不锈钢表面阴极微弧电沉积氧化铝膜层的性能

以0.4 mol/L Al（NO₃）₃乙醇溶液为电解液,用阴极微弧电沉积方法在304不锈钢表面制备了80μm厚的氧化铝膜层。分析了膜层的形貌、成分和相组成,测试了膜层的抗高温氧化和电化学腐蚀性能。结果表明.电沉积膜层由γ-Al₂O₃和α-Al₂O₃组成。膜层中含有少量的Fe、Cr、Ni元素,表明膜/基界面附近的不锈钢基体在微弧放电作用下也参与氧化铝膜层的沉积和烧结过程。氧化铝膜层使不锈钢在800℃恒温氧化速率明显降低,表明其抗高温氧化性能得到提高。同时,其腐蚀电位正向移动,腐蚀电流密度降低1个数量级,表明其耐腐蚀性能得到提高。

Preparation and Characterization of Alumina Coating on Stainless Steel by Cathodic Microarc Electrodeposition

An alumina coating of 80μm thick was fabricated on the surface of 304 stainless steel by cathodic microarc electrodeposition in 0.4 mol/L Al（NO₃）₃ ethanol solution.The morphology,composition and phase constituent of the alumina coating were analyzed by scanning electron microscope（SEM） and X-ray diffraction（XRD）,and the high-temperature oxidation and electrochemical corrosion behaviors of the coating were evaluated.The results show that the coating is composed ofγ-AI₂O₃ andα-AI₂O₃ phases, and the coating contains a little Fe,Cr,Ni elements,which confirm that the stainless steel substrate near the coating/steel also takes part in the deposition and sintering process of alumina coating under cathodic microarc discharge.The oxidation rate of the coated stainless steel at 800℃isothermal oxidation test is obviously reduced.Meanwhile,its corrosion potential increases positively and its corrosion current density decreases about one order of magnitude,indicating that the corrosion resistance is improved.