Application of electrochemical polishing in surface treatment of additively manufactured structures: A review

The accelerated growth of additive manufacturing (AM) technologies has greatly aided the expansion of the affiliated manufacturing industry, leading to cost savings in labor, materials, and time. However, manufacturing defects still limit the range of potential applications of AM components. Among the various surface treatments existing for AMed parts, electrochemical techniques have been considered as a promising way to improve the surface roughness, mechanical properties, corrosion resistance and biocompatibility of the fabricated parts. The application of electrochemical techniques in AM is gradually getting more attention. This work focuses mainly on directed energy deposition (DED) or laser powder bed fusion (L-PBF) fabricated metals and systematically evaluates the existing body of knowledge on electrochemical applications for metallic AMed parts based on the dissolution curve. According to the different regions of the dissolution curve (passivation, polishing, and pitting), the applicable principles of electrochemical techniques are introduced and comprehensively detailed. The main influencing factors including electrolyte types, electrochemical parameters, material characteristics, and processing methods of electrochemical applications are comprehensively discussed. Lastly, hybrid manufacturing possibilities and practical applications of electrochemical techniques are detailed. This work identifies the gaps in the existing scientific understanding and describes the prospects for electrochemical polishing in surface treatment of AMed parts in industrial applications.