Microstructure Influence on the Corrosion of Permanent Mould Cast Magnesium Alloy AJ62 in Engine Coolant

摘要

Powertrain applications of alloy AJ62 arose from itscomparative resistance to high temperature deformation among magnesium alloys. In this research, AJ62 permanent- mould cast in different section thicknesses was subjected to immersion corrosion in commercially-available enginecoolant. The objective was to determine corrosion behaviourvariation among casting thicknesses. Corrosion productaccumulation suggests passive film formation, and unlike inother media, the film exhibits certain stability. Extremethicknesses were used to generate polarization curves fortheir respective microstructures in engine coolant. Variationwith casting section thickness was observed in the curves.These preliminary results indicate coarsened microstructuresreduce corrosion resistance of the permanent mold cast AJ62 alloy.