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Title: Nucleation and growth behavior of multicomponent secondary phases in entropy-stabilized oxides
Abstract

The rocksalt structured (Co,Cu,Mg,Ni,Zn)O entropy-stabilized oxide (ESO) exhibits a reversible phase transformation that leads to the formation of Cu-rich tenorite and Co-rich spinel secondary phases. Using atom probe tomography, kinetic analysis, and thermodynamic modeling, we uncover the nucleation and growth mechanisms governing the formation of these two secondary phases. We find that these phases do not nucleate directly, but rather they first form Cu-rich and Co-rich precursor phases, which nucleate in regions rich in Cu and cation vacancies, respectively. These precursor phases then grow through cation diffusion and exhibit a rocksalt-like crystal structure. The Cu-rich precursor phase subsequently transforms into the Cu-rich tenorite phase through a structural distortion-based transformation, while the Co-rich precursor phase transforms into the Co-rich spinel phase through a defect-mediated transformation. Further growth of the secondary phases is controlled by cation diffusion within the primary rocksalt phase, whose diffusion behavior resembles other common rocksalt oxides.

Graphical abstract

 
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Award ID(s):
2011967
NSF-PAR ID:
10377036
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Cambridge University Press (CUP)
Date Published:
Journal Name:
Journal of Materials Research
Volume:
38
Issue:
1
ISSN:
0884-2914
Page Range / eLocation ID:
p. 198-214
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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