韩东,连勇,张津.K2ZrF6对镁合金微弧氧化膜抗点燃性能的影响[J].表面技术,2021,50(6):55-63.
HAN Dong,LIAN Yong,ZHANG Jin.Effect of K2ZrF6 on Ignition Resistance of Micro-arc Oxidation Coatings on Magnesium Alloys[J].Surface Technology,2021,50(6):55-63 |
| K2ZrF6对镁合金微弧氧化膜抗点燃性能的影响 |
| Effect of K2ZrF6 on Ignition Resistance of Micro-arc Oxidation Coatings on Magnesium Alloys |
| 投稿时间：2020-12-30 修订日期：2021-06-01 |
| DOI：10.16490/j.cnki.issn.1001-3660.2021.06.005 |
| 中文关键词: 镁合金 微弧氧化 氟锆酸钾 抗点燃性能 热防护 组织结构 |
| 英文关键词:magnesium alloys micro-arc oxidation K2ZrF6 ignition resistance thermal protection microstructure |
| 基金项目:国家重点研发计划(2016YFB0301105) |
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| Author | Institution |
| HAN Dong | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;Beijing Key Laboratory for Corrosion Erosion and Surface Technology, Beijing 100083, China |
| LIAN Yong | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;Beijing Key Laboratory for Corrosion Erosion and Surface Technology, Beijing 100083, China |
| ZHANG Jin | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;Beijing Key Laboratory for Corrosion Erosion and Surface Technology, Beijing 100083, China |
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| 中文摘要: |
| 目的 降低镁合金在高温环境下起火燃烧的风险，同时探索微弧氧化膜是否具有抗点燃的热防护功能。方法 采用添加不同含量K2ZrF6的碱性硅酸盐电解液体系，在AZ91D镁合金表面制备微弧氧化膜，研究不同浓度K2ZrF6对微弧氧化膜抗点燃性能的影响。采用扫描电镜观察燃烧前微弧氧化膜的微观结构变化，结合XRD分析涂层的相组成，并借助抗点燃性能测试装置，考察微弧氧化膜的起燃时间。结果 添加K2ZrF6制备的微弧氧化膜主要由MgO、Mg2SiO4、MgF2和ZrO2组成。随着K2ZrF6含量的增加，膜层中大尺寸缺陷减少，致密性和厚度显著提高，表面粗糙度先增加、后降低。添加0~10 g/L K2ZrF6的微弧氧化膜的致密性较差，这类微弧氧化层在火焰的作用下，会形成大量的烧蚀孔洞和纵向扩展裂纹;添加15、20 g/L K2ZrF6的微弧氧化膜，具有更为致密的内层，这类微弧氧化膜直到基体完全熔化变形，才会出现横向扩展裂纹，导致涂层失效。AZ91D镁合金经过含15 g/L K2ZrF6的电解液微弧氧化处理后，起燃时间最长，抗点燃性最好。结论 K2ZrF6浓度对微弧氧化膜抗点燃性的影响主要体现在对其致密性的影响上，内层的致密结构能够减少在高温火焰作用下形成的烧蚀孔洞，以及延缓裂纹的产生，从而阻碍熔融的液态镁和镁蒸气向外扩散，减缓氧化反应的程度，提高涂层的抗点燃性。 |
| 英文摘要: |
| This paper aims to reduce the risk of magnesium alloys fire under high temperature and verify the ignition resistance of the micro-arc oxidation (MAO) coatings. The MAO ceramic coatings on AZ91D magnesium alloy were fabricated by adding potassium fluorozirconate (K2ZrF6) into alkaline silicate electrolyte, and the influence of K2ZrF6 on ignition resistance of the coatings were studied. The microstructure of the coatings before ignition were observed by Scanning Electron Microscope (SEM), and X-ray Diffraction Spectrometer (XRD) was used for the phase identification. Ignition resistance of MAO coatings formed on AZ91D magnesium alloy in different content K2ZrF6 were investigated by the ignition resistance torch test. The coatings fabricated in K2ZrF6-containing electrolyte are mainly composed of MgO, Mg2SiO4, MgF2 and ZrO2. The number of large size defects in the MAO coatings is reduced, the density and thickness increase gradually and the surface roughness increases firstly and then decreases with the increasing of K2ZrF6 content. The MAO coatings formed in 0~10 g/L K2ZrF6 electrolyte have the poor densification and tend to appear a large number of ablative holes and longitudinal propagation cracks under high temperature flame. The MAO coatings prepared in 15 g/L and 20 g/L K2ZrF6 electrolyte have the denser inner structure, and do not lose their protection until the matrix is completely melted and deformed, forming transverse propagation cracks. Under the K2ZrF6 concentration of 15 g/L, the coating has the longest ignition time and the best ignition resistance. The effect of K2ZrF6 concentration on the ignition resistance of the MAO coatings is mainly through increasing the density of the coatings to enhance the ignition resistance. The dense structure of the inner layer can reduce the ablative holes and delay the propagation of crack under the high temperature flame, thus preventing the outward diffusion of molten liquid magnesium and magnesium vapor, slowing down the oxidation reaction and improving the ignition resistance of the coating. |
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