添加剂对氧化铝粉体粒径的影响

为了获得高纯度超细粒径的氧化铝粉体，在采用溶胶凝胶法制备过程中必须添加某些添加剂.用激光粒度分析仪研究了表面活性剂在粉体制备过程中对粉体粒径的影响，用x射线衍射仪研究了晶种和相变添加剂对氧化铝粉体晶型的影响.研究发现，阳离子表面活性剂（TZZ）为较理想的制备超细氧化铝粉体的表面活性剂.当溶胶中不含表面活性剂时粉体表面改性是必然的，因为表面改性可以防止粉体团聚；当溶胶中含有表面活性剂时，表面改性的作用不明显.晶种和相变添加剂有利于稳定晶型αAl₂O₃的生成，而在溶胶中表面活性剂含量较适宜的情况下对氧化铝粉体粒径影响不大.同时，在烧结过程中，硝酸铵会分解释放出多种气体，析出的气体对烧结的固体有粉碎作用.

Effect of additives on particle size of alumina powder

In order to obtain alumina powder with high purity and ultrafine particle, some additives must be added during preparing the powder with the sol gel method. The influence of surfactants on the particle size of powder in the preparation process was studied with laser particle size analyzer. The effect of crystal seed and phase transformation additive on the crystal forms of the alumina powder was investigated with XRD （X ray diffractometer）. It is found that the cationic surfactant （TZZ） is an ideal surfactant for preparing ultrafine Al₂O₃ powder. The surface modification is necessary to prevent the conglomeration of powder if there is no surfactant in sol. The surface modification action is not remarkable if there is a surfactant in sol. The cyrstal seed and phase transformation additive are beneficial for obtaining the stable cystal form αAl₂O₃, but have little effect on the particle size of the alumina powder when the content of surfactants in sol is appropriate. Meanwhile, in the sintering process, ammonium nitrate decomposes and releases various gases, which can smash the sintering powder.