Surface Characteristics of Additively Manufactured 316L Stainless Steel with Plasma Electrolytic Polishing

Metal additive manufacturing faces challenges in directly fabricating end-use components due to the poor surface quality. Plasma electrolytic polishing (PEP) is an efficient and environmentally friendly surface treatment technology, demonstrating significant potential to enhance the surface quality of additively manufactured metal components. In this study, the surface characteristics of additively manufactured 316L stainless steel polished by PEP, including surface morphology, chemical composition, and wettability, are systematically investigated. First, the influence of key processing parameters, such as polishing time, voltage, electrolyte temperature, and concentration, on surface roughness was comprehensively examined through a series of experiments. The surface roughness was significantly reduced from 10.479 μm to 2.195 μm by using an optimized parameter combination: a polishing voltage of 300 V, an electrolyte concentration of 3%, an electrolyte temperature of 75°C, and a polishing time of 30 min. Then, surface characteristics of specimens treated with optimized PEP process parameters were studied and compared with those of as-fabricated specimens. Results showed that defects on the surface of as-fabricated specimens, such as adhered powders and oxides, were effectively removed by PEP. In addition, PEP can significantly improve the wettability of the specimens, with the contact angle decreasing from 80.9° to 39.4°. This study provides a comprehensive analysis of the characteristics of PEP of additively manufactured 316L stainless steel, indicating its potential for post-processing applications.