Temperature Effect on the Austenitic Stainless Steel UNS N08031 Used in the Wet Method Phosphoric Acid Production

Abstract

The influence of temperature (between 20 and 80 °C) on the electrochemical behaviour of UNS N08031 (Alloy 31) was evaluated in a contaminated phosphoric acid solution, which simulates the typical concentrations used in the industrial wet process (40 wt.% H₃PO₄, 2 wt.% H₂SO₄ and 0.42 wt.% KCl). Alloy 31 electrochemical behaviour was studied by means of polarisation curves and electrochemical impedance spectroscopy. Results demonstrated that temperature decreases the corrosion resistance of Alloy 31.