High-temperature thermal expansion of lime, periclase, corundum and spinel |
| |
| Authors: | G Fiquet P Richet G Montagnac |
| |
| Institution: | (1) Laboratoire des Sciences de la Terre, UMR CNRS 5570 Ecole Normale Supérieure de Lyon, 69364 Lyon cedex 07, France, FR;(2) Institut de Physique du Globe, ESA CNRS 7046 4 place Jussieu, 75252 Paris cedex 05, France, FR;(3) Laboratoire des Sciences de la Terre, UMR CNRS 5570 Ecole Normale Supérieure de Lyon, 69364 Lyon cedex 07, France, FR |
| |
| Abstract: | The high-temperature cell parameters of lime (CaO), periclase (MgO), corundum (Al2O3), and spinel (MgAl2O4) have been determined from 300 up to 3000 K through X-ray diffraction experiments with synchrotron radiation. The good agreement
found with dilatometric results suggests that vacancy-type defects do not make a large contribution to thermal expansion for
these oxides, even near the melting point, justifying the use of X-ray diffraction for determining volume properties up to
very high temperatures. Thermal expansion coefficients were determined from the measured cell volumes with equations of the
form α=α0 + α1
T + α2/T 2. Along with available isobaric heat capacity and compressibility data, these derived coefficients clearly show that anharmonic
effects contribute little to the isochoric heat capacities (C
v
) of CaO, MgO, and Al2O3, which do not depart appreciably from the 3nR Dulong and Petit limit.
Received: 31 March 1999 / Revised, accepted: 23 June 1999 |
| |
| Keywords: | X-ray diffraction High-temperature Oxides Thermal expansion Anharmonicity |
| 本文献已被 SpringerLink 等数据库收录！ |
|
