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US4528121A Expired / Lapsed US ⏱️ 0.0 years remaining

Electroconductive ceramics

Assignee: Hitachi Ltd
•
Filing: 1983-10-27
•
Granted: 1985-07-09
•
Expires: 2003-10-27
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Abstract

Abstract Electroconductive ceramic materials with high density, high mechanical strength, high endurance to repeated current supply and excellent thermal shock resistance can be obtained by mixing 5 to 70 parts by weight of Al 2 O 3 or alumina ceramic materials containing 95% by weight or more of Al 2 O 3 and 30 to 95 parts by weight of at least one electroconductive material selected from of ZrB 2 , ZrC, ZrN, ZrSi 2 , TaB 2 , TaC, TaN, TaSi 2 , TiB 2 , TiC, TiN, Mo 2 B 5 and MoSi 2 adding a molding binder, molding the mixture and sintering the molded mixture. The electroconductive ceramic is usable for heaters, glow plug heaters, electrical gas ignitors, kerosine gasifying burners, and electrodes or conductors for water processing or dialysis.

Inventors

  • 👤 Yasuo Matsushita
  • 👤 Kousuke Nakamura
  • 👤 Tetuo Kosugi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 02:27
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/01; C04B35/10; C04B35/111; C04B35/56; C04B35/5607; C04B35/5611; C04B35/5622; C04B35/58007; C04B35/58014; C04B35/58028; C04B35/5805; C04B35/58064; C04B35/58071; C04B35/622; C04B35/64; C04B35/645; F; F23; F23Q; F23Q7/00; F23Q7/22; H; H01; H01B; H01B1/00; H01B1/14; H01C; H01C7/00; H01C7/02; H01C7/022; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/141

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 85 words
An electroconductive sintered ceramic which comprises 5 to 70 parts by weight of (a) alumina or an aluminous ceramic containing at least 95% by weight of Al 2 O 3 , and 30 to 95 parts by weight of (b) an inorganic compound which exhibits a positive resistance-temperature coefficient and which is selected from the group consisting of ZrB 2 , ZrC, ZrN, ZrSi 2 , TaB, TaC, TaN, TaSi 2 , TiB 2 , TiC, TiN, Mo 2 B 5 and MoSi 2 .
Claim 2
Dependent Claim 85 words
An electroconductive sintered ceramic which comprises 5 to 70 parts by weight of (a) alumina or an aluminous ceramic containing at least 95% by weight of Al 2 O 3 , and 30 to 95 parts by weight of (b) an inorganic compound which exhibits a positive resistance-temperature coefficient and which is selected from the group consisting of ZrB 2 , ZrC, ZrN, ZrSi 2 , TaB, TaC, TaN, TaSi 2 , TiB 2 , TiC, TiN, Mo 2 B 5 and MoSi 2 .
Claim 3
Dependent Claim 27 words
The electroconductive sintered ceramic according to claim 1, which has an electrical resistivity of not more than 1 Ωcm at room temperature and a positive resistance-temperature coefficient.
Claim 4
Dependent Claim 37 words
The electroconductive sintered ceramic according to claim 1, which further comprises as a sintering aid at least one substance selected from the group consisting of MgO, SiO 2 , CaO, Li 2 O and TiO 2 .
Claim 5
Dependent Claim 16 words
The electroconductive sintered ceramic according to claim 3, further comprising as a particle growth regulator MgO.
Claim 6
Dependent Claim 41 words
The electroconductive sintered ceramic according to claim 4, wherein the total amount of the sintering aid and the particle growth regulator does not exceed 5% by weight based on the amount of the Al 2 O 3 within said sintered ceramic.

References Cited (Backward Citations)

US3895219A Cited
US3875746A Cited
US4008183A Cited
US4006106A Cited
US3968057A Cited
US4443361A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-07-08 1989-01-07 1989-07-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-07-08 1993-01-07 1993-07-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-07-08 1997-01-07 1997-07-09 $7700.00 Window Closed / Lapsed

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