engleski

Influence of flowing on the inhibition of carbon steel by a multicomponent non-toxic inhibitor

Several blends of carboxylic acid salts have been investigated in a flow system and compared with results obtained under stagnant conditions to be used as corrosion inhibitors for carbon steel in the near neutral media.The effectiveness and the mechanism of inhibition were estimated by potentiodynamic polarisation measurements and confirmed by a mass loss detection.Synergistic behaviour of calcium gluconate and sodium benzoate (22), and gluconate with tannin (23), as inhibitors for mild steel was shown by experiments under stagnant conditions. In the actual study mixtures of calcium and zinc salts and sodium benzoate were used in different ratio and concentration to get a synergistic effect assessed in the flowing media.A series of experiments has been performed in a tap water and another one in chloride solutions in order to detect the efficiency of inhibitor in brines and the seawater.The ratio and concentration of components in a blend and the type of cations, calcium or zinc, influenced the anodic dissolution of steel and cathoduic reduction reaction. In another series of measurements the addition of a low amount of sodium meta-silicate, widely known in the literature and classified as an anodic inhibitor, forming the protective layer on the metal surface, was found to increase the inhibition effect of some investigated blends.All compounds used are environmentally completely acceptable.

carbon steel ; inhibition ; flowing system ; carboxylic acid salts

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