TY - JOUR

T1 - Phase relations, thermal conductivity and elastic properties of ZrO2 and HfO2 polymorphs at high pressures and temperatures

AU - Sagatova, Dinara N

AU - Sagatov, Nursultan E

AU - Gavryushkin, Pavel N

AU - Solodovnikov, Sergey F

PY - 2023/12/13

Y1 - 2023/12/13

N2 - In the present study, P-T phase diagrams of ZrO2 and HfO2 for a wide pressure range of 0-150 GPa at 0-2500 K were calculated for the first time using density functional theory with the method of lattice dynamics within the quasi-harmonic approximation. We calculated P-T conditions for a full sequence of high-pressure transformations, P21/c → Pbca → Pnma → P6̄2m, for both compounds. At low temperatures, these transformations for ZrO2 are obtained at 7.6 GPa (P21/c → Pbca), 13.4 GPa (Pbca → Pnma), and 143 GPa (Pnma → P6̄2m), while for HfO2 similar polymorphic transitions are obtained at 9 GPa (P21/c → Pbca), 16 GPa (Pbca → Pnma), and 126 GPa (Pnma → P6̄2m), correspondingly. At high temperatures, for both ZrO2 and HfO2 the P21/c and Pbca structures transform into the P42/nmc modification. In addition, the thermal conductivity and elastic properties of the ZrO2 and HfO2 polymorphs were calculated and compared with the available experimental and theoretical data.

AB - In the present study, P-T phase diagrams of ZrO2 and HfO2 for a wide pressure range of 0-150 GPa at 0-2500 K were calculated for the first time using density functional theory with the method of lattice dynamics within the quasi-harmonic approximation. We calculated P-T conditions for a full sequence of high-pressure transformations, P21/c → Pbca → Pnma → P6̄2m, for both compounds. At low temperatures, these transformations for ZrO2 are obtained at 7.6 GPa (P21/c → Pbca), 13.4 GPa (Pbca → Pnma), and 143 GPa (Pnma → P6̄2m), while for HfO2 similar polymorphic transitions are obtained at 9 GPa (P21/c → Pbca), 16 GPa (Pbca → Pnma), and 126 GPa (Pnma → P6̄2m), correspondingly. At high temperatures, for both ZrO2 and HfO2 the P21/c and Pbca structures transform into the P42/nmc modification. In addition, the thermal conductivity and elastic properties of the ZrO2 and HfO2 polymorphs were calculated and compared with the available experimental and theoretical data.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85180005090&origin=inward&txGid=86f729f4b2ea1f3ad05ff6c8e571d137

U2 - 10.1039/d3cp04690g

DO - 10.1039/d3cp04690g

M3 - Article

C2 - 38032101

VL - 25

SP - 33013

EP - 33022

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 48

ER -