Isotropic negative thermal expansion in ZrW 2 O 8 and HfW 2 O 8 from 1100 to 1275°C (in EN)
Abstract
ZrW2O8(ZrO2•2WO3) and HfW2O8(HfO2•2WO3) have been the focus of thermal expansion studies due to their isotropic negative thermal expansion (NTE) measured previously at temperatures below 775°C. This work presents measurements of these materials at their thermodynamically stable temperature ranges of 1105 and 1257°C for ZrW2O8and 1105–1276°C for HfW2O8, where they were characterized with in situ, powder X‐ray diffraction. The linear coefficients of thermal expansion were measured to be −5.52 × 10−6and −4.87 × 10−6°C−1for ZrW2O8and HfW2O8, respectively. The mechanism leading to this NTE is discussed. Powder samples were synthesized by a solution‐based process called the organic–inorganic steric entrapment method. In situ characterization in air was carried out at the National Synchrotron Light Source II using a hexapole lamp, optical furnace and the Advanced Photon Source using a quadrupole lamp, optical furnace to achieve elevated temperatures.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-06CH11357; AC02-98CH10886
- OSTI ID:
- 2582717
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 7 Vol. 107; ISSN 0002-7820
- Publisher:
- American Ceramic SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- EN
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