Tuning the reactivity and energy release rate of I2O5 based ternary thermite systems

Xu, Feiyu; Biswas, Prithwish; Nava, Giorgio; Schwan, J.; Kline, Dylan J.; Rehwoldt, Miles C.; Mangolini, Lorenzo; Zachariah, Michael R.

doi:10.1016/j.combustflame.2020.12.047

Cited by 30 publications

(28 citation statements)

References 37 publications

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“…The fact that oxygen release precedes ignition and that the addition of Si results in an overall decreasing trend in the ignition temperature suggests that the oxidation is fuel-controlled, and that addition of Si can promote initiation. These results are consistent with a parallel study from our group, where we observe a similar decreasing trend in the ignition temperature upon nSi addition in a similar thermite system (Al/Si/I 2 O 5 ) …”

Section: Resultssupporting

confidence: 93%

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Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Ghildiyal

Biswas

et al. 2020

ACS Appl. Mater. Interfaces

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Biocidal nanothermite composites show great potential in combating biological warfare threats because of their high-energy-release rates and rapid biocidal agent release. Despite their high reactivity and combustion performance, these composites suffer from low-energy density because of the voids formed due to inefficient packing of fuel and oxidizer particles. In this study, we explore the potential of plasma-synthesized ultrafine Si nanoparticles (nSi, ∼5 nm) as an energetic filler fuel to increase the energy density of Al/Ca(IO3)2 energetic-biocidal composites by filling in the voids in the microstructure. Microscopic and elemental analyses show the partial filling of mesoparticle voids by nSi, resulting in an estimated energy density enhancement of ∼21%. In addition, constant-volume combustion cell results show that nSi addition leads to a ∼2–3-fold increase in reactivity and combustion performance, as compared to Al/Ca(IO3)2 mesoparticles. Oxidation timescale analyses suggest that nSi addition can promote initiation due to faster oxygen transport through the oxide shell of Si nanoparticles. At nSi loadings higher than ∼8%, however, slower burning characteristics of nSi and sintering effects lead to an overall degradation of combustion behavior of the composites.

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Section: Resultssupporting

confidence: 93%

“…These results are consistent with a parallel study from our group, where we observe a similar decreasing trend in the ignition temperature upon nSi addition in a similar thermite system (Al/Si/I 2 O 5 ). 43 3.3.2. Constant Volume Combustion and Temperature Measurements.…”

Section: Resultsmentioning

confidence: 99%

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Ghildiyal

Biswas

et al. 2020

ACS Appl. Mater. Interfaces

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“…Ammonia borane (AB) and other chemical hydrides − possess higher enthalpy of oxidation than commonly employed metallic or metalloid fuels in solid-state propellants such as Al, Ti, Si, and Mg, − on both a gravimetric and molar basis (Figure ). Owing to its high gravimetric hydrogen content (19.6%) and low hydrogen generation temperature, AB has found considerable interest in the hydrogen storage application communities as has investigation of its dehydrogenation mechanism. − However, for its application in solid-state propellants, complete oxidation of the constituent boron in addition to hydrogen is essential to exploit its high energy content.…”

Section: Introductionmentioning

confidence: 99%

Rerouting Pathways of Solid-State Ammonia Borane Energy Release

et al. 2021

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Ammonia borane (NH3BH3, AB) represents a promising energy-dense material for hydrogen storage and propulsion; however, its energy release mechanisms on oxidation by solid-state oxidizers are not well understood. In this study, through in situ time-of-flight mass spectrometry supported by attenuated total reflection-Fourier transform infrared spectroscopy and density functional theory calculations, we investigate the fundamental reaction mechanisms involved in the energy release from solid-state AB with different chemical oxidizers. We show that the reaction of AB with oxidizers like KClO4 is mediated by [NH3BH2NH3]+[BH4]− (DADB) formation, resulting in its kinetic entrapment into low-energy BNH x clusters that are resistant to further oxidation, thus limiting complete energy extraction. In contrast, with an ammonium-based oxidizer such as NH4ClO4, the presence of NH4 + ions enables AB to follow an alternative reaction pathway forming [NH3BH2NH3]+[ClO4]− rather than DADB, thus inhibiting the formation of BNH x species and facilitating its complete oxidation. This alternative reaction route causes the AB/NH4ClO4 system to exhibit remarkably higher energy release rates over that of AB/KClO4 (∼27x) and the standard Al/NH4ClO4 propellant (∼7x).

