Magnesium alloys have some excellent properties such as ligh quality, high specific strength and stiffness, high damp and recoverd easily. So magnesium alloys have been used widely for the housings of automobile parts, cellular phones and notebook computers in recent years However, a drawback due to the poor corrosion resistance of magnesium alloys has limited their engineering applications, especially when the concentrations of heavy metal impurities such as iron, nickel and copper are high. On the other hand, surface treatments are necessary to protect against corrosion because electrochemically.
