LATTICE DIFFUSION FROM THE GRAIN-BOUNDARY IN THE SINTERING OF METAL POWDERS

Although sintering maps have been in use since 1974, there is no expli cit solution for the diffusion of atoms from the grain boundary to the neck by lattice diffusion. The approximate solutions in the literatur e are considered and their weaknesses examined. Two new solutions are presented, an upper limit solution with surface curvature at a maximum all along the neck, and a more accurate solution in which the form of the surface curvature at the neck can be varied as appropriate. The a pplicability of the solutions in regions of lattice diffusion dominanc e is considered vis a vis the coupled solution for lattice and boundar y solution. Finally the effect of the new solution is shown for sinter ing maps.