祝海涛,孙金峰,孟永强,王立伟,彭珍珍,汪殿龙.Na2WO4含量对镁合金微弧氧化膜层颜色和耐蚀性的影响[J].表面技术,2023,52(10):241-249.
ZHU Hai-tao,SUN Jin-feng,MENG Yong-qiang,WANG Li-wei,PENG Zhen-zhen,WANG Dian-long.Effect of Na2WO4 Content on Color and Corrosion Resistance of Micro-arc Oxidation Coating on Magnesium Alloy[J].Surface Technology,2023,52(10):241-249 |
| Na2WO4含量对镁合金微弧氧化膜层颜色和耐蚀性的影响 |
| Effect of Na2WO4 Content on Color and Corrosion Resistance of Micro-arc Oxidation Coating on Magnesium Alloy |
| 投稿时间：2022-09-23 修订日期：2023-02-10 |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.10.019 |
| 中文关键词: 镁合金 黑色膜层 微弧氧化 Na2WO4 耐腐蚀性 微观结构 |
| 英文关键词:magnesium alloy black coating micro-arc oxidation Na2WO4 corrosion microstructure |
| 基金项目:国家自然科学基金(52101015);河北省高等学校科学技术研究项目(BJK2022020);河北省自然科学基金(E2022208070/E2021208005) |
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| Author | Institution |
| ZHU Hai-tao | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Key Laboratory of Material Near-net Forming Technology in Hebei Province, Shijiazhuang 050018, China |
| SUN Jin-feng | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Hebei Key Laboratory of Flexible Functional Materials, Shijiazhuang 050000, China |
| MENG Yong-qiang | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Hebei Key Laboratory of Flexible Functional Materials, Shijiazhuang 050000, China |
| WANG Li-wei | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Key Laboratory of Material Near-net Forming Technology in Hebei Province, Shijiazhuang 050018, China |
| PENG Zhen-zhen | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Key Laboratory of Material Near-net Forming Technology in Hebei Province, Shijiazhuang 050018, China |
| WANG Dian-long | School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China;Key Laboratory of Material Near-net Forming Technology in Hebei Province, Shijiazhuang 050018, China |
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| 中文摘要: |
| 目的 研究电解液中的Na2WO4含量对AZ31B镁合金微弧氧化膜层的形成过程、颜色、微观结构、耐蚀性能的影响。方法 通过添加不同含量的NH4VO3和Na2WO4的碱性铝酸盐电解液体系，在AZ31B镁合金表面制备黑色的微弧氧化膜层。采用SEM、EDS分析加入不同含量的Na2WO4后膜层表面的微观形貌及元素组成，采用XRD分析物相组成，通过电化学实验表征膜层的耐腐蚀性能。结果 随着Na2WO4含量的增加，微弧氧化过程中的起弧电压下降，膜层的致密性提高，厚度呈先增加后减小的趋势。当Na2WO4的质量浓度为0.5 g/L时，膜层的厚度最大，且此时膜层表面微孔分布均匀，色度最低，耐蚀性最好，自腐蚀电位为−0.138 V，自腐蚀电流密度为2.36×10−7 A/cm2，相较于基体降低了3个数量级。结论 增加Na2WO4含量会使微弧氧化成膜过程中的电弧发生变化，适当增加Na2WO4会提高膜层的厚度，降低膜层的CIE色度，使陶瓷膜层表面的微孔分布得更加均匀致密，从而提高膜层的耐蚀性能。当Na2WO4含量过高时，会使膜层的离子浓度升高，电阻增大，介电击穿电压上升，导致膜层表面被烧蚀，耐腐蚀性能降低。 |
| 英文摘要: |
| In this work, the method preparing micro-arc oxide coating on AZ31B magnesium alloy surface was studied, the formation process of AZ31B magnesium alloy micro-arc oxide ceramic layer was explored by the content of Na2WO4 in electrolyte, and the microstructure and corrosion resistance of AZ31B magnesium alloy were characterized. By using NaAlO2 as the basic electrolyte and adding a small amount of NH4VO3 and Na2WO4 on the surface of AZ31B magnesium alloy, a black micro-arc oxidation ceramic layer was prepared. Scanning electron microscope (SEM) and EDS were adopted to analyze the surface morphology and composition of the coatings with different contents of Na2WO4 and XRD was applied to analyze the phase structure. Electrochemical workstation was used to test the self-corrosion potential and self-corrosion current density of the micro-arc oxidation ceramic layer, and the CIE chromaticity of the coating layer was measured by 3nh chromaticity meter. After experimental verification, NH4VO3 with interaction to Na2WO4 contributed to the successful preparation of the black micro-arc oxidation ceramic layer. Through observation, it was found that with the increase of Na2WO4 content, the arc started to drop. The arc starting voltage was reduced from 320 V to 210 V. In the process of preparation, the micro-arc oxidation coating density was significantly increased and coating thickness increased firstly and then decreased. With the increase of Na2WO4 content, CIE chromaticity decreased firstly and then increased, and the corrosion resistance of the sample increased. When the content of Na2WO4 was 0.5 g/L, the micropores on the surface of the coating were evenly distributed, uniform in size and low in porosity, and the thickness of the coating was the largest at this time. The thickness was 23.8 μm. The CIE chromatic value was the smallest, which was 27.99, and the corrosion resistance was the best. The electrochemical test in 3.5% NaCl solution showed that the self-corrosion potential was −0.138 V and the self-corrosion current density was 2.36×10–7 A/cm2, which decreased by 3 orders of magnitude compared with the matrix. At the same time, compared with the corrosion current density of 1.15×10–5A/cm2, its corrosion current density under the condition of no Na2WO4, decreased by 2 orders of magnitude. However, when sodium tungstate was added to 1 g/L, the coating appeared ablative phenomenon and the corrosion resistance decreased. The self-corrosion current density is not different from that of the matrix. It is concluded that the increase of Na2WO4 content will change the arc in the process of micro-arc oxidation and reduce the arc starting voltage. An appropriate increase of Na2WO4 will increase the thickness of the coating layer, reduce the CIE value of the coating layer, make the distribution of micropores on the surface of the ceramic coating layer more uniform and compact, improve the compactness of the coating layer, and thus improve the corrosion resistance of the coating layer. However, when the content of Na2WO4 is too high, the concentration of ions in the coating layer will increase, and more ions will adsorb to the surface of the coating layer for reaction. The resistance of the coating layer increases, leading to the rise of dielectric breakdown voltage, resulting in the surface ablation of the coating layer and decrease in coating densification and corrosion resistance. |
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