The Synthesis, Characterization And Application Of Al/B/Fe₂O₃Nano-composite Energetic Materials

In order to achieve the high energy release rate and energy density, oxidizing andreducing agents were intimately mixed in the nanometer size.Throug the sol-gel method,Al/B/Fe2O3nanocomposite energetic materials were prepared and then used in HTPBcomposite propellant to verify their performance. The main work and conclusion are asfollows:Through the addition of the powder directly,the Al/B/Fe2O3nanocomposite energeticmaterials were prepared by sol-gel method combined with ultrasonic method.The structureof Al/B/Fe2O3were characterized by thermogravimetric analysis, differential scanningcalorimetry, scanning electron microscopy, X-ray diffraction, and an impact sensitivitytest. It showed Al/B/Fe2O3nanocomposite energetic materials are composed by the nanoAl, micro-B and nano Fe2O3. A part of nano Al and micro B involve in the formation ofthe gel. The particle diameters are in micron level macroscopically and microscopicallythey are in nanometer size.The thermal properties of Al/B/Fe2O3nanocomposite energetic materials weremeasured through TG-DSC. It shows the reaction enthalpy heat can reach up to1.6KJ/g and theheat of combustion of Al/B/Fe2O3energetic materials reach10.69MJ/kg, which is3.6times than that of Al/Fe2O3and1.8times than that of Al/B/Fe2O3prepared by physicalblending. It consistent with that sol-gel method can significantly reduce the Al/B/Fe2O3nanocomposite thermite reaction of energetic materialsThe combustion properties of Al/B/Fe2O3energetic materials were measured usinghigh-speed cameras. It shows the burning rate Al/B/Fe2O3energetic materials can achieve200mg/s, which is7times than that of Al/B/Fe2O3prepared by physical blending. With thecontentof nano-aluminum increasing, the burning rate of Al/B/Fe2O3energetic materialsincreases. Others result shows the sensitivity of Al/B/Fe2O3energetic materials wassignificantly lower than normal blended sample. Sol-gel method can effectively reduce thethermite reaction enthalpy loss in an inert atmosphere. The density is up to2.95g/cm3,which is significantly higher than the density of ordinary blended sample and the densitycan be adjusted by changing the content of Al and B.The catalytic activities of Al/B/Fe2O3nanothermites on the thermal decomposition ofcommon components of propellant were studied through TG-DSC.It showed Al/B/Fe2O3 nanocomposite energetic materials exhibit better catalytic thermal decomposition on AP.Higher catalyst addition favors further decomposition of AP. Meanwhile, the energeticmaterials prepared by sol-gel have better catalytic ability than ordinary blend samples.The catalytic mechanism of Al/B/Fe2O3nanothermites was studied. It showsnano-Fe2O3particles play the leading role in Al/B/Fe2O3nanothermites on thermaldecomposition of AP. In addition, the obtained Al/B/Fe2O3nanothermites have highercatalytic activity than the simple mixed sample, which is attributed to the large specifcsurface area and the nano-porous structure. DSC results also show that the Al/B/Fe2O3nanocomposite energetic materials have good compatibility with HTPB and DOS.After adding the Al/B/Fe2O3nanocomposite energetic materials, the viscosity of thepropellant slurry is seen to increase.The more content of Al/B/Fe2O3nanocompositeenergetic materials, the higher of the viscosity. The content of Al/B/Fe2O3nanocompositeenergetic materials may not exceed10%. When the processing temperature is60℃, thepot life of propellant is7h.The mechanical test shows when content of Al/Fe2O3nanocomposite energeticmaterials is1%, the tensile strength and elongation at break of the propellant increased by15.3%and32.1%, respectively. Thermal performance tests show Al/B/Fe2O3nanocomposite energetic materials are a good catalyst for the HTPB propellent. Highercatalyst addition favors further decomposition. When adding of1wt.%Al/B/Fe2O3nanothermites decreases the decomposition temperature of AP on the propellent by59℃.