Study On The Synthesis And Catalytic Characteristics Of Metal And Composite Metal Nanopowders

Nanometer Ni and Cu powders, NiB, CuNiB and NiCu composite metal nanopowders were prepared by chemical reduction, and their average particle size were 50nm, 20nm, 20nm, 60nm and 40nm respectively. The optimal conditions to prepare nanometer metal and composite metal powders were also studied. The catalytic effects of these metal and composite metal nanopowders on the thermal decomposition of AP and AP/HTPB composite solid propellant were studied by thermal analysis (DTA). Nanometer Ni, Cu and Al powders decreased the second thermal decomposition temperature of AP by 113.5℃ , 130.2 ℃ and 51.8 ℃ respectively, and NiB, CuNiB and NiCu composite metal nanopowders decreased that by 64.9℃, 146.1℃ and 140.4℃. The DTA heat release of AP in the presence of metal and metal composite nanopowders was obviously higher than that of pure AP. This reveals that metal and composite metal nanopowders have good catalytic effects on the second thermal decomposition of AP, and the effects of CuNiB and NiCu nanopowders are higher than that of Cu, Ni and NiB nanopowders. Cu and composite metal nanopowders can also catalyse the first decomposition of AP, while Ni and Al nanopowders hinder it. The catalytic effect of metal composite nanopowders was enhanced with the increase of the proportional of Cu. Nanometer metal and composite metal powders also decreased the thermal decomposition temperature of the AP/HTPB propellant, and its heat release increased clearly, showing catalytic effects on the thermal decomposition of the AP/HTPB propellant. It can be found that the effect of metal and composite metal nanopowders on the thermal decomposition of AP is different from that of AP/HTPB propellant. The mechanism of catalyzing the thermal decomposition of AP is that metal oxiders acts as the intermedium in the process of election tranfer and metal nanopowders react with the decomposed product of AP.