环氧型防腐涂层在深海环境的电化学行为分析

Electrochemical Behaviour of Epoxy Anticorrosive Coatings in Deep-sea Environment

目的评价铝合金基环氧型防腐涂层在深海环境的腐蚀防护性能,为铝合金结构在深海环境下的腐蚀防护提供支撑。方法采用近底悬浮式深海环境试验装置和深海高压模拟试验系统,分别开展环氧型防腐涂层体系实海试验与室内模拟深海试验,研究铝合金基环氧型防腐涂层在深海环境下的防护性能与电化学行为。结果某海域实海结果显示,经历0.5 a的1000 m深海试验后,环氧防腐涂层对铝合金基体的防护状态良好,涂层附着力强度仍旧保持在9 MPa以上。室内模拟深海试验结果显示,在5~20 d的试验周期内,试验初期涂层电阻均在10^(10)Ω·cm^(2)以上,涂层电容则在10^(‒10)F/cm^(2)数量级。随着试验时间的增加,涂层电阻减小,电容增加。其中3000 m模拟深海环境下,涂层电阻从初始的3.995×10^(10)Ω·cm^(2)锐减至3.264×10^(7)Ω·cm^(2),下降了3个数量级,涂层电容则从初始的8.818×10^(‒10)F/cm^(2)上升至1.765×10^(‒9)F/cm^(2)。静水压力影响结果显示,随着试验压力的增加,涂层电阻逐渐减小,涂层电容和吸水率逐渐增加。在试验后期,1000、2000、3000 m模拟深海环境下,涂层电阻分别为3.044×10^(10)、4.305×10^(9)、3.264×10^(7)Ω·cm^(2),而涂层吸水率则分别为4.32%、8.09%和15.84%。结论1000~3000 m深海环境下,深度每增加1000 m,浸泡初期相同时间的涂层吸水率增加近1倍。

This work aims to evaluate the anticorrosion performance of aluminum alloy-based epoxy anticorrosive coating in deep-sea environment,and provide support for anticorrosion of aluminum alloy structure in deep-sea environment.Natural deep-sea environmental exposure experiments and laboratory simulated deep-sea corrosion tests of aluminum-based epoxy anti-corrosive coatings were carried out respectively with the near-bottom suspending deep-sea environmental test facility and the the simulated deep-sea high-pressure test system to study the protection performance and electrochemical behavior of aluminum alloy-based epoxy anticorrosive coating in deep-sea environment.The field exposure results in the South China Sea showed that the epoxy coatings displayed good protection effect for aluminum substrates with the adhesion strength of>9 MPa.The labo-ratory simulated deep-sea results showed that,within 5-20 d of test cycle,the coating resistance values in the initial stage were above 10^(10)Ω·cm^(2)with the coating capacitance values of 10^(‒10)F/cm^(2)orders of magnitude.With the tests proceeding,the coating resistance values decreased,and the capacitance values increased.And for the simulated 3000 m conditions,the coating resis-tance values declined sharply from the initial 3.995×10^(10)Ω·cm^(2)to 3.264×10^(7)Ω·cm^(2).The results of static water pressure effect showed that the coating resistances gradually decreased and the water absorption percentages increased with the pressure in-creasing.In the later stage,the coating resistance values were 3.044×10^(10)Ω·cm^(2),4.305×10^(9)Ω·cm^(2)and 3.264×10^(7)Ω·cm^(2),and the water adsorption of the coatings was 4.32%,8.09%and 15.84%respectively.It is concluded that the water absorption of coatings immersed for the same period of time in the initial stage is nearly doubled with every increase of 1000 m depth in the 1000-3000 m deep-sea environment.