Enhancing the thermal reactivity of Al/Ni composites via in-situ coating of NiCl₂

In this study, a novel technique was devised to activate Al/Ni nanocomposites via thermal treatment of aluminum-nickel alloy coated with ammonium perchlorate (Al/Ni@AP) in argon, featuring in-situ coating of NiCl₂ on the surface of Al/Ni. To comprehensively explore the reaction characteristics, a series of methods were employed, including differential scanning calorimetry, scanning electron microscopy, kinetic analysis as well as ignition performance analysis. The results demonstrated that the in-situ coating of NiCl₂ onto the surface of Al/Ni nanocomposites substantially enhanced their thermal reactivity in contrast to the untreated Al/Ni counterparts. SEM imaging revealed conspicuous structural modifications, which provided as clear evidence of the presence of the coating layer and its profound influence on the interfacial characteristics within the nanocomposites. Under the influence of NiCl₂, the originally two-step intermetallic reaction was integrated into a single step, and the activation energy of the Al/Ni intermetallic reaction underwent sharp decline by 35.3 %. The intermetallic reaction process of Al/Ni fundamentally depends on two-dimensional growth of nuclei. Upon the introduction of NiCl₂, the reaction model was found to follow within the range between two- and three-dimensional growth of nuclei, indicating a significant alteration in the reaction kinetics. Compared to Al/Ni, which boasted an ignition delay time of 531.4 ms, the Al/Ni@NiCl₂ composite exhibited a remarkable reduction in ignition delay time, shortened by 20.3 %. These results firmly validate the efficacy of the argon thermal treatment methodology in fabricating Al-based composites with enhanced thermal reactivity characteristics.