Powder injection molding of biocompatible stainless steel biodevices

Abstract Although various materials have been exploited throughout history to restore damaged organs, metallic biodevices are preferred in the biomedical industry because of their superior ability to withstand high static or cyclic loads. An implant is a medical device manufactured to replace a damaged biological structure. Medical implants are manmade devices and their biocompatibility plays an important role in determine the life of inserted implant. This review presents previous research conducted in the field of corrosion resistance and mechanical properties of bioimplants made of 316L stainless steel (SS) powder using the powder injection molding process. It also establishes a motivational link between the past and present to encourage researchers to conduct constructive studies on the most problematic areas of bioimplants. This article presents a critical review on powder selection, manufacturing techniques, debinding processes, and sintering conditions of 316L SS powders. It also focuses on the influence of powder shape, powder size, powder-to-binder ratios and their effects on densification in terms of corrosion and mechanical properties. In this paper, practical densification approaches are divided into three categories: activation sintering, optimized solid loading, and bimodal mixtures. Additionally, suggestions for the formation of a passive oxide layer on the outer surface of 316L stainless steel implants using powder densification approaches and optimization of sintering parameters are proposed.