Claims
- 1. A method for heat treating a coated substrate wherein an intermediate layer of tungsten is first deposited on the substrate and then an outer coating is deposited on the tungsten intermediate layer and wherein the outer coating having a substantially layered microstructure substantially free of cracks is comprised of a chemical vapor deposited mixture of tungsten and tungsten carbide wherein the tungsten carbide phase consists of W.sub.2 C or W.sub.3 C or a mixture of W.sub.2 C and W.sub.3 C, said method comprising heating said coated substrate to a temperature in the range from about 300.degree. C. to about 500.degree. C. in a non-reactive atmosphere for a period of time to confer substantially higher erosion and abrasion wear resistance to the outer coating than the coating in its heated treated condition but which does not result in substantial degradation of the mechanical properties of the substrate or in formation of undesirable inter-metallic layers.
- 2. A method according to claim 1 wherein the period of time of heat treating is at least one hour.
- 3. A method according to claim 1 wherein the heat treating atmosphere is maintained at or below atmospheric pressure.
- 4. A method according to claim 1 wherein said heat treating atmosphere is hydrogen, argon, helium, nitrogen or a mixture of two or more said gases.
- 5. A method according to claim 1 wherein an intermediate layer of nickel is deposited on the substrate prior to deposition of said tungsten.
- 6. A method according to claim 1 wherein said substrate is a ferrous or non-ferrous alloy.
- 7. A method for conferring substantial erosion and abrasion wear resistant properties on a substrate, comprising, product on the substrate an intermediate layer of tungsten deposited on the substrate and then a chemical vapor deposited outer coating having a substantial layered microstructure substantially free of cracks of a mixture of tungsten and tungsten carbide wherein the tungsten carbide phase consists of W.sub.2 C or W.sub.3 C or a mixture of W.sub.2 C and W.sub.3 C, and heating said coated substrate to a temperature in the range from about 300.degree. C. to about 500.degree. C. in a non-reactive atmosphere for a period of time to confer substantially higher erosion and abrasion wear resistance to the outer coating than the coating in its unheated treated condition but which does not result in substantial degradation of the mechanical properties of the substrate or in formation of undesirable inter-metallic layers.
- 8. A method according to claim 7 wherein the period of time of heat treating is at least one hour.
- 9. A method according to claim 7 wherein the heat treating atmosphere is maintained at or below atmospheric pressure.
- 10. A method according to claim 7 wherein the heat treating atmosphere is hydrogen, argon, helium, nitrogen or a mixture of two or more said gases.
- 11. A method according to claim 7 wherein an intermediate layer of nickel is deposited on the substrate prior to deposition of said tungsten.
- 12. A method according to claim 7 wherein said substate is a ferrous or non-ferrous alloy.
- 13. A method according to claim 7 wherein said substrate is a stainless steel.
- 14. A method according to claim 13 wherein said substrate is heat treated to a temperature of about 500.degree. C.
- 15. A method according to claim 7 wherein said substrate is a titanium alloy.
- 16. A method according to claim 15 wherein said substrate is heat treated to a temperature of less than about 500.degree. C.
Parent Case Info
This is a division of application Ser. No. 07/157,550, filed Feb. 17, 1988, now U.S. Pat. No. 4,873,152, issued Oct. 10, 1989.
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Divisions (1)
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Number |
Date |
Country |
Parent |
157550 |
Feb 1988 |
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