Effect of Fe, Ni, and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy under different pH conditions
Keywords:Al-Si alloy, pH environment, Corrosion, gravimetric analysis, surface resistivity, SEM
Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13 was performed using conventional gravimetric measurements and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyser (EDX) investigations. The highest corrosion rate was observed at pH 13 followed by pH 1, while in the pH range of 3.0 to 11, there is a high protection of surface due to formation of stable surface oxide film. The highest corrosion rate at pH 13 is due to presence of sodium hydroxide in the solution in which the surface oxide film is soluble. At pH 1, however, high corrosion rate can be attributed to dissolution of Al due to the surface attack by aggressive chloride ions. Presence of Fe, Ni and Cr in hyper-eutectic Al-Si automotive alloy has significant effect on the corrosion rate at both environmental pH values. Resistivity of alloy surfaces initially decreases at pH 1 and pH 13 due to formation of thin films. The SEM images of corroded samples immersed in pH 1 solution clearly show pores due to uniform degradation of the alloy. In pH 13 solution, however, the corrosion layer looks more packed and impermeable.
[ P. S. Mohanty, J. E. Gruzleski, Acta Mater 44(9) (1996) 3749-3760.
R. K. Singh, A. Telang , S. Das, American Journal of Engineering Research 5(8) (2016) 133-137.
M. S. Kaiser, International Journal of Materials Science and Engineering 5(2) (2017) 87-94.
M. N. E. Efzan, H. J. Kong, C. K. Kok, Advanced Materials Research 845 (2013) 355-359.
S. G. Shabestari, H. Moemeni, Journal of Materials Processing Technology 153–154 (2004) 193-198.
S. G Shabestari, Materials Science and Engineering A 383 (2004) 289-298.
R. S. Rana, R. Purohit, S. Das, International Journal of Scientific and Research Publications 2(6) (2012) 1-7.
A. Kumar, G. Sharma, C. Sasikumar, S. Shamim, H. Singh, Applied Mechanics and Materials 789-790 (2015) 95-99.
H. H. Strehblow, Corrosion Mechanism in theory and practice. Marcel Dekker, New York, (1995)
X. Cao, J. Campbell, Materials Transactions 47(5) (2006) 1303-1312.
S. A. Awe, S. Seifeddine, A. E. W. Jarfors, Y. C. Lee, A. K. Dahle, Advanced Materials Letters 8(6) (2017) 695-701.
W. Eidhed, Journal of Materials Science and Technology 24(1) (2008) 45-47.
S. Adhikari, Alkaline dissolution of aluminium: surface chemistry and subsurface interfacial phenomena, Ph.D thesis, Lowa State University, Ames, Lowa, USA, (2008)
M. Pourbaix, Atlas of electrochemical equilibria in aqueous solutions, 2nd edition, National Association of Corrosion Engineers, Houston, TX, USA.1974.
D. Prabhu, P. Rao, Arabian Journal of Chemistry 10(2) (2017) 2234-2244.
J. R. Galvele, Journal of the Electrochemical Society 123(4) (1976) 464-474.
N. Birbilis, M. K. Cavanaugh, R. G. Buchheit, Corrosion Science 48(12) (2006) 4202-4215.
B. A. Shaw, T. L. Fritz, G. D. Davis, W. C. Moshier, Journal of the Electrochemical Society 137(4) (1990) 1317-1318.
M. Al Nur, M. S. Kaiser, International Journal of Mechanical and Materials Engineering 11(11) (2017) 1736-1740.
M. S. Kaiser and S. Dutta, International Journal of Advances in Materials Science and Engineering 1(1) (2014) 9-17.
A. A. El Maghraby, The Open Corrosion Journal 3 (2010) 54-57.
A. Skolakova, P. Novak, D. Vojtech, T. F. Kubatik, Materials and Design 107 (2016) 491-502.
T. S. Kim, C. Suryanarayana, B. S. Chun, Materials Science and Engineering 278 (2000) 113–120.
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