| 摘要: |
| 为了提高 MgF2 膜层的耐腐蚀性能,利用微弧氧化工艺,通过在 NH4F-EG 电解液中添加纳米 SiC 颗粒,在 AZ31 镁合金表面制备含 SiC 的 MgF2 -SiC 膜层,并探究纳米 SiC 颗粒的浓度对 MgF2 膜层组成、结构和耐腐蚀性能的影响。 采用 SEM、EDS、XRD、XPS 等测试方法对含 SiC 的 MgF2 膜层的微观组织、元素含量和物相组成进行分析,利用电化学工作站对膜层的耐腐蚀性能进行测试。 结果表明:电解液中的纳米 SiC 颗粒成功进入 MgF2 膜层中。 随着电解液中纳米 SiC 浓度的增加,膜层中的 Si、C 元素含量增加,Mg、F 元素含量减少,膜层变得致密平整,孔隙率减少,膜层缺陷得到有效改善,膜层厚度减小;MgF2 膜层的耐腐蚀性能先增大后减小,当电解液中纳米 SiC 的浓度为 5 g / L 时,膜层的耐腐蚀性能最优。 因此,在 NH4F-EG 电解液中添加纳米 SiC 颗粒,可以在 AZ31 镁合金表面制备出含 SiC 的 MgF2 -SiC 膜层, 且耐腐蚀性能优于不含 SiC 的 MgF2 膜层。 |
| 关键词: 微弧氧化 纳米 SiC MgF2 膜层 AZ31 镁合金 耐腐蚀性能 |
| DOI：10.11933/j.issn.1007-9289.20190915001 |
| 分类号:TG174.44 |
| 文章编号:1007-9289(2020)01-0024-10 |
| 文献标识码:A |
| 基金项目:中科院“十三五”规划重点培育项目 |
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| Preparation and Corrosion Resistance of MgF2 Coating Containing SiC Nanoparticles on AZ31 Magnesium Alloy |
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AN Jinghua1,2, QI Yuming1, PENG Zhenjun1, LIANG Jun1
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1.State key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 , China;2.College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 , China
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| Abstract: |
| To prepare the MgF2 -SiC coatings containing SiC nanoparticle to further improve corrosion resistance of MgF2 coatings. MgF2 coatings containing nano-SiC were fabricated on surface of AZ31 magnesium alloy in non-aqueous electrolyte taking NH4F-EG as main salt and SiC nanoparticle as additive according to micro-oxidation process The influence of different concentrations of nano-SiC on the microstructure and corrosion resistance of MgF2 coatings were studied. The microstructure and composition of the coatings were investigated by SEM, EDS, XRD, XPS. The corrosion resistance of the coatings was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. Results show that SiC nanoparticles in electrolyte are successfully incorporated into the MgF2 coatings. The content of C and Si increased while the content of Mg and F decreased with the increase of nano-SiC concentration in electrolyte. The coatings porosity and thickness of MgF2 coatings reduced and defects effectively improved. Compared with the SiC-free MgF2 coatings, the MgF2 coatings containing nano-SiC are more compact. The corrosion resistance of the MgF2 coatings first increases and then decreases. The MgF2 coatings have the best corrosion resistance when 5 g / L SiC nanoparticle incorporates into electrolyte. Results show that addition of SiC nanoparticles in the NH4F-EG electrolyte can produce SiC-rich MgF2 -SiC coatings on the surface of AZ31 magnesium alloy, and its corrosion resistance is superior to those of SiC-free MgF2 coatings. |
| Key words: micro-arc oxidation(MAO) SiC nanoparticle MgF2 coatings AZ31 magnesium alloy corrosion resistance |
