Oriented graphite layer and formation
First Claim
1. 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°
C. and 1350°
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; and
(d) thereafter cooling the metallic substrate to a temperature below about 200°
C., thereby providing a precipitated oriented graphite film at a surface of said substrate.
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Accused Products
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° and 1350° C. for saturational diffusion of carbon into the substrate and cooling to a temperature below about 200° 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.
23 Citations
10 Claims
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1. A method of forming an oriented graphite coating on a metallic substrate comprising the steps of:
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(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°
C. and 1350°
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; and(d) thereafter cooling the metallic substrate to a temperature below about 200°
C., thereby providing a precipitated oriented graphite film at a surface of said substrate. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming an oriented graphite coating on a metal base material tube comprising the steps of:
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(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°
C. and 1350°
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°
C., thereby providing a precipitated oriented graphite film at said other side of said metal foil; and(d) bonding said metal foil one side to the outer surface of said metal base material tube and in thermal contact therewith. - View Dependent Claims (7, 8, 9, 10)
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Specification