title: New techniques for high-temperature melting measurements in volatile refractory materials via laser surface heating.
abstract: An original technique for the measurement of high-temperature phase transitions was implemented based on a laser-heating method, enabling chemically unstable, refractory materials to be melted under controlled conditions. This technique includes two independent but correlated methods: In the first, fast multichannel pyrometry is employed to measure thermograms and spectral emissivity; in the second, a low-power probe laser beam is used for the detection of reflectivity changes induced by phase transitions on the sample surface. The experiments are carried out under medium ( approximately 10(2) kPa) or high ( approximately 10(2) MPa) inert-gas pressures in order to kinetically suppress evaporation in volatile or chemically instable samples. Two models for the simulation of the laser-heating pulses are as well introduced. Some results are presented about the successful application of this technique to the study of the melting behavior of oxides such as UO(2+x), ZrO(2), and their mixed oxides. The method can be extended to a broad class of refractory materials.
authors.affiliation: European Commission, Joint Research Centre, Institute For Transuranium Elements (ITU), Karlsruhe, Germany. dario.manara@ec.europa.eu
authors.forename: D
authors.initials: D
authors.lastname: Manara
authors.forename: M
authors.initials: M
authors.lastname: Sheindlin
authors.forename: W
authors.initials: W
authors.lastname: Heinz
authors.forename: C
authors.initials: C
authors.lastname: Ronchi