Diffusion

· The steps involved in forming a part by sintering are shown.
· In the first stage, size selected particles are pressed together in the required shape to form a green part.

From: Edwards & Endean, "Manufacturing with Materials," Butterworths (1990)

· Mechanical interactions bond the material in stage 1.
· Sintering expands the contact area between the particles which grow together by stage 2. The piece still contains connected pores and channels.
· By stage 3, continued sintering has removed most pores and the density is about 95% theoretical.