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.