电解液对微弧氧化陶瓷膜结构与耐蚀性的影响

Effect of electrolytes on structure and corrosion resistance of micro arc oxidation ceramic coatings

在3种不同的电解液体系中,利用微弧氧化技术在AZ91D镁合金表面原位生长了陶瓷膜.通过扫描电镜、X射线衍射、电化学分析等方法研究了陶瓷膜的形貌特征、相结构及耐腐蚀性能.研究表明,在相同反应条件下,不同电解液体系中生成的陶瓷膜结构和性能不同,硅酸钠体系中生成的陶瓷膜厚度大、偏铝酸钠体系中生成的陶瓷膜较薄,偏铝酸钠与硅酸钠的混合体系中生成的陶瓷膜致密、耐腐蚀性能较好.三体系中生成的陶瓷膜中都含有MgO,偏铝酸钠体系陶瓷膜中含有MgA l2O4、硅酸钠体系中含有Mg2S iO4,混合体系中则这两种物质都存在.

Ceramic coatings were prepared in situ on AZ91D Magnesium alloy by micro arc oxidation in three different electrolyte solutions. Morphology feature, phase composition and corrosion resistance properties of the prepared ceramic coatings were studied by SEM, XRD and electrochemical methods. The result showed that the structure and corrosion resistance of ceramic coatings formed in different electrolytes were different under the same technology conditions. The prepared ceramic coatings in sodium silicate solution was thick, while the prepared film in sodium aluminate solution was thin. And the prepared coating in the compound solution of sodium silicate and sodium aluminate was compact and had better corrosion-resistance. MgO existed in the prepared coatings of all the three kinds of solutions; MgAl2 04 existed in that of sodium aluminate solution and Mg2SiO4 existed in that of sodium silicate solution, both of them existed in that of the compound solution.