风电用环氧玻璃鳞片涂层防腐性能的电化学研究

Electrochemical Performance of Epoxy Glass Flake Coating for Marine Wind Power

通过分析环氧玻璃鳞片涂层的电化学交流阻抗谱(EIS)、电阻电容和特征频率的变化特点,对其在各个浸泡阶段的防护机理进行了研究.结果表明:在浸泡初期,环氧玻璃鳞片涂层良好的屏蔽作用可阻挡水分子和腐蚀介质的渗入;在浸泡中期,环氧玻璃鳞片涂层因吸水饱和而失效,导致腐蚀介质渗透到钢铁基材表面,发生电化学反应而引起腐蚀,但是,由于腐蚀产物添堵了孔隙,再加上玻璃鳞片的层状分布使腐蚀介质渗入得以延缓,从而使腐蚀速率降低;在浸泡后期,环氧玻璃鳞片涂层快速失效,腐蚀产物大幅增加导致膨胀剥落,腐蚀介质直接和钢铁基材发生电化学反应,防护能力极低.

Through the analysis of the electrochemical impedance spectroscopy（EIS）, the resistance capaci- tance and the characteristic frequency of the epoxy glass flake coating, the protective mechanism were studied. Results show that in the early stage of immersion, the epoxy glass flake coating has good shiel- ding effect, which can prevent the infiltration of water molecules and the corrosive medium~ in the immer- sion medium, epoxy glass flake coating fails due to water saturation, resulting in corrosion spread into the steel substrate surface, electrochemical reaction and corrosion, but because the corrosion product fills pores and layered glass {lake corrosion medium makes in-depth growth path, which effectively lowers the corrosion rate of coating; in the late period of immersion, the epoxy glass flake coating is quickly ineffec- tive, and the increase of the corrosion product causes the expansion of the coating. The corrosive medium directly has an electrochemical reaction with the metal substrate, the coating is completely ineffective, and the protection ability becomes very poor.