Characterization of ZrO2 and Al2O3 Bioceramics Obtained by Gelcasting

Gelcasting is a novel method of forming ceramics and has been increasingly employed in preparing complex-shaped, near-net-shape advanced materials. In this work, alumina, zirconia and alumina-zirconia bioceramics were shaped by gelcasting, using MAM-MBAM monomer system, with subsequent sintering and characterization. High purity tetragonal ZrO2 (3mol%Y2O3) and square Al2O3 powders were used as starting powders. Powder mixture containing 80 wt.% of alumina and 20 wt.% of tetragonal zirconia were obtained by milling/homogenization. In all cases, the suspension obtained had at least 55 vol.% solid loading. Ceramic bodies were demolded, dried and characterized by green relative density. The compacts were sintered in air at 1550 and 1575 degrees C, for 120 minutes, with controlled heating-rate to facilitate organic compounds removal. Sintered samples were characterized by relative density, and analyzed by X-Ray diffraction and scanning electronic microscopy. Hardness and fracture toughness were determined using Vicker's indentation method.