Interaction between Single-Walled Carbon Nanotubes and Reactive Nanoparticle Constituents in Multilayered Al/NiO Nanocomposite

Single-walled carbon nanotubes (CNTs) were added into layered Al/NiO nanothermite composites to tune their energetic and reaction properties. Scanning electron microscopy (SEM) images showed a direct contact between the Al and NiO layers, where the presence of CNTs in a designated layer was clearly visible. Thermochemical data obtained from differential scanning calorimetry (DSC) demonstrated that these composites, although modified with CNTs in either the Al or the NiO layer, exhibited a nearly constant onset temperature, implying comparable reaction initiation mechanisms. However, different amounts of energy release, accompanied by formation of distinct layer composition and microstructures of their products, were observed. It was further revealed that, by means of mass spectrometry, SEM, and X-ray diffraction analysis, upon the initiation of the thermite reaction between Al and NiO at the interface layer, the reaction between CNTs and NiO nanoparticles produced CO and CO2, which promoted the gas–solid chemistry and gas diffusion within the microstructure of the composite. Both increased the energy release and resulted in less agglomerated reaction products. In comparison, adding CNTs into the Al layer did not bring a significant change to the condensed-phase reaction mechanism which was proposed previously for the Al/NiO composite