Metal dissolution during OER in equimolar CrCoNi alloy highlights the need for metal ion quantification to assess catalyst efficiency and stability.
Source: BAM
The development of multi-principal element alloys (MPEAs) has gained significant attention in recent years, as these materials combine outstanding mechanical strength, stability, and corrosion resistance. Among them, CrCoNi is considered highly promising for applications in aggressive environments. In this study, the long-term corrosion resistance of CrCoNi in 1 M sulfuric acid was compared with that of CrCoNiFeMn to assess the influence of additional alloying elements on stability.
Samples were exposed for 28 days under immersion and electrochemical conditions. A combination of electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and inductively coupled plasma mass spectrometry (ICP-MS) was employed to characterize passive film formation, metal dissolution, and surface morphology.
The results demonstrate that CrCoNi exhibits superior long-term corrosion resistance in sulfuric acid. This improvement is attributed to the formation of a stable, Cr-rich passive layer that effectively suppresses substrate dissolution. By contrast, CrCoNiFeMn tends to form porous mixed oxides that provide less protection and gradually promote degradation. Importantly, the long-term experiments revealed corrosion mechanisms that remain hidden in short-term tests, highlighting the necessity of extended exposure studies for realistic material assessment.
This work not only provides new insights into the corrosion behavior of MPEAs but also establishes a foundation for the rational design of more durable alloys for use in energy-intensive and chemical process industries.
Long-term corrosion studies of CrCoNi and CrMnFeCoNi in sulfuric acid
Annica Wetzel, Ann-Kathrin Hans, Marcus von der Au, Izabella Brand, Gunther Wittstock, Ozlem Ozcan & Julia Witt
npj Materials Degradation, 2025