Tin Powder addition effects on sinterability & microstructure of stainless steel

Powder metallurgy involves forming processing of metal powders into useful metallic parts. In fact this process is a unique method which can produce porous parts so that its porosities, distribution and pour size are controllable. Stainless steel filters are commonly made from steel or alloy powder via pressing and sintering. In this research, ST.ST.316L and ST.ST. 316Lt + 2%wt Sn powders have been used to from filter by using uniaxial press to forming powder and then sintered. When Tin powder added sinterability showed improved. Tin addition affected microstructure so that grain growth was obvious evidence, also pore size expansion occurred. Grain coarsing in the sintered tin added stainless steel samples may indicate that liquid tin accelerates atomic diffusion related processes occurring during heating of powder compacts. Also, some pores created by Tin particle disappearance, were observed in addition to those initiated by original voids in the green compacts. The remained porosity was between 46 to 38 %.