Al₂O₃-ZrO₂ COMPOSITES PREPARED BY GELCASTING

The effects of pH value, the amount of dispersant, ZrO₂(3Y) content and solid volume fraction on viscosity of ZTA ceramic slurries were discussed. The mechanical properties and microstructure of sintered ZTA samples by gelcasting were investigated. The results show that low viscosity ZTA ( 20% ZrO₂) suspension with 55% solid volume fraction is obtained at pH 8.5 and 0.9% dispersant. The sintered sample prepared with high solid volume fraction of the suspension has the advantages of compact structure, uniformity distribution of ZrO₂ particles and higher content of t-ZrO₂ phase. Its bending strength and fracture toughness are 631.5 MPa and 7.64 MPa · m^1/2 under the test condition, respectively.