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Schematic for activation energy of high energetic systems; sufficient energy (activation energy) is required to initiate the reaction
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Ammonium perchlorate (APC) is the most common oxidizer for highly energetic systems. The initial decomposition of APC is an endothermic process. This behavior withstands high activation energy and could render high burning rate. We report on the sustainable fabrication of TiO2 nanoparticles; a novel catalyzing agent for APC. Mono-dispersed TiO2 par...
Citations
... To achieve high performance and reduce aggregation, the encapsulation approach can achieve a good dispersion of nanocatalyst in AP particles. The anti-solvent to solvent ratio affects nanocatalyst encapsulation [17][18][19]. Anti-solvent concentrations rise, resulting in higher nucleation rates and smaller crystals. AP encapsulation with catalyst NPs can ensure a higher burning rate due to the high homogeneity, dispersion, and interfacial surface area. ...
The universal burning rate modifier used in composite solid propellants is copper chromite. The fabrication of copper chromite nanoparticles (CCNs) is highly appreciated; as superior performance could be accomplished. This research looks at how copper chromite nanoparticles can be made in a sustainable way using hydrothermal processing. Mono-dispersed particles with a medium particle size of 12 nm were seen in TEM micrographs. The XRD diffractogram revealed a crystalline structure. The co-precipitation approach was used to incorporate CCNs into ammonium perchlorate (AP). Differential scanning calorimetry (DSC) and thermal gravimetric analysis were used to analyze the activity of catalysis in CCNs on AP breakdown (TGA). The enthalpy of AP breakdown was enhanced from 742 J/g to 1391 J/g. CCNs caused the Peak of high-temperature decomposition shift toward lower temperatures, resulting in the overlapping of the two peaks into a single peak. At 244 °C, CCNs showed a decrease in AP endothermic phase transition. These characteristics could ensure high-burning-rate catalyzed decomposition processes.
... It's widely accepted that thermal decomposition kinetics play a vital role in its combustion behavior [2]. The thermal decomposition of AP is a complex process that is affected by different conditions such as shape, crystalline phase, and crystal purity [3][4][5][6][7]. AP thermal decomposition depends on physical and chemical interaction among decomposition products [8,9]. ...
Ferric oxide is a universal catalyst. Reactive metal fuel can act as a high energy dense material such as aluminum which is marked by the very high gravimetric and volumetric heat output. This manuscript reports on the fabrication of colloidal ferric oxide nanoparticles of 5 nm. Colloidal ferric oxide/aluminum nanothermite mixture was integrated into ammonium percholorate (AP) via the coprecipitation technique. The shape and particles size of the prepared nano ferric oxide were investigated by using TEM instrument. Uniform dispersion of Al/Fe2O3 in the ammonium perchlorate matrix was verified using EDAX instrument. Nanothermite particles offered enhanced AP decomposition enthalpy by 120 % using DSC. Nanothermite colloid offered a decrease in AP activation energy by 51 and 40 % using Friedman and Ozawa models respectively. AP decomposition mechanism was reported to go through three consequent mechanisms including the first order mechanism, two-dimensional diffusion reactions, and one- dimensional diffusion mechanism according to extent of reacted fraction (α) of 0-0.25, 0.3-0.6, and 0.6-0.9 respectively. The results show that the catalyzing ability of the nanothermites was confirmed and has shown a superior effect on the AP energetic system.
... In the case of AP, this catalysis affects the endothermic decomposition of the oxidizer. Transition metal oxides can catalyze AP thermal decomposition, with significant changes in combustion characteristics [35][36][37][38]. Ferric oxide is the most active of these catalysts, mainly if used in the nano-scale range [39,40]. ...