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“…Among these shapes, the core− shell structure has received extensive attention because of its unique properties, including highly specific surface area, controllable pore size, uniform distribution, excellent exothermicity as well as compatibility with MEMS systems. 10,27,28 The latter method focuses on accelerating the participation of Al in the reaction, such as reducing the fuel size, 29−31 multimetal fuels, 32,33 annealing and quenching aluminum, 13,34,35 and decomposing the alumina layer. 36,37 Among these methods of modifying fuels, reducing the aluminum size could bring many advantages, including fast reaction rate and low initial redox reaction temperature.…”

Section: Introductionmentioning

confidence: 99%

“… The former method focuses on the meticulous architecture design of the thermite system, realizing a variety of structural forms, for instance multilayered, ,− 3D macroporous, − and core–shell − structures. Among these shapes, the core–shell structure has received extensive attention because of its unique properties, including highly specific surface area, controllable pore size, uniform distribution, excellent exothermicity as well as compatibility with MEMS systems. ,, The latter method focuses on accelerating the participation of Al in the reaction, such as reducing the fuel size, − multimetal fuels, , annealing and quenching aluminum, ,, and decomposing the alumina layer. , Among these methods of modifying fuels, reducing the aluminum size could bring many advantages, including fast reaction rate and low initial redox reaction temperature . However, aluminum naturally develops a 3–5 nm alumina shell upon exposure to oxygen, which leads to reduced active aluminum content at smaller particle sizes, presenting a barrier to the interaction of aluminum with the oxidizer .…”

Section: Introductionmentioning

confidence: 99%

Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe₂O₃ Thermites

Chen

et al. 2021

ACS Appl. Energy Mater.

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Thermites are a class of significant energetic materials widely used in aerospace propulsion, explosion, pyrotechnics, thermal batteries, and power generation. Although nanothermites exhibit fast reaction rates and high energy density, micron-sized thermites remain of practical importance over nanothermites due to their low electrostatic discharge (ESD) sensitivity, lower cost, and smaller dead mass. Herein, we develop micron-sized core−shell gallium-based liquid metal-modified Al@Fe 2 O 3 (GLM-Al@ Fe 2 O 3 ), which exhibits high energy density and low laser ignition energy. At an equivalence ratio of 1.3, the differential scanning calorimetry results show that the total heat release of GLM-Al@Fe 2 O 3 reaches 2555 J•g −1 , which is much higher than that of the control sample (1424 J•g −1 ) prepared by a similar process. The density of GLM-Al@Fe 2 O 3 (φ = 1.3) was characterized by a gas pycnometer analyzer, and its volumetric energy density could reach 9.96 kJ•cm −3 . Laser-ignited combustion performance of GLM-Al@Fe 2 O 3 was markedly reinforced in terms of the decreased ignition energy. Additionally, the ESD ignition threshold of GLM-Al@ Fe 2 O 3 is higher than 1 J, which revealed that the as-prepared GLM-Al@Fe 2 O 3 was insensitive to electrostatic discharge. The facile and efficient strategy in this work provides inspiration to enhance the energy output performance and maintain the ESD safety of micron-sized thermites, which could show great potential in various civilian and military applications.

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Tuning the reactivity and energy release rate of I2O5 based ternary thermite systems

Cited by 30 publications

References 37 publications

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Rerouting Pathways of Solid-State Ammonia Borane Energy Release

Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe₂O₃ Thermites

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Tuning the reactivity and energy release rate of I2O5 based ternary thermite systems

Cited by 30 publications

References 37 publications

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

Rerouting Pathways of Solid-State Ammonia Borane Energy Release

Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe2O3 Thermites

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Product

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Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe₂O₃ Thermites