添加剂K_(2)ZrF_(6)和EDTA-Na与电压及其交互作用对镁合金微弧氧化膜耐蚀性的影响

Effects of K_(2)ZrF_(6)and EDTA-Na additives,voltage and their interactions on corrosion resistance of micro-arc oxidation coatings on magnesium alloys

在磷酸盐电解液体系中于AZ91D镁合金表面制备微弧氧化膜层.基于正交实验研究添加剂K_(2)ZrF_(6)和EDTA-Na、电压及其交互作用对膜层的影响.通过TT260数字式涡流测厚仪、SEM和XRD检测膜层厚度、微观形貌及物相组成.采用HNO_(3)点滴实验评价膜层在酸性介质中的耐蚀性能.结果表明:K_(2)ZrF_(6)、EDTA-Na、电压及其交互作用对膜层厚度和耐蚀性影响不同.电压对膜层厚度和耐蚀性的影响非常显著,随电压升高,膜层厚度和耐蚀性均明显增加.K_(2)ZrF_(6)单独对膜层厚度没有显著影响,对耐蚀性存有一定的影响.EDTA-Na单独对膜层厚度和耐蚀性无显著影响.而K_(2)ZrF_(6)与电压间存在着显著的交互作用.最终使得在高浓度的K_(2)ZrF_(6)、高浓度的EDTA-Na和高电压搭配时,可获得综合性能更优异的膜层.

Micro-arc oxidation(MAO)coatings were prepared on AZ91D magnesium alloys in alkaline phosphate-based electrolyte.The effects of the additives of K 2ZrF 6 and EDTA-Na,voltage,and their interactions on the coatings were studied based on orthogonal experiment.The thicknesses,morphologies and phase composition of the coatings were examined by using TT260 eddy-current coating thickness gauge,SEM and XRD,respectively.The corrosion resistance of the coatings in acidic media was evaluated by the HNO_(3)spot test.The results showed that K 2ZrF 6,EDTA-Na,voltage and their interactions exhibit different effects on the thickness and corrosion resistance of MAO coatings.The effect of the loading voltage on the thickness and corrosion resistance of the coatings is significant.With the voltage increasing,the thickness and the corrosion resistance of the coatings are both improved significantly.The individual factor of K 2ZrF 6 has little effect on the coating thickness,but it exhibits a certain impact on corrosion resistance of the coatings.The individual factor of EDTA-Na has little effect on the coating thickness and corrosion resistance,While the interaction between K 2ZrF 6 and voltage is very significant,and the coatings with more excellent comprehensive properties can be obtained when a high concentration of K 2ZrF 6 and high concentration of EDTA-Na combine with high loading voltage.