Electrochemical corrosion behavior of arc sprayed Zn and Zn15Al coatings in simulated salina soil and neutral meadow soil solutions

Abstract

Arc sprayed Zn and Zn15Al coatings were chosen to protect the metal ends of prestressed high-strength concrete (PHC) pipe piles against corrosion of salina soil in northern china and neutral meadow soil in northeast China. The corrosion behavior of the coated Q235 steel samples in two simulated soil solutions were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The experimental results show that the corrosion of the matrix Q235 steel in both simulated solutions is remarkably inhibited by Zn and Zn15Al coatings. The corrosion products on Zn and Zn15Al are thick, compact, firm and protective. The corrosion current density i _corr of both Zn and Zn15Al-coated samples is decreased evidently with corrosion time, and the charge transfer resistance R _ct is increased greatly. The corrosion resistance indexes of Zn and Zn15Al in simulated neutral meadow soil solution are more outstanding than those in salina soil. The corrosion resistance of Zn15Al in salina soil is slightly superior to that of Zn. When the sprayed coatings are sealed with epoxy resin, the corrosion resistance of the coatings is further enhanced markedly.

Keywords

arc spray / coating / soil / corrosion / electrochemical

References

[1] Fisher A. K., Bullen F., Beal D. The Durability of Cellulose Fibre Reinforced Concrete Pipes in Sewage Applications [J]. Cem. Concr. Res., 2001, 31(4): 543-553.

[2] Miyata Y., Nakano H., Abe M., . Effectiveness of Polyethylene Coating for Steel Pipe Piles [J]. Mater. Perform., 2006, 45(12): 24-27.

[3] Han Q W, Wei Y L. Low Durability of PHC Pipe Piles [N]. Guangdong Jianshe Newspaper, 2006-12-29-B03

[4] Berger D. M. Electrochemical and Galvanic Corrosion of Coated Steel Surfaces [J]. Chem. Eng. (New York), 1982, 89: 109-112.

[5] Du C. W., Li X. G., Liang P., . Effects of Microstructure on Corrosion of X70 Pipe Steel in an Alkaline Soil [J]. J. Mater. Eng. Perform., 2009, 18(2): 216-220.

[6] Lin B. L., Lu X. Y., Li L. Corrosion Behaviors of Metal End of PHC Pipe Pile in Simulated Soil Solutions [J]. J. Central South Univ. (Sci. Technol.), 2011, 42(2): 434-440.

[7] Vourlias G., Pistofidis N., Stergioudis G. Ability of Metallic Coatings to Protect Low Carbon Steels from Aqueous Corrosion [J]. Corros. Eng. Sci. Technol., 2008, 43(2): 163-172.

[8] Papavinasam S., Attard M., Arseneult B., . State-of-theart of Thermal Spray Coatings for Corrosion Protection [J]. Corros. Rev., 2008, 26(2–3): 105-146.

[9] Hou B. R., Zhang J., Duan J. Z., . Corrosion of Thermally Sprayed Zinc and Aluminium Coatings in Simulated Splash and Tidal Zone Conditions [J]. Corros. Eng. Sci. Technol., 2003, 38(2): 157-160.

[10] Tobe S. A Review on Protection from Corrosion, Oxidation and Hot Corrosion by Thermal Spray Coatings. ASM Thermal Spray Society, German Welding Society, and High Temperature Society of Japan, 1998 Nice ASM International 3-11.

[11] Lee S. H., Lee H. S., Kyung J. W., . Anti-Corrosion Performance of Zn-Al Thermal Metal Spraying Method Using Steel Structures [J]. Key Eng. Mater. Adv. Fract. Damage Mech. VI, 2007, 348–349: 453-456.

[12] Liu Y., Zhu Z. X., Chen Y. X., . Electrochemical Corrosion Behavior of Arc Sprayed Zn-Al Coatings [J]. Trans. Nonferrous Met. Soc. China, 2004, 14(SI): 443-445.

[13] Chaliampalias D., Vourlias G., Pistofidis N., . A Morphological and Microstructural Study of Flame-Sprayed Zinc Coatings on Low-Alloyed Steels as a Contribution to Explaining their Corrosion Resistance [J]. Phys. Status Solidi. (A) Appl. Mater., 2008, 205(7): 1566-1571.

[14] Tsuyoshi M., Kazuo F., Yasuyuki T., . Corrosion Rate and Corrosion Behavior of Al-2%Zn Alloy Spray Coating in Sodium Chloride Solution at Low Temperature [J]. Corros. Eng., 2005, 54(11): 520-525.

[15] Kuroda S., Kawakita J., Takemoto M. An 18-year Exposure Test of Thermal-Sprayed Zn, Al, and Zn-Al Coatings in Marine Environment [J]. Corrosion, 2006, 62(7): 635-647.

[16] Lin B. L., Lu X. Y., Li L. Corrosion Behaviors of Arc Spraying Single and Double Layer Coatings in Simulated Dagang Soil Solution [J]. Trans. Nonferrous Met. Soc. China, 2009, 19(6): 1 556-1 561.

[17] Yang X. Z., Yang W. Electrochemical Thermodynamics of Metallic Corrosion: Potential-pH Diagrams and their Applications [M], 1991 Beijing Chemical Industry Press 21-86.

[18] Cachet C., Ganne F., Joiret S., . EIS Investigation of Zinc Dissolution in Aerated Sulphate Medium. Part II: Zinc Coatings [J]. Electrochim. Acta, 2002, 47(21): 3409-3422.

[19] Cao C. N., Zhang J. Q. Introduction to Electrochemical Impedance Spectroscopy [M], 2002 Beijing Science Press 143-189.

[20] Weng D., Jokiel P., Uebleis A., . Corrosion and Characteristics of Zinc and Manganese Phosphate Coatings [J]. Surf. Coat. Technol., 1997, 88(1–3): 147-156.

[21] Tang N., Ooij W. J., Gorecki G. Comparative EIS Study of Pretreatment Performance in Coated Metals [J]. Prog. Org. Coat., 1997, 30(4): 255-263.

[22] Benedetti A. V., Sumodjo P. T. A., Nobe K., . Electrochemical Studies of Copper, Copper-Aluminium and Copper-Aluminium-Silver Alloys: Impedance Results in 0.5 M NaCl [J]. Electrochim. Acta, 1995, 40(16): 2657-2668.

[23] Yao J. M. College Physics (II) [M], 2008 Beijing Beijing Institute of Technology Press 317-322.