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采用海水压力罐模拟深海高压环境,利用电化学阻抗谱(EIS)、三维视频显微镜和扫描电子显微镜(SEM)等手段,对比研究了改性环氧防腐涂层在常压海水环境和模拟深海高压环境(6 MPa海水压力)下的失效行为。结果表明,试样在深海高压环境下浸泡30 d后,涂层阻抗已降低到105Ω·cm~2;而常压环境下,涂层阻抗仅降低到108Ω·cm~2,深海高压环境促使涂层更快地吸水达到饱和状态,高压环境导致涂层下的金属腐蚀活性面积不断增大,基体金属腐蚀速率不断增加。SEM观察表明,高压导致环氧防腐涂层中的颜填料发生脱附,使涂层/金属基体界面弱化,腐蚀活性表面积增大,从而导致涂层破损和基体腐蚀。
The seawater pressure tank was used to simulate the deep sea pressure environment. Electrochemical impedance spectroscopy (EIS), three-dimensional video microscope and scanning electron microscope (SEM) were used to study the effects of modified epoxy anti-corrosion coatings on the environment of seawater under normal pressure and simulated deep- Environment (6 MPa seawater pressure) Failure behavior. The results show that the impedance of the coating has been reduced to 105Ω · cm ~ 2 after immersed for 30 days under the conditions of deep sea pressure. Under atmospheric pressure, the impedance of the coating only decreases to 108Ω · cm ~ 2. The layer absorbs water more quickly to a saturation state, and the high-pressure environment causes the area of the metal corrosion activity under the coating to increase continuously, and the corrosion rate of the base metal increases continuously. SEM observation showed that the high pressure led to the desorption of the pigments and fillers in the epoxy anticorrosive coating, weakening the interface of the coating / metal matrix and increasing the surface area of the corrosion active, resulting in coating damage and matrix corrosion.