Evaluation of the Corrosion Resistance of Aluminum Alloy Matrix/ 2.5% Particulate Glass Reinforced Composite in Various Media

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Author(s) Ihom, A.Paul | Nyior, G. Bem | Nor Iv, Justine | Segun, Solaogun | Ogbodo, Joy
Pages 560-568
Volume 1
Issue 10
Date October, 2012
Keywords Evaluation, corrosion, aluminium alloy composite, sodium hydroxide, hydrochloric acid, and sodium chloride
Abstract

Evaluation of the corrosion resistance of aluminum alloy matrix/ 2.5% particulate glass reinforced composite in various media has been carried out. The work started with the casting of the composite using stir-cast method. This was followed by sample preparation, preparation of the sodium chloride solution, hydrochloric acid solution, sodium hydroxide solution, and then the setting up of the experiment. Various equipment were used during this period which included, sample lathe used for the preparation of the specimens, electronic digital balance, flat-bottomed flask, thread, brush, stopper rubber, pH meter, hand air blower, and beakers. The result was recorded every Thursday after every seven days for five weeks. The result revealed that for the composite exposed in 5 weight percent NaCl solution the highest weight loss occurred at 336 hours of exposure time which corresponded to 0.6 percent weight loss and a corrosion rate of 18.99 mpy. The pH was between 6 – 7.62, throughout the exposure time of the specimens in the NaCl solution. For the specimens exposed in 10 weight percent HCl solution, the highest weight loss of 2220 mg occurred at 840 hours corresponding to 21.62 percent weight loss and a corrosion rate of 280.998 mpy, while the medium remained acidic throughout the period of the exposure. For the specimens exposed in 10 weight percent sodium hydroxide solution the highest weight loss of 4110 mg occurred at 840 hours corresponding to a percent weight loss of 40.45 percent and a corrosion rate of 540.227 mpy. The pH of the medium remained alkaline throughout the period of the experiment. The result of the work lead to the following conclusions: the composite can be used in an environment containing sodium chloride since the corrosion rate falls within the recommended corrosion range of 1-200 mpy for usefully resistant materials, the composite cannot be used either for holding HCl solution or as a structural material where HCl solution is found, the composite cannot be used as a container for holding NaOH solution or in an environment where NaOH solution is found, since it selectively dissolves the composite, leaving behind an altered residual structure, the weight loss, the percentage weight loss, and the corrosion rate expressed in mpy all agree with the physical appearance of the specimens after the exposure time of the test, and the monitored pH of the solution also agreed with the test results.

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