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
安晓丽 1马颖 1李正强 1衡志丹1
作者信息
- 1. 兰州理工大学材料科学与工程学院,甘肃 兰州 730050
- 折叠
摘要
[目的]在Na2SiO3-Na3PO4 复合电解液中研究着色盐Na2WO4 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 Na2WO4 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Na2WO4的质量浓度增大,所得膜层的颜色逐渐加深,添加22.05 g/L Na2WO4时所得膜层颜色最深,而添加19.98 g/L Na2WO4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Na2WO4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.
Abstract
[Introduction]The effect of mass concentration of Na2WO4 as a colorant on microstructure and properties of the micro-arc oxidation(MAO)coating formed on A356 aluminum alloy in a Na2SiO3-Na3PO4 composite electrolyte was studied.[Method]The dosage of Na2WO4 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),energy-dispersive spectrometer(EDS),and X-ray diffractometer(XRD).The corrosion resistance of MAO coatings was evaluated through HNO3 dropping corrosion test and potentiodynamic polarization curve measurement in 3.5%NaCl solution.[Result]After adding Na2WO4 to the electrolyte,the color of MAO coating was gradually deepened.The MAO coating prepared with 22.05 g/L of Na2WO4 had the deepest color,while that prepared with 19.98 g/L of Na2WO4 had the best corrosion resistance.[Conclusion]After adding Na2WO4 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Key words
aluminum alloy/micro-arc oxidation/sodium tungstate/black coating/corrosion resistance引用本文复制引用
基金项目
甘肃省科技重大专项(22ZD6GA008)
出版年
2024
NETL
NSTL
万方数据