US4519942A
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US
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Semiconductive ceramic compositions with a nonlinear volt-ampere characteristic, and process for preparing coherent bodies of such compositions
Assignee: Taiyo Yuden Co Ltd
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Filing: 1981-07-06
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Granted: 1985-05-28
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Expires: 2001-07-06
Abstract
Abstract Ceramic materials suitable for use in varistors, enabling the same to function both as such and as capacitors. The ceramic compositions comprise a major proportion of SrTiO 3 , the balance being (1) one or more of Nb 2 O 5 , Ta 2 O 5 , WO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 6 O 11 , Dy 2 O 3 , Y 2 O 3 , and Sm 2 O 3 , for making the compositions semiconductive, and (2) one or more of V 2 O 5 , Cr 2 O 3 , CuO, Cu 2 O, MoO 3 , and MnO 2 , for improving the nonlinear volt-ampere characteristic of the compositions. If desired, for improving the coherency of bodies molded from the compositions, there can be added one or more of GeO 2 , ZnO, B 2 O 3 , and PbO. For use as varistors the mixture of the above ingredients, all in finely divided form and made coherent with a binder, is molded into desired shape under pressure. The moldings are first fired in a nonoxidative atmosphere and then further heated in an oxidative atmosphere. Electrodes can be formed as by silver painting.
Inventors
- 👤 Nobutatsu Yamaoka
- 👤 Akira Tsukada
- 👤 Kazuo Sasazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:25
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/47; H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/115
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
149 words
A semiconductive ceramic composition with a nonlinear volt-ampere characteristic, particularly well suited for varistors, consisting essentially of: (a) from about 90.000 to about 99.989% SrTiO 3 ; (b) from about 0.001 to about 5.000% of at least one metal oxide, for making the composition semiconductive, selected from the group consisting of Nb 2 O 5 , Ta 2 O 5 , WO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 6 O 11 , Dy 2 O 3 , Y 2 O 3 , and Sm 2 O 3 ; and (c) from about 0.010 to about 5.000% of at least one other metal oxide, for improving the nonlinear volt-ampere characteristic of the composition, selected from the group consisting of V 2 O 5 , Cr 2 O 3 , CuO, Cu 2 O, MoO 3 , and MnO 2 .
Claim 2
Dependent Claim
149 words
A semiconductive ceramic composition with a nonlinear volt-ampere characteristic, particularly well suited for varistors, consisting essentially of: (a) from about 90.000 to about 99.989% SrTiO 3 ; (b) from about 0.001 to about 5.000% of at least one metal oxide, for making the composition semiconductive, selected from the group consisting of Nb 2 O 5 , Ta 2 O 5 , WO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 6 O 11 , Dy 2 O 3 , Y 2 O 3 , and Sm 2 O 3 ; and (c) from about 0.010 to about 5.000% of at least one other metal oxide, for improving the nonlinear volt-ampere characteristic of the composition, selected from the group consisting of V 2 O 5 , Cr 2 O 3 , CuO, Cu 2 O, MoO 3 , and MnO 2 .
Claim 3
Dependent Claim
191 words
A semiconductive ceramic composition with a nonlinear volt-ampere characteristic, particularly well suited for varistors, consisting essentially of: (a) from about 86.000 to about 99.979% SrTiO 3 ; (b) from about 0.001 to about 5.000% of at least one metal oxide, for making the composition semiconductive, selected from the group consisting of Nb 2 O 5 , Ta 2 O 5 , WO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 6 O 11 , Dy 2 O 3 , Y 2 O 3 , and Sm 2 O 3 ; (c) from about 0.010 to about 5.000% of at least one other metal oxide, for improving the nonlinear volt-ampere characteristic of the composition, selected from the group consisting of V 2 O 5 , Cr 2 O 3 , CuO, Cu 2 O, MoO 3 , and MnO 2 ; and (d) from about 0.010 to about 4.000% of at least one still other metal oxide, for improving the coherency of bodies molded from the composition, selected from the group consisting of GeO 2 , ZnO, B 2 O 3 , and PbO.
Claim 4
Dependent Claim
191 words
A semiconductive ceramic composition with a nonlinear volt-ampere characteristic, particularly well suited for varistors, consisting essentially of: (a) from about 86.000 to about 99.979% SrTiO 3 ; (b) from about 0.001 to about 5.000% of at least one metal oxide, for making the composition semiconductive, selected from the group consisting of Nb 2 O 5 , Ta 2 O 5 , WO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 6 O 11 , Dy 2 O 3 , Y 2 O 3 , and Sm 2 O 3 ; (c) from about 0.010 to about 5.000% of at least one other metal oxide, for improving the nonlinear volt-ampere characteristic of the composition, selected from the group consisting of V 2 O 5 , Cr 2 O 3 , CuO, Cu 2 O, MoO 3 , and MnO 2 ; and (d) from about 0.010 to about 4.000% of at least one still other metal oxide, for improving the coherency of bodies molded from the composition, selected from the group consisting of GeO 2 , ZnO, B 2 O 3 , and PbO.
References Cited (Backward Citations)
US3933668A
Cited
US4191665A
Cited
US4292209A
Cited
US4283753A
Cited
US4362637A
Cited
US4347167A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |