Corrosion Resistance Properties of As-Sintered 17-4 PH Samples Additive-Manufactured Through Binder Jetting

The corrosion resistance and microstructural characteristics of 17-4 PH stainless steel fabricated through Metal Binder Jetting (MBJ) were investigated through Cyclic Potentiodynamic Polarization (CPP), Open Circuit Potential (OCP) monitoring, SEM-EDX, optical microscopy, XRD, and chemical etching. Electrochemical tests revealed that as-sintered samples exhibited isotropic corrosion performance across different build-up orientations and directions. The CPP tests indicated the formation of a passive film with limited stability, while the monitoring of the OCP showed initial instability, followed by stabilization over time. Microstructural analysis indicated the presence of microporosities and a structure consisting of martensitic and ferritic grains in the as-sintered 17-4 PH, alongside copper and niobium segregations at grain boundaries, which may deeply influence localized corrosion susceptibility. These findings suggest that the as-sintered 17-4 PH fabricated through MBJ exhibits comparable corrosion behavior to 17-4 PH additive-manufactured through other techniques in which the sintering process is involved. The study highlights the influence of microstructure on electrochemical performance and underscores the need for post processing treatments to enhance corrosion resistance.