Corrosion Behavior of Zinc Alloy Layers
Abstract
The alloying of zinc with some additional elements in specific quantities could be reliably used in the hot-dip coating process. These elements conferr substantially improved performance to the end-product specially by improving corrosion resistance.
In this paper the influence of adding different percentages of aluminum and bismuth into the zinc bath was researched.
The technological conditions for obtaining zinc-bismuth-aluminium coatings with 0.27% - 0.52% bismuth and 0.11% Al are presented. The degree of microalloying and assimilation in the zinc bath was determined by spectrometric analysis of alloy samples, taken from the melt at different time intervals.
Corrosion resistance of the layers was assessed by two types of tests: corrosion behaviour in seawater for a period of five weeks and electrochemical tests in 3% NaCl solution. Both applied corrosion tests show an increase in corrosion resistance to bismuth content increasing and metallographic analysis of samples corroded shows a general corrosion process.
References
[2]. Khadoudj Guessoum, Delphine Veys-Renaux, Emmanuel Rocca, Kamel Belhamel - Corrosion behaviour of zinc–cerium alloys: Role of intermetallic phases, Corrosion Science, vol. 53, Issue 5, May 2011, p. 1639-1645.
[3]. Lijing Yang, Yangming Zhang, Xuduo Zeng, Zhenlun Song - Corrosion behaviour of superplastic Zn–Al alloys in simulated acid rain, Corrosion Science, vol. 59, June 2012, p. 229-237.
[4]. Shengqiang Ma, Jiandong Xing, Dawei Yi, Hanguang Fu, Guofeng Liu, Shengchao Ma - Microstructure and corrosion behavior of cast Fe–B alloys dipped into liquid zinc bath, Materials Characterization, vol. 61, Issue 9, September 2010, p. 866-872.
[5]. John Zervoudis, Graeme Anderson - A Review of Bath Alloy Additives and their Impact on the Quality of the Galvanized Coating, Teck Cominco Metals Ltd. 120 est, Suite 1500 Toronto, Ontario, Canada, p. 4.
[6]. ***, Galvanising Reactive Steels, a guide for galvanizers and specifies, International Lead Zinc Research Organisation, Research Triangle Park, NC.
[7]. Xinhua Wang, Jintang Lu, Chunshan Che, Gang Kong - The behavior of lead during the solidification of Zn–0.1Al–0.1Pb coating on batch hot-dipped steel, Applied Surface Science, vol. 254, Issue 8, 15 February 2008, p. 2466-2471.
[8]. Gagne M. - Zinc Bismuth Alloys for After Fabrication Hot Dip Galvanizing, American Galvanizers Association Tech Forum 1997, Houston, TX.
[9]. J. Pedersen - Latest developments in nickel-zinc galvanizing, Cominco Ltd Ontario, Canada, on line.
[10]. Pistofidis N., Vourlias G., Pavlidou E., Stergioudis G. - Effect of Ti, Ni and Bi addition to the corrosion resistance of Zn hot-dip galvanized coatings, Journal of optoelectronics and advanced materials 2007, vol. 9, no. 6, p. 1653.
[11]. Tamara Radu, Florentina Potecasu, Maria Vlad - Research on obtaining and characterization of zinc micro-alloyed with bismuth coatings, Metalurgia International, nr. 1/2011, ISSN 1582-2214, p. 44-48.
[12]. ***, The Role of Aluminium in Continuous Hot-Dip Galvanizing, GalvInfoNote 1.9, Rev 1.0, mar. 2009.
[13]. ***, Zinc Bath Management on Continuous Hot-Dip Galvanizing, GalvInfoNote 2.4.1 Rev 1.0 Aug-09.
[14]. S. Sepper, P. Peetsalu, M. Saarna - Methods for evaluating the appearance of hot dip galvanized coatings, Agronomy Research Bio system Engineering Special Issue 1, 2011, p. 229-236.
[15]. ***, ASM Metals Hand Book Alloy Phase Diagrams.
