US4440547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina coated silicon nitride cutting tools
Assignee: Verizon Laboratories Inc
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Filing: 1982-05-20
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Granted: 1984-04-03
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Expires: 2002-05-20
Abstract
Abstract Cutting tools and cuttng tool inserts having improved mechanical and chemical wear resistance under demanding conditions of machining speed, temperature, or workpiece hardness comprise a silicon nitride substrate body having at least one hard, adherent coating layer of aluminum oxide. The silicon nitride substrate body consists essentially of a first phase of silicon nitride and a refractory second phase comprising silicon nitride and an effective amount of a densification aid selected from the group consisting of silicon dioxide, aluminum oxide, magnesium oxide, yttrium oxide, hafnium oxide, zirconium oxide, the lanthanide rare earth oxides, and mixtures thereof.
Inventors
- 👤 Vinod K. Sarin
- 👤 Sergej-Tomislav Buljan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:45
CPC Classifications
B; B23; B23B; B23B27/00; B23B27/14; B23B27/148; C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B41/00; C04B41/45; C04B41/50; C04B41/5025; C04B41/5053; C04B41/80; C04B41/81; C04B41/85; C04B41/87; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
A coated ceramic cutting tool comprising a densified silicon nitride substrate body having at least one adherent coating layer; said substrate body consisting essentially of a first phase of silicon nitride and a refractory second phase comprising silicon nitride and an effective amount of a densification aid selected from the group consisting of silicon dioxide, aluminum oxide, magnesium oxide, yttrium oxide, hafnium oxide, zirconium oxide, the lanthanide rare earth oxides, and mixtures thereof; said adherent coating layer consisting essentially of aluminum oxide.
Claim 2
Dependent Claim
82 words
A coated ceramic cutting tool comprising a densified silicon nitride substrate body having at least one adherent coating layer; said substrate body consisting essentially of a first phase of silicon nitride and a refractory second phase comprising silicon nitride and an effective amount of a densification aid selected from the group consisting of silicon dioxide, aluminum oxide, magnesium oxide, yttrium oxide, hafnium oxide, zirconium oxide, the lanthanide rare earth oxides, and mixtures thereof; said adherent coating layer consisting essentially of aluminum oxide.
Claim 3
Dependent Claim
26 words
A coated ceramic cutting tool in accordance with claim 1 wherein said adherent coating layer is of a thickness between about 0.1 microns and 10 microns.
Claim 4
Dependent Claim
26 words
A coated ceramic cutting tool in accordance with claim 2 wherein said adherent coating layer is of a thickness between about 1.0 and about 10 microns.
Claim 5
Dependent Claim
32 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid is present in an amount of between about 1 and about 25 weight percent of said substrate body.
Claim 6
Dependent Claim
32 words
A coated ceramic cutting tool in accordance with claim 4 wherein said densification aid is present in an amount of between about 1 and about 5 weight percent of said substrate body.
Claim 7
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 5 wherein said densification aid comprises silicon dioxide.
Claim 8
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid comprises magnesium oxide.
Claim 9
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid comprises aluminum oxide.
Claim 10
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid comprises yttrium oxide.
Claim 11
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid comprises hafnium oxide.
Claim 12
Dependent Claim
17 words
A coated ceramic cutting tool in accordance with claim 1 wherein said densification aid comprises zirconium oxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |