"Melting of tantalum at high pressure determined by angle dispersive x-ray synchrotron diffraction in a double-sided laser-heated diamond-anvil cell",
D. Errandonea, M. Somayazulu, D. Hausermann, and H. K. Mao
Journal of Physics: Condensed Matter 15, 7635-7649 (2003)

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The high pressure and high temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, being the melting temperature in good agreement with previous laser-heated DAC experiments, but contradicting several theoretical calculations and previous piston-cylinder apparatus experiments. A small melting slope is estimated (dTm/dP ~24 K/GPa at 1 bar) and a possible explanation for this behaviour is given. Finally, a P-V-T equation of states is obtained, being the temperature dependence of the thermal expansion coefficient and the bulk modulus estimated.