摘要
涂层金属的耐腐蚀性能取决于其对腐蚀介质的的阻挡能力 ,在水溶液及含水大气中则主要取决于水分子及其它侵蚀性粒子 (O2 、Cl-等 )的渗透能力 .介绍了Fick扩散条件下H2 O在涂层中的扩散行为及其与涂层阻抗间的关系 ,并探讨阻抗方法在涂层评价中的适用条件 .
In the present paper a review was given on water diffusion behaviors in polymer films and coating impedance according to Fickian process.In the case of linear Fickian diffusion,a mathematical relationship between the water-uptake in organic coatings and capacitance,C,of coatings was established.The change rate of coating capacitance was mainly depended on the water diffusion coefficient,D,in coatings.In the initial stage of water-uptaking,a linear relationship is shown in the curves lnC(t)～time 0.5 ,with the slope proportional to D 0.5 .Under the non-linear diffusion,water preferentially penetrated through the cracks or the boundaries of foreign particles by shearing diffusion,while in the bulk coatings by linear one.The contribution by linear diffusion could be eliminated with the presence of obvious porosity,and the coating capacitance was mainly determined by the porosity of coatings,θ.The slope of the linear part in lnC(t)～t 0.5 curves was proportional to θ 0.5 .
出处
《中国腐蚀与防护学报》
CAS
CSCD
2002年第5期311-315,共5页
Journal of Chinese Society For Corrosion and Protection
基金
国家重点研究发展规划 (G19990 6 5 0 )资助项目
关键词
有机涂层
水传输
Fick扩散
阻抗
organic coatings,water transport,Fickian diffusion,impedance
