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利用微弧氧化和化学镀镍在AZ91D镁合金表面制备了复合涂层,采用动电位极化曲线测试和电化学阻抗测试等方法研究微弧氧化和化学镀镍复合涂层在3.5%NaCl溶液中的腐蚀行为。结果表明,复合涂层使基体镁合金的腐蚀电位提高了1.339V,自腐蚀电流密度降低为基体的1/10;在浸泡初期和中期,复合涂层通过阻碍腐蚀介质向基体的传质和腐蚀产物的输运提高了镁合金的耐腐蚀性,经270h的浸泡,复合涂层完全失效。
The composite coating was prepared on the surface of AZ91D magnesium alloy by micro-arc oxidation and electroless nickel plating. The effects of micro-arc oxidation and electroless nickel plating composite coating in 3.5% NaCl solution were investigated by potentiodynamic polarization curve test and electrochemical impedance measurement. Corrosion behavior. The results show that the corrosion resistance of the matrix magnesium alloy is increased by 1.339V and the self-corrosion current density is reduced to 1/10 of that of the matrix by the composite coating. During the initial and intermediate immersion cycles, the composite coating inhibits the mass transfer and corrosion of the matrix The transport of the product improved the corrosion resistance of the magnesium alloy. The composite coating completely failed after soaking in 270h.