Effect of binder composition on properties of 316L stainless steel bimodal powder feedstock

Abstract

Metal powder composites for powder injection molding (PIM) technology have been studied. Stainless steel 316L bimodal powders consisting of both nano and microparticles and multicomponent binders based on PLA/PMMA (feedstock I), paraffin wax/PE-LD/PMMA (feedstock II) and polyethylene wax (feedstock III) were used to obtain feedstock. The effect of the binder composition on the characteristics of feedstocks and sintered compacts was investigated. The use of PMMA in a binder allows maintaining the strength of the compacts to high temperatures when sintering. The debinding of "green compacts" from feedstock III leads to an almost complete removal of paraffin wax, and the "brown" parts retain their shape only due to the low-temperature sintering of nanoparticles. The use of the paraffin wax as a binder requires an increase in the content of the bimodal metal powder in the feedstock to 95 wt% to increase the strength of the compacts. Feedstocks and molded compacts were characterized by TEM, SEM, DSC-TG methods.