High Pressure Study And Electronic Structure Of The Super-Alloy Hfir3

The crystallographic structure of HfIr3 was studied as a function of pressure using X-ray diffraction technique. No phase transition was observed up to a pressure of 27.6 GPa, with a total volume contraction of V/V-0 congruent to 0.92. The bulk modulus value, calculated from the X-ray experimental data and from the sound-velocity technique, are B=279+/-4 and 297.9+/-2.5 GPa, respectively. The relatively high value of the bulk modulus, combined with a high density value of rho=20564 kg/m(3), and a high hardness value of 6.05+/-0.26 GPa, positions this compound as a possible application for extreme environments. The electronic structure of HfIr3, studied with the full potential linearized augmented plane calculations technique, indicates that the main cause for the unusual properties of this compound are the Iridium unfilled 5d-shell of this atom.