The 3D metal–organic framework (MOF), MIL-88B, built from the trivalent metal ions and the ditopic 1,4-Benzene dicarboxylic acid linker (H2BDC), distinguishes itself from the other MOFs for its flexibility and high thermal stability. MIL-88B was synthesized by a rapid microwave-assisted solvothermal method at high power (850 W). The iron-based MIL-88B [Fe3.O.Cl.(O2C–C6H4–CO2)3] exposed oxygen and iron content of 29% and 24%, respectively, which offers unique properties as an oxygen-rich catalyst for energetic systems. Upon dispersion in an organic solvent and integration into ammonium perchlorate (AP) (the universal oxidizer for energetic systems), the dispersion of the MOF particles into the AP energetic matrix was uniform (investigated via elemental mapping using an EDX detector). Therefore, MIL-88B(Fe) could probe AP decomposition with the exclusive formation of mono-dispersed Fe2O3 nanocatalyst during the AP decomposition. The evolved nanocatalyst can offer superior combustion characteristics. XRD pattern for the MIL-88B(Fe) framework TGA residuals confirmed the formation of α-Fe2O3 nanocatalyst as a final product. The catalytic efficiency of MIL-88B(Fe) on AP thermal behavior was assessed via DSC and TGA. AP solely demonstrated a decomposition enthalpy of 733 J g⁻¹, while AP/MIL-88B(Fe) showed a 66% higher decomposition enthalpy of 1218 J g⁻¹; the main exothermic decomposition temperature was decreased by 71 °C. Besides, MIL-88B(Fe) resulted in a decrease in AP decomposition activation energy by 23% and 25% using Kissinger and Kissinger–Akahira–Sunose (KAS) models, respectively.
... Transition metal oxides can catalyze AP thermal decomposition, with significant changes in combustion characteristics. [35][36][37][38] Ferric oxide is the most active of these catalysts, mainly if used in the nano-scale range. [39,40] Nanostructured energetic systems can experience smaller critical diameters, high reaction rate, high heat output, as well as high heat release rate. ...
The 3D metal-organic framework (MOF), MIL-88B, built from the trivalent metal ions and the ditopic 1,4-Benzene dicarboxylic acid linker (H2BDC), distinguishes itself from the other MOFs for its flexibility and high thermal stability. MIL-88B was synthesized by a rapid microwave-assisted solvothermal method at high power (850 W). The iron-based MIL-88B [Fe3.O.Cl.(O2C-C6H4 -CO2)3] exposed oxygen and iron content of 29% and 24%, respectively, which offers unique properties as an oxygen-rich catalyst for energetic systems. Upon dispersion in an organic solvent and integration into ammonium perchlorate (AP) (the universal oxidizer for energetic systems), the dispersion of the MOF particles into the AP energetic matrix was uniform (investigated via elemental mapping using an EDX detector). Therefore, MIL-88B(Fe) could probe AP decomposition with the exclusive formation of mono-dispersed Fe2O3 nanocatalyst during the AP decomposition. The evolved nanocatalyst can offer superior combustion characteristics. XRD pattern for the MIL-88B(Fe) framework TGA residuals confirmed the formation of α-Fe2O3 nanocatalyst as a final product. The catalytic efficiency of MIL-88B(Fe) on AP thermal behavior was assessed via DSC and TGA. AP solely demonstrated a decomposition enthalpy of 733 J g-1 , while AP/MIL-88B(Fe) showed a 66% higher decomposition enthalpy of 1218 J g-1 ; the main exothermic decomposition temperature was decreased by 71 °C. Besides, MIL-88B(Fe) resulted in a decrease in AP decomposition activation energy by 23% and 25% using Kissinger and Kissinger–Akahira–Sunose (KAS) models, respectively.
... activation energy) [4][5][6]. Optimization between performance and sensitivity is a crucial issue [7][8][9]. ...
Surface oxygen of oxide catalyst has low coordination number; they are negatively charged. Surface oxygen can act active site for decomposition of energetic nitramines (i.e. HMX). Additionally hydrous catalyst surface can release active OH radicals. Colloidal oxide particles can fulfil these requirements. Furthermore oxide particles can induce thermite reaction with aluminium particles. This study reports on the facile fabrication of colloidal ferric oxide particles of 5 nm average particle size. Aluminium nanoplates of 100 nm particle size were dispersed in ferric oxide colloid. Colloidal Fe2O3/Al binary mixture was integrated into HMX matrix via co-precipitation technique. SEM micrographs demonstrated uniform dispersion of nanothermite particles into energetic matrix. Naonothermite particles experienced dramatic change in HMX thermal behaviour with increase in total heat release by 63% using DSC. The impact of thermite particles on HMX kinetic decomposition was evaluated via an integral isoconversional method using KAS, and Kissinger models. The mean value of apparent activation was reduced by 23.5 and 24.3% using Kissinger and KAS models respectively. This dramatic change in HMX decomposition could be ascribed to ferric oxide reactivity. Facile integration of colloidal thermite particles into HMX can secure high interfacial surface area.
