| In this dissertation, in order to prevent the oxidation of Al, meliorate the problem that micro-Al powders accelerated the thermal deposition of propellant inconspicuously and disperse the catalyst(nano-Cu) very well, shell-core nano-Cu/Al composite powders were prepared by means of electroless copper planting method and displacement method to deposite Cu on superfine Al.To the electroless copper plating method, natrium hypophosphite and formaldehyde were used as the reducer of the electroless planting. Orthogonal designs were used to optimize the bath components and processing parameters. Then the characteristics of the composite powders, including the surface morphology, the structure and the surface components, were investigated by XRD, SEM and EDS. The results indicated that, with the using of either reducer, Al were all coated by a compact nano-copper film which was composed of nano-copper appeared in crystal state. Then grinding the Cu/Al and AP together and using the DSC to analyse the catalytic effect of the Nano-Cu/Al composites on the thermal decomposition of AP. The results indicated that the composites have preferable catalytic effect, including making the peak of the thermal decomposition decreasing and the peak of the low and high decomposition overlapping so that it can release more energies(1.184kJ·g-1).Displacement method was also used to prepare the nano-Cu/Al composite powders. The reaction happened in the solution involving NaF(complexing reagent) and glutin (protective reagent). The Cu particles, whose average diameter were about 14.42nm, were uniformly and continuously coated on the aluminum particles. The surface area of the composite powders was increased to 16.26m2·g-1 compared with 0.19m2·g-1 of the raw aluminum. Using DSC to analyst these composites' catalytic effect on the thermal deposition of AP, the results showed that the peak of the high thermal deposition of the AP decrease to 338.32℃ and it can also released more energies(0.960kJ·g-1)。... |
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