Influence of temperature on alloy 31 in abrasion-corrosion conditions of phosphoric acid medium
Résumé
The abrasion-corrosion behavior of the alloy 31 was tested at different temperatures 25 °C, 40 °C, 60 °C and 80 °C in polluted phosphoric acid medium. Electrochemical measurements were investigated using techniques such as electrochemical impedance spectroscopy and potentiodynamic polarization. In order to determine the oxides and hydroxides formed at the interface of the alloy, we opted for surface treatment techniques: SEM-EDX, UV-Vis-NIR spectroscopy, and X-ray diffraction. The results showed an increase in current densities, which means that these conditions favor the hydrogen evolution reaction and influence the parameters of the passive film. Moreover, this effect can be explained by an increase in the activity of the aggressive ions adsorbed on the surface, thereby accelerating the dissolution process and the exchange kinetics between the electrode surface and the electrolyte. UV-Vis-IR spectroscopy and X-ray diffraction analysis exhibited that temperature favors the formation of metal oxides on the surface, which the EIS discloses that film was less protective. © 2019 by CEE (Center of Excellence in Electrochemistry).