Preparation of MgO–Y2O3 Composite Ceramic by Aqueous Gel Casting

MgO–Y 2 O 3 composite ceramics were prepared by gel-casting technology. The surface of MgO powder is passivated with H 3 PO 4 ethanol solution. The treated powder can be dispersed in water with a dispersant. The powder surface modification process was verified by pH, Zeta potentials, Fourier transmission infrared absorption spectroscopy (FT-IR), the absorbance of suspension and rheological properties. The obtained stable suspensions were gel cast, dried, and sintered at 1400 °C for 30 min under 35 MPa. As a comparison, the powder was compressed by die pressing and sintered at the same temperature and pressure. After sintering, the MgO–Y 2 O 3 composite ceramic with a theoretical density of 97.29% can be prepared by aqueous gel casting process. The properties of MgO–Y 2 O 3 composite ceramic fabricated by gel casting are better than die pressing.