Library Item
Thermoelastic properties of ReB2 at high pressures and temperatures and comparison with Pt, Os, and Re
Description:
We have measured the phase stability and thermoelastic equation of state of ultrahard rhenium diboride at pressures up to 30?GPa and temperatures up to 2500?K using a laser heated diamond anvil cell in conjunction with synchrotron X-ray diffraction. ReB2 is shown to be stable throughout this pressure and temperature region. The ratio of the c-axis to the a-axis provides a monitor of the annealing of plastic stresses during compression. We show that ReB2 has a small thermal anisotropy but a large mechanical anisotropy. Combining this new data set with previously existing results from a large volume press yields a thermoelastic equation of state with a Grüneisen parameter of 2.4 (0.08) and a q of 2.7. A comparison of ReB2 with other high electron density incompressible metals—Os, Re, and Pt—shows that ReB2 has the lowest thermal pressure and the highest bulk modulus.
