Evaluating corrosion propagation in steel with damaged protective coating

Abstract

Corrosion is a leading cause of degradation in steel structures, particularly in environments exposed to marine and industrial conditions. Protective coatings are commonly employed to prevent corrosion, but mechanical damage during fabrication, transportation, and installation can compromise these coatings, leading to corrosion propagation. This study focuses on the corrosion behavior of steel samples with intentionally damaged protective coatings, simulating realworld scenarios. Five coating systems were evaluated: hot-dip galvanizing, thermal spray metallizing, marine-grade epoxy, and two duplex systems. These coatings were subjected to accelerated corrosion testing based on ASTM G85 Annex A5 standards, designed to simulate harsh environmental conditions. Corrosion progression was monitored through halfcell potential measurements and visual inspection. The results indicate that duplex coatings, combining sacrificial and barrier protection, provided superior resistance to corrosion propagation after damage, compared to single-layer coatings. This study highlights the importance of selecting durable coatings for steel infrastructure, particularly in environments prone to mechanical damage. The findings offer valuable insights into material selection and maintenance strategies, contributing to the improvement of long-term performance in steel structures exposed to corrosive environments.