Irreversible Phase-Changes in Nanophase RE-doped M2O3 and their Optical Signatures
Technical Report,01 Feb 2010,31 May 2015
Washington State University Pullman
Pagination or Media Count:
Luminescent rare-earth doped metal oxides are evaluated as potential temperature sensors that are seeded into explosive fireballs and collected post-detonation for analysis. The sensors consist of amorphous precursors which, once subjected to thermal exposure, undergo irreversible phase transitions such as decomposition, nucleation, and grain growth. The extent and degree of these phase transitions depends on temperature and heating duration. The phase transitions are monitored via spectral changes in the fluorescence of the luminescent rare-earth dopants. The spectral emission of these dopants is very sensitive to the configuration of the oxygen ions surrounding the dopant. As this configuration changes, the spectral emission properties change and this change can be correlated with the temperature the materials were exposed to. The correlation is based upon laboratory-based reference measurements. The functionality of these temperature sensors was demonstrated during several explosion tests. By using two different sensor materials combined with a kinetic analysis, it is possible to simultaneously extract information about temperature and heating duration. Initial results using this approach were demonstrated.