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Influence of the Zinc Chromate coating on the corrosion of ASTM A-500 and galvanized A-500 steel exposed into a salt fog corrosion chamber

Abstract:

In this research work it has been analyzed the influence of the Zinc chromate coating on the corrosion of ASTM A-500 and galvanized A-500 steels exposed in a salt spray corrosion chamber, according to the ASTM B117 Standard. Two surface cleaning methods were used prior to applying the coating, considering the SSPC-SP-3 and SSP-SP-5 standards, namely a mechanical cleaning and a blast cleaning. The samples were put into the chamber with exposure times of 200, 250 and 350 h. Different equipment were used for recording the information that was used to calculate the corrosion rate. Through visual assessments according to the ASTM-D610 and ASTM D-714 standards, the corrosion degree and the blistering frequency, re-spectively, were determined. The materials without coating and coated after the two surface cleaning methods were compared. The results obtained have demonstrated that galvanized steel exhibited a lower corrosion rate.