hrvatski

Elektrokemijsko istraživanje svojstava oksidnog filma na visokolegiranom čeliku 304 u fluoridnom mediju

The properties of the oxide film formed on stainless steel 304 in deaerated 0.01 and 0.1 mol L−1 NaF solutions with different pH values were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results revealed that corrosion of stainless steel 304 increases with increasing concentration of fluoride ions. In 0.01 mol L-1 NaF, pH = 4.5 corrosion rate was 0.45 g cm-2 h-1, while in 0.1 mol L-1 NaF, pH = 4.5 corrosion rate increases to 1, 58 g cm-2 h-1. Influence of pH value on corrosion rate was negligible in studied experimental conditions. The experimental data are interpreted in terms of the point defect model for passivity of stainless steel 304, assuming that predominant point defects on passive film of stainless steel 304 are cation vacancies. Diffusivity and concentration of point defects were estimated from the Warburg - type impedance.

visokolegirani čelik 304, fluoridni ion, pasivni film, ciklička voltametrija, elektrokemijska impedancijska spektroskopija, točkasti defekti

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