碳酸钠浓度对AZ31B镁合金阳极氧化膜耐蚀性的影响  

Effect of the concentration of sodium carbonate in electrolyte on corrosion resistance of anodic oxide film prepared therein on AZ31B magnesium alloy

作　　者：张锋刚[1] ZHANG Fenggang(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723000,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723000

出　　处：《电镀与涂饰》2023年第8期6-11,共6页Electroplating & Finishing

基　　金：陕西省自然科学基础研究计划项目(2018JM5021);陕西理工大学科研项目(SLGKY2002,SLGPT2019KF01-08)。

摘　　要：为了改善镁合金阳极氧化膜的耐腐蚀性能,向环保型NaOH-Na_(2)SiO_(3)-Na_(2)B_(4)O_(7)基础电解液中添加Na_(2)CO_(3),在AZ31B镁合金表面制备阳极氧化膜。采用扫描电镜(SEM)、光学显微镜(OM)、X射线衍射仪(XRD)和动电位极化曲线法,研究了Na_(2)CO_(3)质量浓度(≤30 g/L)对AZ31B镁合金表面阳极氧化膜的表面形貌、截面形貌、相结构和耐蚀性的影响。结果表明:AZ31B镁合金阳极氧化组织由Mg O相和Mg2Si O4相组成,基本不受Na_(2)CO_(3)浓度的影响。随着Na_(2)CO_(3)浓度的增大,AZ31B镁合金阳极氧化膜表面微孔尺寸先减小后增大,氧化膜厚度呈现“先增大,后减小,再增大”的变化趋势。Na_(2)CO_(3)可显著提高阳极氧化膜的耐蚀性,而表面微孔尺寸减小是耐蚀性提高的主要原因。当Na_(2)CO_(3)质量浓度为15 g/L时,AZ31B镁合金阳极氧化膜较厚(约11μm),微孔较小,耐蚀性最好。Na_(2)CO_(3) was added to an environmentally friendly NaOH-Na_(2)SiO_(3)-Na_(2)B_(4)O_(7) electrolyte for anodization of AZ31B magnesium alloy to improve the corrosion resistance of anodic oxide film on its surface.The effect of the mass concentration of Na_(2)CO_(3) in a range of 0 to 30 g/L on surface morphology,cross-sectional morphology,phase structure,and corrosion resistance of the anodic oxide film on AZ31B magnesium alloy was studied by scanning electron microscopy(SEM),optical microscopy(OM),X-ray diffraction(XRD),and dynamic polarization curve measurement.The results showed that the addition of Na_(2)CO_(3) had no significant effect on the phase structure of anodic oxide film,which consisted of MgO phase and Mg2SiO4 phase.The micropore size of anodic oxide film on AZ31B magnesium alloy was decreased initially and then increased with the increasing of Na_(2)CO_(3) concentration,while the film thickness presented a trend of“increasedecrease-increase”.The corrosion resistance of the anodic oxide film was improved by the addition of Na_(2)CO_(3) due to the decrease of micropore size.The anodic oxide film of AZ31B magnesium alloy prepared with 15 g/L of Na_(2)CO_(3) in electrolyte was relatively thick(about 11μm in thickness)and had small-sized pores,showing the optimal corrosion resistance.

关 键 词：镁-铝合金 阳极氧化 碳酸钠 相结构 厚度 耐蚀性 

分 类 号：TG146.2[一般工业技术—材料科学与工程]