Preparation and Corrosion-resistance of Super-hydrophobic Mg Alloys

Four simple methods of fabricating a super-hydrophobic film on magnesium alloy through the employment of two chemical reagents and two surface modifiers were investigated. The Mg alloys were chemically etched by CuCl2 or ZnSO4 first and then modified with low surface energy material of oleic acid or stearic acid. After modification, the obtained samples show super-hydrophobicity with static contact angle to reach higher than 150 and the sliding angle of about 6.5. The super-hydrophobicity of obtained samples are stable; the water contact angle remains above 150 after being exposed in air for six months. Compared with the electrochemical properties of the four super-hydrophobic samples, it can be found that the sample that is etched by CuCl2 and then self-assembled by stearic acid has the best corrosion resistance with the corrosion potential E-corr improved by 0.33 V, reaching to -1.11 V. The diameter of capacitive arc is also 6 similar to 7 times larger than that of substrate.