Structure of liquid oxides at very high temperatures

The structural characterization of condensed matter by synchrotron radiation combined with neutron data constitutes a powerful structural tool in material science. In order to investigate refractory liquids at very high temperatures, we have developed a new analysis chamber for performing combined X-ray absorption and diffraction measurements by using laser heating and aerodynamic levitation. A similar system has been designed for neutron experiments. This high temperature equipment presents several advantages: the container does not physically or chemically perturb the sample, heterogeneous nucleation during cooling is suppressed and pollution by the container is removed. This cell can operate under various gas conditions from room temperature up to 3000 deg. C obtained by means of a sealed 125 W CO2 laser. Experiments have been performed at LURE, ESRF and at ISIS. We have studied the local structure around the cations in several liquid and solid oxides. We have shown that high temperature synchrotron data combined with neutron results provide detailed structural information on liquid alumina