Expounding the interaction of ultraviolet irradiation and tribocorrosion on soap fiber enhanced epoxy coating

Abstract A self-dispersing composite lithium soap fiber (CLSF) as high-performance filler is introduced into epoxy coating for enhancing the ultraviolet (UV) irradiation and tribocorrosion resistance. The storage modulus and the lowest-frequency impedance value of the epoxy coating with 1 wt% CLSF (CLSF-1) after UV irradiation are increased by 1.5 times and an order of magnitude, respectively. Its wear rate under tribocorrosion condition is decreased by 70.11% with the highest open circuit potential value. Moreover, the damage mechanism under compound conditions is ascertained. The interaction of UV irradiation and tribocorrosion on soap fiber enhanced epoxy coating can be depicted as follows: on the one hand, the effective shielding layer formed by highly dispersed CLSF reflects UV light and inhibits the photo-oxidation reaction of epoxy coatings, allowing the improvement in the structure stability and tribocorrosion resistance of coating; on the other hand, wear aggravates corrosion. The material loss weakens the barrier effect of coating against corrosion media, and worn surface as defect area becomes fast diffusion channels for aggressive ions, thus accelerating the corrosion reaction. Our study reveals basic features of UV and tribocorrosion damages and can provide a guidance to resist extreme conditions for other coatings.