New experimental approach to study solid combustion reactions using synchrotron radiation.

摘要

We have recently utilized the high intensity characteristic of synchrotron radiation and performed a series of proof-of-principle time-resolved x-ray diffraction (TRXRD) experiments at the Brookhaven National Synchrotron Light Source to follow the phase transformations in a number of solid combustion systems in-situ at high temperature. A photo-diode array (Princeton Instrument) which is capable of recording a full scan of 1024 pixels in 4 msec, was used as a position-sensitive detector to record the TR-diffraction patterns from the reacting specimen situated in a specially designed reaction chamber-diffractometer with a vertical (theta)--2(theta) geometry. The systems thus far studied include: Ti + C = TiC; Ti + C + xNi = TiC + xNi; Al + Ni = AlNi(sub 0). In the latter reaction, we were able to achieve a time resolution of 20 msec and record the formation of pre-reactive phases, melting of the reactants, reaction intermediates and final products in a total scan time of two minutes. These synchrotron experiments open a new route to study the chemical dynamics and phase transformation of reactive systems in-situ, at high temperature and under other external perturbations in the time domain of a few milliseconds which has not been possible before.