The influence of strontium(Sr) and rare earth(RE) elements on the corrosion behavior of AZ91D magnesium alloy was investigated by conventional corrosion testing and electrochemical measurements in 3.5% NaCl solution.After comparing the mass loss and hydrogen evolution of the samples,the microstructures of the alloys and the morphologies of their corrosion product films were characterized by electron probe microanalysis-energy dispersive spectrometry(EPMA-EDS) and Auger electron spectroscopy(AES).Compared with individual addition of Sr or RE to AZ91D,the combinative addition of 0.5% Sr and 1% RE to AZ91D successfully decreases the corrosion rate further,which can be attributed to the depression of micro-galvanic couples,as well as the formation of more protective film due to aluminum enrichment.The combinative addition of strontium and rare earth elements to AZ91D magnesium alloy appears to be a promising approach to increase its corrosion resistance.
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