Patent US4704168A successfully refreshed from Google Patents.
US4704168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion-beam nitriding of steels
Assignee: United States, NASA THE, Administrator of
•
Filing: 1986-01-29
•
Granted: 1987-11-03
•
Expires: 2006-01-29
Abstract
Abstract A surface of a steel substrate is nitrided without external heating by exposing it to a beam of nitrogen ions under a low pressure. The pressure is much lower than that employed for ion-nitriding, and an ion source is used instead of a glow discharge. Both of these features reduce the introduction of impurities into the substrate surface.
Inventors
- 👤 Joshua Salik
- 👤 Theodore E. Hubbell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:07
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/36; C23C8/38
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
109 words
In a method of forming a nitrided layer without a compound layer on a surface of a steel substrate selected from the group consisting essentially of super nitralloys and stainless steels, the improvement comprising positioning said substrate in a vacuum chamber at ambient temperature, reducing the pressure in said chamber to about 3×10 -4 Torr, striking said surface with a beam of nitrogen ions having energies between about 0.5 keV and about 1.5 keV within said chamber in the absence of a discharge, and independently controlling the voltage and current of said ions to maintain said beam thereby forming said nitrided layer without external heating of said steel substrate.
Claim 2
Dependent Claim
109 words
In a method of forming a nitrided layer without a compound layer on a surface of a steel substrate selected from the group consisting essentially of super nitralloys and stainless steels, the improvement comprising positioning said substrate in a vacuum chamber at ambient temperature, reducing the pressure in said chamber to about 3×10 -4 Torr, striking said surface with a beam of nitrogen ions having energies between about 0.5 keV and about 1.5 keV within said chamber in the absence of a discharge, and independently controlling the voltage and current of said ions to maintain said beam thereby forming said nitrided layer without external heating of said steel substrate.
Claim 3
Dependent Claim
26 words
A method of nitriding as claimed in claim 1 wherein the substrate is a super nitralloy and the nitrogen ions strike the surface about 50 minutes.
Claim 4
Dependent Claim
27 words
A method of nitriding as claimed in claim 1 wherein the substrate is a stainless steel and the nitrogen ions strike the surface for about 70 minutes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-02 | 1991-05-04 | 1991-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-02 | 1995-05-04 | 1995-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-02 | 1999-05-04 | 1999-11-03 | $7700.00 | Window Closed / Lapsed |