具有异常放热现象的Fe-Nb-B-Y非晶合金燃烧机理

The functional groups in traditional energetic materials typically contain C, N, and O. These elements are usually unstable and sensitive to external stimuli. Moreover, the chemicals used during the preparation process of traditional energetic materials are toxic and pose many safety and environmental issues. As one of the metastable materials, high-energy-state amorphous alloys are potential candidates for new energetic materials with high combustion heat, low ignition temperature, non-toxicity, and improved safety. In this work, the combustion mechanism of Fe-based amorphous ribbons with an anomalous exothermic phenomenon was systematically studied using in situ synchrotron X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Experimental results show that compared to Fe-Nb-B-Y amorphous alloys with normal thermophysical and combustion behaviors, (Fe_0.72B_0.24Nb_0.04)_95.5Y_4.5 amorphous ribbons with anomalous exothermic phenomena possess low ignition temperature and self-propagating combustion behavior due to the catalysis of the rapid crystallization exothermic process. The anomalous exothermic phenomenon and associated liquid-liquid phase transitions can cause rapid crystallization at elevated temperatures during heating, followed by multi-step oxidation. On the other hand, it was possible to significantly reduce the activation energy of high-temperature oxidation. The liquid-liquid phase transition can lower the energy barrier of the oxidation reaction. In this way, the oxidation reaction at high temperatures can be promoted. The results suggest that the liquid-liquid phase transition has an "induced activation" effect on the combustion of Fe-based amorphous alloys.