| Abstract Scope |
The stainless steel industry relies on alloying elements such as Cr, Mn, and Ni, conventionally introduced via ferroalloys produced through energy-intensive carbothermic routes. Chromium and manganese oxides are thermodynamically more stable than iron and nickel oxides, making them difficult to reduce with molecular hydrogen. Hydrogen co-reduction of metal oxide powder blends leverages easily reducible elements as thermodynamic facilitators via the Le Châtelier principle, offering a low-carbon pathway to stainless steel synthesis. Here, we investigate co-reduction of oxide blends ranging from two- to five-element systems, targeting master alloy compositions remelted with iron to produce stainless steel. For some systems, we compare molecular hydrogen and hydrogen plasma as reductants. Using in-situ X-ray diffraction, we track phase evolution, reduction sequences, and transient intermediate phases. We demonstrate that molecular hydrogen and hydrogen plasma operate through distinct kinetic pathways, establishing hydrogen co-reduction as a viable route toward sustainable master alloy production for stainless steel. |