Low-temperature exothermic reactions in fully dense Al–CuO nanocomposite powders

Ermoline, Alexandre; Stamatis, Demitrios; Dreizin, Edward L.

doi:10.1016/j.tca.2011.10.002

Cited by 37 publications

(18 citation statements)

References 39 publications

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“…The lower performance associated with the slowly quenched mixture may be attributed to low temperature surface chemistry reactions (i.e., reactive sintering) between Al and CuO which has been reported by others [19]. However, with fast quenching, these composites still showed increased flame speed when annealed to 170 and 200 °C.…”

Section: Introductionmentioning

confidence: 62%

A slice of an aluminum particle: Examining grains, strain and reactivity

McCollum

Smith

Hill

et al. 2016

Combustion and Flame

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Micron-scale aluminum (Al) particles are plagued by incomplete combustion that inhibits their reactivity. One approach to improving reactivity is to anneal Al particles to increase dilatational (volumetric) strain which has also been linked to increased combustion performance. While optimal annealing temperatures have been identified (roughly 300 °C), little is known about cooling rate effects on particle combustion performance. This study examines the effect of quenching after annealing Al microparticles to 100, 200 and 300 o C on intra-particle dilatational strain and reactivity. Synchrotron X-ray diffraction analysis of the particles reveals the cooling rates in the range from 0.007 to 0.38 K/s have little effect on the dilatational strain of the aluminum-core, alumina-shell particles. The annealed and quenched Al particles were then combined with a metal oxidizer (copper oxide) to examine reactivity. Flame propagation experiments follow the same trend: flame speeds are unchanged until a critical annealing temperature of 300 °C is reached and performance is maintained for each annealing temperature regardless of cooling rate. These results show that altering the mechanical properties and combustion performance of Al particles is strongly dependent on the annealing temperature and unchanged with variation in cooling rate. The contributions from elastic and plastic deformation mechanisms on strain are also considered and additional experimental results are shown on the microstructure of an Al particle. Focused ion beam milling of an Al particle to electron transparency was combined with transmission electron microscope imaging in order to examine the microstructure of the Al particles. This confirmed that the Al microparticles have a polycrystalline structure shown by grains all exceeding 100 nm in size.

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Section: Introductionmentioning

confidence: 62%

A slice of an aluminum particle: Examining grains, strain and reactivity

McCollum

Smith

Hill

et al. 2016

Combustion and Flame

View full text Add to dashboard Cite

show abstract

“…Additional experimental studies focusing on the lowtemperature reactions exploited isothermal and scanning microcalorimetry using a TAM III calorimeter by TA Instruments [144,145,153,154]. Reaction rates were quantified at temperatures as low as 303 K for Al$MoO 3 and Al$CuO thermites.…”

Section: Thermites Prepared As Fully Dense Nano-composite Powdersmentioning

confidence: 99%

“…Although the mechanism of the generation of the Mott potential across an interface produced between two solid reactants remains subject of active research [156], CM model was applied to such an interface earlier [157]. Following that work, and modifying the CM equations for an interface produced around a spherical oxide inclusion in a metal matrix [158], the CM model was applied to describe an early reaction in nanocomposite thermites produced by ARM [144,145,147,153,154]. Effectively, the CM reaction describes growth of the Al 2 O 3 film thickness h, as:…”

Section: Thermites Prepared As Fully Dense Nano-composite Powdersmentioning

confidence: 99%

“…Instead, it is an effective thickness of a precursor phase, which transforms into Al 2 O 3 during the reaction. Detailed analyses of TA measurements focusing on the low-temperature reactions identified the CM model parameters, which are shown in Table 6 and describe such reactions for both Al$CuO [144,145,147] and Al$MoO 3 [153] nanocomposite thermites. Term E 2 , the contribution of the Mott potential, is treated as a linear function of temperature following Ref.…”

Section: Thermites Prepared As Fully Dense Nano-composite Powdersmentioning

confidence: 99%

“…Term E 2 , the contribution of the Mott potential, is treated as a linear function of temperature following Ref. [144]. The effect of temperature on the Mott potential was discussed in more detail elsewhere, see for example Ref.…”

Section: Thermites Prepared As Fully Dense Nano-composite Powdersmentioning

confidence: 99%

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