VAPOR DEPOSITION OF TUNGSTEN ON ROCKET NOZZLE INSERTS
BUREAU OF MINES ROLLA MO METALLURGY RESEARCH CENTER
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Six graphite nozzle insele inserts. summary rept. for period ending 30 June 61, by F. W. Hoertel. 30 June 61, 8p. incl. table. Sponsored by the Department of the Navy Unclassified report DESCRIPTORS Rocket motor nozzles, Vapor plating, Metal coatings, Tungsten, Graphite, Beryllium compounds, Oxides, Rhenium, Refrac tory materials, Coatings, Fracture Mechanics, Microstructure. Six graphite nozzle inserts, 3 with a coating of Re, were coated with W. The most drastic effects encountered during firing tests of the inserts were attributed to the high ignition pressure which resulted from the small throat diameter 0.423 in.. Microscopical examination of a cross section of a coated mock-up insert showedAN ADHERENT, MECHANICAL BOND BE WEEN THE GRAPHITE AND THE W. One of the W-coated nozzles with a Re barrier layer was sectioned and examined metallurgically. The macrostructure of the sectioned insert revealed 1 fracture, transverse to the W deposit, near the center of the nozzle. The microstructure indicated no alloying of the W with the Re. Spectrographic analysis of the W showed trace contaminations of Fe, Mn, Mo, Ni, Si, and Cu. Three beryllia inserts and l beryllia-W insert were coated with W. Transverse cracks appeared in the substrates of the W-coated beryllia nozzle. No cracks appeared in the W-coated nozzle with the beryllia-W substrate.