Corrosion‐Protection of T122 Steel Using g‐C ₃ N ₅ ‐Embedded Epoxy Coatings

ABSTRACT Corrosion‐protection performance of a polymeric coating composed of g‐C 3 N 5 (CN) combined with epoxy (EP) on a T122 steel is systematically evaluated in two corrosive environments i.e., 3.5% NaCl and 0.1 M H 2 SO 4 . The electrochemical corrosion experiments suggest that the g‐C 3 N 5 concentration significantly affects the performance of EP towards the corrosion protection. The composite of EP containing 2% g‐C 3 N 5 (TEP2CN) exhibited the highest polarization/noise resistance values ( R p and R n , respectively) and showed the best performance against corrosion. This is mostly attributed to the blockage of the pores in the EP by the low quantity of added g‐C 3 N 5 which subsequently prohibits the ionic diffusion to the T122 steel surface. However, upon increasing the g‐C 3 N 5 ‐content to 5% (in TEP5CN), the protection performance degrades significantly because in this case, the coating partially delaminates facilitating the passage of the corrosive ions to diffuse through the coating to the T122 steel. The obtained electrochemical results suggest that the CN, when embedded in optimized quantity, can significantly improve the corrosion resistance of epoxy‐based coatings.