The results show that these three kind of materials are effective to reduce the a - phase - transformation temperature and accelerate the a - phase - transformation process . no bough - like structure was found in the doping production of heat - treatment 结果表明:这三种物质均有明显的降低氧化铝相变温度,促进氧化铝相变的作用,得到的焙烧产物中基本上没有“树枝状”结构。