... Decreasing the pyrolysis temperature of AP can increase the burning rate and reduce the ignition delay time of CSPs. Besides, increasing the heat release of AP decomposition can boost the specific impulse of CSPs (Boldyrev, 2006;Elbasuney and Yehia, 2019;Hao et al., 2016). Therefore, promoting the thermal decomposition of AP can enhance the energy characteristics of CSPs. ...
To address the aggregation problem of nanocatalysts in ammonium perchlorate (AP), AP/Fe3O4 core-shell composites (CSC) were synthesized by nanodispersion-assisted antisolvent recrystallization induced self-assembly method. DFT and FTIR test results reveal that covalent bonds between citrate and Fe3O4 along with hydrogen bonds between citrate and AP drive the formation of AP/Fe3O4 CSC. With coating 5.4 wt% Fe3O4, the high-temperature decomposition peak temperature of AP is decreased by 91.3 °C, the heat release is increased by 125% and the apparent activation energy is lowered by 47.9%. AP/Fe3O4 CSC exhibit excellent thermal decomposition performance because the highly dispersed nanocatalysts on AP surface provide more catalytic sites and accelerate the reaction heat transferring from burning surface to condensed AP. Guided by this strategy, AP/Co3O4 and AP/Fe2O3 CSC were also prepared with enhanced thermal decomposition performance, which indicates this strategy has good applicability to improve the catalytic performance of nano metal oxides for AP decomposition.
... The catalytic effect of the thermite nanoparticles could be mainly ascribed to ferric oxide. Ferric oxide particles are characterized with hydrous surface; the surface bonded OH groups could be evolved as free radicals at low decomposition temperature (Elbasuney et al. 2020c;Elbasuney, Gobara, and Yehia 2019;Elbasuney and Yehia 2019b). Active ȮH radicals would attack HMX molecules and could abstract hydrogen from HMX molecule (Wei et al. 2009). ...
HMX is one of the most powerful energetic materials; however, HMX experience low sensitivity and high activation energy. Whereas ferric oxide particles can act as catalyst for HMX decomposition with change in its decomposition kinetics from C-N bond cleavage to hydrogen atom abstraction; ferric oxide can induce vigorous thermite reaction with aluminum particles. Consequently, thermite particles can catalyze HMX decomposition, and enhance its decomposition enthalpy. This study reports on the fabrication and of ferric oxide nanoparticles of 5 nm particle size. Ferric oxide NPs and aluminum nanoplates of 100 nm were effectively integrated into HMX via co-precipitation technique. Elemental mapping was performed using EDAX detector; uniform dispersion of nanothermite particles was confirmed. Nanothermite particles experienced enhanced HMX decomposition enthalpy by 53%, with decrease in decomposition temperature by 13°C. The impact of nanothermite particles on HMX kinetic decomposition was evaluated using two different analysis models including differential isoconversional method of model-free Friedman analysis, and integral isoconversional method of Ozawa. Thermite nanoparticles demonstrated drastic decrease in HMX activation energy by 24 and 30% using Friedman and Ozawa models, respectively. The developed colloidal nanothermite particles demonstrated superior catalytic effect with enhanced decomposition enthalpy.
... Nanothermites can experience reaction rate 100 times compared with conventional counterparts [4][5][6]. Much research has been directed to the development of nanothermites for initiation means, propulsion, micro-actuator, and electric match compositions [4,[7][8]. Electric match includes a thin metal wire (bridge wire) coated with a dab of heat-sensitive pyrotechnic composition [9]. Hot solid or liquid particles are desirable for first-fire compositions. ...
... While NC experienced mean activation energy of 430 KJ·mol -1 ; MnO2/Al/NC nanocomposite demonstrated mean activation of 388 KJ·mol -1 . MnO2 particles with negative oxygen surfaceand hydrous surface can act as efficient catalyst with decrease in activation enenrgy[7][8]13]. ...
