We have obtained pressure-volume-temperature (P-V-T) equation of state for hexagonal tungsten carbide (α-WC) up to 32 GPa and 1673 K using synchrotron x-ray diffraction in a multianvil apparatus at the SPring-8 facility. MgO and Au were used as pressure calibrants. A least-squares fit of the P-V-T -data to a high-temperature Birch-Murnaghan equation of state yielded V0 =20.750±0.002 Å3, KT =384±4 GPa, K′ =4.65±0.32, temperature derivative of the bulk modulus ( KT /T) P =-0.014±0.002 GPa/K, and thermal expansion α= a0 + a1 T with a0 =0.96 (±0.05) × 10-5 K-1 and a1 =0.48 (±0.05) × 10-8 K-2. The data showed an anisotropic nature of compressibility, with the a -axis (K Ta =341±6 GPa) more compressible than the c -the axis (K Tc =506±12 GPa) as well as an anisotropic temperature dependence of K T. The estimated thermal Grüneisen parameters are 1.44-1.64 and the Debye temperature is calculated to be 1220 K, which is different from previous estimates.
ASJC Scopus subject areas
- Physics and Astronomy(all)