Diffusion Mechanism for Tungsten Sintering Kinetics

Abstract

The sintering kinetics of cold‐pressed tungsten powders have been determined from 1300° to 1750°C. Diffusion coefficients calculated from the sintering kinetics are considerably larger than the diffusion coefficients determined for volume self‐diffusion in tungsten. The activation energy for the sintering process is 110.7 kcal/mole, lower than the activation energy for volume self‐diffusion. The larger diffusion coefficients and lower activation energy of the sintering process are indicative that the densification of tungsten powder in the temperature range 1300°–1750°C is probably a grain boundary diffusion controlled process.