曹雅心,王梦杰,周凡,杨鸿飞.KOH浓度对LA103Z镁锂合金微弧氧化成膜过程及膜层耐蚀性的影响[J].表面技术,2021,50(3):348-355.
CAO Ya-xin,WANG Meng-jie,ZHOU Fan,YANG Hong-fei.Effect of KOH Concentration on the Growth Process and Corrosion Resistance of Micro-arc Oxidation (MAO) Coatings on LA103Z Mg-Li Alloy[J].Surface Technology,2021,50(3):348-355 |
| KOH浓度对LA103Z镁锂合金微弧氧化成膜过程及膜层耐蚀性的影响 |
| Effect of KOH Concentration on the Growth Process and Corrosion Resistance of Micro-arc Oxidation (MAO) Coatings on LA103Z Mg-Li Alloy |
| 投稿时间：2020-03-16 修订日期：2020-06-22 |
| DOI：10.16490/j.cnki.issn.1001-3660.2021.03.038 |
| 中文关键词: 镁锂合金 微弧氧化 氢氧化钾 生长过程 耐蚀性 |
| 英文关键词:magnesium lithium alloy MAO potassium hydroxide growth process corrosion resistance |
| 基金项目:西安市科技创新计划(201805064ZD15CG48) |
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| Author | Institution |
| CAO Ya-xin | State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China |
| WANG Meng-jie | State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China |
| ZHOU Fan | State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China |
| YANG Hong-fei | Xi’an Flit Heat Treatment Co., Ltd, Xi’an 710061, China |
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| 中文摘要: |
| 目的 探索电解液中KOH浓度对LA103Z镁锂合金微弧氧化成膜过程及膜层耐蚀性能的影响规律。方法 通过恒压微弧氧化法，在KOH质量浓度分别为2、4、6 g/L的硅酸盐系电解液中制备微弧氧化膜层。采用扫描电子显微镜(SEM)观察微弧氧化膜层的表面形貌和截面形貌，采用Image-J软件分析膜层的孔隙率和厚度，通过电化学试验表征膜层的耐腐蚀性能。结果 随KOH浓度的升高，微弧氧化过程中通过试样的电流密度增大，膜层表面微孔数目减少、孔径增大，膜层厚度也增加，试样的耐蚀性先升高后降低。当KOH的质量浓度为4 g/L时，膜层表面微孔大小均一、分布均匀，孔径尺寸较小，为2~4 μm，孔隙率最低，为3.56%，膜层内部结构较致密，耐蚀性最好，其自腐蚀电流密度为0.26 μA/cm2，与基体相比降低了2个数量级。结论 KOH浓度的改变主要影响微弧氧化成膜过程火花放电阶段的形貌。适当升高KOH浓度可有效改善膜层表面的微孔分布，增加膜层厚度，提高膜层致密度，从而提高膜层耐蚀性。当KOH浓度过高时，膜层内部大孔洞和裂纹等缺陷增多，膜层耐蚀性降低。 |
| 英文摘要: |
| This paper aims to explore the effect of KOH concentration on the growth process and corrosion resistance of MAO coatings on LA103Z Mg-Li alloy. The method adopted in this paper is to prepare the MAO coatings by constant voltage MAO method in the silicate electrolyte system with KOH concentration of 2 g/L, 4 g/L, 6 g/L, respectively. Surface and cross-section morphologies of the MAO coatings were observed by scanning electron microscope (SEM), the porosity and thickness of the MAO coatings were analyzed by Image-J software, and the corrosion resistance of MAO coatings was characterized by electrochemical test. The results showed that with the increase of KOH concentration, the current density passing through the sample increased during micro-arc oxidation process, the number of micropores decreased, the pore size increased, and the thickness of the coating also increases. The corrosion resistance of the sample increases first and then decreases with the increase of KOH concentration. When the KOH concentration is 4 g/L, the micropores on the surface of the coating are uniform and evenly distributed, and the pore size is small (about 2~4 μm), the porosity is the lowest (about 3.56%), and the internal structure of the filmcoating is relatively dense. The coating exhibits the best corrosion resistance, and its self-corrosion current density is 0.26 μA/cm2, which is 2 orders of magnitude lower than that of the substrate. The change of KOH concentration mainly effects the morphology of the coating in the spark discharge stage during the MAO process. Increasing KOH concentration properly can effectively improve the micropores distribution, increase the thickness and the density of the coating, so as to improve the corrosion resistance of the coating. However, when the KOH concentration is too high, the defects such as large holes and cracks inside the coating increase, and the corrosion resistance of the coating decreases. |
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