Performance of organic coatings upon cyclic mechanical load

Abstract

A number of engineering structures fail due to the fatigue damage resulting from cyclic mechanical stress. However, as far as organic coatings are concerned this degradation factor remains underestimated. In the paper the authors propose a methodology combining global electrochemical impedance spectroscopy and local atomic force microscopy measurements for evaluation of coating resistance to an impact of repetitive mechanical stress. Typical epoxy coating designated for ship hull protection has been tested in as-received state as well as after pre-exposure to elevated temperature. Application of atomic force microscopy-based approach helped to reveal and spatially localize the spots of organic coating degradation onset. The mechanism and process of defect formation and propagation has been shown on a microscopic scale.