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Title: Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

Abstract

Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP 2O 7 family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV 2O 7 and HfV 2O 7 were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV 2O 7 and HfV 2O 7 exhibited a very strong dependence on pressure (~700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV 2O 7 was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively).

Authors:
; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1345410
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 249; Journal Issue: C
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE

Citation Formats

Gallington, Leighanne C., Hester, Brett R., Kaplan, Benjamin S., and Wilkinson, Angus P. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate. United States: N. p., 2017. Web. doi:10.1016/j.jssc.2017.02.014.
Gallington, Leighanne C., Hester, Brett R., Kaplan, Benjamin S., & Wilkinson, Angus P. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate. United States. doi:10.1016/j.jssc.2017.02.014.
Gallington, Leighanne C., Hester, Brett R., Kaplan, Benjamin S., and Wilkinson, Angus P. Mon . "Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate". United States. doi:10.1016/j.jssc.2017.02.014.
@article{osti_1345410,
title = {Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate},
author = {Gallington, Leighanne C. and Hester, Brett R. and Kaplan, Benjamin S. and Wilkinson, Angus P.},
abstractNote = {Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP2O7 family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV2O7 and HfV2O7 were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV2O7 and HfV2O7 exhibited a very strong dependence on pressure (~700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV2O7 was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively).},
doi = {10.1016/j.jssc.2017.02.014},
journal = {Journal of Solid State Chemistry},
number = C,
volume = 249,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}
  • Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP{sub 2}O{sub 7} family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} exhibited a very strong dependence on pressure (∼700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression alsomore » reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV{sub 2}O{sub 7} was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively). - Graphical abstract: The temperature at which ZrV{sub 2}O{sub 7} transforms to a phase displaying negative thermal expansion is strongly pressure dependent. The high temperature form of ZrV{sub 2}O{sub 7} is elastically stiffer than the low temperature form. - Highlights: • The order-disorder phase transition temperatures in ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} are strongly pressure dependent (∼700 K.GPa). • The high temperature (disordered) phase of ZrV{sub 2}O{sub 7} is much stiffer than the ambient temperature (ordered) phase. • Compression reduces the magnitude of the negative thermal expansion in the high temperature phase of ZrV{sub 2}O{sub 7}.« less
  • Cited by 2
  • No abstract prepared.
  • Phase transformations and thermal expansions were studied for compounds having the ..cap alpha..-PbO/sub 2/ type of structure in the ZrO/sub 2/-HfO/sub 2/-TiO/sub 2/-SnO/sub 2/ system. Continuous phase transformation of ZrTiO/sub 4/ accompanied by a marked shrinkage of the b parameter was confirmed. All the compounds including HfTiO/sub 4/ existed as dimorphs, although the difference in the b parameters between the high- and low-temperature forms decreased with the content of Hf and Sn in the Zr/sub 1-x/Hf/sub x/TiO/sub 4/ system and the Zr/sub x/Ti/sub y/Sn/sub z/O/sub 4/ (x + y + z = 2) system, respectively. The striking contrast in thermalmore » expansions between ZrTiO/sub 4/ and HfTiO/sub 4/ was confirmed for furnace-cooled specimens at a rate of 10/sup 0/Cmin. The high-temperature ZrTiO/sub 4/ quenched from 1500/sup 0/C exhibited thermal expansion significantly smaller than that of the furnace-cooled ZrTiO/sub 4/. The low-temperature ZrTiO/sub 4/ heated at 1000/sup 0/C for 720 h exhibited thermal expansion larger than that of the furnace-cooled ZrTiO/sub 4/. The thermal expansion of furnace-cooled Zr/sub x/Ti/sub y/Sn/sub z/O/sub 4/ (x + y + z = 2) decreased with the Sn content, and that of ZrTi/sub 0.4/Sn/sub 0.6/O/sub 4/ was found to be almost identical with that of HfTiO/sub 4/. A number of anomalies exhibited by these mixed oxides are noticed. And a hypothesis based on the interaction of orbitals by using d electrons of highly charged cations has been proposed to explain the anomalies.« less