Electrochemical Behavior of Passive Films Formed on the Surface of Coarse-,Fine-and Ultra-fine-Grained AA1050 Based on a Modified PDM
来源期刊：Acta Metallurgica Sinica2016年第7期
论文作者：Seyed Omid Gashti Arash Fattah-alhosseini Yousef Mazaheri
文章页码：629 - 637
摘 要：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 coarse-grained（CG）,fine-grained（FG） and ultrafine-grained（UFG） 1050 Al alloy（AA1050） samples in alkaline media（pH value of 8.0） based on a modification of point defect model（PDM）.The EIS results revealed that the polarization resistance increased from about 22.71-120.33 kΩ cm2for 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 2.19 × 1021-0.61 × 1021 cm-3and 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.
Seyed Omid Gashti，Arash Fattah-alhosseini，Yousef Mazaheri
Department of Materials Engineering,Bu-Ali Sina University
摘 要：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 coarse-grained（CG）,fine-grained（FG） and ultrafine-grained（UFG） 1050 Al alloy（AA1050） samples in alkaline media（pH value of 8.0） based on a modification of point defect model（PDM）.The EIS results revealed that the polarization resistance increased from about 22.71-120.33 kΩ cm2for 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 2.19 × 1021-0.61 × 1021 cm-3and 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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