Corrosion Behaviour of Hypereutectic Al-Si Automotive Alloy in Different pH Environment
Corrosion behaviour of hypereutectic Al-19Si automotive alloy in different pH=1, 3, 5, 7, 9, 11, and 13 environments was carried out using conventional gravimetric measurements and was complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. Gravimetric analysis confirmed that the highest corrosion rate is shown at pH 13 followed by pH 1. Minimum corrosion occurs in the pH range of 3.0 to 11 due to establishment of passive layer on the surface. The highest corrosion rate at pH 13 is due to the presence of sodium hydroxide in the solution which dissolves the surface oxide film at a steady rate. At pH 1, it can be attributed that the presence of aggressive chloride ions serves to pick up the damage of the passive films at localized regions. With varying exposure periods by both, the environment complies with the normal corrosion rate profile that is an initial steep rise followed by a nearly constant value of corrosion rate. Resistivity increases in case of pH 1 solution for the higher pit formation and decreases at pH 13 due to formation of thin film. The SEM image of corroded samples immersed in pH 1 solution clearly shows pores on the surface and in pH 13 solution, and the corrosion layer seems more compact and homogenous and not porous.
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 M. S. Kaiser and Swagata Dutta, “Corrosive wear behavior of commercial aluminium engine block and piston in 3.5% NaCl solution,” International Journal of Chemical, Material and Environmental Research, vol. 2, no. 2, pp. 1-9, 2015.
 S. Zor, M. Zeren, H Ozkazanc and E. Karakulak, “Effect of Cu content on the corrosion of Al-Si eutectic alloys in acidic solutions,” Anti-Corrosion Methods and Materials, vol. 57, no. 4, pp. 185-191, 2010.
 T. Giulio and F. Alberto, “The effects of microstructure heterogeneities and casting defects on the mechanical properties of high-pressure die-cast AlSi9Cu3(Fe) alloys,” Metallurgical and Materials Transactions A, vol. 45, no. 12, pp.5486-5498, 2014.
 M. Javidani and D. Larouche, “Application of cast Al–Si alloys in internal combustion engine components,” International Materials Reviews, vol. 59, no. 3132, pp. 1-27, 2014.
 E. Tillova and M. Chalupova, “Solution treatment effect on microstructure and mechanical properties of automotive cast alloy,” Materials Engineering, vol. 19, pp. 39-46, 2012.
 M. S. Kaiser and S. Dutta, “Comparison of corrosion behaviour of commercial aluminium engine block and piston in 3.5% NaCl solution” International Journal of Advances in Materials Science and Engineering, vol. 1, no. 1, pp. 9-17, 2014.
 J. J. Manappallil, “Basic Dental Materials,” 3rd Edition, Published by Jaypee Brothers Medical Publishers (P) Ltd, 2010.
 Z. R. Muslim, H. I. Jaafer and M. Q. Fahem, “The effect of pH level on corrosion rate of aluminium and copper,” International Journal of Basic and Applied Science, vol. 2, no. 4, pp. 89-92, 2014.
 P. B. Madakson, I. A. Malik, S. K. Laminu and I. G. Bashir, “Effect of anodization on the corrosion behavior of aluminium alloy in HCl acid and NaOH,” International Journal of Materials Engineering, vol. 2, no. 4, pp. 38-42, 2012.
 Z. R. Muslim and A. A. Abbas, “The effect of pH and temperature on corrosion rate stainless steel 316L used as biomaterial,” International Journal of Basic and Applied Science, vol. 4, no. 2, pp. 17-20, 2015.
 H. H. Strehblow, “Corrosion mechanism in theory and practice,” Marcel Dekker, New York, 1995.
 S. Adhikari, “Alkaline dissolution of aluminium: surface chemistry and subsurface interfacial phenomena” Ph.D thesis, Lowa State University, Ames, Lowa, USA, 2008.
 L. L. Shreir, “Corrosion: Metal/Environment Reactions,” 2nd Edition, Published by Elsevier Science, 2013.
 M. S. Kaiser, “Effects of solution treatment on wear behaviour of Al-12Si-1Mg piston alloy containing trace Zr” MAYFEB Journal of Materials Science, vol. 1, pp. 27-38, 2016.
 S. K. Chaudhurt, V. Warke, S. Shankar and D. Apelian, “Localized recrystallization in cast Al-Si-Mg alloy during solution heat treatment dilatometric and calorimetric studies,” Metallurgical and Materials Transactions A, vol. 42, no. 10, 3160-3169, 2011.
 A. A. E. Maghraby, “Surface Investigations of Aluminum in 2M Hydrochloric Acid Solution,” The Open Corrosion Journal, vol. 3, pp. 54-57, 2010.
 P. Deepa and R. Padmalatha, “Corrosion behaviour of 6063 aluminium alloy in acidic and in alkaline media,” Arabian Journal of Chemistry, vol. 5, no. 6, pp. 2690-2705, 2013.
 I. Boukerche, S. Djerad, L. Benmansour, L. Tifouti and K. Saleh, “Degradability of aluminum in acidic and alkaline solutions,” Corrosion Science, vol. 78, pp. 343–352, 2014.
 T. Notoya and T. Ishikawa, “Corrosion of aluminium-copper alloy and inhibition action of benzotriazole, tolyltriazole and hydroquinone in sodium hydroxide solution,” Bulletin of the Faculty of Engineering, Hokkaido University, vol. 105, pp. 1-7, 1981.