High pressure dissociation of CaTiO3 perovskite into CaO and CaTi2O5 - Archive ouverte HAL Access content directly
Journal Articles Physics of the Earth and Planetary Interiors Year : 2022

High pressure dissociation of CaTiO3 perovskite into CaO and CaTi2O5

(1) , (1) , (1) , (1) , (1) , (1) , (2) , (3) , (1)
1
2
3

Abstract

In this study, we investigated phase transformations of CaTiO3 perovskite using x-ray diffraction at high pressure and high temperature up to 170 GPa and 4500 K in a laser-heated diamond-anvil cell. We report a high-pressure dissociation of CaTiO3 into CaO-B2 and CaTi2O5 with a monoclinic P2/m structure, instead of the expected transformation of the orthorhombic distorted perovskite structure into a post-perovskite phase. We propose that this transition may be favored by the B1 to B2 phase change of CaO at around 60 GPa. In order to provide additional information on the high pressure properties of CaTiO3 perovskite, we measured its melting temperature using CO2 laser heated diamond anvil cell up to 55 GPa yielding a fit of the melting curve to a Kraut-Kennedy empirical law according to: Tm(K) = 2188 ∗ [1 + 4.23 ∗ (ΔV/V0)]. To provide some further insight into the thermodynamic properties of CaTiO3, we determined the P-V-T equation of state of the orthorhombic mineral perovskite, fitted by using a third order Birch-Murnaghan equation of state and a Berman thermal expansion model. The fit of the data yields to K0 = 180.6(4) GPa, K′0 = 4 (fixed), ∂K/∂T = −0.022(1) GPa K−1, α1 = 3.25(5) x 10−5 K−1, α2 = 1.3(1) x 10−8 K−2
Embargoed file
Embargoed file
0 3 5
Year Month Jours
Avant la publication

Dates and versions

hal-03853131 , version 1 (15-11-2022)

Identifiers

Cite

B Truffet, G Fiquet, G Morard, M A Baron, F Miozzi, et al.. High pressure dissociation of CaTiO3 perovskite into CaO and CaTi2O5. Physics of the Earth and Planetary Interiors, In press, ⟨10.1016/j.pepi.2022.106968⟩. ⟨hal-03853131⟩
0 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More