EFFECT OF Al CONTENT ON THE CORROSION BEHAVIOR OF MAGNESIUM ALLOY

摘要

Corrosion behavior of magnesium alloy with different Al content was investigated by polarization curves and electrochemical impendence spectroscopy (EIS). The capacitance property and the multiple-layer structure of the passive film formed on Mg-56%Al alloy were studied by Mott-Schottky approach and potentiostatic-galvanostatic (P-G) transient technique respectively. The results revealed that 56% Al content was the critical content for the highest corrosion resistance of Mg-Al alloy. Mg-56%Al alloy was metallic glassy and exhibited apparent spontaneous passiviation. There was a multiple-layer passive film formed on surface, which consisted of P-type semiconductor film and N-type semiconductor film. The passive film had highest stability and corrosion resistance around the conversion potential that the film semiconductivity conversed from P-type to N-type.