Corrosion inhibition effect of sodium phytate on brass in NaOH media. Potential-resolved formation of soluble corrosion products

摘要

Corrosion inhibition of brass by phytate in alkaline media was evaluated by cyclic voltammetry, UV-vis spectra, derivative cyclic voltabsorptometry (DCVA) and scanning electron microscopy. A thin-layer electrochemical cell was fabricated with an appropriate light-path-length. A high corrosion inhibition efficiency of phytate on brass was achieved in 0.1 mol dm~(-3) NaOH. Soluble ions such as Zn(OH)_4~(2-), Cu(Ⅰ) intermediate ion, Cu(OH)_4~(2-) and another Cu(Ⅱ)-O complex, were monitored in situ under potentiostatic and potentiodynamic conditions. The DCVA curves at given wavelengths show five positive and three negative peaks corresponding to the potential-resolved formation and reduction of various soluble corrosion products.