Segregation passivation makes cost-effective stainless steel resistant to corrosion and hydrogen embrittlement

Stainless steels are essential materials in sustainable energy conversion systems, particularly in hydrogen-related applications. However, their susceptibility to hydrogen embrittlement and corrosion limits their long-term use, creating a need for advanced alloys capable of resisting environmentally assisted damage and mechanical failure. Here, we design a cost-effective austenitic stainless steel. The key innovation involves the atomic-scale passivation of grain boundaries through nitrogen decoration. This enhances resistance to failure, achieving about 3.8-fold increase in corrosion resistance and a 1.35-fold increase in hydrogen embrittlement resistance compared to commercial 316L. The steel exhibits very low hydrogen diffusivity (~7.8 × 10^-17 square meters per second), mitigating hydrogen embrittlement at ambient temperature, an advantage over conventional steels. In addition, formation of a dense passive film improves corrosion resistance in environments such as dilute hydrochloric acid, sulfuric acid, and caustic soda. The outstanding resistance of the stainless steel against such harsh coupled environmental conditions qualifies it as a promising candidate for sustainable and secure infrastructure in the emerging hydrogen economy.