Investigation on corrosion fatigue property of epoxy coated AZ31 magnesium alloy in sodium sulfate solution

The epoxy coating was applied to improve the corrosion fatigue behavior of AZ31 magnesium alloy in 3.5 wt.% Na2SO4 solution. The bonding interface and the fracture surfaces were investigated by scanning electron microscope. And the compositions were analyzed by energy dispersive spectrometer after corrosion fatigue test. The corrosion fatigue limit of the coated specimens in 3.5 wt.% Na2SO4 solution was found to be improved. The strain matching ability between the epoxy coating and the substrate was the key to determining the fatigue crack initiation mechanism.