Pressure-volume-temperature equation of state of tungsten carbide to 32 GPa and 1673 K

We have obtained pressure-volume-temperature (P-V-T) equation of state for hexagonal tungsten carbide (alpha-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 Mumaghan equation of state yielded V(0) = 20.750+/-0.002 angstrom(3), K(T) = 384+/-4 GPa, K' = 4.65+/-0.32, temperature derivative of the bulk modulus (partial derivative K(T)/partial derivative(T))p=-0.014+/-0.002 GPa/K, and thermal expansion alpha=a(0)+a(1)T with a(0) = 0.96(+/-0.05) x 10(-5) K(-1) and a(1) = 0.48(0.05) x 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 Griineisen parameters are 1.44-1.64 and the Debye temperature is calculated to be 1220 K, which is different from previous estimates. (C) 2010 American Institute of Physics. [doi:10.1063/1.3481667]