Nanocomposite and mechanically alloyed reactive materials as energetic additives in chemical oxygen generators

Machado, M. A.; Rodriguez, Daniel A.; Aly, Yasmine; Schoenitz, Mirko; Dreizin, Edward L.; Shafirovich, Evgeny

doi:10.1016/j.combustflame.2014.04.005

Cited by 21 publications

(5 citation statements)

References 26 publications

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“…The rates of reaction at elevated temperatures become important for predicting the ignition behavior of magnesium and related energetic systems. Additionally, kinetics of magnesium oxidation may serve as a useful reference for assessments of reactivity of alloys employing magnesium, e.g., Al·Mg alloys prepared by mechanical milling for advanced energetics. − …”

Section: Introductionmentioning

confidence: 99%

Oxidation of Magnesium: Implication for Aging and Ignition

2016

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Magnesium is widely used in pyrotechnic formulations; it is also a component of reactive alloys, e.g., AlMg and BMg, which are potential fuels for explosives and propellants. Despite its widespread applications, the kinetics of oxidation of Mg powders are not well quantified. Such kinetics are of fundamental importance for the models aimed to describe thermally induced ignition of metal powders. In addition, for Mg the issue of aging is important because its oxide, MgO, is porous. In this work, magnesium oxidation by both oxygen and steam was studied by thermo-analytical measurements for micron-sized spherical powders. Heat flow calorimetry and thermogravimetric analysis were used to quantify reaction rates for low and elevated temperature ranges, respectively. Experiments with spherical powders with different but overlapping particle size distributions were used to identify the location of the reaction interface. The reaction was found to occur at the interface of metal and the growing oxide layer for all oxidizing conditions. The reaction is thus rate limited by diffusion of oxidizer to the metal surface. Kinetics of oxidation for both dry and humid oxidizing environments were quantified using thermo-analytical measurements and different data processing techniques. The activation energy of magnesium oxidation in humid environments at low temperatures is close to 60 kJ/mol. Activation energy for oxidation of magnesium in oxygen is 148 kJ/mol. For oxidation of magnesium in steam at elevated temperatures, the activation energy increases linearly from approximately 130 to 360 kJ/mol, while the thickness of the oxide layer is growing up to 2.4 μm. Simplified diffusion-limited reaction models were developed for oxidation of magnesium in both oxygen and steam. The models enable one to predict both preignition reactions occurring upon heating of Mg particles and the time of Mg powder aging when exposed to moisture or oxygen at different temperatures.

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Section: Introductionmentioning

confidence: 99%

Oxidation of Magnesium: Implication for Aging and Ignition

2016

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“…is study analyzed the effects of three oxides (Co 2 O 3 , Co 3 O 4 , and Fe 2 O 3 ) and three metals (Fe, Mg, and Mn) on the thermal decomposition of NaClO 3 [15]. [12], the pyrolysis rate (TG) in the thermogravimetric test can be calculated by equation (4).…”

Section: Naclo 3 Pyrolysis Reaction Analysismentioning

confidence: 99%

“…Furthermore, the oxygen production and production rate of the oxygen candle are not affected by changes in the ambient temperature, humidity, and pressure [1][2][3]. erefore, oxygen candles have been widely employed in aviation, submarine, mine rescue, and other fields [4].…”

Section: Introductionmentioning

confidence: 99%

Coupling Effect of Metals and Oxides on the Oxygen Supply Performance of Sodium Chlorate Oxygen Candle

Gao

Kariman

et al. 2021

Journal of Chemistry

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In this study, to explore the influence of metals and oxides on the oxygen production rate and stability of sodium chlorate oxygen candles, 28 experimental samples were investigated. The effects of Co2O3, Co3O4, and Fe2O3 with different mass fractions on the thermal decomposition temperature and thermal decomposition rate of sodium chlorate were compared and analyzed. Co3O4 (5%) was obtained to reduce the thermal decomposition range to 260–450°C and reduce the pyrolysis interval ∆T to 46.2°C. Through the development of three metals (Fe, Mg, and Mn), under four mass fractions (2%, 4%, 6%, and 8%) mixed with Co3O4 (5%), the results of the effective oxygen production efficiency test for the thermal decomposition reaction of sodium chlorate demonstrated that Mn (6%)–Co3O4 (5%) exhibited the best catalytic and heat coupling effect; the effective oxygen production efficiency of 97.8% was achieved. Oxygen candle oxygen supply experiment was conducted; the oxygen candle composition for the test was determined to be NaClO3 (86%), Mn (6%), Co3O4 (5%), and kaolin (3%); in the four stages of the oxygen candle oxygen supply reaction test, the average oxygen supply rate reached 1.647 L/min, actual oxygen production was 28 L, and effective oxygen production rate of the oxygen candle was 53.6%. An increase of 9% was observed compared to the previous similar studies. The results of this study present a formula to optimize the oxygen supply of the oxygen candle, which is crucial for improving the oxygen supply performance of the oxygen candle.

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“…Most traditional energetic materials might produce free oxygen in the plasma phase of the explosion. The presence of oxidizer (such as thermites or hybrid materials containing sufficient oxidizer) could enhance the performance of the energetic materials due to the availability of oxygen inside the matrix itself [10,11]. Thermites are composed of fuel and oxidizer which are able to undergo reduction-oxidation (Redox) reaction and caused the oxidation reaction to produce a stable oxide and free metal from the reduction process of the metallic oxide.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a novel nanothermite colloid based on CuO coated CNTs on the thermo-analytical characteristics of 1,3,5-trinitro-1,3,5-triazinane

Elbeih

2021

Preprint

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Nanothermite colloid is a promising field of research used to enhance the characteristics of energetic materials. In this study, pre-treated surfaces of multiwall-carbon nanotubes (MWCNTs) were catalysed to help the deposition of a metal and the coating process by copper (Cu) nanoscale layer through electroless deposition. The formed hybrids coated by Cu were treated at 250°C to form MWCNTs coated by CuO. Isopropyl alcohol was used to suspend the coated MWCNTs with aluminium nanoparticles (120 nm) in order to form nano thermite colloid by ultrasonic technique. The presence of CuO layer plays the role of an active oxidizer for the Aluminum nanoparticles. The obtained colloid was incorporated and dispersed in 1,3,5-trinitro-1,3,5-triazinane (RDX). The influence of colloid on RDX decomposition kinetic was evaluated using the isoconversional methods (modified Kissinger-Akahira-Sunose (KAS) methods). The mean value of apparent activation energy was reduced by 37.5 %. This dramatic change in RDX decomposition ascribed trait to the nano-thermite colloid reactivity and the facile integration of colloidal thermite particles with the RDX.

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Nanocomposite and mechanically alloyed reactive materials as energetic additives in chemical oxygen generators

Cited by 21 publications

References 26 publications

Oxidation of Magnesium: Implication for Aging and Ignition

Oxidation of Magnesium: Implication for Aging and Ignition

Coupling Effect of Metals and Oxides on the Oxygen Supply Performance of Sodium Chlorate Oxygen Candle

Investigation of a novel nanothermite colloid based on CuO coated CNTs on the thermo-analytical characteristics of 1,3,5-trinitro-1,3,5-triazinane

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