Corrosion performance of 2205 duplex stainless steel in simulated hydrometallurgical processes: A study of uniform and crevice corrosion
Davood Nakhaie, Edouard Asselin
Abstract
The corrosion behavior of SAF 2205 duplex stainless steel (DSS) is studied under acidic conditions of hydrometallurgical processes. The focus is on uniform and crevice corrosion. A Central Composite Design (CCD) was employed to evaluate the effects of temperature, sulfuric acid, hydrogen peroxide, and chloride concentration on the corrosion rate and critical crevice temperature (CCT) of 2205 DSS. Analysis of variance (ANOVA) revealed that the uniform corrosion rate is primarily influenced by temperature and chloride concentration, with both factors accelerating the corrosion of the alloy. However, the uniform corrosion rate of 2205 DSS remained generally below the 100 µm/yr threshold. Moreover, the CCT of the alloy decreased with increasing concentrations of Cl − and H 2 O 2 , while higher concentrations of H 2 SO 4 improved CCT, likely due to inhibition by sulfate ions. These findings enhance the current understanding of the corrosion resistance of 2205 DSS in aggressive environments, offering valuable insights for the application of this alloy in hydrometallurgical processes. • SAF 2205 DSS showed uniform corrosion rates below 100 µm/yr, influenced by temperature and chloride concentration. • Cl⁻ and H₂O₂ reduced the CCT of the alloy, while H₂SO₄ improved it by inhibiting localized corrosion. • Oxidizing agents like H₂O₂ and Cu(II) reduced uniform corrosion by shifting potentials to the passive region. • High Cl⁻ concentrations increase crevice corrosion risk, highlighting the need for chloride control.