Corrosion of Copper in Aqueous Lithium Bromide Concentrated Solutions by Immersion Testing

The corrosion rate of copper produced by lithium bromide (LiBr) concentrated solutions of 400 g/L and 700 g/L (4.61 M and 8.06 M) at room temperature, 70°C, and 110°C was studied using immersion testing. The corroded copper concentration was determined with two techniques: weight loss and differential pulse polarography (DPP₅₀). Corrosion of copper at room temperature and 70°C followed a power tendency with exposure time, whereas at 110°C it followed a linear tendency for short exposure times, remaining practically constant for long exposure times. The corrosion product was studied using scanning electron microscopy (SEM). The corrosion product formed in 400-g/L LiBr solutions presented a crystalline and granular morphology, associated with a mixture of copper bromide (CuBr) and copper(II) oxide-copper(II) hydroxide (CuOCu[OH]₂). However, the corrosion product formed in 700-g/L LiBr solutions presented a gelatinous and amorphous morphology, associated with a mixture of CuBr and copper trioxybromide (CuBr₂·3Cu[OH]₂).