氟锆酸钾对AZ31镁合金微弧氧化膜层的影响

Effect of K_2ZrF_6 on coatings of AZ31 magnesium alloy prepared by micro-arc oxidation

在磷酸盐碱性电解液中加入氟锆酸钾(K_2ZrF_6),利用微弧氧化技术(MAO)在AZ31镁合金表面制备了陶瓷膜层,研究了电解液中K_2ZrF_6对MAO膜层的形貌、相组成和耐腐蚀性能等的影响。结果表明,电解液中添加K_2ZrF_6能使MAO膜层变得更加均匀,也降低了膜层的表面粗糙度,所形成的MAO膜层主要是由Mg O,Mg F2和Zr O2相组成。长时间浸泡和电化学测试结果表明,电解液中添加K_2ZrF_6提高了MAO膜层的耐蚀性。本实验电解液中添加2.5 g/L K_2ZrF_6时,所形成的MAO膜层的耐蚀性最好,而过高浓度K_2ZrF_6会对膜层的耐蚀性产生负作用。

The ceramic coatings on AZ31 magnesium alloy was formed by micro-arc oxidation method through adding potassium fluorozirconate（K2 Zr F6） into alkaline phosphate electrolyte,and the influence of K2 Zr F6on surface morphology,phases and corrosion residence of the coatings was studied.The results indicate that after addition of K2 Zr F6into the electrolyte,the uniformity of the coatings increases and roughness decreases,and the coatings fabricated in K2 Zr F6-containing electrolytes consists of Mg O,Mg F2 and Zr O2.Besides,the coatings have better corrosion resistance than that of the coatings formed in K2 Zr F6-free electrolytes.The suitable concentration of K2 Zr F6is 2.5 g /L.However,excessive concentration（5 g /L and 10 g /L） of K2 Zr F6has negative effect on the corrosion resistance of the MAO coatings compared with the coatings formed in 2.5 g /L K2 Zr F6-containing electrolytes.