Electrochemical behavior of laser powder bed fusion fabricated 316L stainless steel in a nitric acid solution

Abstract

The purpose of this work is to study the microstructure and electrochemical performance of 316L stainless steel fabricated by the laser powder bed fusion (LPBF) and commercial rolling (Roll) in 0.5M nitric acid solution. The LPBF-manufactured 316L stainless steel had a higher corrosion resistance in nitric acid solution than the Roll steel. According to the electrochemical studies, the impedance modulus (| Z|10mHz) of the LPBF alloy was twice as great as its roll counterpart after 1 day of immersion in nitric acid solution and about 1 kΩ cm2. Moreover, the potentiodynamic polarization test showed that the LPBF alloy had one-fourth the ipass value as the Roll sample, suggesting that the passive layer on the surface of additive manufactured samples is more stable and enriched with Cr2O3. Additionally, the LPBF microstructure did not contain harmful phases like TiN, which can adversely affect the protection performance of the passive layer.