Evaluation of Corrosion Resistance of 316L stainless steel with or without SiC additions produced via Directed Energy Deposition

Metal additive manufacturing technologies, such as the Directed Energy Deposition (DED) process, offer promising flexibility to develop novel metallic alloys through the mixing of different powders, and to produce monolithic or functionally graded coatings [1]. Both the manufacturing process and material composition are known to significantly impact the microstructure of such AM metals. This study investigates the microstructure and corrosion characteristics of 316L stainless steel and 316L combined with silicon carbide (SiC), both produced by DED, in comparison to a wrought reference material. The electrochemical corrosion behavior in a 0.5M NaCl solution was correlated to observed microstructural features of the various materials. Electrochemical testing, performed using potentiostatic and potentiodynamic polarization methods at room temperature, revealed that 316L stainless steel exhibits excellent corrosion resistance. This was observed both in the homogeneous wrought reference and in cellular structures formed due to elemental segregation induced by DED technique. Microstructural and pitting development were examined using light microscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS). The findings indicate that the presence of SiC influences surface properties, potentially preventing the occurrence of pitting corrosion depending on its concentration.