Melt-driven mechanochemical phase transformations in moderately exothermic powder mixtures
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Melt-driven mechanochemical.pdf
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Author(s)
Garroni, Sebastiano
Delogu, Francesco
Humphry-Baker, Samuel A
Schuh, Christopher A
Date Issued
August 2016
Journal
Nature Materials
Publisher
Springer Nature
Citation
Humphry-Baker, Samuel A. et al. “Melt-Driven Mechanochemical Phase Transformations in Moderately Exothermic Powder Mixtures.” Nature Materials 15, 12 (August 2016): 1280–1286 © 2017 Macmillan Publishers Limited, part of Springer Nature
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Author's final manuscript
Abstract
Usually, mechanochemical reactions between solid phases are either gradual (by deformation-induced mixing), or self-propagating (by exothermic chemical reaction). Here, by means of a systematic kinetic analysis of the Bi–Te system reacting to Bi₂Te₃, we establish a third possibility: if one or more of the powder reactants has a low melting point and low thermal effusivity, it is possible that local melting can occur from deformation-induced heating. The presence of hot liquid then triggers chemical mixing locally. The molten events are constrained to individual particles, making them distinct from self-propagating reactions, and occur much faster than conventional gradual reactions. We show that the mechanism is applicable to a broad variety of materials systems, many of which have important functional properties. This mechanistic picture offers a new perspective as compared to conventional, gradual mechanochemical synthesis, where thermal effects are generally ignored.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1038/nmat4732
