Preparation And Characterization Of Nanometer Aluminum Powder - Based Composites

Nano-aluminum is the common metallic fuel in composite energetic material. Compared to micro aluminum and regular aluminum, it can reduce the diffusion limitation and increase the rate of oxidation in contribution to improving the combustion performance. However, the high specific surface area and great surface energy make it easy to agglomertate, leading to the smaller contact area, which limits the utilization of nanoaluminum. So, in order to achieve excellent performance, efforts such as enhancing the contact area of the reactants and reducing the union of Al nanoparticles should be made. In this paper, three kinds of composites, Al/AP, Al/CuO, Al/CuO-AP nanocomposites were prepared. The as prepared nanocomposites were characterized and their exothermic behaviors and combustion performances were tested. The main works are as follows:(1) The preparation of Al/AP nanocomposites:The Al/AP nanocomposites were prepared as follows:AP particles were dissolved by acetone and then certain amount of Al nanoparticles were dispersed in the solvent, finally nanocomposites were prepared through solvent evaporation crystallization method and then were characterized. Results show that the Al/AP nanocomposites are spherical, well-dispersed and the nanocomposites were prepared through physical action and have no impurities. DTA results and combustion performances show that the existence of AP is beneficial to the exothermal behavial and combustion performance, and Al/AP nanocomposites with 40% weight ratio of Al nanoparticles have the best combustion performance.(2) The preparation of Al/CuO nanocomposites:Firstly, three kinds of CuO nanoparticles were prepared by quick-precipitation method, in which Cu(NO3)2·3H2O, DMAC and NaOH were chosen as raw material, and results show that the spherical-like CuO particles are spherical, well-dispersed with the average size of 5-6 nm; the belt-like CuO particles are well-dispersed with the width of 30 nm and the length of 500 nm; the spindle-like CuO particles are well-dispersed with the average size of 200 nm and the length of 400 nm. Then the Al/CuO composites were prepared through the simply mixed method and the self-assemble method, respectively. Results show that the composites prepared by self-assemble method have better exothermal behavial than those prepared by the simply mixed method., and the composites prepared through spherical-like CuO and Al have the highest exothermal changes; at last, under the foundation of these findings, the effects of molar rate on the exothermal changes were researched, results show that when the molar rate is 1.8, the composites have the highest enthalpy changes (2.994 kJ/g).(3) The preparation of Al/CuO-AP nanocomposites:The Al/CuO-AP nanocomposites were prepared as follows:AP particles were dissolved by acetone and then certain amount of Al/CuO nanocomposites were dispersed in the solvent, finally nanocomposites were prepared through solvent evaporation crystallization method and then were characterized. Results show that the AP particles are covered on the surface of Al/CuO nanocomposites the nanocomposites were prepared through physical action and have no impurities. And the existence of AP is beneficial to the exothermal behavial and enhancing the mass transfer process of the combustion process of Al/CuO composites, and Al/CuO-AP nanocomposites with 60% weight ratio of Al/CuOcomposites have the best combustion performance.