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在60℃实验条件下以3种无溶剂环氧防腐涂层为研究对象,利用称重法研究了在不同流速3.5%NaCl溶液中水在涂层中的扩散行为,采用开路电位法(OCP)和电化学阻抗谱技术(EIS)研究了不同流速下涂层的失效行为。结果表明,胺类固化粉末涂层和酚醛固化粉末涂层在实验流速范围内、酚醛胺固化液体涂层在较低流速范围内,水在涂层中的扩散符合Fick II模型,而酚醛胺固化液体涂层在4 m/s高流速下水在涂层中的扩散偏离Fick II模型;随着流体流速增加,涂层的饱和吸水量增加,水在涂层中的扩散系数变大;实验流速范围内3种无溶剂涂层失效过程分为3个阶段;流体流速明显加速了酚醛固化粉末涂层和酚醛胺固化液体涂层的劣化,对胺类固化粉末涂层失效影响不明显。
Under the experimental conditions of 60 ℃, three kinds of solvent-free epoxy anticorrosive coatings were taken as the research object. The diffusion behavior of water in the coatings with different flow rate of 3.5% NaCl solution was studied by weighing method. The open circuit potential method (OCP) And electrochemical impedance spectroscopy (EIS) to study the failure behavior of coatings at different flow rates. The results show that the amine curing powder coating and phenolic curing powder coating in the experimental flow rate range, phenalkamine curing liquid coating at a lower flow rate range, water diffusion in the coating in line with the Fick II model, and phenalkamine curing The diffusion of water in the coating at a high flow rate of 4 m / s deviates from the Fick II model. As the fluid velocity increases, the saturated water absorption of the coating increases and the diffusion coefficient of water in the coating becomes larger. The experimental flow rate range Three kinds of solvent-free coating failure process is divided into three stages; fluid flow rate significantly accelerated the phenolic curing powder coating and phenalkamine curing liquid coating degradation, amine curing powder coating failure is not obvious.