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Fluidization and coating of very dense powders by fluidized bed chemical vapour deposition.

Rodriguez, Philippe and Caussat, Brigitte and Ablitzer, Carine and Iltis, Xavière and Brothier, Méryl Fluidization and coating of very dense powders by fluidized bed chemical vapour deposition. (2013) Chemical Engineering Research and Design, 91 (12). 2477-2483. ISSN 0263-8762

(Document in English)

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Official URL: http://dx.doi.org/10.1016/j.cherd.2012.11.007


The hydrodynamic behaviour of a very dense tungsten powder, 75 µm in median diameter and 19,300 kg/m3 in grain density, has been studied in a fluidized bed at room temperature using nitrogen and argon as carrier gas. Even if fluidization was achieved, the small bed expansion indicated that it was imperfect. Then, the fluidization was studied at 400 °C in order to investigate the feasibility of coating this powder by Fluidized Bed Chemical Vapour Deposition (FBCVD). In particular, the influence of the H0/D ratio (initial fixed bed height to reactor diameter) on the bed thermal behaviour was analysed. It appeared that at least 1.5 kg of powder (corresponding to a H0/D ratio of 1.8) was necessary to obtain an isothermal bed at 400°C. Finally, first results about alumina coatings on the tungsten powder by FBCVD from aluminium acetylacetonate are detailed. They show that for the quite low temperatures tested, the coatings are uniform on all bed particles and are formed of amorphous carbon containing alumina. This study demonstrates the efficiency to combine fluidization (instead of spouted bed) and CVD to coat such very dense powders.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Chemical Engineering Research and Design: http://www.sciencedirect.com/science/article/pii/S0263876212004546
HAL Id:hal-03526389
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Laboratory name:
Deposited On:10 Sep 2013 11:06

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