基于配方均匀试验优化微弧氧化电解液浓度配比  

Optimizing Electrolyte Formulas for Micro-arc Oxidation Based on Uniform Formula Experimental Design

作　　者：杨登科 马颖[1] 安凌云 张睿峰 吴雄飞 孙乐[1] 王占营[1] YANG Deng-ke;MA Ying;AN Ling-yun;ZHANG Rui-feng;WU Xiong-fei;SUN Le;WANG Zhan-ying(State Key Laboratory of advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050

出　　处：《表面技术》2021年第3期338-347,共10页Surface Technology

基　　金：甘肃省创新研究群体计划(1111RJDA011)。

摘　　要：目的研究电解液中各电解质不同浓度配比下微弧氧化膜层的制备、微观结构及耐蚀性能,以确定最优配方。方法基于配方均匀试验方法,在硅酸盐系电解液中对AM60B镁合金进行微弧氧化处理。引入微弧氧化反应的可行性和微弧氧化膜层的成膜性两个试验指标,分别评判本研究中某电解液配方是否具有实际应用价值,以及评价在某个电解液配方下所制得膜层的合格程度。利用涡流测厚仪、扫描电镜(SEM)、X射线衍射(XRD)、电子探针(EPMA)、硝酸点滴实验以及电化学实验等方法,分别表征膜层的厚度、微观结构、物相组成、元素成分及耐蚀性能。结果当电解液中NaOH的质量浓度小于10 g/L时,方能获得表观完整且色泽均匀的微弧氧化膜层。当NaOH和KF的浓度配比接近,且两者之和约为Na_(2)SiO_(3)所占配比时,即Na_(2)SiO_(3)为19.24 g/L、NaOH为8.80 g/L、KF为11.96 g/L时,膜层中孔径的尺寸小,缺陷少,致密度最高,此时膜层的耐蚀性最好,与基体相比,该膜层的硝酸点滴耐蚀性提高了39倍,电化学耐蚀性提高了3个数量级。膜层主要由MgO、Mg_(2)SiO_(4)及少量的MgF_(2)、MgAl_(2)O_(4)组成,但含量有差别。结论实验设计方法的选择是保证本研究结果有效性的核心和关键。电解液中NaOH的浓度高低是决定某电解液配方是否具有实用价值的首要因素。只有Na_(2)SiO_(3)、NaOH和KF三者间具备适当的配比时,才能降低膜层中的微孔尺寸,减少微裂纹,提高其致密度,并能够在膜层中沉积更多的优质物相,这些是增强膜层耐蚀性的前提和保障。In an effort to finalize the optimal formula,the research work was conducted to probe into the preparation,their microstructures and corrosion resistances of micro-arc oxidation(MAO)coatings under different concentration ratios of electrolytes.Based on uniform formula experimental design,AM60B magnesium alloys underwent micro-arc oxidation treatment in silicate-containing electrolyte solution.The two response indexes,micro-arc oxidation feasibility and formability of micro-arc oxidation coating,were designated to verify if the formula for a certain electrolyte solution involved in the paper had practical application potential and evaluate if the coating made under a certain electrolyte solution formula was acceptable.Eddy current thickness gauge,scanning electron microscope(SEM),X-ray diffraction(XRD),electron-probe micro analyzer(EPMA),spotting test and electrochemical test were employed to characterize the thickness,microstructure,phase composition,element composition and corrosion resistance of the coatings,respectively.The results have shown that where the NaOH concentration in the electrolyte solution was less than10 g/L,complete and evenly-colored MAO coating could be prepared.And where NaOH and KF shared almost the same concentration ratio and the sum of the both approximated Na_(2)SiO_(3) ratio,namely Na_(2)SiO_(3) was 19.24 g/L,NaOH 8.80 g/L and KF 11.96 g/L,the coating possessed attribute of small micropore size,less defect and great compactness.At this point,the coating performed the best in corrosion resistance.Compared with the matrix,spotting corrosion resistance of the coating was improved by 39 times and its electrochemical corrosion resistance was improved by 3 magnitudes.The coatings in the paper mainly comprised MgO,Mg_(2)SiO_(4) and a small amount of MgF_(2) and MgAl_(2)O_(4),varying with each other in content.The choice of experimental designing is key to validity of the research results.The concentration of NaOH in electrolyte solution is of crucial importance to the practicability of a cert

关 键 词：镁合金 微弧氧化 配方均匀试验 电解液 微观组织 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]