电解液组成对AZ91D镁合金微弧氧化的影响  

Effect of constituents of electrolyte on micro-arc oxidation of AZ91D Mg alloys

作　　者：郭洪飞[1] 安茂忠[1] 霍慧彬[1] 徐莘[1] 

机构地区：[1]哈尔滨工业大学应用化学系,黑龙江哈尔滨150001

出　　处：《材料科学与工艺》2006年第2期116-119,共4页Materials Science and Technology

摘　　要：在含有NaA lO2、KF的电解质溶液中,采用恒电流方式对AZ91D镁合金进行微弧氧化获得陶瓷膜.研究了电解液组分及浓度对陶瓷氧化膜厚度及表面形貌的影响,同时,采用动电位极化曲线及电化学交流阻抗评价了陶瓷氧化膜的耐蚀性.研究发现:NaA lO2单独存在时即可产生火花放电现象,但得到的氧化膜较薄;氟化钾的加入可以显著增加氧化膜厚度,膜厚的增长速度与氟化钾的加入量呈线性关系.SEM表面形貌分析表明:电解质浓度较低时产生的氧化膜宏观上较粗糙、微观上颗粒结合紧密;高浓度时得到的氧化膜宏观上细致光滑,微观上存在明显的孔洞和放电隧道,呈熔融状态结合在一起.动电位极化曲线及电化学交流阻抗的测试一致表明,经微弧氧化处理后的镁合金耐蚀性显著提高.Micro-arc oxidation of AZ91D magnesium alloy was studied in solutions containing NaAlO2 and KF at a constantly applied current density. The experimental phenomenon that occurred at the anode surface was analyzed . The effect of constituents and concentration of electrolyte on coating thickness was also investigated SEM was employed to examine the surface morphology. Polarization curve and EIS were used to evaluate the corrosion resistance of ceramic coatings formed on magnesium alloys. It was concluded that sparks could be seen at the anode surface when the electrolyte only contained NaAlO2 and a thin silver gray film was formed at the anode surface. An increase of the coating thickness was not evident even with an increase of the NaAlO2 content. However, the addition of KF increased the coating thickness considerably and a line function was built up between the coating thickness and KF content. A few pores and micro cracks were observed on the ceramic coating surface when the concentration of electrolyte was increased. The corrosion resistance of ceramic coatings was improved considerably compared to magnesium alloy substrate .

关 键 词：镁合金 微弧氧化 陶瓷膜 耐蚀性 表面形貌 

分 类 号：TG174.45[金属学及工艺—金属表面处理]