Density measurements and structural properties of liquid and amorphous metals under high pressure

Abstract

We have implemented an in situ X-ray diffraction analysis method suitable for the determination of pressure–volume–temperature equations of state in the critical case of liquid and amorphous materials over an extended thermodynamic range (T>2000 K and P>40 GPa). This method is versatile, it can be applied to data obtained using various angle-dispersive X-ray diffraction high pressure apparatus and, contrary to in situ X-ray absorption techniques, is independent from the sample geometry. Further advantage is the fast data acquisition (between 10 and 300 s integration time). Information on macroscopic bulk properties (density) and local atomic arrangement (pair distribution function g(r)) can be gathered in parallel. To illustrate the method, we present studies on liquid Fe–S alloys in the Paris Edinburgh press and in laser-heated diamond anvil cell (DAC), and measurements on Ce glass in DAC at room temperature.

Keywords:

• density measurements
• liquid and amorphous materials
• high pressure

Acknowledgements

The authors thank the ESRF staff of the High Pressure Beamline ID27 (S. Bauchau and M. Mezouar) for the X-ray experiments, and P. Ochin (Institut de Chimie et des Matériaux de Paris-Est, Paris, France) for the starting materials synthesis. We also thank C. Sanloup and L. Belhadi for fruitful discussions. This work was supported by the French National Research Agency (ANR) grant no. 2010-JCJC-604-01 and the PlanetLab program of French National Research Agency (ANR) grant no. ANR-12-BS04-0015-04.