TU Darmstadt / ULB / TUbiblio

Kinetic control in the synthesis of metastable polymorphs: Bixbyite-to-Rh2O3(II)-to-corundum transition in In2O3

Bekheet, Maged F. and Schwarz, Marcus R. and Kroll, Peter and Gurlo, Aleksander (2015):
Kinetic control in the synthesis of metastable polymorphs: Bixbyite-to-Rh2O3(II)-to-corundum transition in In2O3.
In: Journal of Solid State Chemistry, 229Elsevier Science Publishing, pp. 278-286, ISSN 00224596,
[Online-Edition: http://dx.doi.org/10.1016/j.jssc.2015.06.007],
[Article]

Abstract

An example for kinetic control of a solid-state phase transformation, in which the system evolves via the path with the lowest activation barrier rather than ending in the thermodynamically most favorable state, has been demonstrated. As a case study, the phase transitions of indium sesquioxide (In2O3) have been guided by theoretical calculations and followed in situ under high-pressure high-temperature conditions in multi-anvil assemblies. The corundum-type rh-In2O3 has been synthesized from stable bixbyite-type c-In2O3 in two steps: first generating orthorhombic Rh2O3-II-type o′-In2O3 which is thermodynamically stable at 8.5 GPa/850 °C and, thereafter, exploiting the preferred kinetics in the subsequent transformation to the rh-In2O3 during decompression. This synthesis strategy of rh-In2O3 was confirmed ex situ in a toroid-type high-pressure apparatus at 8 GPa and 1100 °C. The pressure–temperature phase diagrams have been constructed and the stability fields of In2O3 polymorphs and the crystallographic relationship between them have been discussed.

Item Type: Article
Erschienen: 2015
Creators: Bekheet, Maged F. and Schwarz, Marcus R. and Kroll, Peter and Gurlo, Aleksander
Title: Kinetic control in the synthesis of metastable polymorphs: Bixbyite-to-Rh2O3(II)-to-corundum transition in In2O3
Language: English
Abstract:

An example for kinetic control of a solid-state phase transformation, in which the system evolves via the path with the lowest activation barrier rather than ending in the thermodynamically most favorable state, has been demonstrated. As a case study, the phase transitions of indium sesquioxide (In2O3) have been guided by theoretical calculations and followed in situ under high-pressure high-temperature conditions in multi-anvil assemblies. The corundum-type rh-In2O3 has been synthesized from stable bixbyite-type c-In2O3 in two steps: first generating orthorhombic Rh2O3-II-type o′-In2O3 which is thermodynamically stable at 8.5 GPa/850 °C and, thereafter, exploiting the preferred kinetics in the subsequent transformation to the rh-In2O3 during decompression. This synthesis strategy of rh-In2O3 was confirmed ex situ in a toroid-type high-pressure apparatus at 8 GPa and 1100 °C. The pressure–temperature phase diagrams have been constructed and the stability fields of In2O3 polymorphs and the crystallographic relationship between them have been discussed.

Journal or Publication Title: Journal of Solid State Chemistry
Volume: 229
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Metastable phases, Indium oxide, In situ characterization, Density functional theory, High pressure, Phase transitions
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 08 Jan 2016 09:22
Official URL: http://dx.doi.org/10.1016/j.jssc.2015.06.007
Identification Number: doi:10.1016/j.jssc.2015.06.007
Funders: The financial support by the German Research Foundation DFG (Grant number GU 992/8-1) within the priority programme SPP 1236 and DESY are greatly acknowledged., The authors would also like to thank Christian Lathe for technical support and the Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, for the opportunity to perform measurements at the MAX200X press.
Export:
Suche nach Titel in: TUfind oder in Google
Send an inquiry Send an inquiry

Options (only for editors)

View Item View Item