Research on nonlinear corrosion law of epoxy coating on steel bridges based on image processing

This paper adopted the accelerated corrosion test method to study the corrosion law of epoxy coatings on steel bridges. An image processing algorithm based on MATLAB was used to perform grayscale conversion, normalized histogram drawing, and binary image processing on the surface morphology images of coated specimens. Four coated specimens were prepared and placed in the cyclic accelerated corrosion environment. The coated specimens were subjected to the accelerated corrosion test for 90 days, observed changes in coating thickness and corrosion area rate and analyzing the corrosion laws of epoxy coatings in different corrosion environments. Using image processing technology to process images of coating corrosion and analyze the corrosion mechanism of coatings. The research results indicate that the corrosion rate of epoxy coatings exhibits a non-linear corrosion law of slow corrosion in the early stage and accelerated corrosion in the middle and later stages. The corrosion rate of epoxy coatings in saltwater corrosive environments is faster than in freshwater corrosive environments. Based on the corrosion laws and mechanisms of coatings, a nonlinear corrosion function model for epoxy coatings on steel bridges under different accelerated corrosion environment was established, which has a high correlation with experimental data.