Preparation and Corrosion Resistance of CeO2/Stearic Acid Superhydrophobic Coating on Magnesium Alloy
Magnesium alloy,as the lightest engineering metal material,has high damping ca-pacity and heat conductivity,high specific stiffness and specific strength,high recovery and excellent anti electromagnetic interference performance.Therefore,magnesium alloy has a broad prospect in aviation and automobile industry.However,the high chemical activity of magnesium and its porous oxide film lead to low corrosion of magnesium alloy.Super hydro-phobic surface gives magnesium alloy super hydrophobic ability,which makes it difficult for corrosion medium to penetrate into super hydrophobic surface,and improves corrosion re-sistance of magnesium alloy.In this paper,cerium oxide/stearic acid superhydrophobic coat-ing was prepared on the surface of AZ31B magnesium alloy.The effect of temperature and time of hydrothermal reaction on the corrosion resistance of the coating was studied.The phase composition,microstructure and element composition of the coating on the surface of magnesium alloy were tested by X-ray diffraction(XRD),scanning electron microscope(SEM)and EDS.The corrosion resistance of CeO2/stearic acid superhydrophobic coating was characterized by electrochemical test,and the hydrophobicity of the coating was tested by ultra-hydrophobic test.It is found that 120℃and 6 h are the best temperature and time for hydrothermal reaction.Under this condition,the coating with the thickness of about 13 μm is composed of a large number of fine spherical particles closely connected with each oth-er,which is dense and complete.The phase composition of the coating is CeO2.Electro-chemical test results show that the corrosion current density of the CeO2/stearic acid com-posite coating is 5.36×10-6 A·cm-2,which is reduced by an order of magnitude com-pared with that of the bare magnesium alloy substrate.And the diameter of the electrochem-ical capacitive of arc the composite coating increases obviously,indicating the enhanced cor-rosion resistance of magnesium alloy substrate.At the same time,the composite coating al-so has good superhydrophobicity,and the static contact angle of water is 161°.
万方数据
维普
