涂层界面失效过程的ESPI无损检测方法

基于激光电子散斑干涉技术(ESPI),对涂层失效过程的电子散斑干涉技术检测平台进行设计搭建,在不破坏涂层前提下,观察到浸泡失效过程中涂层的原位、实时和动态干涉条纹,并对其进行优化处理.将原位、实时观察到的条纹与零时刻条纹图像相减后进行计算机二值化处理,得到反映涂层失效信息的原位、实时及动态图像.针对环氧色漆/碳钢涂装体系,证实了电子散斑干涉技术分析的有效性,并根据其检测图像的变化,将环氧涂层的浸泡过程分为三阶段:初期没有斑点,涂层完好;中期出现模糊的斑点,涂层防护作用下降;后期出现清晰的黑色大斑点,涂层丧失防护能力.实现了涂层/金属界面失黏、膜下金属腐蚀微观发展过程原位、实时和动态的无损检测.

ESPI nondestructive testing for coating interface failure

A detection platform of coating failure processes was designed and constructed on the basis of laser electronic speckle pattern interferometry (ESPI).In situ,real-time and dynamic speckle interference fringes were observed and optimized without destroying the coating.An image of coating failure information was acquired by subtracting the zero moment stripe from the in situ and realtime stripes observed and binarizing the results.An experiment of the epoxy color paint/carbon steel system demonstrated the validity of ESPI.According to the ESPI image change,the immersion process of the epoxy color paint coating was divided into three stages:no spots in the initial stage,several blurry spots in the second stage and many clear spots in the last stage.As a result,we successfully realize the in situ,real-time and dynamic nondestructive testing of the coating interface failure and the microcosmic progress of underfilm metal corrosion.