Erosion–Corrosion Effect on the Alloy 316L in Polluted Phosphoric Acid

Abstract

The physical factors such as the abrasive particles (AP) cause a mechanical rupture of the passive film in the polluted phosphoric acid. In this sense, the electrochemical methods and mass loss measurement were used to study the effect of these abrasive particles. X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy analysis (SEM/EDX) and UV–Vis–NIR spectroscopy methods were employed to analyze the material surface. The experimental results of X-ray diffraction showed that the AP affect the formation of passive film by decreasing the intensity of ferritic phases after 6 h of immersion. The measurements of polarization reveal that the erosion–corrosion accentuates the anodic dissolution of the material, which is manifested by an increase of the activation and passivity of current densities. The EIS exhibited a decrease in the polarization resistance of material caused by the reduction of the film thickness. The interpretation of the UV–Vis–NIR spectroscopy showed that the mechanical effect diminishes the passive film formation. In addition, the passive current density increases under the abrasion–corrosion condition which was approved by Mott–Schottky analysis. It is manifested by the formation of a porous outer layer and decrease in the properties of the inner layer, which was observed by UV–Vis–NIR and Mott–Schottky analysis, respectively.