ELECTRODEPOSITION OF EROSION AND OXIDATION RESISTANT COATINGS FOR GRAPHITE

A literature survey resulted in the inclusion in the program of the borides and/or carbides of Ta, Hf, Si, Zr, B, Nb, and W, and the nitrides of B and Si. Specimens were coated with Zr, f or Ta borides, and ZrO2, SiC, and BN. Thermal expansion tests for the Cr-Zr boride cermet showed contraction occ...

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Bibliographische Detailangaben
Hauptverfasser:	WRIGHT, C H, BARGERO, G F, HUMINIK, J JR
Format:	Report
Sprache:	eng
Schlagworte:	ANTIOXIDANTS BORIDES BORON COMPOUNDS CARBIDES CERAMIC COATINGS CERAMIC MATERIALS CERMETS COATINGS ELECTRODEPOSITION EROSION GRAPHITE HAFNIUM COMPOUNDS METAL COMPOUNDS METALLIC COMPOUNDS NIOBIUM COMPOUNDS NITRIDES OXIDES PLATING PROCESSING REFRACTORY COATINGS ROCKET NOZZLES SHOCK RESISTANCE SILICIDES SILICON COMPOUNDS TANTALUM CAPACITORS TELEVISION GUIDANCE THERMAL EXPANSION TUNGSTEN COMPOUNDS
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Beschreibung
Zusammenfassung:	A literature survey resulted in the inclusion in the program of the borides and/or carbides of Ta, Hf, Si, Zr, B, Nb, and W, and the nitrides of B and Si. Specimens were coated with Zr, f or Ta borides, and ZrO2, SiC, and BN. Thermal expansion tests for the Cr-Zr boride cermet showed contraction occurred between 300 and 800 F. This phenomenon was attributed to gas evolution, loss of water of hydration, stress relaxation, and sintering of cracks and voids. The opposite effect occurred on cooling for expansion between 1200 and 1000 F. Ta and Zr boride coatings on graphite exhibited superior oxidation resistance; ZrO2 showed the best thermal shock properties. Zr boride and oxide, and Hf boride powders incorporated in the Cr electrodeposition process produced promising cermet coatings. Specifications for the test motor are listed, a d tests were made on uncoated graphite nozzles.