Influence of Temperature Gradients on Sintering: Experimental Tests of a Theory

Abstract

The H2O‐catalyzed sintering of MgO in temperature gradients between 1303 and 1233 K is compared to sintering of isothermal samples. Both the changes in sample dimensions in planes normal to the temperature gradients and the increases in density for a fixed sintering time are greater than predicted on the assumption that densification in a temperature gradient is a function only of each local temperature in the gradient. Under the conditions used, neither vapor transport nor transport through a liquid phase is important. The results, therefore, support a recent prediction that temperature gradients supplement surface energy changes in driving sintering and related processes not only by vapor transport, as expected from earlier studies, but also by a surface, grainboundary, or bulk diffusion path.