Investigation on Corrosion Resistance Properties of 17-4 PH Bound Metal Deposition As-Sintered Specimens with Different Build-Up Orientations

Additive manufacturing is a promising and emerging technology that can transform the global manufacturing and logistics by cutting costs and times of production. Localized corrosion resistance properties of 0 degrees, 45 degrees, and 90 degrees build-up orientations of 17-4 PH as-sintered samples, manufactured by means of Bound Metal Deposition (BMD), have been investigated by electrochemical and morphological investigations. The cyclic potentiodynamic polarization curves and the open circuit potential monitoring, together with potential drop analysis, revealed that the BMD localized corrosion resistance properties were lowered if compared to a wrought 17-4 PH: a characteristic anodic behavior and many drops in potential were recorded for BMD, whilst the wrought specimens presented a typical passive behavior with pitting corrosion. Morphological investigations by scanning electron microscopy and energy-dispersive X-ray analysis revealed the presence of porosities and defects, especially for the 90 degrees build-up orientation, and inclusions of SiO2. The 45 degrees build-up orientation showed the best corrosion resistance properties among all the BMD specimens, even though defects and porosities were observed, suggesting that their morphology and geometry influenced the overall corrosion behavior.

Automated summary

It is found in the study that the localized corrosion resistance properties of BMD samples manufactured by additive manufacturing technology are lower than those of traditionally manufactured 17-4 PH samples. Among the different build-up orientations, the 45-degree orientation showed the best corrosion resistance properties, despite the presence of defects and porosities.