Electrophoretic deposition and thermo-chemical properties of Al/Fe₂O₃ nanothermite thick films

We have successfully fabricated α-Fe₂O₃ oxidizers with different shapes, including nanoparticles (NPs, diameter: ~22.1 nm), nanorods (NRs, length: 385.3 nm) and nanowires (NWs). For the Al/Fe₂O₃ NPs thermite reaction, as the nominal weight ratio for Al/Fe₂O₃ (NPs) reaches 2.5:1, the fastest combustion velocity (2.03 m/s), the largest instant plume propagation speed (10.71 m/s) as well as the maximum heat release (~9.46 kJ/g) can be achieved. However, with the same nominal weight ratio, the average combustion velocity and the instant plume speed of Al/Fe₂O₃ (NRs) and Al/Fe nitrilotriacetic acid precusors NWs (FeNTA,) nanothermite are only about 0.16 m/s and 4.96 m/s, and 0.098 m/s and 3.28 m/s, respectively. This is probably due to the shape difference that renders different contact configurations between nano-fuel and nano-oxidizer. In addition, an incomplete calcination of FeNTA is also responsible for such a low combustion velocity. The reaction products were further identified by SEM and XRD analysis. Accordingly, the reaction mechanisms for the examined nanothermites were mainly controlled by the oxygen transfer dynamics.