Decomposition of. cap alpha. -aluminum hydride power. 3. Simultaneous photolytic-thermal decomposition
The simultaneous effects of uv photolysis and thermal decomposition (coirradiation) on ..cap alpha..-AlH/sub 3/ powder have been investigated between 60 and 150/sup 0/C. From the kinetic analysis, this temperature range can be divided into two distinct regimes; the first region from 60 to 110/sup 0/C delineates a transition between the photolysis and coirradiation, and the second region from 110 to 150/sup 0/C involves only coirradiation. The fractional decomposition (..cap alpha..) vs time curves are sigmoidal in shape between 110 and 150/sup 0/C much like the thermal decomposition data at these temperatures. The transition-region curves change with temperature and/or light intensity to resemble either the low-temprature photolysis or the high-temperature coirradiation curves. The high-temperature coirradiation ..cap alpha..(t) curves are faster and have induction, acceleratory, and decay periods similar to those for the thermal decomposition, but different kinetics are applicable with lower activation energies (kJ/mol): (51.1 vs 107.0, 130.1 vs 158.0, and 132.8 vs 164.0, respectively). In the transition region, an empirical relationship describes the induction period, but the acceleratory period has the same linear relationship with time as the high-temperature coirradiation. The synergistic effect of uv light and heat is evidenced in the lower activation energies and faster decomposition rates noted for reactions involving the additional uv light stimulus. The changing interaction of light- and heat-induced species and the complex behavior of the resultant kinetics is noted during the transition region. 4 figures, 4 tables.
- Research Organization:
- State Univ. of New York, Stony Brook
- DOE Contract Number:
- E(11-1)2715
- OSTI ID:
- 6205592
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 85:13
- Country of Publication:
- United States
- Language:
- English
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Decomposition of. cap alpha. -aluminum hydride powder. 1. Thermal decomposition
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36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM HYDRIDES
PHOTOLYSIS
PYROLYSIS
ACTIVATION ENERGY
EXPERIMENTAL DATA
KINETICS
POWDERS
TEMPERATURE DEPENDENCE
ULTRAVIOLET RADIATION
ALUMINIUM COMPOUNDS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ENERGY
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
RADIATIONS
THERMOCHEMICAL PROCESSES
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Cermets
& Refractories- Radiation Effects
400201 - Chemical & Physicochemical Properties