A University of Hong Kong stainless steel alloy self-passivates through a mechanism that corrosion science says should not work. The breakthrough attacks the largest cost component in green hydrogen production. A stainless steel alloy from a Materials Today study, featured in a University of Hong Kong press release on May 10, does something that corrosion science textbooks say is impossible. SS-H2, developed by Professor Mingxin Huang's team, resists corrosion at 1,700 millivolts in chloride media. Conventional stainless steels fail catastrophically at those voltages. The difference is manganese. The prevailing view in corrosion science is that manganese impairs corrosion resistance. Every metallurgy curriculum teaches this. SS-H2 inverts the relationship through what the researchers call sequential dual-passivation: first, the standard chromium oxide film forms. Then at approximately 720 millivolts, a manganese-based layer forms on top of it.…