Electrochemical Behavior of Passive Films Formed o

Authors: Seyed Omid Gashti Arash Fattahalhosseini Yousef Mazaheri

Publish Date: 2016/05/18

Volume: 29, Issue: 7, Pages: 629-637

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Abstract

Electrochemical impedance spectroscopy EIS and Mott–Schottky analysis were carried out to evaluate the electrochemical behavior of the passive films formed on the surface of coarsegrained CG finegrained FG and ultrafinegrained UFG 1050 Al alloy AA1050 samples in alkaline media pH value of 80 based on a modification of point defect model PDM The EIS results revealed that the polarization resistance increased from about 2271–12033 kΩ cm2 for UFG sample when compared to CG sample annealed sample The semiconductor properties of the passive films formed on CG FG and UFG AA1050 samples in the test solution were investigated by employing Mott–Schottky analysis in conjunction with PDM The results indicated that donor densities were in the range of 219 × 1021–061 × 1021 cm−3 and decreased with grain refinement Finally all electrochemical tests showed that the electrochemical behavior of AA1050 alloy was improved by decreasing the grain size mainly due to the formation of thicker and less defective oxide films

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