不同厚度无溶剂环氧防腐涂层的阻抗特征和水传输研究

Research on Impedance Property and Water Transport of Solvent-free Epoxy Anticorrosion Coatings with Varying Thickness

应用电化学阻抗谱技术研究了3.5%Na Cl溶液中30μm和60μm新型MYF无溶剂环氧涂层在Q235钢材表面的阻抗模型演变。两种厚度涂层的电化学过程均可分为5个阶段,但又不相同。30μm和60μm涂层电容的对数和时间的平方根在浸泡初期呈线性关系,为典型的菲克扩散特征。之后60μm涂层电容增长速度减慢,出现一段非菲克扩散过程,表现出两段吸收特征。30μm涂层在菲克扩散阶段后即达到吸水饱和状态。通过对菲克扩散方程的计算,得到了包含时间变量和位置变量的水在涂层中的动力学方程。

By applying electric chemical impedance spectrum technology, impedance model evolution of MYF solvent-free epoxy coatings with film thickness at 30 μm and 60 μm in 3.5%Na Cl solutions were studied. Five stages in electric chemical process could be seen for the two thicknesses. At initial immersion period, logarithm and square root of electric capacity of the two thicknesses showed linear relations as typical Fick＇s diffusion characteristics. After that, for the coating at 60 μm, the increase of electric capacity slowed down and indicated non-fick＇s diffusion characteristics. Two absorption characters were found. As for the coating at 30 μm, water absorption reached saturation stage after Fick＇s diffusion characteristics stage. Kinetic equation of water in coating including time and position was gained by Fick＇s diffusion equation.