Enhanced energy performance from core–shell structured Al@Fe2O3 nanothermite fabricated by atomic layer deposition. Issue 12 (23rd January 2017)

• Record Type: Journal Article
• Authors: Qin, Lijun; Yan, Ning; Li, Jianguo; Hao, Haixia; Zhao, Fengqi; Feng, Hao
• Is Part Of: RSC advances. Volume 7:Issue 12(2017)
• Page Start: 7188
• Page End: 7197
• Publication Date: 2017-01-23
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra25251f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The energy performances of nanothermite materials are dependent on the mass transport, diffusion distance, and interfacial contact area between the fuel and the oxidizer. Abstract : The energy performances of nanothermite materials are dependent on the mass transport, diffusion distance, and interfacial contact area between the fuel and the oxidizer. In this work, we utilize an atomic layer deposition (ALD) technique to deposit Fe2 O3 directly onto the surface of Al nanoparticles, producing a core–shell structured nanocomposite (Al@Fe2 O3 ). Quartz crystal microbalance measurement and mass gain analysis reveal that the average Fe2 O3 film growth rate is 0.12–0.13 nm per cycle. The thickness of the Fe2 O3 layer deposited on the Al nanopowder can be precisely controlled by adjusting the number of ALD cycles. Structural characterization results demonstrate complete encapsulation of Al nanoparticles by conformal γ-Fe2 O3 layers and confirm the formation of core–shell nanocomposites. The energy release and combustion properties of the nanothermites are investigated by differential scanning calorimetry and laser ignition tests. Compared to mechanically mixed Al–Fe2 O3 nanopowders, the Al@Fe2 O3 nanothermite has a lower onset temperature and a higher energy output. Besides, the thermite reaction of Al@Fe2 O3 is several times faster than that of a mixture of Al–Fe2 O3 nanopowders. The improved energy performance is mostly attributed to the uniform distribution of Al and Fe2 O3 on the nanometer scale, which effectively reduces the diffusion distance and maximizes the interfacial contact area between the oxidizer and the fuel.