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Two regimes of oxidation by water are revealed for nanocrystalline aluminum prepared by the mechanical activation of its mixture with graphite and distributed in the matrix of amorphous carbon. At the temperatures 50 ° C < T < 90 ° C, nanosized aluminum particles interact with water under quasi-isothermal conditions. The main products are hydrogen and pseudoboehmite AlOOH; a low content of bayerite Al(OH) 3 is also formed. After the induction period, the kinetics of interaction can be satisfactorily described by the law of a diminishing sphere. The effective activation energy of the reaction is equal to 61 ± 10 kJ/mol and is identical for the samples of submicron aluminum prepared by different procedures. At temperatures above 90-95 ° C, the oxidation of mechanically activated aluminum by water is transformed into a thermally self-accelerated explosion process. Under these conditions, the oxidation of aluminum to α -Al 2 O 3 is accompanied by an exothermal reaction between the metal and the carbon matrix during which aluminum carbide Al 4 C 3 is formed.

Changes in the crystal structure and composition of aluminum and graphite powder mixtures in the course of their joint mechanical treatment in a vibration mill were monitored by the adsorption and X-ray diffraction techniques. It was shown that, at absorbed energy doses of 8-10 kJ/g, the grinding and mixing of aluminum with graphite is completed by the formation of an intermediate structure of Al/C composite, where aluminum showed an anomalously high reactivity. The interaction of aluminum with water was used to study its reactivity in the composite. The formation of the composite preceded the stage of chemical interaction between carbon and aluminum atoms.

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