When small quantities of silica introduced into the powder batch in a grinding equipment made out of 85 to 90% of alumina more non uniform micro structures were formed in such materials a grind boundary phase was always formed. In the case of grinding equipment made out of pure alumina or pure zirconium more uniform micro structures with relatively narrow particle size distribution were obtained. In case of pure alumina equipment no measurable impurities could be established. Whereas when zirconium equipment was used impurities of zirconium particles noticed which might be generated from the wear out of zirconium grinding media.
Hence in most of the high purity alumina powder preparation methods, pure alumina grinding media and pure alumina lined grinding equipments are used. In certain applications where zirconium is added deliberately to improve the toughness of the alumina products. In such cases zirconium grinding media and zirconium lined equipments are used for preparing the zirconium doped alumina powder.
To be contd….
