Electrochemical Behaviors of Q420 Hot Galvanized Plate in Simulated Concrete Pore Solution

Abstract:

The electrochemical behaviors of Q420 hot galvanized plate in the simulated concrete pore solution are studied by means of polarization curves and AC impedance. The result shows that, when the Q420 galvanized plate is in the simulated concrete pore solution, the stable and protective calcium zincate grains can be produced on the coating surface of the galvanized steel, so that the coating can enter the passive state and prevent the further corrosion of zinc in the alkaline environment. When the carbonification occurring in the concrete reduces the pH of medium or changes the medium environment due to the intrusion of Cl^-, some small corrosion pores occur at the grain boundary of zinc grain first, then the calcium zincate grain Ca [Zn (OH)₃]₂·2H₂O begins to be produced near the small pores, and with the gradual growth of calcium zincate grain, the zinc layer surface is gradually coated to form the protective layer with gradually increasing corrosion resistance. After the zinc base is fully coated by the calcium zincate grain, the corrosion current density declines to about the critical passive value, and the zinc layer is in the passive state. When Cl^- enters the corrosive concrete environment, Cl^- will destroy the primary corrosion product film calcium zincate covering the galvanized coating, so that the galvanized coating can enter the active state again.

• Periodical: Advanced Materials Research (Volumes 941-944)
• Pages: 854-857
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.941-944.854
• Online since: June 2014
• Authors: Qi Lei Sun*, Ze Rui Liu
• Keywords: Electrochemical Impedance Spectroscopes, Hot Galvanized Plate, Polarization Curve, Simulated Concrete Pore Solution

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