Unconventional Alloys Confined in Nanoparticles: Building Blocks for New Matter

Summary Manufacturing unconventional alloys remains challenging owing to the seamless interplay between kinetics and thermodynamics. High-entropy alloys (HEAs), for example, enable paradigm shifts in materials science but these shifts are hindered by traditional liquid-solid transformations. In contrast, vapor–crystal transformations offer the most kinetically efficient pathways to form alloys. Here, a well-mixed vapor is quenched to create 55 distinct alloys confined in nanoparticles (NPs), including unprecedented ones. This confinement is found to stabilize their alloyed states. Unlike precursor feeding, a microseconds-long oscillatory spark mixes the vapors and determines the composition of the alloy NPs. To epitomize practicalities, we apply the NPs as integral building blocks for high-performance catalysts and to nanoscale additive manufacturing. The resulting HEA nanostructures cannot be fabricated by other additive manufacturing techniques. The present work breaks the miscibility limits, thereby providing a powerful roadmap to uncharted territories in metallurgy, catalysis, and additive manufacturing.