Oriented graphite layer and formation
AssigneeUnion Carbide Corporation
InventorsClifford M. Detz, John B. Lightstone
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Abstract
An oriented graphite layer is formed on a metallic substrate by providing a coating of particulate carbon thereon, heating the coated substrate in a non-reactive atmosphere to a temperature of between 800.degree. and 1350.degree. C. for saturational diffusion of carbon into the substrate and cooling to a temperature below about 200.degree. C., thereby providing a precipitated oriented graphite film at the surface of the substrate. The substrate may be formed by covering a copper or copper alloy member with a continuous layer of nickel, cobalt, nickel alloy or cobalt alloy. In another embodiment, the substrate with an attached graphite coating is spirally bonded onto a copper tube for use in the field of condensation heat transfer.
Claims10
A method of forming an oriented graphite coating on a metallic substrate comprising the steps of:
- (a) forming said metallic substrate by covering a copper or copper alloy base member with a continuous layer of nickel, nickel alloy, cobalt or cobalt alloy;
- (b) providing a substantially uniform coating of particulate carbon on the metallic substrate;
- (c) heating the coated metallic substrate in a nonreactive atmosphere to a temperature of between 800.degree. C. and 1350.degree. C. and below the melting point of said metallic substrate and maintaining said temperature for a period of time sufficient for saturational diffusion of said carbon into said substrate;
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- (d) thereafter cooling the metallic substrate to a temperature below about 200.degree. C., thereby providing a precipitated oriented graphite film at a surface of said substrate.
A method of forming an oriented graphite coating on a metal base material tube comprising the steps of:
- (a) providing a substantially uniform coating of particulate carbon on one side of a thin metal foil;
- (b) heating the coated metal foil in a nonreactive atmosphere to a temperature of between 800.degree. C. and 1350.degree. C. and below the melting point of said metal foil, and maintaining said temperature for a period of time sufficient for saturational diffusion of said carbon through said metal foil from said one side to the other side thereof;
- (c) thereafter cooling the metal foil to a temperature below about 200.degree. C., thereby providing a precipitated oriented graphite film at said other side of said metal foil;
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- (d) bonding said metal foil one side to the outer surface of said metal base material tube and in thermal contact therewith.
Dependencies are inferred from the claim text.