Accession Number : ADD018712

Title :   Diamond Film Deposition on Graphite

Descriptive Note : Patent, Filed 29 Aug 95, patented 5 Aug 97

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Moran, Mark B ; Klemm, Karl A ; Johnson, Linda F

Report Date : 05 Aug 1997

Pagination or Media Count : 7

Abstract : A continuous, adhering film of polycrystalline diamond is grown on a graphite substrate from diamond crystallite nucleated at a metal layer on the substrate when subjected to a microwave activated plasma of hydrogen and a carbon containing gas. Pyrolytic graphite and cured graphite adhesive are effective and other forms of graphite may be effective. Effective metals are chromium, nickel, and titanium. Diamond nucleation apparently occurs at crystallite of metal carbides nucleated by carbon from the plasma so that other carbide forming metals may be effective. Metal not nucleated as the carbide is, apparently, etched away by the plasma; and the diamond film is effectively deposited directly on the graphite since the diamond film is not contaminated by the metal even at the graphite interface where carbide contamination was less than 0.2 percent from a 2500 A chromium film. The diamond film deposition occurs at substrate temperatures as low as 650 deg C. and may be facilitated by a positive voltage bias of the substrate relative to an enclosing vacuum chamber wall. Partial coating of a graphite surface with the metal results in diamond deposition only at the coated portion.

Descriptors :   *FILMS, *DIAMONDS, *GRAPHITE, *DEPOSITION, *POLYCRYSTALLINE, CARBIDES, SUBSTRATES, NUCLEATION, CARBON, TITANIUM, CHROMIUM

Subject Categories : Organic Chemistry
      Coatings, Colorants and Finishes
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE