Electrochemical polishing versus mechanical polishing of AISI 304: surface and electrochemical study

Abstract

AISI 304 is essential for vital industries, e.g., aerospace, nuclear plants, pharmaceutical, chemical, and medical industries. Enhancement of AISI 304 surface characteristics is required for protection, durability, and better performance. Different methods were used for surface modification like mechanical polishing (MP) and electrochemical polishing (EP). Scanning electron microscopy, atomic force microscopy, and gloss values revealed the alleviation of humps, imperfection and roughness, and leveling. Smoothness and brightening of the surface after EP (∆R = − 1.206 nm) was more than that of MP treatment (∆R = − 0.562 nm). Energy dispersive X-ray analysis showed increase of Cr, Ni, and Mn content while the content of Fe decreased after EP treatment. Potentiodynamic polarization of EP AISI 304 in 3.5% NaCl revealed a high polarization resistance (R p = 2786 kΩ) and low corrosion rate of 2.74 × 10 −5 mm year −1 ). These parameters were compared to that of MP AISI 304 of lower polarization resistance (R p = 168 kΩ) and higher corrosion rate of 6.01 × 10 −5 mm year −1 ). Potentiodynamic polarization shows that the E corr was −61.09 mV for EP samples compared to −127 mV for MP samples and that the corrosion rate for MP samples was higher than that of EP samples. Mott-Schottky analysis shows a donor densities of 1.370 × 10 22 cm −3 for the EP samples vs. 3.014 × 10 21 cm −3 for MP samples, while acceptor densities of 8.304 × 10 21 cm −3 for EP samples vs. 7.389 × 10 22 cm −3 for MP samples compared to unpolished sample of donor density of 2.036 × 10 21 cm −3 and acceptor density of 8.784 × 10 20 cm −3 which evidenced the better performance for EP treatment. The results were supported by electrochemical impedance spectroscopy as well.

Biological Corrosion Resistance and Osteoblast Response of 316LVM Polished Using Electrolytic Plasma

“…In comparison with the untreated samples, Cr/Fe was significantly increased after EPP, which was consistent with the change trend of 316 stainless steel after electrochemical polishing [6]. This suggests that iron is more easily removed than chromium during EPP, which may be attributed to the fact that electrochemical reaction is the main method for material removal [37,38] and the chemical properties of Cr oxides are more stable than those of Fe [39], with relatively less removal.…”

Surface Modification of Gallium Arsenide by Electrochemical Methods in Different Electrolyte Compositions

“…8 All these modifications of the method are based on the crystal treatment with the acid or alkali solutions. 9,10 The result of such treatment can be the formation of the films on the crystal surface, 11,12 polishing, 13 surface passivation, 14,15 and the formation of the developed semiconductor nanorelief. 16,17 The main advantages of the electrochemical method are its simplicity, cheapness, process speed, and the lack of need to use high-tech and costly equipment.…”