Al/Cu2O thermite compatibility studies by x-ray photoelectron and x-ray induced auger spectroscopy

Wang, P.S.; Haws, L.D.; Moddeman, W. E.; Rengan, Aravind Kumar

doi:10.1016/0304-3894(82)85019-x

Cited by 9 publications

(3 citation statements)

References 4 publications

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“…Second, in the case of CuO/Al top , the aluminum oxide layer may grow more due to its proximity to CuO x and the intrinsic roughness of the CuO surface. The latter effect was already observed and discussed in powder mixtures of Al and Cu 2 O. Wang et al found that the thickness of the oxide layer on Al powders increased when they were compacted with Cu 2 O powder.…”

Section: Discussionsupporting

confidence: 54%

“…Besides alumina, there is also the appearance of copper and the three species coexist together over a range of ∼10 nm, after which the aluminum content is lowered and the copper oxide layer is reached, as evidenced by two intense Cu-L 3 and -L 2 white lines. Wang et al 26 found that the thickness of the oxide layer on Al powders increased when they were compacted with Cu 2 O powder.…”

Section: Resultsmentioning

confidence: 99%

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Structure and Chemical Characterization at the Atomic Level of Reactions in Al/CuO Multilayers

Abdallah

Zapata

Lahiner

et al. 2018

ACS Appl. Energy Mater.

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Sputter-deposited Al/CuO multilayers exhibit fast combustion reactions in which an exothermic chemical reaction wavecontrolled by the migration of oxygen atoms from the oxide matrix toward the aluminum layers through interfacial layersmoves throughout the multilayer at subsonic rates (meters per second to tens of meters per second). We directly observed the structural and chemical evolution of Al/CuO/Al multilayers upon heating to 700 °C using high-magnification transmission electron microscopy (TEM) and scanning TEM, providing simultaneous subnanometrer imaging resolution and detailed chemical analysis. Interestingly, as deposited, the trilayer is characterized by two distinct interfacial layers: 4.1 ± 0.2 nm thick amorphous alumina and a 15 ± 5 nm thick mixture of AlO x and Cu x Al y O z , at the bottom interface and top interface, respectively. Upon heating, we accurately characterized the evolving nature and structure of these interfaces, which are rapidly replaced by the reaction terminal oxide (Al 2 O 3 ). For the first time, we unraveled the release of gaseous O from the sparse columnar and defective CuO well below reaction onset (at ∼200 °C) which accumulates at interfaces and contributes to initiate the Al oxidation process at the vicinity of native interfaces. The oxidation process is demonstrated to be accompanied by a continuous densification and modification of the CuO layer. Between 300 and 350 °C, we observed a brutal shrinkage of the CuO layer (14% loss of its initial thickness) leading to the mechanical fracture in the top alumina growing layer. Consequently, this latter becomes highly permeable to oxygens leading to a brutal enhancement of the oxidation rate (×4). We also characterized stressed-induced interfacial delamination at 500 °C pointing clearly to the mechanical fragility of the top interface after the CuO transformation. Altogether, these results permit one to establish a multistep reaction scenario in Al/CuO sputter-deposited films supporting to an unprecedented level a mechanistic assignation of differential scanning calorimetry peaks. This study offers potential benefits for the development of aging models enabling the virtual prediction of the calorimetric response of exothermic Al/CuO thin-film reactions.

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Section: Discussionsupporting

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Structure and Chemical Characterization at the Atomic Level of Reactions in Al/CuO Multilayers

Abdallah

Zapata

Lahiner

et al. 2018

ACS Appl. Energy Mater.

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“…The popularity of aluminum in such reaction composition is largely due to its low melting point (933 K) and the high thermodynamic stability of the reaction product, Al 2 O 3 (Δ H f =−1676 kJ/mol at 25°C) in addition to its abundance 29 . Although of less industrial importance, copper‐based thermites have been known for their use as chemical heat sources 30 and in reaction synthesis 31 . The Al/Cu 2 O system reacts according to with a computed adiabatic temperature of 2397 K 32…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Consolidation and Ignition Characteristics of Thermite Composites

Pillai

Hadjiafxenti

Doumanidis

et al. 2011

Int J Applied Ceramic Tech

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The fabrication and characterization of metal-based energetic composite materials are currently being examined for a range of new applications. A newly developed ultrasonic consolidation process is used for the synthesis of Al/Fe 2 O 3 and Al/ Cu 2 O compacts over a wide range of powder ratios at room temperature. Powder consolidation was achieved by a multistep procedure involving simultaneous application of pressure and ultrasonic vibrations. The observed reaction characteristics of the composites are similar to those of previously reported thermite compacts prepared by a traditional powder metallurgy method.

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Magnetron Sputtered Al‐CuO Nanolaminates: Effect of Stoichiometry and Layers Thickness on Energy Release and Burning Rate

Bahrami

Taton

Conedera

et al. 2014

Propellants Explo Pyrotec

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This paper reports on the reaction characteristic of Al/CuO reactive nanolaminates for different stoichiometries and bilayer thicknesses. Al/CuO nanolaminates are deposited by a DC reactive magnetron sputtering method. Pure Al and Cu targets are used in argon‐oxygen gas mixture plasma and an oxygen partial pressure of 0.13 Pa. This process produces low stress multilayered materials, each layer being in the range of 25 nanometers to one micrometer. Their structural, morphological, and chemical properties were characterized by high resolution transmission electron microscopy (HR‐TEM), X‐ray Diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). The heat of reaction and onset temperature were measured using differential scanning calorimetry (DSC). Under stoichiometric conditions, the reactivity quickly increases with the decrease of Al/CuO bilayer thickness. The burning rate is 2 m s−1 for bilayer thickness of 1.5 μm and reaches 80 m s−1 for bilayer thickness of 150 nm. At constant heating rate, the Al/CuO heat of reaction depends on both stoichiometry and bilayer thickness. When the bilayer thickness exceeds 300 nm, the heat of reaction decreases; it seems that only the region near the interface reacts. The best nanolaminate configuration was obtained for Al/CuO bilayer thickness of 150 nm.

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Al/Cu2O thermite compatibility studies by x-ray photoelectron and x-ray induced auger spectroscopy

Cited by 9 publications

References 4 publications

Structure and Chemical Characterization at the Atomic Level of Reactions in Al/CuO Multilayers

Structure and Chemical Characterization at the Atomic Level of Reactions in Al/CuO Multilayers

Ultrasonic Consolidation and Ignition Characteristics of Thermite Composites

Magnetron Sputtered Al‐CuO Nanolaminates: Effect of Stoichiometry and Layers Thickness on Energy Release and Burning Rate

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