Surface hardening of Ti alloys by gas-phase nitridation: kinetic control of the nitrogen activity
OwnerFrank Ernst, Arthur Heuer +1inventors
InventorsFrank Ernst, Arthur Heuer, Gary Michal
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Abstract
The present invention relates to surface hardening of a metal surface of a work piece formed of titanium and titanium alloys. The method comprises the steps of heating the work piece; exposing the metal surface to a nitrogen gas having a partial pressure lower than about 10−2 Pa; and maintaining the work piece in the nitrogen gas so that nitrogen is absorbed onto the surface of the work piece and diffused into the work piece for a desired distance while preventing the formation of nitrides on the surface of the work piece and within the work piece.
Claims16
A method for surface hardening of a metal surface of a work piece formed of a metal from the group consisting essentially of titanium and titanium alloys, said method comprising the steps of:
- heating the work piece to a desired temperature of less than about 1000° C.;
- exposing the metal surface to a nitrogen gas having a partial pressure lower than about 10−2 Pa;
- and
- maintaining the work piece in the nitrogen gas for a period of time so that nitrogen is absorbed onto the surface of the work piece and diffused into the work piece for a desired distance while preventing the formation of nitrides on the surface of the work piece and within the work piece.
A method for surface hardening of a metal surface of a work piece formed of a metal from the group consisting essentially of titanium and titanium alloys, said method comprising the steps of:
- heating the work piece to a first temperature of less than about 1000° C.;
- exposing a surface of the work piece to a nitrogen gas having a first pressure that is determined by a second temperature to which a first powder of metal nitride and a second powder of the corresponding metal forming the metal nitride are exposed;
- and
- maintaining the work piece in the nitrogen gas for a period of time so that nitrogen is absorbed onto the surface of the work piece and diffused into the work piece for a desired distance while preventing the formation of nitrides on the surface of the work piece and within the work piece.
Dependencies are inferred from the claim text.