Galvanic Corrosion Behavior of Zinc/Steel Couple under Thin Electrolyte Layer

摘要

Galvanic corrosion exists widely in atmospheric environment. In this study, the most common used structure material - low carbon steel and its protective coating materials - zinc were chosen to form the galvanic couple, and coplanar zinc/steel galvanic corrosion behavior has been investigated by electrochemical methods and scanning electrochemical method under thin electrolyte layer (TEL), simulating the atmospheric corrosion environment. The results indicate that the corrosion resistance of steel and zinc is sensitive to the TEL thickness. The cathodic current density and the diameter of capacitive arc of steel increase and decrease respectively with the decreasing TEL thickness. When coupled together, galvanic current between zinc and steel is sensitive to the TEL thickness and cathode/anode area ratio. Steel can be well protected when coupled with zinc under present atmospheric corrosion environments.