Melt-driven mechanochemical phase transformations in moderately exothermic powder mixtures
Author(s)Garroni, Sebastiano; Delogu, Francesco; Humphry-Baker, Samuel A; Schuh, Christopher A
MetadataShow full item record
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.
DepartmentMassachusetts Institute of Technology. Department of Materials Science and Engineering
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
Author's final manuscript