Al-PTFE (aluminum-polytetrafluoroethene) is regarded as one of the most promising reactive materials (RMs). In this work, Ni (Nickel) was added to Al-PTFE composites for the purpose of improving the energy density and damage effect. To investigate the thermal behavior, mechanical properties and reaction characteristics of the Al-Ni-PTFE composites, an Al-PTFE mixture and an Al-Ni mixture were prepared by ultrasonic mixing. Six types of Al-Ni-PTFE specimens with different component mass ratios were prepared by molding sintering. Simultaneous thermal analysis experiments were carried out to characterize the thermal behavior of the Al-PTFE mixture and the Al-Ni mixture. Quasi-static compression tests were performed to analyze the mechanical properties and reaction characteristics of the Al-Ni-PTFE specimens. The results indicate that the reaction onset temperature of Al-Ni (582.7 °C) was similar to that of Al-PTFE (587.6 °C) and that the reaction heat of Al-Ni (991.9 J/g) was 12.5 times higher than that of Al-PTFE (79.6 J/g). With the increase of Ni content, the material changed from ductile to brittle and the strain hardening modulus and compressive strength rose first and then subsequently decreased, reaching a maximum of 51.35 MPa and 111.41 MPa respectively when the volume fraction of Ni was 10%. An exothermic reaction occurred for the specimens with a Ni volume fraction no more than 10% under quasi-static compression, accompanied by the formation of Ni-Al intermetallic compounds. In the Al-Ni-PTFE system, the reaction between Al and PTFE preceded the reaction between Al and Ni and the feasibility of increasing the energy density and damage effect of the Al-Ni-PTFE reactive material by means of Ni-Al reaction was proved.
To explore the effect of the addition of poly(vinylidene fluorine) (PVDF) to a nanothermite system, an Al/MnO2/PVDF energetic nanocomposite was prepared using an electrospray method, Al/MnO2 nanothermite was prepared as a control group.
In this work, thermal properties and kinetics of Al-nanoparticles/α-MnO 2 nanorods thermite were reported. The α-MnO 2 nanorods were synthesized using a hydrothermal method and were characterized by X-ray powder diffraction (XRD) and X-ray photoelectron spectra (XPS), then combined with Al nanoparticles based on the ultrasonic mixing method to prepare the nanostructure thermite. Besides, both pure components and mixture were characterized by field emission scanning electron microscopy (FE-SEM) to observe their morphologies and structures. Subsequently, the thermal properties of Al/α-MnO 2 nanostructure thermite were studied on the basis of thermogravimetric-differential scanning calorimetry (TG-DSC). According to the TG-DSC tests, the calculation results of activation energy for kinetics of Al/α-MnO 2 thermite were obtained using different isoconversional methods. It was found that Al/α-MnO 2 nanostructure thermite has high heat release and low onset temperature, and the heat release of the nanostructure thermite was approximately 1146.6 J g -1 .
To investigate the effect of the addition of poly (vinylidene fluoride) (PVDF) on nanothermites, Al/MoO3/PVDF energetic nanocomposites were prepared using electrospraying method. As a control group, Al/MoO3 was also designed. Then, both samples were tested by FE-SEM, XRD and TG-DSC. TG-DSC results showed that the Al/MoO3/PVDF energetic nanocomposites released more than 934.0 J g−1 with two obvious exothermic peaks. Compared with the control group of 800.7 J g−1 heat, it changed the thermal performance to some extent. There were Mo2C among the residues products after the reaction via XRD. The activation energy (Ea) was analyzed using the Kissinger method under different heating rates by DSC. The addition of PVDF reduced the Ea of the thermites. To explore the combustion performance, a preliminary experiment was designed. The Al/MoO3/PVDF energetic nanocomposites were easier to ignite and the burning was more durable, which was significant in solid propulsion and applications requiring extended combustion time.
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