Preparation, characterization, and use of metal hydrides for fuel systems. Progress report, June 1, 1979-August 31, 1980. Final report
The chemical reactivity of aluminum hydride, the alkaline-earth metal hydrides, and the alkali-metal alanates was investigated. All of the materials can be photolytically decomposed at room temperature with high intensity uv light to produce hydrogen gas irreversibly. ..cap alpha..-AlH/sub 3/, LiAlH/sub 4/ and NaAlH/sub 4/ powders can be irreversibly isothermally decomposed at elevated temperatures. Exposure of the material to /sup 60/Co ..gamma.. rays modifies the decomposition. The rate constants of all thermal decomposition stages are increased with increasing dose, and the overall time to complete the decomposition is shortened. This effect has been interpreted as the result of the formation of additional decomposition nuclei by the radiation. The activation energies for the ..gamma..-ray pre-irradiated material are the same as for the pristine material indicating that the same decomposition process is occurring in both. ..gamma..-ray pre-irradiation also modifies the photolytic decomposition kinetics. However, the induced effects are complex and each material behaves differently with increasing ..gamma..-ray dose. The crystal structure determinations on single crystal NaAlH/sub 4/ indicated that a different number of conjugate hydrogen atoms surround the alkali metal atoms in the alanates as the atomic weight of the alkali metal increases. The kinetic parameters and the behavior of the materials to uv light and various pretreatments can be used to evaluate the practical usefulness of these solids as lightweight hydrogen gas generators. Of all the hydrides examined, ..cap alpha..-AlH/sub 3/ satisfies almost all of the necessary criteria. Apart from the fact that ..cap alpha..-AlH/sub 3/ decomposes irreversibly to yield hydrogen and it cannot be recharged in situ, the material is ideal as a solid hydrogen gas generator. The residue is recyclable, the material is stable to water vapor and the decomposition temperature ideal.
- Research Organization:
- State Univ. of New York, Stony Brook (USA). Dept. of Materials Science and Engineering
- DOE Contract Number:
- AS02-76ER02715
- OSTI ID:
- 5227605
- Report Number(s):
- DOE/ER/02715-T1; COO-5000-5; ON: DE82009654
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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08 HYDROGEN
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM HYDRIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
DECOMPOSITION
PHOTOLYSIS
BARIUM HYDRIDES
CALCIUM HYDRIDES
MAGNESIUM HYDRIDES
SODIUM HYDRIDES
STRONTIUM HYDRIDES
RESEARCH PROGRAMS
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
HYDRIDES
HYDROGEN COMPOUNDS
KINETICS
MAGNESIUM COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATION CHEMISTRY
RADIATION EFFECTS
REACTION KINETICS
SODIUM COMPOUNDS
STRONTIUM COMPOUNDS
360206* - Ceramics
Cermets
& Refractories- Radiation Effects
080201 - Hydrogen- Chemisorption Storage
400500 - Photochemistry
400201 - Chemical & Physicochemical Properties