9 September 1994 Preparation of W-WOx cermets for solar selective absorbers
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Proceedings Volume 2255, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII; (1994) https://doi.org/10.1117/12.185362
Event: Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, 1994, Freiburg, Germany
Abstract
W-WOx Cermets have been prepared by chemical vapor deposition of W(CO)6 in the presence of oxygen and by the subsequent reduction of the WOx with H2. The vapor was produced by sublimation; the vapor pressure of W(CO)6 is a function of the temperature of the source and the flow rate of the carrier gas. During film formation the substrate temperatures were between 300 and 400 degree(s)C, the pressure range was 1 to 105 Pa, the gas flow rates ranged from 0,2 to 4500 sccm. The deposition rate as a function of pressure and flow rate is best described according to a theory by Holman and Huegel. The surface geometry of the films depends on pressure, temperature and gas velocities. The reduction treatment was done with a mixture of 10% H2 and 90% N2 for 30 minutes at 490 degree(s)C. The properties of the cermet films were analyzed by reflection spectroscopy in the range 0,3 to 25 micrometers , x-ray and SEM investigations. A model for the change of the structure by ageing in the temperature range up to 800 degree(s)C is suggested.
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Ludwig K. Thomas, Ludwig K. Thomas, Andreas Berghaus, Andreas Berghaus, Michael Ray Jacobson, Michael Ray Jacobson, } "Preparation of W-WOx cermets for solar selective absorbers", Proc. SPIE 2255, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, (9 September 1994); doi: 10.1117/12.185362; https://doi.org/10.1117/12.185362
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