Work

Corrosion behavior and electrochemical properties of heat-treated Fe-20Cr-18Ni-6Mo-0.8Cu-0.2N-La alloys in alkaline seawater

Year: 2025

Type: article

Abstract: This study examines the microstructure, corrosion resistance, and electrochemical behavior of Fe–20Cr–18Ni–6Mo–0.8Cu–0.2N–La alloys after heat treatment at different temperatures. The results show that heating the alloy to 1200 °C for 1 h leads to the dissolution of second-phase particles, and the undissolved precipitation is Mo-rich phase σ-FeCrMo. Loss-in-weight analysis indicates that corrosion resistance is better at 75 °C than at 50 °C, with the 0.5 wt% alloy showing the lowest corrosion rate (75 °C: 0.0116 mm/a). Electrochemical tests indicate the 0.5 wt% La alloy shows the lowest corrosion current densities of 5.272 × 10 −7 A/cm 2 at 50 °C and 1.183 × 10 −6 A/cm 2 at 75 °C, demonstrating superior corrosion resistance as a cathode. Surface roughness analysis shows that the surface roughness is decreased after alkaline seawater (ASW) corrosion at 75 °C. This study highlights the potential of austenitic stainless steels as cathode materials for hydrogen (H 2 ) production from seawater electrolysis (SWE).

Source: npj Materials Degradation

DOI: 10.1038/s41529-025-00682-8