Accession Number : AD0623992

Title :   AN INVESTIGATION OF BARRIER COATINGS ON GRAPHITE MOLDS FOR CASTING TITANIUM.

Descriptive Note : Final rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Reaves,W. A. ; Chapin,E. J.

Report Date : 13 OCT 1965

Pagination or Media Count : 43

Abstract : The coatings included: a solid solution of MgO and ZrO2; a true oxide compound, CaZrO3; and two single oxides, Gd2O3 and Y2O3. The compound oxides were applied to specially cleaned ATJ grade graphite-mold hollowcylinder inserts by an oxy-acetylene flame spray method, and the single oxides were applied in similar inserts by a plasma spray technique. The MgO, ZrO3 and CaZrO3 coatings were considered to be insufficiently resistant under casting conditions to qualify as satisfactory barrier coatings. The rare earth oxide Gd2O3 was found to be resistant to molten titanium during casting and to provide a good barrier between the graphite mold substrate and the cast metal, with no significant increases in either oxygen or carbon content. The oxide Y2O3 was found to have the best characteristics as a barrier coating. This oxide did not appear to be wetted by the molten metal cast against it nor to introduce any significant amounts of contaminants into the case metal. The barrier coatings were not effective in altering the high heat extraction capability of the graphite substrate and thus did not provide any improvement in solidification center line shrinkage. (Author)

Descriptors :   (*COATINGS, MOLDINGS), (*MOLDINGS, COATINGS), (*TITANIUM, CASTING), GRAPHITE, OXIDES, MAGNESIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, CALCIUM COMPOUNDS, ZIRCONATES, GADOLINIUM COMPOUNDS, YTTRIUM COMPOUNDS, IMPURITIES, PROTECTIVE TREATMENTS, FLAME SPRAYING

Subject Categories : Coatings, Colorants and Finishes
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE