Passivation of the surface of aluminum nanopowders by protective coatings of the different chemical origin

Kwon, Young-Soon; Gromov, A. A.; Strokova, Julia I.

doi:10.1016/j.apsusc.2006.12.124

Cited by 130 publications

(66 citation statements)

References 10 publications

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“…The formation of nano γ-Al 2 O 3 by slow non-isothermal oxidation (0.5-20.0 K/min) occurs at low temperatures (T = 673-773 K) for electroexplosive nAl [23]. Furthermore, the different definitions of the intense oxidation onset temperature and other parameters on the DTA/DSC/TGA curves can lead to confusing comparisons Copyright © 2017 Institute of Industrial Organic Chemistry, Poland between different datasets [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. For certain nAl samples with a specific surface area 12 m 2 /g, the mass fraction of micron-sized particle clusters (1-3 µm) could be 68 wt.%, but the number of clusters was only 2% of the total number of particles [56].…”

Section: Analysis Of Powder Characteristics and Their Comparison Withmentioning

confidence: 99%

“…In spite of this, available data suggest that these powders are highly sensitive to the storage environmental conditions [26,31,32].…”

Section: Introductionmentioning

confidence: 99%

“…Fresh air-passivated nAl particles are usually characterized by Al 2 O 3 shell thicknesses in the range 2 nm to 6 nm, irrespective of particle size. The amorphous oxide layers on nAl particles become crystallized at a defined thickness (7-8 nm) during a storage period of 2-3 years at room temperature [26]. However, none of the existing passivation approaches [27][28][29][30] allow nAl particles to reach values of the metallic aluminium content comparable with µAl's metallic content (98-99 wt.%), even assuming large clusters to be present in nAl.…”

Section: Introductionmentioning

confidence: 99%

“…Immediately after production, the nAl powders require passivation or coating procedures to avoid self-ignition and self-sintering of the particles [23][24][25][26][27]. nAl, obtained in inert gas media (argon, nitrogen or their mixtures) by any of the existing methods, is normally pyrophoric in air, because the amount and the rate of heat release from the oxidation reaction is high enough to heat the nanoparticle to its ignition temperature (~670 K for 100 nm nAl particles).…”

Section: Introductionmentioning

confidence: 99%

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Nanoaluminium: is there any Relationship between Powder Particles’ Size, Non-Isothermal Oxidation Data and Ballistics?

Gromov¹,

Teipel²

2017

Cent. Eur. J. Energ. Mater.

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This article focuses on data analyses and comparisons for aluminium nanopowders (or nanoaluminium, nAl) reactions under slow (0.5-20.0 K/min, using DTA/DSC/TGA) and fast (>10000 K/min, combustion in solid propellant formulations) non-isothermal oxidation. Particle sizes were defined through the BET method. Active Al content was related with the averaged reactivity parameters, taken from published DTA/DSC/TGA data. The specific oxidation onset temperature for nAl was poorly correlated with the BET particle size under the conditions investigated. Furthermore, the BET particle size exhibited no correlation with the observed ballistic response (burning rate) at 3.0 MPa. A logarithmic correlation y = 17.484 ln(x) -5813, with R² = 0.73, was found between nAl particle size and its aluminium content. A calibration equation for the oxidation onset temperature as a function of nAl particle size was determined as y = −0.0071x 2 + 3.3173x + 479.32, with R² = 0.75. Specific features of the nAl (metallic aluminum content in nAl and the oxidation onset temperature) can be predicted based on the measured powder parameters (such as BET particle size).

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Section: Analysis Of Powder Characteristics and Their Comparison Withmentioning

confidence: 99%

“…In spite of this, available data suggest that these powders are highly sensitive to the storage environmental conditions [26,31,32].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanoaluminium: is there any Relationship between Powder Particles’ Size, Non-Isothermal Oxidation Data and Ballistics?

Gromov¹,

Teipel²

2017

Cent. Eur. J. Energ. Mater.

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“…In powdered form, all the materials formed tight micron-scale aggregates, as had been observed previously for both bare NPs and NPs protected by inorganic and organic surface layers. 55,60,64 Although many details of the nanoscale structure exceeded the spatial-resolution capability of STXM (40 nm under the experimental conditions used), on a large scale the Al-OA NPs were monodispersed and had a uniform distribution of metallic Al and Al2O3. In contrast, the STXM images of the 18 and 100…”

Section: Resultsmentioning

confidence: 99%

Chemical and Morphological Inhomogeneity of Aluminum Metal and Oxides from Soft X-ray Spectromicroscopy

Altman

Pemmaraju²,

Alayoǧlu³

et al. 2017

Inorg. Chem.

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ABSTRACT. Oxygen and aluminum K-edge X-ray absorption spectroscopy (XAS), imaging from a scanning transmission X-ray microscope (STXM), and first principles calculations were used to probe the composition and morphology of bulk aluminum metal, α-and γ-Al2O3, and several types of aluminum nanoparticles. The imaging results agreed with earlier transmission electron microscopy studies that showed a 2 to 5 nm thick layer of Al2O3 on all the Al surfaces. Spectral interpretations were guided by examination of the calculated transition energies, which agreed well with the spectroscopic measurements. Features observed in the experimental O and Al K-edge XAS were used to determine the chemical structure and phase of the Al2O3 on the aluminum surfaces. For unprotected 18 and 100 nm Al nanoparticles, this analysis revealed an oxide layer that was similar to γ-Al2O3 and comprised of both tetrahedral and octahedral Al coordination sites. For oleic-acid protected Al nanoparticles, only tetrahedral Al oxide coordination sites were observed.The results were correlated to trends in the reactivity of the different materials, which suggests that the structures of different Al2O3 layers have an important role in the accessibility of the underlying Al metal towards further oxidation.Combined, the Al K-edge XAS and STXM results provided detailed chemical information that was not obtained from powder X-ray diffraction or imaging from a transmission electron microscope.

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Passivation of the surface of aluminum nanopowders by protective coatings of the different chemical origin

Cited by 130 publications

References 10 publications

Nanoaluminium: is there any Relationship between Powder Particles’ Size, Non-Isothermal Oxidation Data and Ballistics?

Nanoaluminium: is there any Relationship between Powder Particles’ Size, Non-Isothermal Oxidation Data and Ballistics?

Chemical and Morphological Inhomogeneity of Aluminum Metal and Oxides from Soft X-ray Spectromicroscopy

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