Corrosion-resistant coatings for high-temperature high-sulfur- activity applications. Final report [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1992. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 30 pages : digital, PDF file
- Additional Creators:
- Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- The previously started experiments to verify the feasibility of obtaining molybdenum and molybdenum carbide coatings from oxide-based melts were continued. A molten salt bath consisting of an equimolar mixture of Na₂WO₄ and K₂WO₄ was used. The molybdenum and carbon species were introduced as alkali molybdate and carbonate. The coating morphology depends strongly on melt composition, temperature and moisture content. Application of initial pre-electrolysis significantly changes the composition and morphology of the coatings. Using non-lithium alkali salts, coatings of better quality were obtained. Adding 3-8 mol% Na₂B₄O₇ to the basic non-lithium bath composition was observed to cause significant morphology and quality changes. Bath compositions produce a more uniform small-grain-size coating and they do not require extensive purification. Constant current and reverse and/or pulse current patterns were applied during plating. The latter produces smaller-grain-size coatings at the same working temperature. Research was undertaken to deposit Mo and Mo₂ C films on a substrate 2.5 cm by 3.8 cm in area. Using an orthogonal factorial design, a new series of experiments has been carried out to investigate the effect of the evaporation rate of Mo(CO)₆ as a precursor. From the weight gain of the substrate, initial conclusions have been drawn about the optimal conditions for maximum evaporation rate, deposition rate and thickness. Thicker coatings (a few μm) have been obtained which show two different types of crystallites growing on an initially amorphous film. A two dimensional transport and reaction kinetics model for a parallel-plate PECVD reactor was outlined. The PECVD results will be used to verify the model. The primary parameters to be explored are those representing the deposition kinetics of Mo and C.
- Published through SciTech Connect., 01/01/1992., "lbl--32234", "DE93001527", and Chen, B.; Selman, J.R.; Aladjov, B.
- Type of Report and Period Covered Note:
- Topical; 01/01/1992 - 01/01/1992
- Funding Information:
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