Grain growth kinetics study of advanced oxide ceramic materials

The goal of this work was to study the grain growth kinetics of five different materials: tetragonal ZrO2 (doped 3mol.% Y2O3 and particle size 80 nm), two cubic ZrO2 (doped 8 mol.% Y2O3 and particle sizes 80 and 140 nm) and two hexagonal Al2O3 (with particle sizes 100 and 240 nm). These ceramic powders were isostatically pressed and then they were isothermally sintered at 3 different temperatures for 1-60 hours. The biggest coarsening was discovered during temperature increase to sintering temperature. The dwelt at sintering temperature was not so important for coarsening. The activation energy of grain growth QG, growth exponent n and kinetic constant k0 were discovered for four materials. The activation energy of grain growth was 511±49 kJ/mol for tetragonal ZrO2, 645±84 kJ/mol for cubic ZrO2 a 428±75 kJ/mol a 606±24 kJ/mol for Al2O3. Possibility of kinetic window of sintering process for cubic ZrO2, tetragonal ZrO2, and Al2O3 with particle size 240 nm (doped MgO) were discovered by comparison of established activation energy of grain growth QG with activation energy of sintering QS from literature. Kinetic window of sintering process wasn’t found for high purity alumina with particle size 100 nm