title: In-situ TEM visualization of vacancy injection and chemical partition during oxidation of Ni-Cr nanoparticles.
abstract: Oxidation of alloy often involves chemical partition and injection of vacancies. Chemical partition is the consequence of selective oxidation, while injection of vacancies is associated with the differences of diffusivity of cations and anions. It is far from clear as how the injected vacancies behave during oxidation of metal. Using in-situ transmission electron microscopy, we captured unprecedented details on the collective behavior of injected vacancies during oxidation of metal, featuring an initial multi-site oxide nucleation, vacancy supersaturation, nucleation of a single cavity, sinking of vacancies into the cavity and accelerated oxidation of the particle. High sensitive energy dispersive x-ray spectroscopy mapping reveals that Cr is preferentially oxidized even at the initial oxidation, leading to a structure that Cr oxide is sandwiched near the inner wall of the hollow particle. The work provides a general guidance on tailoring of nanostructured materials involving multi-ion exchange such as core-shell structured composite nanoparticles.
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors.forename: Chong-Min
authors.initials: CM
authors.lastname: Wang
authors.affiliation: FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, Oregon 97124, USA.
authors.forename: Arda
authors.initials: A
authors.lastname: Genc
authors.affiliation: FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, Oregon 97124, USA.
authors.forename: Huikai
authors.initials: H
authors.lastname: Cheng
authors.affiliation: FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, Oregon 97124, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Pullan
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Baer
authors.affiliation: Fundamental and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Bruemmer