DEPENDENCE OF SINTERABILITY ON STATE OF AGGLOMERATION OF ULTRAFINE ZrO2，（Y2O3） POWDERS
(Department of Nonferrous Metallurgy; Central South University of Technology . Changsha 410083)
Abstract: The dependence of sinterability on the state of agglomeration of ultrafine ZrO2(Y2O3) powders prepared by coprecipitation was investigated. The results showed that the powder prepared by direct drying and calcination of the water-washed gels was poorly sinterable with sintered density as low as 89% of theoretical value. The powder sinterability could be markedly improved by ball milling, and the sintered density could be increased to 96% of theoretical value under the same sintering condrtions.Highly sinterable powders were prepared by adding some surfactants or by alcohol dehydration before gel drying, and the relative sintered densities greater than 985% were obtained. Sinterability mainly depended on the state of agglomeration of powders. The relation between sintered density and the state of agglomeration of powders was discussed.
Key words: zirconia; ultrafine powder; agglomeration; sinterability