Investigation of corrosion resistance of 17-4 PH stainless steel additive-manufactured by Bound Metal Deposition and Binder Jetting

In the past decades, Additive Manufacturing (AM) has gained the interest of many industries because of its capability to produce complex parts and customized components near the place where they are needed. Moreover, several challenges still need to be addressed, including material quality, process reproducibility, and certification of the produced parts, to guarantee the safety and reliability of components produced using this manufacturing technology. Notably, there is a lack of research on the corrosion resistance properties of additive-manufactured metals and metal alloys obtained by state-of-the-art technologies such as Bound Metal DepositionTM and Binder JettingTM. To address this gap, this study developed novel methods to investigate the corrosion resistance of 3D printed stainless steel. In this work, the corrosion resistance properties of Bound Metal DepositionTM and Binder JettingTM additive-manufactured samples were investigated through electrochemical methods, such as cyclic potentiodynamic and open circuit potential monitoring and analysis, and morphological investigations using optical and scanning electron microscopy techniques. 17-4 PH stainless steel plates with different build-up orientations were printed and investigated in the as-sintered and heat-treated conditions. The results showed that the presence of oxides and defects, which cannot be prevented and are caused by the printing and sintering processes, are detrimental to the passive film properties in neutral sodium chloride solutions. Remarkably, the heat treatments improved the localized corrosion resistance properties of the samples; some of these samples even reached similar properties to that of a 17-4 PH obtained by conventional metallurgy. This study not only fills a crucial gap in the existing literature but also provides a foundation for future research into optimizing printing parameters and post-processing treatments to obtain stainless steel components characterized by good quality, reproducibility and reliability in terms of corrosion resistance properties.