A356铝合金微弧氧化黑色膜层的制备及耐蚀性  

Preparation and corrosion resistance of black micro-arc oxidation coating on A356 aluminum alloy

作　　者：安晓丽 马颖[1] 李正强 衡志丹 AN Xiaoli;MA Ying;LI Zhengqiang;HENG Zhidan(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《电镀与涂饰》2024年第8期42-49,共8页Electroplating & Finishing

基　　金：甘肃省科技重大专项(22ZD6GA008)。

摘　　要：[目的]在Na_(2)SiO_(3)-Na_(3)PO_(4)复合电解液中研究着色盐Na_(2)WO_(4)的质量浓度对A356铝合金表面微弧氧化膜层结构和性能的影响。[方法]采用比例分割分批试验设计方法优选出Na_(2)WO_(4)的添加方案。利用色差宝、涡流测厚仪、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD),分别对膜层的颜色、厚度、微观形貌、元素分布和物相组成进行表征。膜层的耐蚀性通过硝酸点滴腐蚀试验和在3.5%NaCl溶液中测量动电位极化曲线来检测。[结果]随着电解液中Na_(2)WO_(4)的质量浓度增大,所得膜层的颜色逐渐加深,添加22.05 g/L Na_(2)WO_(4)时所得膜层颜色最深,而添加19.98 g/L Na_(2)WO_(4)时所得膜层的耐蚀性最佳。[结论]在基础电解液中加入着色盐Na_(2)WO_(4)后,膜层中沉积出使膜层显深色的钨氧化物,令膜层颜色加深,并提高了膜层的致密性和耐蚀性。[Introduction]The effect of mass concentration of Na_(2)WO_(4)as a colorant on microstructure and properties of the micro-arc oxidation(MAO)coating formed on A356 aluminum alloy in a Na_(2)SiO_(3)-Na_(3)PO_(4)composite electrolyte was studied.[Method]The dosage of Na_(2)WO_(4)was determined by a proportional batching method.The color,thickness,micromorphology,element distribution,and phase composition of the MAO coatings were characterized by using color meter,eddy current thickness meter,scanning electron microscope(SEM),energydispersive spectrometer(EDS),and X-ray diffractometer(XRD).The corrosion resistance of MAO coatings was evaluated through HNO_(3)dropping corrosion test and potentiodynamic polarization curve measurement in 3.5%NaCl solution.[Result]After adding Na_(2)WO_(4)to the electrolyte,the color of MAO coating was gradually deepened.The MAO coating prepared with 22.05 g/L of Na_(2)WO_(4)had the deepest color,while that prepared with 19.98 g/L of Na_(2)WO_(4)had the best corrosion resistance.[Conclusion]After adding Na_(2)WO_(4)as a colorant to the electrolyte,tungsten oxides are deposited in the MAO coating,making the MAO coating appear darker and improving its compactness and corrosion resistance.

关 键 词：铝合金 微弧氧化 钨酸钠 黑色膜 耐蚀性 

分 类 号：TG174.451[金属学及工艺—金属表面处理]