Effect of Passivation Treatments on the Corrosion Resistance Properties of As-sintered 17-4 PH Additive-Manufactured by Binder Jetting Technology

Binder Jetting (BJ) is an additive manufacturing technology that can produce alloy components at a higher speed and resolution than other systems. However, the localized corrosion resistance properties of BJ stainless steel are lower than those obtained with conventional manufacturing processes. This study aims to evaluate the effects of passivation treatments on the corrosion behavior of as-sintered 17-4 PH samples fabricated through BJ. The samples were treated with four acidic solutions: 15 %, 20 %, 40 % HNO₃, and 40 % HNO₃ + 1 % HF. The localized corrosion resistance properties were evaluated through Cyclic Potentiodynamic Polarization (CPP) tests in a neutral pH sodium chloride electrolyte. The treatments significantly enhanced the localized corrosion resistance properties of as-sintered BJ samples, determining the typical passive anodic behavior of the CPP curve, which was not shown in the untreated samples. Moreover, higher concentrations of HNO₃ (40%) improved the pitting corrosion resistance, while adding HF was ineffective. The study paves the way for broader industrial applications of additive-manufactured stainless steel, emphasizing the critical role of improving localized corrosion resistance properties through passive treatments.