Understanding the Oxidation Behavior of Fe/Ni/Cr and Fe/Cr/Ni Core/Alloy Nanoparticles
In this work we describe a method to prepare core/alloy nanoparticles (CA NPs) based on transition metal alloys with tunable oxidation properties. We investigated the use of chromium and nickel carbonyl based precursors to control shell deposition and thickness at a Fe cores producing Fe/Cr/Ni and Fe/Ni/Cr CA NPs. We compared the systems by monitoring resistance to oxidation and found that it is highly dependent on the shell and alloy sequence as well as thickness, with thin Fe/Cr/Ni having the best stainless behavior. The CA NP growth was monitored by TEM, and composition was assessed by XPS. Oxidation was quantified by both powder XRD and XPS. The results were analyzed in light of alloy miscibility and diffusion, as well as lattice strains and interfacial oxidation rates.