溶胶共沉淀法制备氧化锆氧化铝复合粉体

Preparation of ZrO_2 and Al_2O_3 composite powder by gel co-precipitation method

用溶胶共沉淀法辅以共沸蒸馏法工艺制备ZrO_2/Al_2O_3复合粉体,研究了pH值和锆与铝的离子比对复合粉体和用这种复合粉体制备的瓷体的力学性能的影响.结果表明:随着溶胶体系pH值的增大,粉体粒径也相应增大.在制备粉体的混合溶液的pH值为8.6左右时,粉体没有明显的团聚且粒径分布均匀.随着氧化铝相对含量的提高,高弹性模量的Al_2O_3在烧结过程中起钉扎作用,阻碍Zr^(4+)(Y^(3+))扩散传质的进行和晶界的移动,从而抑制了ZrO_2晶体的生长,细化了ZrO_2晶粒,表现为氧化锆的结晶温度、烧结体密度和复合陶瓷强度的提高.

Gel co-precipitation method and heterogeneous azeotropic distillation technics were used in the preparation of ZrO2 and Al2O3 composite powder. The effect of pH values and the ratio of ZrO2/Al2O3 on the properties of the composite powder and the composite ceramics was investigated. The results show that the t-ZrO2 /Al2O3 composite powder with well dispersed and less agglomeration was obtained at pH value of 8.6. In the sintering process, the alumina with high elastic modulus develops its pinning effect, blocking the Zr4＋（Y3＋） mass transfer process and the movement of grain boundary. The grain growth of zirconia was inhibited with the increasing content of alumina, which resulted in higher crystallization temperature of zirconia, higher density and higher strength of composite ceramics.