Corrosion and Metallurgical Characteristics of AZ31B Magnesium Alloy Under NaCl Environment

An investigation was carried out to quantify and characterize the corrosion behaviour of AZ31B magnesium alloy. The specimens were underwent immersion, salt spray, pitting and galvanic corrosion tests in order to quantify and characterize the corrosion rates of the AZ31B specimens with the influence of different pH values, chloride ion concentration and the corrosion time. An attempt was also made to develop an empirical relationship to predict the corrosion rate of AZ31B magnesium alloy. Three factors, five level, central composite rotatable design matrix was used to minimize the number of experimental conditions. Response surface methodology was used to develop the relationship. The developed relationship can be effectively used to predict the corrosion rate of AZ31B magnesium alloy at 95% confidence level. The results show that the corrosion rate was higher in salt spray corrosion tests than the immersion, pitting and galvanic corrosion tests.