Ultrasonic homogenization of equivolumetric Al2O3/ZrO2 suspensions

The equivolumetric ZrO2-Al2O3 ceramic composite shows very good mechanical properties due to its interpenetrating microstructure; unfortunately it is very difficult to achieve a well dispersed aggregates' free mixture. In thi s paper ultrasonication was used as a dispersion and mixing aid for aqueous suspension of ZrO2-Al2O3 powders. The suspensions were stabilised using ei ther an electrostatic or an electrosteric mechanism. The influence of ultra sonication time as well as solid contents in the suspensions were investiga ted via rheological measurements. The goal was to optimise the process in o rder to obtain a well dispersed system without aggregates. The results indi cate that there is, for every system, a threshold time over which aggregate s start to reappear. (C) 2000 Kluwer Academic Publishers.