Inhibition and facilitation mechanisms of galvanic corrosion between carbon fiber and steel in atmospheric environments

Abstract

For a steel structure with carbon fiber-reinforced polymer (CFRP) bonded reinforcement, galvanic corrosion is thermodynamically favored between the carbon fiber and metal. However, understanding of corrosion behaviors and mechanisms between two materials in atmospheric environments remain limited. This study investigated the galvanic corrosion behavior between carbon fiber and steel based on activation-controlled kinetics. The inhibition and facilitation factors of galvanic corrosion in an atmospheric environment were examined, including the material properties of the carbon fiber and the dynamic influence of system resistance, water-film condition, and temperature variation. The results revealed that localized pitting corrosion is prone to occurring near the electrical contact points of the two materials. Under extreme atmospheric conditions, the galvanic corrosion rate increases by 1–2 orders of magnitude as the reaction shifts from diffusion control to activation control. Additionally, elevated temperatures exacerbate this effect, with the galvanic corrosion rate exhibiting greater sensitivity to temperature changes than steel self-corrosion. Finally, a simplified macroscopic circuit model was proposed to integrate the inhibition and facilitation mechanisms, based on the four coupling modes governed by the Butler–Volmer equation. The present results provide new insights regarding the corrosion and deterioration mechanism of CFRP bonded components.