氧化石墨烯/聚酯树脂涂层的制备及耐腐蚀性能

Preparation of GO/Polyester Resin Coatings and Its Corrosion Resistance

石墨烯具有阻隔性好、机械强度高、比表面积大等优异的性能,被广泛应用于防腐涂料领域。本研究在聚酯树脂粉末中加入分散性较好的氧化石墨烯(GO),利用静电喷涂技术在经硅烷偶联剂预处理的6063铝合金基体上制备了不同氧化石墨烯含量的聚酯体系涂层。通过EDS能谱分析硅烷膜的成分,并通过电化学试验评价硅烷膜的腐蚀行为;采用纳米压痕仪表征涂层与基体的结合力;通过全浸泡试验和中性盐雾试验研究氧化石墨烯添加量对聚酯体系涂层耐腐蚀性能的影响。结果表明,硅烷膜的自腐蚀电压为-0.831 V,自腐蚀电流密度为5.361×10^(-8) A/cm^(2),钛锆膜的自腐蚀电压为-0.967 V,自腐蚀电流密度为8.350×10^(-8) A/cm^(2),即与钛锆膜相比,硅烷膜的自腐蚀电位高、自腐蚀电流密度小,耐腐蚀性能更优;经硅烷偶联剂预处理涂层的临界载荷值L_(C1)为2035.71 mN,L_(C2)为3066.66 mN,均大于经钛锆膜预处理的涂层的临界载荷值(1667.40 mN),即经硅烷偶联剂预处理的涂层与基体的结合力更强;与未添加氧化石墨烯的聚酯涂层相比,氧化石墨烯添加量为0.5%(质量分数)的聚酯涂层的失重量及失重率最小,1000 h盐雾腐蚀后涂层表面的孔隙和腐蚀坑也均减少,其耐腐蚀性能明显增强。即在聚酯树脂涂料中添加0.5%(质量分数)氧化石墨烯时,涂层的耐腐蚀性能显著提高。

Graphene was widely used in the field of anticorrosive coatings because of its excellent properties such as good barrier property,high mechanical strength and large specific surface area.Graphene oxide with good dispersion was added into polyester resin powder and the po-lyester coating with different contents of GO was prepared on 6063 aluminum alloy substrate pretreated with silane coupling agent by electrostatic spraying technology.The composition of silane film was analyzed by EDS spectrum and corrosion resistance of silane membrane was evaluated by electrochemical experiments;nano-indentation test was used to characterize the adhesion between coating and substrate;the effect of GO on the corrosion resistance of polyester coating was studied by immersion test and neutral salt spray test.The results showed that the corrosion potential of silane film was-0.831 V,which was higher than that of Zr-Ti film(-0.967 V),and the corrosion current density of silane film was 5.361×10^(-8) A/cm^(2),which was lower than that of Zr-Ti film(8.350×10^(-8) A/cm^(2)).Compared with the TiZr film,the silane film had higher self-corrosion potential,lower self-corrosion current density and better corrosion resistance.The critical load value L_(C1) and L_(C2) of the coating on the substrate surface pretreated with silane coupling agent were 2035.71 mN and 3066.66 mN,respectively,which were higher than those pretreated by Zr-Ti film(1667.40 mN),and the adhesion between the coating and the substrate was stronger.Compared with the polyester coating without GO,the polyester coating with a mass fraction of 0.5%GO had the lowest weight loss and weight loss rate,and the surface of polyester coating showed fewer pores and corrosion pits after the 1000 h salt spray experiment,so its corrosion resistance was evidently enhanced.Thus,the corrosion resistance of the coating was significantly improved when GO was added to the polyester resin coating with a mass fraction of 0.5%.