镁合金表面PEF膜与PEO膜腐蚀防护行为的对比研究

齐玉明, 刘思勤, 罗兰, 彭振军, 梁军, 王鹏

表面技术 ›› 2021, Vol. 50 ›› Issue (6) : 41-54, 147.

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PDF(36663 KB)
表面技术 ›› 2021, Vol. 50 ›› Issue (6) : 41-54, 147. DOI: 10.16490/j.cnki.issn.1001-3660.2021.06.004
专题——微弧氧化在腐蚀领域中的应用

镁合金表面PEF膜与PEO膜腐蚀防护行为的对比研究

  • 齐玉明1, 刘思勤1, 梁军1, 王鹏1, 罗兰2, 彭振军2
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Comparison of Corrosion Behaviour of PEF and PEO Coatings on Mg Alloys

  • QI Yu-ming1, LIU Si-qin1, LIANG Jun1, WANG Peng1, LUO Lan2, PENG Zhen-jun2
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摘要

目的 对比研究镁合金表面新型等离子体电解氟化(PEF)膜与传统等离子体电解氧化(PEO)膜的腐蚀防护行为。方法 分别在中性和酸性腐蚀介质中,通过开路电位监测和动态电位极化曲线测试表征了膜层的电化学腐蚀行为,通过浸泡实验和盐雾实验表征了膜层的长效腐蚀行为。通过SEM、EDS和XRD等方法表征了膜层的原始微观结构和组成,分析了腐蚀形貌和腐蚀产物。结果 PEF膜与PEO膜均可以为镁合金基材提供有效的腐蚀防护作用。相较于PEO膜,PEF膜在浸泡实验和盐雾实验中,都具有更为优异的腐蚀防护性能,但在动态电位极化测试中,具有更正的自腐蚀电位和更大的自腐蚀电流密度,表明其腐蚀倾向更低,但腐蚀速率更高。结论 总体而言,PEF膜在中性和酸性环境中都具有更好的腐蚀防护性能。PEO膜在中性环境中的腐蚀防护失效机制主要是腐蚀介质的扩散,在酸性环境中的腐蚀防护失效机制主要是膜层化合物的溶解和消耗;PEF膜在中性和酸性环境中的腐蚀防护失效机制都是腐蚀介质的扩散。

Abstract

The work aims to compare the novel PEF coating and conventional PEO coating in terms of corrosion behavior. The electrochemical corrosion behavior was evaluated by means of OCP monitoring and potentiodynamic polarization tests in neutral and acidic corrosive media, while the long-term corrosion behavior by immersion and salt spraying tests. SEM, EDS and XRD were employed to characterize the coatings’ original microstructure and composition, as well as the characteristics of the corroded coatings and resultant corrosion products. The results show that the PEF coating was effective to protect Mg alloys from corrosion damage as well as the PEO coating. The PEF coating was performed better than the PEO coating in corrosion resistance during the immersion and salt spraying tests, but showed a higher corrosion potential and corrosion current density which respectively indicated a lower corrosion tendency and a higher corrosion rate. In sum, the PEF coating was performed better than the PEO coating in corrosion resistance. The corrosion failure of the PEF coating was mainly attributed to the diffusion of the neutral corrosive medium or the dissolution of the coating in acidic corrosive medium. The corrosion failure of the PEF coating was attributed to the diffusion of the corrosive media.

关键词

镁合金;等离子体电解氟化;等离子体电解氧化;腐蚀防护行为

Key words

magnesium alloy; plasma electrolytic fluorination; plasma electrolytic oxidation; corrosion behavior

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导出引用
齐玉明, 刘思勤, 罗兰, 彭振军, 梁军, 王鹏. 镁合金表面PEF膜与PEO膜腐蚀防护行为的对比研究[J]. 表面技术. 2021, 50(6): 41-54, 147
QI Yu-ming, LIU Si-qin, LUO Lan, PENG Zhen-jun, LIANG Jun, WANG Peng. Comparison of Corrosion Behaviour of PEF and PEO Coatings on Mg Alloys[J]. Surface Technology. 2021, 50(6): 41-54, 147

基金

国家自然科学基金(52071325)

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