US4516105A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal oxide varistor with non-diffusable electrodes
Assignee: Toshiba Corp
•
Filing: 1982-07-06
•
Granted: 1985-05-07
•
Expires: 2002-07-06
Abstract
Abstract Disclosed is a metal oxide varistor which comprises; a sintered body containing (a) ZnO as a principal component, and (b), as auxiliary components, Bi, Co and Mn in amounts of 0.05˜2 mole %, 0.05˜2 mole % and 0.05˜2 mole %, when calculated in terms of Bi 2 O 3 , Co 2 O 3 and MnO 2 , respectively, and at least one selected from Al, In and Ga in amounts of 1×10 -4 ˜3×10 -2 mole %, when calculated in terms of Al 2 O 3 , In 2 O 3 and Ga 2 O 3 , respectively; said sintered material having been reheated at a temperature of 650°˜900° C. after sintering; and a non-diffusible electrode provided on said sintered body. The metal oxide varistor has excellent pulse response and volt-ampere non-linearity even with respect to a pulse having a short rise time of less than a microsecond.
Inventors
- 👤 Motomasa Imai
- 👤 Takashi Takahashi
- 👤 Osamu Furukawa
- 👤 Hideyuki Kanai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:22
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
130 words
A metal oxide varistor which comprises (1) a sintered body containing (a) ZnO as a principal component, (b) Bi, Co and Mn each in amounts of about 0.05 to about 2 mole %, when calculated in terms of Bi 2 O 3 , Co 2 O 3 and MnO 2 , respectively, and (c) at least one selected from Al, In and Ga in amounts of about 1×10 -4 to about 3×10 -2 mole %, when calculated in terms of Al 2 O 3 , In 2 O 3 and Ga 2 O 3 , respectively, said sintered body having been reheated at a temperature of about 700° to about 900° C. after sintering; and (2) a non-diffusible electrode provided on said sintered body after reheating of said sintered body.
Claim 2
Dependent Claim
130 words
A metal oxide varistor which comprises (1) a sintered body containing (a) ZnO as a principal component, (b) Bi, Co and Mn each in amounts of about 0.05 to about 2 mole %, when calculated in terms of Bi 2 O 3 , Co 2 O 3 and MnO 2 , respectively, and (c) at least one selected from Al, In and Ga in amounts of about 1×10 -4 to about 3×10 -2 mole %, when calculated in terms of Al 2 O 3 , In 2 O 3 and Ga 2 O 3 , respectively, said sintered body having been reheated at a temperature of about 700° to about 900° C. after sintering; and (2) a non-diffusible electrode provided on said sintered body after reheating of said sintered body.
Claim 3
Dependent Claim
66 words
The metal oxide varistor according to claim 1, wherein said sintered body further comprises at least one selected from the group consisting of Sb, Mg and Ni in amounts of about 0.1 to about 3 mole %, about 0.1 to about 15 mole % and about 0.05 to about 2 mole % when calculated in terms of Sb 2 O 3 , MgO and NiO, respectively.
Claim 4
Dependent Claim
24 words
The metal oxide varistor according to claim 1, wherein said sintered body is reheated at a temperature of about 700° to about 870° C.
Claim 5
Dependent Claim
35 words
The metal oxide varistor according to claim 1, wherein said non-diffusible electrode is a paste electrode baked at a temperature such that the diffusion of frit components therein into said sintered body does not occur.
Claim 6
Dependent Claim
18 words
The metal oxide varistor according to claim 1, wherein said non-diffusible electrode is an Al flame-spray coated electrode.
Claim 7
Dependent Claim
17 words
The metal oxide varistor according to claim 1, wherein said non-diffusible electrode is an Al vapor-deposited electrode.
Claim 8
Dependent Claim
17 words
The metal oxide varistor according to claim 1, wherein said non-diffusible electrode is an Al sputtered electrode.
Claim 9
Dependent Claim
17 words
The metal oxide varistor according to claim 1, wherein said non-diffusible electrode is a Ni electroless-plated electrode.
Claim 10
Independent Claim
136 words
A method for forming a metal oxide varistor, comprising the steps of: (a) preparing a sintered body containing (a) ZnO as a principal component, (b) Bi, Co and Mn each in amounts of about 0.05 to about 2 mole %, when calculated in terms of Bi 2 O 3 , C 2 O 3 and MnO 2 , respectively, and (c) at least one selected from Al, In and Ga in amounts of about 1×10 -4 to about 3×10 -2 mole %, when calculated in terms of Al 2 O 3 , In 2 O 3 and Ga 2 O 3 , respectively; (b) after step (a), reheating said sintered body only once at a temperature of about 700° to about 900° C., and (c) after said reheating, providing on said sintered body a non-diffusible electrode.
Claim 11
Independent Claim
136 words
A method for forming a metal oxide varistor, comprising the steps of: (a) preparing a sintered body containing (a) ZnO as a principal component, (b) Bi, Co and Mn each in amounts of about 0.05 to about 2 mole %, when calculated in terms of Bi 2 O 3 , C 2 O 3 and MnO 2 , respectively, and (c) at least one selected from Al, In and Ga in amounts of about 1×10 -4 to about 3×10 -2 mole %, when calculated in terms of Al 2 O 3 , In 2 O 3 and Ga 2 O 3 , respectively; (b) after step (a), reheating said sintered body only once at a temperature of about 700° to about 900° C., and (c) after said reheating, providing on said sintered body a non-diffusible electrode.
Claim 12
Dependent Claim
45 words
A method according to claim 9, wherein said non-diffusible electrode is provided on said sintered body by one selected from the group consisting of baking at a temperature such that diffusion of frit components into said sintered body does not occur, flame-spraying, sputtering, and electroless-plating.
References Cited (Backward Citations)
US2791521A
Cited
US3611073A
Cited
US3670216A
Cited
US3863193A
Cited
US3899451A
Cited
US3999159A
Cited
JPS5150203A
Cited
JPS5150202A
Cited
US4045374A
Cited
US4165351A
Cited
US4042535A
Cited
JPS5261787A
Cited
US4046847A
Cited
US4243622A
Cited
JPS5622123A
Cited
EP0029749A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-06 | 1988-11-05 | 1989-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-06 | 1992-11-05 | 1993-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-06 | 1996-11-05 | 1997-05-07 | $7700.00 | Window Closed / Lapsed |