Investigation of Zinc metallic coating properties formed on low carbon steel in alkaline and sulfate electrolytes by plasma electrolytic saturation
Subject Areas : journal of New Materialsفریبا Momeni 1 , سید محمد موسوی خوئی Mousavi Khoee 2
1 - کارشناسی ارشد خوردگی و حفاظت فلزات،دانشکده مهندسی مواد،دانشگاه صنعتی امیرکبیر تهران
2 - دانشیار،عضو هیئت علمی داشگاه امیرکبیر،دانشگاه صنعتی امیرکبیر تهران
Keywords: Corrosion Resistance, Polarization, Zinc Metal Coating, Plasma Electrolytic Saturation,
Abstract :
Electrolytic plasma galvanization is one of the newest methods for corrosion protection of steels. In this research, Plasma electrolytic (PE) method were used for zinc deposition on st12 steel. Work-Pieces were connected to the cathode of high voltage direct current source and were placed inside electrolyte. Sodium hydroxide alkaline solution including 3 wt% zinc dissolved in saturated HCl acid and 30 wt% ZnSO4 solution were used as electrolytes and NaCl were added to increase the electrical conductivity. Surface morphology and composition of coatings was analyzed by SEM and EDAX. Corrosion behavior was also evaluated by DC polarization in 3.5 wt% NaCl.Results showed that zinc deposition formed broccoli type morphology coating because of the plasma spark actions. Corrosion resistance of steel increased by zinc coating to the more active potential and changing of electrolyte type from ZnSO4 to alkaline (zinc ion saturated) solution increased electric conductivity and so PE process current increases to 3A and initial spark generation voltage decreases to 50 V. .
1- P. Gupta, G. Tenhundfeld, E.O. Daigle, D. Ryabkov. Surface and Coatings Technology,2007,“Electrolytic plasma technology: Science and engineering-An overview”.
2- P. Gupta, G. Tenhundfeld, E.O. Daigle, D. Ryabkov,” Electrolytic plasma Technology”, Surface and Coatings Technology, 2005.
3-امیرحسین اعتضادی/مجتبی نصر اصفهانی/احسان صائب نوری/بازدارندگی از خوردگی مس به وسیله فیلم های لایه نازک خود مجموعه سازشیف باز در محیط های اسیدی/مواد نوین/جلد5/شماره1/پاییز1393.
4- P.Taheri, M.Aliofkhazraei,Ch. Dehghanian, A.R. Sabour, A phenomenological model of plasma electrolytic saturation (PES) of steel in related solutions, Tenth international conference on plasma surface engineering, Germany, 2006.
5- X.Nie, C.Tsotsos, A.Wilson, A.L.Yerokhin, A.Leyland, A.Matthews. Surface and Coatings Technology, 2001, Characteristics of a plasma electrolytic nitrocarburising treatment for steels, Vol. 139, pp. 135-142.
6- A. L. Yerokhin, X. Nie, A. Leyland, A. Matthews and S. J. Dowey ,Surface and Coatings Technology 1999, “Plasma electrolysis for surface engineering”, 122: p.73-93,
7- G. Yong-jun, W. XIAY “Correlation between discharging property and coatings microstructure during plasma electrolytic oxidation”, Trans. Nonferrous Met. SOC. China 16, pp.1097-1102, 2006.
8- A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews, S.J. Dowey, Surface and Coatings Technology, 1999, “Review of plasma electrolysis for surface engineering”.
9-. Singh A.K., Jha G., Chkrabarti S., “ Spangle formation on hot-dip galvanized steel sheet and its effects on corrosion-resistance properties”, Journal of corrosion engineering, Vol.59,No: 2, 2003.
10- Kanamaru T, Nakayama M, “ Alloying reaction control in production of galvannelaed steel”، Mater Sci Res Int, 1995,Vol:1, 150.
11- Mackowiak J, Short N.R، “Metallurgy of galvanized coatings”, Int Met Reviews, 1979.Vol:1.345.
12- S. Moon, Y. Jeong “ Generation mechanism of microdischarges during plasma electrolytic oxidation of Al in aqueous solutions”, Corrosion Science 51, pp. 1506–1512, 2009.
13- Zapponi M., Quiroga A., Perez T, “segregation of alloying elements during the hot-dip coating solidification process”, Surface and Coating Technology, Vol: 122,1999,18-20.