Nanostructured energetic materials can fit with advanced energetic first-fire, and electric bridges (microchips). Manganese oxide, with active surface sites (negatively charged surface oxygen, and hydroxyl groups) can experience superior catalytic activity. Manganese oxide could boost decomposition enthalpy, ignitability, and propagation rate. Furthermore manganese oxide could induce vigorous thermite reaction with aluminium particles. Hot solid or liquid particles are desirable for first-fire compositions. This study reports on the facile fabrication of MnO 2 nanoparticles of 10 nm average particle size; aluminium nanoplates of 100 nm average particle size were employed. Nitrocellulose (NC) was adopted as energetic polymeric binder. MnO 2 /Al particles were integrated into NC matrix via co-precipitation technique. Nanothermite particles offered an increase in NC decomposition enthalpy by 150 % using DSC; ignition temperature was decreased by 8 ⁰ C. Nanothemrite particles offered enhanced propagation index by 261 %. Kinetic study demonstrated that nanothermite particles experienced drastic decrease in NC activation energy by - 42, and - 40 KJ mol ⁻¹ using Kissinger and KAS models respectively. This study shaded the light on novel nanostructured energetic composition, with superior combustion enthalpy, propagation rate, and activation energy.
... Energetic nanocomposite can offer novel performance characteristics in terms of combustion enthalpy as well as thermal decomposition kinetics [1,2]. HMX (C 4 H 8 N 8 O 8 ) is one of the most common energetic materials for solid propellants, explosives, and pyrotechnics [3]. ...
Even though HMX is one of the most vigorous energetic materials for solid propellants, explosives, and pyrotechnics; it has high thermal stability and low sensitivity to common catalysts. Metal oxides with hydrous surface can release active O˙\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{\text{{O}}}$$\end{document}H radicals at low temperature. These active radicals could attack HMX heterocyclic ring and alter HMX decomposition mechanism form C-H bond cleave to hydrogen atom abstraction. This study reports on the facile synthesis of Fe2O3 nanoparticles (NPs) of 8 nm average particle size. Aluminum NPs of 80 nm was employed in combination with Fe2O3 NPS; this nanothermite binary mixture can induce not only catalytic effect but also vigorously-exothermic thermite reaction with high heat output. Colloidal thermite mixture Fe2O3/Al was effectively-integrated into HMX crystals via co-precipitation technique. Uniform distribution of nanothermite particles into HMX was confirmed via elemental mapping using EDAX. Nanothermite mixture as high energy density material offered an increase in HMX total heat release by 82% using DSC. Furthermore, nanothermite particles offered superior catalytic effect with decrease in HMX activation energy by 25% using Kissinger method. Kinetic decomposition parameters using KAS model were found to be in good agreement with Kissinger's model. Colloidal nanothermite particles can act as high energy density material, and as a catalyst with decrease in required activation energy.
... Optimization between performance and sensitivity is a crucial issue [5][6][7]. HMX is one of the most vigorous energetic nitramines; however the performance of energetic materials is limited to hydrocarbon combustion [8][9]. One of the most common oxidizer for nanothermite applications is ferric oxide. ...
... Where β is the heating rate; A is the pre-exponential factor. In this manuscript the integral isoconvertional method of Kissinger-Akahira-Sunose (KAS) equation (6) has been adopted for activation energy calculation. ...
Oxygen atoms on the surface of oxide catalysts have low coordination number; they are negatively charged. Surface oxygen can act active sites for decomposition of energetic nitramines (i.e. HMX); additionally hydrous surface can release active ȮH radicals. Colloidal oxide particles can fulfil these requirements. Furthermore oxide particles can induce thermite reaction with aluminium particles. This study reports on the facile fabrication of colloidal ferric oxide particles of 5 nm; Colloidal Fe 2 O 3 /Al binary mixture was integrated into HMX matrix via co-precipitation technique; uniform dispersion of nanothermite particles was verified using SEM. Naonothermite particles experienced dramatic change in HMX thermal behaviour with an increase in total heat release by 63 %. The impact of themrite particles on HMX kinetic decomposition was evaluated using an integral isoconversional method of KAS, and Kissinger models. The mean value of apparent activation was reduced by 23.5 % and 24.3 % using Kissinger and KAS models respectively. This dramatic change in HMX decomposition can be ascribed to the ferric oxide reactivity and the facile integration of colloidal thermite particles.
