1×108??cm. Y2O3- doped AlN sample with over 3wt% Y2O3 had an electrical resistivity about 1×1010??cm. 4wt% Y2O3 doped AlN ceramic had the electrical resistivity of 1.60×1010??cm with the maximum relative density of 99.08%.
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