Patent US4652276A successfully refreshed from Google Patents.
US4652276A
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High toughness silicon nitride cutting tools
Assignee: Valenite LLC
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Filing: 1986-03-10
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Granted: 1987-03-24
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Expires: 2006-03-10
Abstract
Abstract A silicon nitride cutting tool primarily for cutting cast iron comprises a granular phase consisting essentially of silicon nitride and an intergranular amorphous phase consisting essentially of magnesium oxide, yttrium oxide and silicon oxide wherein the components are present in specified amounts and ratios.
Inventors
- 👤 Stephen J. Burden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:56
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; B; B24; B24D; B24D3/00; B24D3/02; B24D3/04; B24D3/14; B24D3/16
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
A silicon nitride cutting tool for cast iron comprising a granular phase consisting essentially of silicon nitride and an intergranular amorphous phase consisting essentially of magnesium oxide, yttrium oxide, and silicon oxide wherein said magnesium oxide is present in an amount from about 0.5 to about 10 weight percent of the total, said yttrium oxide is present in an amount of about 2.5 to about 10 weight percent of the total wherein the ratio of yttrium oxide to magnesium oxide is from about 1:1 to about 7:1, and the balance consists of less than five percent by weight impurities and milling medium.
Claim 2
Dependent Claim
102 words
A silicon nitride cutting tool for cast iron comprising a granular phase consisting essentially of silicon nitride and an intergranular amorphous phase consisting essentially of magnesium oxide, yttrium oxide, and silicon oxide wherein said magnesium oxide is present in an amount from about 0.5 to about 10 weight percent of the total, said yttrium oxide is present in an amount of about 2.5 to about 10 weight percent of the total wherein the ratio of yttrium oxide to magnesium oxide is from about 1:1 to about 7:1, and the balance consists of less than five percent by weight impurities and milling medium.
Claim 3
Dependent Claim
57 words
A silicon nitride cutting tool according to claim 1 consisting from 80 to 97 percent silicon nitride, 0.5 to 10.0 weight percent magnesium oxide, and from 2.5 to 10.0 weight percent yttrium oxide wherein the weight ratio of yttrium oxide to magnesium oxide must be in the range of from 0.1 to 1 to 4.0 to 1.
Claim 4
Dependent Claim
46 words
A silicon nitride cutting tool according to claim 2 wherein the composition of the intergranular phase consists of from 10 to 60 weight percent SiO 2 , from 25 to 70 weight percent Y 2 O 3 and from about 5 to 45 weight percent MgO.
Claim 5
Dependent Claim
28 words
A silicon nitride cutting tool according to claim 2 wherein aluminum oxide is present as an impurity in amounts up to 1 weight percent of the total composition.
Claim 6
Dependent Claim
31 words
A silicon nitride cutting tool according to claim 3 wherein tungsten carbide and/or titanium nitride is present as an impurity in amounts less than 3 weight percent of the total composition.
Claim 7
Dependent Claim
24 words
A silicon nitride cutting tool according to claim 3 wherein the oxygen content of the silicon nitride is from 0.1 to 3.5 weight percent.
References Cited (Backward Citations)
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US4434238A
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US4365022A
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US4424066A
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US4426209A
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US4557244A
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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) | 1990-03-23 | 1990-09-22 | 1991-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-23 | 1994-09-22 | 1995-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-23 | 1998-09-22 | 1999-03-24 | $7700.00 | Window Closed / Lapsed |