稀土氧化物对SPS烧结AlN陶瓷电性能的影响

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

Effect of Rare Earth Oxides on Electrical Properties of SparkPlasma Sintered AlN Ceramics

AlN ceramics doped with rare earth oxide (Sm₂O₃, Y₂O₃) were prepared by Spark 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 electrical resistivity values of 1×10¹⁰-1×10¹² Ω•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 Ω•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 Ω•cm. Y₂O₃- doped AlN sample with over 3wt% Y₂O₃ had an electrical resistivity about 1×10¹⁰ Ω•cm. 4wt% Y₂O₃ doped AlN ceramic had the electrical resistivity of 1.60×10¹⁰ Ω•cm with the maximum relative density of 99.08%.