含HF-离子稀土转化膜耐蚀性能及表面特征研究
Study on Corrosion Resistance and Surface Structure of RE Conversion Coating with HF-
张 凯, 李文芳, 杜 军
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作者单位：华南理工大学 材料科学与工程学院, 广东 广州 510641
中文关键字：转化膜； tafel曲线； 金属间化合物
英文关键字：conversion coating; tafel curve; intermetallic compounds
中文摘要：采用w(NaCl)=5%溶液浸泡和动电位极化曲线方法评估了转化膜的耐腐蚀性能，结合EDX和SEM等表面分析技术，研究了转化膜表面元素分布及表面形貌特征。结果表明：促进剂A的加入提高了膜层耐腐蚀性能。大量膜层表面不规则颗粒起源于碱腐蚀阶段，是由金属间化合物和异相粒子组成，如AlFeSiMn、β-AlFeSi等。该类颗粒的存在提高了异相界面阴极特性，为Ce沉积提供衬底，同时形成Cu/Al电偶极和尖端应力降低转化膜性能。
英文摘要：The influence of HF- on the corrosion resistance was investigated by 5% NaCl solution at 30 ℃ and potentiodynamic polarization curves. Coating microstructure was analysed by SEM and EDX. The results show that the anticorrosive properties of the coatings enhance by adding accelerant A, and the coating is mainly formed by Ce oxides/hydroxides, but addition of intermetallic compounds (such as AlFeSiMn, β-AlFeSi) and the irregular particles on the surface of the coatings derived from alkali corrosion stage have different opposite effect. The existent particles contribute to the improvement of cathode properties of out phase interface and offer underlay for the depositon of Ce. The electric doublet and tip stress are formed,which can decrease the properties of conversion coating.