Abstract
Magnesia powders having different particle sizes were prepared by a vapor phase oxidation process, and the effect of particle size on their properties was investigated.
The particle size of magnesia powder increased with increasing the flame length of combusting magnesium vapor which was affected by the diffusion coefficient in the flame and the evaporation rate of magnesium. The magnesia powders obtained were highly pure, and especially the contents of U and Th were both below 1ppb. The properties of magnesia powders were strongly affected by the particle size: The green density increased with increasing particle size, whereas the lattice constant decreased with increasing particle size. There was an optimum particle size to achive the maximum sintered density.
