Study the effect of temperature on corrosion resistance on phosphate coating on AZ31 magnesium alloy

A zinc phosphate coating was formed on AZ31 magnesium alloy. The effect of temperature on phosphate coating was investigated. All measurements showed that the phosphate coating was uniform and well adhered. Polarization curves and salt spray tests were used to assess the corrosion protection of coating. All measurements showed that the phosphate coating afforded considerable protection against corrosion. From results obtained، it was deduced that the optimum phosphating temperature was 45°C. Morphology of phosphate film on magnesium alloy was investigated by scanning electron microscopy (SEM).