The stability of aluminum (Al) nanoparticles (ANPs) is a key issue that can determine the energetic properties of Al‐based energetic materials. In this study, a surface functionalization approach is employed, using the chemical adsorption and auto polymerization effects of the 1H, 1H, 2H, 2H‐perfluorodecyltriethoxysilane (FAS‐17), to set up a highly stable barrier coating to water and further endow ANPs with long‐term storage stability and self‐activation reaction capability. The FAS‐17‐modified ANPs (AFNPs) with a superhydrophobic surface show their excellent stability in air and unique strengths in corrosion resistance to water by enhancing diffusion resistance of O2 and preventing the hydration reaction. In terms of energetic performances, compared to the two‐step slow oxidation of ANPs, the heat‐release rate of AFNPs is significantly enhanced, resulting in a drastic oxidation process profiting from the surface reaction between the FAS‐17 and alumina (Al2O3) layer. More importantly, the ignition and combustion properties of AFNPs are also greatly improved, which can undergo self‐propagation combustion with a fairly high energy output even after stored in water. At last, the possible mechanisms of oxidation resistance and self‐activation reaction capacities are also proposed.
This investigation was devoted to exploring the application performance of nano‐combustion catalyst CuCr2O4 in solid propellants. In this paper, raw CuCr2O4 and nano‐CuCr2O4 prepared by the mechanical grinding method were applied in solid propellants containing ammonium perchlorate (AP), which are ammonium perchlorate/ hydroxy‐terminated polybutadiene propellant (AP/HTPB) and ammonium perchlorate/composite modified double‐base propellant (AP/CMDB). And the scanning electron microscope, displacement volume method, thermogravimetric analysis, differential scanning calorimetry, and strand burner method were employed to characterize the performance of AP‐based solid propellants. The results show that the AP/HTPB propellant has fewer defects on the surface of it due to the presence of nano‐CuCr2O4, but it has no significant effect on the AP/CMDB propellant. Nano‐CuCr2O4 can also significantly increase the density of AP/HTPB propellant and AP/CMDB propellant to 1.736 g/cm3 and 1.633 g/cm3, respectively. Nano‐CuCr2O4 obviously advances the decomposition temperature of AP/HTPB propellant and AP/CMDB propellant, which also increases the apparent heat of decomposition. In addition, the burning rate of nano‐CuCr2O4‐AP/HTPB propellant and nano‐CuCr2O4‐AP/CMDB propellant increased to 1.60 mm/s and 3.23 mm/s, with an increase of 28.3 % and 26.3 %, respectively. Therefore, nano‐CuCr2O4 is expected to be widely used in solid propellants due to its excellent properties.
In order to decrease the sensitivity and broaden the application of PETN, PETN/TKX-50 co-crystal with high energy and low sensitivity was prepared through the solvent/non-solvent method.
Composite counter electrodes have
been shown to be a practical
and effective strategy in dye-sensitized solar cell (DSSC) application.
In this work, we designed and prepared a single-crystal Cu
2
ZnSnSe
4
(CZTSe) plate structure on flexible carbon fabric
as a DSSC cathode, which combines the best of the two worlds, namely,
the superior catalytic activity and hierarchical microstructure of
kesterite CZTSe and the high conductivity and expanded framework of
carbon fabric. The composite counter electrode presented a power conversion
efficiency of 8.45% and a long-term bending reservation. The remarkable
device property is due to the high catalytic activity, good adherence
to conductive matrix grains, effective electron migration, and quick
iodide species diffusion of the novel cathode. Our results suggest
that the CZTSe@carbon fabric composite could be a high-efficiency
Pt-free cathode in DSSCs.
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