Effect of diffusion processes on the sintering of metal powders

Conclusions

• 1. The activation of the sintering process following the addition of other metals is linked with the presence, generation, and interaction of structural defects in particles, which facilitate diffusional creep of metal.

• 2. The predominant direction of diffusional fluxes between the parent metal and the addition metal does not appear to be of decisive importance in the activation of the sintering process.

• 3. In the activation of sintering by metallic additions, two physical factors are of significance: thermodynamic instability of the structure of the addition metal in the course of sintering (presence of defects) and generation of defects in the crystalline structure as a result of diffusion processes.

• 4. The mechanism by which various metal additions affect sintering, however, may vary and need not always be determined solely by the intensity of mutual diffusion. The viscosity coefficient of a system can also be lowered by inhibition of the recovery process and reduction in the size of mosaic blocks, as happens in the presence of a nickel addition.

• 5. The sintering process can be activated by metals exhibiting either full or limited mutual solubility.