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Carbon Encapsulation of High Entropy Alloy Nanoparticles with Extraordinary Coercivity and Saturation at Room Temperature
Author(s) -
Tseng ChaoChi,
Chi ChongChi,
Tsai HsinJung,
Yeh JienWei,
Ouyang Hao,
Hsu WenKuang
Publication year - 2020
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.202000137
Subject(s) - materials science , coercivity , alloy , nanoparticle , carbide , quinary , configuration entropy , chemical engineering , nanotechnology , chemical physics , thermodynamics , metallurgy , condensed matter physics , chemistry , physics , engineering
Owing to their unique properties and technological potential, high entropy alloys (HEAs) have become the subject of great interest in the materials science community. HEAs consist of more than four principle elements in equimolar ratio so their configurational entropy is intrinsically greater than one‐principle element based. The increasing surface energy and chemical tendency toward clustering of like atoms at low dimension, however, make production of HEA‐nanoparticles (HEA‐NPs) extremely difficult. A facile production of HEA‐NPs inside carbon nanotubes and nanoparticles is demonstrated in this work. Electron microscopic and elemental analyses confirm encapsulated to be solution phase; some embrace carbides and form multidomains with chemical composition ranging from quaternary to quinary phase. Multidomains and nonmagnetic centers create hardening thus promoting coercivity significantly at room temperature. Alloying induces electron redistribution into high spin states, accounting for observed high saturation. Configurational entropy of encapsulated HEA‐NPs lies on a range comparable with bulk.