Sintering of MgO: Densification and grain growth

The densification rate and grain growth rate of pure MgO powder compacts are measured between 1450 and 1650° C in air. Densification rate in a semilog plot appears to be linear up to about 94% of the theoretical, followed by marked nonlinearity. The time dependence of grain growth is 1/2 at the beginning and then decreases considerably with further sintering. Application of lattice diffusion model to the densification and grain growth data gives calculated diffusion coefficients in fair agreement with the directly measured diffusion coefficients for magnesium; they are also in fair agreement with the literature value of the diffusion coefficients calculated from various other kinetic processes in MgO.