Al_2O_3-15 vol% ZrO_2微粒子系のコロイドプロセス Colloidal Processing for Fine Particles of Al_2O_3-15 vol% ZrO_2 System
Al<SUB>2</SUB>O<SUB>3</SUB>-15vol%ZrO<SUB>2</SUB> composites were produced by colloidal process. Dispersed suspensions consisting of α-Al<SUB>2</SUB>O<SUB>3</SUB> and ZrO<SUB>2</SUB> fine powders were prepared by adjusting the pH value and salt concentration, or adding appropriate amounts of polyelectrolyte. The dispersion of powder particles was characterized by rheological measurement. In multicomponent particle systems, long range particle segregation occurs due to different particle size and specific gravity. The segregation decreases with increasing the salt concentration and/or solid content in the suspensions. The suspensions were consolidated by slip casting and cold isostatic pressing (CIP). They were sintered at temperatures from 1573K to 1793K for 2h in air. The microstructures were observed by SEM. For the specimen sintered at 1673K, the density was more than 98% and the grain size of Al<SUB>2</SUB>O<SUB>3</SUB> matrix was 0.42μm. At 1723K, the density was about 99.5% and the grain size was 0.59-0.70μm.
粉体および粉末冶金 44(4), 356-361, 1997-04-15
Japan Society of Powder and Powder Metallurgy