Corrosion Inhibition of Carbon Steel by Benzotriazole and Lithium Nitrate in Concentrated LiBr-CaCl2 Solution at Elevated Temperature
Masahiko Itoh, Kazutoshi Itoh, Masakiyo Izumiya, Kazuo Tanno
Inhibition of the corrosion of carbon steel in a concentrated LiBr-CaCl2 mixed solution was investigated in a glass sealed-tube at various temperatures. The LiBr-CaCl2 is used as heat storage medium for chemical heat storage in cooling systems. A mixed inhibitor of benzotriazole (BTA) of 0.0017 and lithium nitrate of 0.0015mol/kg-H2O provides excellent inhibition of corrosion in carbon steel when immersed in a mixture of 5.1mol/kg-H2O LiBr and 4.0mol/kg-H2O CaCl2 at 393K. It is assumed that this corrosion inhibition effect, by the mixed inhibitor, is a direct result of the synergestic effect caused by the compact layer composed of Fe3O4 and Fe-BTA which is formed on the surface of carbon steel. The layer formed on carbon steel inhibits the anodic reaction.