عنوان مقاله [English]
Improvement of the corrosion resistance capability by the electropolishing (EP) is one of the most importance process surface modification. In this paper, the effects of two variables perchloric acid concentration and bath temperature on the electropolishing process and the corrosion resistance performance of the Inconel 718 alloy were studied. Evaluation of microstructure and surface roughness quality before and after electropolishing process by the scanning electron microscopy (SEM) and surface roughness test were used, respectively. In order to determine voltage range and current electropolishing to I-V curves were used. The results showed that, obtain to uniform surface and without pores can be achieved only under the conditions has the electrolyte composition as 10 vol% H2O -70 vol% CH3COOH -20 vol% HClO4 and bath temperature is 15 °C. Electropolishing rate in the above conditions at the grain boundaries and inside the grains came close together and lead to a smooth and uniform surfaces. The minimum surface roughness after electropolishing on the above condition amount 0.026 μm obtained. The results of the TOEFL polarization test in a solution of 0.5M H2SO4 + 0.01M KSCN indicated, electropolishing Inconel 718 alloy reduces the corrosion current density and become more Noble in potential (Ecorr). Electropolished samples under optimized conditions has exhibited the highest resistance to corrosion. The reason improving in the corrosion resistance Inconel 718 alloy by electropolishing that was attributed to the formation of very uniform oxide layer on surface and microstructure free of cavities.
 Jacquet, P.A., "Electrolytic Polishing of Metallic Surfaces", Metal Finishing, 1949, Vol. 47, Pp. 48-54.
 Lee, S.J., and Lai, J.J., "The effects of electropolishing (EP) process parameters on corrosion resistance of 316L stainless steel", Journal of Materials Processing Technology, 2003, Vol. 140, Pp. 206–210.
 Taylor, E.J., Crabb, H.M., Garich, H., Hall, T., and Inman, M., "A pulse/pulse reverse electrolytic approach to electropolishing and through-mask electroetching", Faraday Technology, 2012, Pp.768-780.
 Berns, H., Gavriljuk, V., and Riedner, S., "Structure", Engineering Materials, 2013, Pp. 21-83.
 Saito, K., "Development of electropolishing technology for superconducting cavities", Proceedings of the IEEE Particle Accelerator Conference, Portland, United States, 2003, Pp. 462-466.
 Sutow, E.J., "The influence of electropolishing on the corrosion resistance of 316L stainless steel", Journal of Biomedical Materials Research, 1980, Vol. 14, Pp. 587-595.
 Momeni, M., Esfandiari, M., and Moayed, M.H., “Improving pitting corrosion of 304 stainless steel by electropolishing technique", Iranian Journal of Materials Science & Engineering, 2012, Vol. 9, Pp. 34-42.
 Jin, S., Lu, X., Lin, L., and Zhao, K., "Study of buffered electropolishing on niobium sheet", Proceedings of SRF, 2009, Pp. 859-863.
 Eozenou, F., Berry, S., Gasser, Y., and Charrier, J.P., "More information concerning electro-polishing mechanisms in hydrofluoric–sulphuric acid mixtures", 14th International Conference on RF Superconductivity, Berlin, Dresden, 2009.
 Tash, M., Khalifa, W., and Hashash, A., "Effect of metallurgical differences between 356 and 384 alloys on their mechanical properties", Proceedings of The 9th Cairo University International Conference on Mechanical Design and Production (MDP-9), Cairo, Egypt, 2008, Pp. 992-1004.
 Simka. W., and Kaczmarek, M., "Electropolishing and passivation of NiTi shape memory alloy", Electrochimica Acta, 2010, Vol. 55, Pp. 2437–2441.
 Han, G., and Lu, Z., "Improving the oxidation resistance of 316L stainless steel in simulated pressurized water reactor primary water by electropolishing treatment", Journal of Nuclear Materials, 2015, Vol. 467, Pp. 194–204.
 Han, Y., Mei, J., and Peng, Q., "Effect of electropolishing on corrosion of Alloy 600 in high temperature water", Corrosion Science, 2015, Vol. 98, Pp. 72–80.
 Rotty, C., Doche, M.L., Mandroyan, A., Hihn, J.Y., Montavon, G., Moutarlier, V., “Comparison of electropolishing behaviours of TSC, ALM and cast 316L stainless steel in H3PO4/H2SO4”, Surfaces and Interfaces, 2017, Vol. 6, Pp. 170–176.
 Liu, M., Meng, Y., Zhao, Y., Li, F., Gong, Y., Feng, L., “Electropolishing parameters optimization for enhanced performance of nickel coating electroplated on mild steel”, Surface and Coatings Technology, 2016, Vol. 286, Pp. 285–292.
 Paulonis, D.F., and Schirra, J., "Alloy 718 at pratt and whitneyhistorical perspective and future challenges", The Minerals. Metals and Materials Society, 2001, Pp. 13-23.
 Lee, S.J., Lee, Y., and Du, M., "The polishing mechanism of electrochemical mechanical polishing technology", Journal of Materials Processing Technology, 2003, Vol. 140, Pp. 280–286.
 Pelleg, J., "Electropolishing Pure Vanadium", Nuclear Research, 1970, Pp. 457-460.
 Mural, S., Ramachandra, M., Murthy, K.S.S., and Ramant, K.S., "Eiectropoiishing of AI-7Si-0.3Mg Cast Alloy by Using perchloric and Nitric Acid Electrolytes", Materials characterization, 1997, Vol. 38, PP. 273-286.
 Rahman, Z.U., Deen, K.M., Cano, L., Haider, W., “The effects of parametric changes in electropolishing process on surface properties of 316L stainless steel”, Applied Surface Science, 2017, Vol. 410, Pp. 432-444.
 Nazneena, F., Galvina, P., Arriganb, W.M., Thompsonc, M., Benvenutoc, P., and Herzoga, G., "Electropolishing of medical-grade stainless steel in preparation for surface nano-texturing", Journal of Solid State Electrochemistry, 2012, Vol. 16 , Pp. 1389-1397.
 Aihara, H., "Surface and biocompatibility study of electropolished Co-Cr Alloy L605", Master's Theses and Graduate Research, San Jose State University, 2009, Pp. 36-99.