Corrosion behaviour of 6061 Al - 15vol. Pct. SiC composite and its base alloy in a mixture of 1:1 Hydrochloric and sulphuric acid medium

Abstract

Silicon carbide particulate - reinforced aluminum (SiCp-Al) composites possess a unique combination of high specific strength, high elastic modulus, good wear resistance and good thermal stability than the corresponding non-reinforced matrix alloy systems. These composites are potential structural material for aerospace and automotive applications. The corrosion characteristics of 6061 Al/SiCp composite and the base alloy were experimentally assessed. The corrosion test was carried out at different temperatures in 1:1 mixture of hydrochloric acid and sulphuric acid at a concentration range of 0.01 to 1N for each of the acid, as corrosion media using Tafel extrapolation technique and Electrochemical impedance spectroscopy (EIS). The results obtained from Tafel extrapolation technique and Electrochemical impedance spectroscopy were in good agreement. The results showed an increase in the corrosion rate with increases in temperature as well as the increase in the concentration of the corrosion media. The thermodynamic parameters like energy of activation were calculated using Arrhenius theory equation and, enthalpy of activation and entropy of activation were calculated using transition state theory equation. © 2009 by ESG.