ZK60镁合金表面MAO-LDH疏水膜层的一步水热法制备及其耐蚀性能

Preparation of MAO-LDH hydrophobic coating on ZK60 magnesium alloy surface by one-step hydrothermal method and its corrosion resistance

通过一步水热法在ZK60镁合金表面微弧氧化(MAO)膜层上制备了肉豆蔻酸(MA)修饰的Mg-Al层状双金属氢氧化物(LDH)复合膜层,通过场发射扫描电镜(FE-SEM)、X射线衍射仪(XRD)和傅里叶红外光谱仪(FTIR)分析了膜层的微观形貌、物相成分及结构,通过接触角测定仪及电化学工作站分析了膜层的润湿性及耐腐蚀性能。结果表明:制备的MA/LDH膜层成功封闭了MAO的微孔,水热温度为120℃时制备的MA/LDH/MAO复合膜层表面LDH片层较为完整均匀,其接触角最大,为143.42°。ZK60、MAO膜层及不同水热温度制备的MA/LDH/MAO复合膜层的耐蚀性由大到小依次为MA/LDH/MAO-120>MA/LDH/MAO-110>MA/LDH/MAO-130>MAO>ZK60,这归因于MA/LDH/MAO-120膜层具有均匀完整的LDH结构及MA插层/表面修饰LDH作用,可有效提高ZK60镁合金的耐蚀性能。

Mg-Al layered double hydroxide(LDH)composite coatings modified with myristic acid(MA)were prepared on the surface of micro-arc oxidation(MAO)film of ZK60 magnesium alloy by one-step hydrothermal method.Microstructure,phase composition and structure of the coatings were analyzed by means of field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD)and Fourier infrared spectroscopy(FTIR),and the wettability and corrosion resistance of the coatings were analyzed using a contact angle tester and an electrochemical workstation.The results show that the micro-pores on the surface of the MAO film are successfully sealed by MA/LDH coatings.When the hydrothermal temperature is 120℃,the LDH layer on the surface of the MA/LDH/MAO composite coatings is relatively complete and uniform,and the contact angle is the largest,which is 143.42°.The corrosion resistance of the ZK60,MAO film and MA/LDH/MAO composite coatings prepared at different hydrothermal temperatures in descending order is MA/LDH/MAO-120>MA/LDH/MAO-110>MA/LDH/MAO-130>MAO>ZK60.This is attributed to the uniform and complete LDH structure of the MA/LDH/MAO-120 composite coatings and the effect of MA intercalation/surface modification of LDH,which can effectively improve the corrosion resistance of the ZK60 magnesium alloy.