P-V-T equation of state of boron carbide.

We report the P-V-T equation of state measurements of B 4 C to 50 GPa and approximately 2500 K in laser-heated diamond anvil cells. We obtain an ambient temperature, third-order Birch-Murnaghan fit to the P-V data that yields a bulk modulus K 0 of 221(2) GPa and derivative, (d K /d P ) 0 of 3.3(1). These were used in fits with both a Mie-Grüneisen-Debye model and a temperature-dependent, Birch-Murnaghan equation of state that includes thermal pressure estimated by thermal expansion ( α ) and a temperature-dependent bulk modulus (d K 0 /d T ). The ambient pressure thermal expansion coefficient ( α 0  + α 1 T ), Grüneisen γ ( V ) =  γ 0 ( V / V 0 ) q and volume-dependent Debye temperature, were used as input parameters for these fits and found to be sufficient to describe the data in the whole P-T range of this study. This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 1)'.