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US4304576A
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US
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Silicon nitride ceramic tools and a process for their production
Assignee: Niterra Co Ltd
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Filing: 1979-11-05
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Granted: 1981-12-08
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Expires: 1999-11-05
Abstract
Abstract A silicon nitride based ceramic tool is disclosed which is prepared from the starting powder compositions surrounded by and including the lines defined by the points A, B, and C and preferably D, E, and F in the FIGURE.
Inventors
- 👤 Yoshinori Hattori
- 👤 Masayuki Akatsuka
- 👤 Yasushi Matsuo
- 👤 Isamu Fukuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:12
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; Y; Y10; Y10T; Y10T407/00; Y10T407/27
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
156 words
A process for producing high durability ceramic tools, which comprises mixing Si 3 N 4 , MgO, and stabilized zirconia powders stabilized with Y 2 O 3 or CaO in a mixing ratio falling within the area surrounded by and including the lines drawn between the three points of A (Si 3 N 4 :98 wt %; MgO:1 wt %; ZrO 2 :1 wt %), B (Si 3 N 4 :79 wt %; MgO:20 wt %; ZrO 2 :1 wt %), and C (Si 3 N 4 :79 wt %; MgO:1 wt %, ZrO 2 :20 wt %) in triangular coordinates as shown in the FIGURE of the Drawing wherein the three coordinate axes indicate the weight percent Si 3 N 4 , MgO, and stabilized ZrO 2 , respectively, and hot-pressing the resulting mixture at about 1,600° to 1,850° C. at a pressure of not less than about 100 kg/cm 2 under a non-oxidizing atmosphere.
Claim 2
Dependent Claim
156 words
A process for producing high durability ceramic tools, which comprises mixing Si 3 N 4 , MgO, and stabilized zirconia powders stabilized with Y 2 O 3 or CaO in a mixing ratio falling within the area surrounded by and including the lines drawn between the three points of A (Si 3 N 4 :98 wt %; MgO:1 wt %; ZrO 2 :1 wt %), B (Si 3 N 4 :79 wt %; MgO:20 wt %; ZrO 2 :1 wt %), and C (Si 3 N 4 :79 wt %; MgO:1 wt %, ZrO 2 :20 wt %) in triangular coordinates as shown in the FIGURE of the Drawing wherein the three coordinate axes indicate the weight percent Si 3 N 4 , MgO, and stabilized ZrO 2 , respectively, and hot-pressing the resulting mixture at about 1,600° to 1,850° C. at a pressure of not less than about 100 kg/cm 2 under a non-oxidizing atmosphere.
Claim 3
Dependent Claim
95 words
The process of claim 1, wherein Si 3 N 4 , MgO, and stabilized ZrO 2 powders are mixed in a mixing ratio in the area surrounded by and including the lines drawn between the three points of D (Si 3 N 4 :96 wt %; MgO:2 wt %; ZrO 2 :2 wt %), E (Si 3 N 4 :80 wt %; MgO:18 wt %; ZrO 2 :2 wt %), and F (Si 3 N 4 :80 wt %; MgO:2 wt %; ZrO 2 :18 wt %) in triangular coordinates as shown in the FIGURE.
Claim 4
Dependent Claim
10 words
The ceramic tool prepared by the process of claim 1.
Claim 5
Dependent Claim
10 words
The ceramic tool prepared by the process of claim 2.
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) | 1984-12-07 | 1985-06-08 | 1985-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-07 | 1989-06-08 | 1989-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-07 | 1993-06-08 | 1993-12-08 | $7700.00 | Window Closed / Lapsed |