Effect of Microstructure of Additively Manufactured Inconel 625 on Long-Term Corrosion Behaviour in Sulfuric Acid Media

Abstract The aim of this work was to investigate the effect microstructure Inconel 625 additively manufactured by laser powder bed fusion (LPBF) and laser-assisted directed energy deposition (LDED) on resistance corrosion in sulfuric acid solution. Corrosion tests lasted 30 days, 90 days 180 days. Microstructure characterization performed using light microscopy, scanning scanning-transmission electron microscopy. measurements were conducted polarization curves impedance spectroscopy. After immersion acid, pits observed surface. area fraction increased with prolongation test after equal 9.63% 4.49% LPBF LDED specimens, respectively. higher density occurred along boundaries melt pools, grain cell walls next precipitates. It determined that drop increase current than 625, which mainly related a more intensive propagation areas free energy. Furthermore, weaker is refined preferential sites localized long-term acid.