Synergetic effect of two inhibitors for enhanced corrosion protection on the reinforcing steel in the chloride-contaminated carbonated solutions
By Wang, Danqian; Pan, Chonggen; Liu, Zhicheng; Chen, Keyu; Chen, Na; Liu, Shuhua
Published in Construction and Building Materials
2021
Abstract
The synergetic inhibiting effect of benzotriazole (BTA) and Na2HPO4 for the corrosion of reinforcing steel in the chloride-contaminated carbonated solutions was preliminarily investigated by electrochemical measurements, as well as X-ray photoelectron spectroscopy and scanning electron microscopy/energy dispersive X-ray techniques. Results show that a mixture of BTA and Na2HPO4 acts as an anodic inhibitor. An optimum enhanced inhibition efficiency was obtained for a mixture of 0.05 M BTA and 0.05 M Na2HPO4. The synergistic inhibiting mechanism for steel was proposed, which was by forming a protective film consisting of Fen(BTA)m complex and iron phosphates, as well as hydrogen bonding between them on the steel surface. On the contrary, a mixture of unequal amount of BTA and Na2HPO4 showed an antagonistic effect on corrosion inhibition resulting from the competition between the phosphate ions and BTA- on the steel surface.