高质量薄层石墨烯改性环氧含锌涂层的腐蚀防护机理研究

Study on Corrosion Protection Mechanisms of High-Quality Few-Layer Graphene Modified Zinc Epoxy Coatings

制备了不同配比的高质量薄层石墨烯改性环氧含锌涂层,通过断面形貌表征、交流阻抗测试、吸水率测试等手段分析了不同涂层的腐蚀防护性能,对含锌涂层中应用高质量薄层石墨烯提高防腐性能的机理进行了深入研究,探讨了涂层内部的防腐机理演化过程以及物理阻隔和阴极防护作用对腐蚀防护性能的贡献比例。结果表明:在腐蚀防护过程中,高质量薄层石墨烯的引入能够显著提升环氧合锌涂层的物理阻隔性能。在本文优化的配比下,物理阻隔和阴极防护机理的贡献相当,且有先后次序地发挥作用。此外,石墨烯添加量太多或太少都不能达到最佳的防腐性能。在本研究的0. 2%~10%范围内,当加入的高质量薄层石墨烯质量分数为0. 5%时,涂层的综合腐蚀性能最优,在盐水的浸泡试验中提供的腐蚀防护期长达125 d。

In order to study the evolution of the dominant working mechanism inside the cathodic protection coatings and the respective contribution of the physical barrier and cathodic protection mechanism to the anti-corrosion performance,high-quality few-layer graphene modified epoxy zinc coatings with varying graphene ratios were prepared. By carrying out cross-sectional morphology characterizations,AC electrochemical impedance tests and water absorption tests,the corrosion protection performance of different coatings was measured. It was shown that during the corrosion protection process,the introduction of high-quality few-layer graphene on significantly improve the physical barrier properties of epoxy zinc coating. Under the optimized ratio in this paper,physical barrier and cathodic protection mechanisms played an almost equal dominant role but in succession. Besides,the anti-corrosion performance was the best when the graphene content was 0. 5% in the range of 0. 2%-10% of the dry film. Under this ratio,the coating provided an efficient protection for 125 days in the salt-water immersion test,which was the longest of the examined combinations.