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Deposition of H_2-permselective SiO_2 films

Gavalas, G. R. and Megiris, C. E. and Nam, S. W. (1989) Deposition of H_2-permselective SiO_2 films. Chemical Engineering Science, 44 (9). pp. 1829-1835. ISSN 0009-2509. doi:10.1016/0009-2509(89)85125-5.

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Films of amorphous SiO_2 were deposited within the walls of porous Vycor tubes by SiH_4 oxidation in an opposing-reactants geometry: SiH_4 was passed inside the tube while O_2 was passed outside the tube. The two reactants diffused opposite to each other and reacted within a narrow front inside the tube wall to form a thin SiO_2 film. Once the pores were plugged the reactants could not reach each other and the reaction stopped. At 450°C and 0.1 and 0.33 atm of SiH_4 and O_2, the reaction was complete within 15 min. The thickness of the SiO_2 film was estimated to be about 0.1 μ. Measurements of H_2 and N_2 permeation rates showed that the SiO_2 film was highly selective to H_2 permeation. The H_2: N_2 flux at 450°C varied between 2000 and 3000. Thermal annealing at 600°C reduced somewhat that selectivity. Thermal annealing in the presence of H_2O vapor decreased further the flux of H_2 and increased the flux of H_2. Permeation of H_2 is believed to occur through an activated diffusion mechanism. Applications of such H_2-permeable films to membrane reactors for equilibrium-limited reactions are discussed.

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Gavalas, G. R.0000-0003-1468-6835
Additional Information:© 1989 Pergamon Press. Received 8 September 1988, Accepted 31 January 1989. This work was supported by NSF grant No. CBT-8806101. The authors acknowledge helpful discussions with Dr Dale Powers of Corning Glass Works.
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Issue or Number:9
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Official Citation:G.R. Gavalas, C.E. Megiris, S.W. Nam, Deposition of H2-permselective SiO2 films, Chemical Engineering Science, Volume 44, Issue 9, 1989, Pages 1829-1835, ISSN 0009-2509, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61829
Deposited By: Ruth Sustaita
Deposited On:04 Nov 2015 21:16
Last Modified:10 Nov 2021 22:54

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