Comparative Study of the Corrosion Behavior of AZ31B Magnesium Alloy under Immersion and Salt Fog Environments

Abstract

The comparative evaluation of corrosion behavior of AZ31B magnesium alloy was investigated by conducting immersion and salt spray tests in NaCl solution. The specimens were exposed to immersion and salt spray environments in order to characterize their corrosion rates. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of the AZ31B magnesium alloy in immersion tests and salt spray corrosion tests using response surface methodology. The corrosion morphology observation was carried out by scanning electron microscopy. General corrosion was more prevalent on the immersion surface. However, the pits on the salt spray surface showed larger surface areas, larger volumes, and covered more area on the micrographs as compared to the pits on the immersion surfaces, due to the pit debris that trapped chloride ions within the pits. Finally, it concludes that the AZ31B magnesium alloys are suitable for immersion conditions than salt spray environments.