Article ID Journal Published Year Pages File Type
1469065 Corrosion Science 2013 21 Pages PDF
Abstract

•The corrosion rate of each Mg–RE alloy was substantial and was faster than that of high-purity Mg.•The corrosion rates of the solution heat-treated alloys were probably caused by the particles and/or Fe-rich particles.•The corrosion of as-cast alloys was attributed to micro-galvanic acceleration by the second phases.

Corrosion behaviour was characterised in salt spray and in 3.5% NaCl solution saturated with Mg(OH)2 of as-cast and solution heat-treated binary Mg–RE alloys. The corrosion rate in the immersion test for the solution heat-treated Mg–RE alloys was substantial, and was greater than that of high-purity Mg. These corrosion rates were probably caused by the particles in the microstructure and/or by Fe rich particles precipitated during the solution heat-treatment. The corrosion rate in the immersion tests for each as-cast Mg–RE alloy was greater than that of high-purity Mg, attributed to micro-galvanic acceleration caused by the second phase. Corrosion rates in salt spray had a general correlation with corrosion rates in the immersion tests, but there were differences. The values of apparent valence were always less than 2 consistent with Mg corrosion being only partly under electrochemical control.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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