Corrosion Behavior of Carbon Steel in Lithium Bromide Solution

Weight‐loss tests and electrochemical techniques are used to study the inhibition of BTA and Na 2 MoO 4 either individually or in different combinations for carbon steel in boiling 10.24 mol/L LiBr solution containing 0.07 mol/L LiOH. The result indicates the corrosion of carbon steel is effectively inhibited when BTA or Na 2 MoO 4 is added to the solution individually. The adsorptions of BTA or Na 2 MoO 4 on carbon steel surfaces can be well fitted to a Langmuir adsorption isotherm. The free energy of adsorption of BTA and Na 2 MoO 4 are −45.07 kJ/mol and −40.69 kJ/mol, respectively. The corrosion rate is decreased to the minimal value, which is 8.39 μm/y, when 7.28 × 10 −4 mol/L Na 2 MoO 4 and 8.39 × 10 −4 mol/L BTA are added to a 10.24 mol/L LiBr solution containing 0.07 mol/L LiOH. The inhibition mechanism of the above mixed inhibitors results from the complemental effect of the compact inner layer film composed of Fe‐BTA and the absorbed MoO 4 2− in small quantity of the active site and the outer layer. The passive film of the coordination compound and the adsorbed MoO 4 2− prevent Br − from absorbing and effectively decrease the corrosion of carbon steel.