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US4840926A
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High frequency wave absorbing ceramics
Assignee: Denso Corp
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Filing: 1987-11-25
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Granted: 1989-06-20
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Expires: 2007-11-25
Abstract
Abstract A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 55 to 85 mol % of lead iron niobate Pb(Fe1/2Nb1/2)O3, from 10 to 40 mol % of lead iron tungstate Pb(Fe2/3W1/3)O3 and not more than 20 mol % of lead nickel tantalate Pb(Ni1/3Ta2/3)O3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe1/2Nb1/2)O3, lead iron tungstate Pb(Fe2/3W1/3)O3 and lead nickel tantalate Pb(Ni1/3Ta2/3)O3.
Inventors
- 👤 Toshiki Saburi
- 👤 Nobuyuki Ohya
- 👤 Toru Yamazaki
- 👤 Taisei Katoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/495; C04B35/497
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
89 words
A high frequency wave absorbing ceramics of a ternary composition comprising lead iron niobate Pb(Fe 1/2 Nb 1/2 )O 3 , lead iron tungstate Pb(Fe 2/3 W 1/3 )O 3 and lead nickel tantalate Pb(Ni 1/3 Ta 2/3 )O 3 , the composition ratio in the ternary composition lying in the inside (including the boundary) of a quadrangle A--B--C--D in the ternary phase diagram shown in FIG. 1, and the high frequency wave absorbing ceramics having a dielectric constant of 13,000 or more at a frequency of 1 MHz.
Claim 2
Dependent Claim
89 words
A high frequency wave absorbing ceramics of a ternary composition comprising lead iron niobate Pb(Fe 1/2 Nb 1/2 )O 3 , lead iron tungstate Pb(Fe 2/3 W 1/3 )O 3 and lead nickel tantalate Pb(Ni 1/3 Ta 2/3 )O 3 , the composition ratio in the ternary composition lying in the inside (including the boundary) of a quadrangle A--B--C--D in the ternary phase diagram shown in FIG. 1, and the high frequency wave absorbing ceramics having a dielectric constant of 13,000 or more at a frequency of 1 MHz.
Claim 3
Dependent Claim
51 words
The high frequency wave absorbing ceramics according to claim 1, wherein the ternary composition is expressed as (1-x)(1-y)Pb(Fe 1/2 Nb 1/2 )O 3 (1-x)yPb(Fe 2/3 W 1/3 )O 3 xPb(Ni 1/3 Ta 2/3 )O 3 in which y is from 0.19 to 0.34 when x is 0.05 in the above equation.
Claim 4
Dependent Claim
83 words
The high frequency wave absorbing ceramics according to claim 1, wherein the ternary composition is expressed as (1-x)(1-y)Pb(Fe 1/2 Nb 1/2 )O 3 (1-x)yPb(Fe 2/3 W 1/3 )O 3 xPb(Ni 1/3 Ta 2/3 )O 3 in which the third ingredient composition molar ratio x (hereinafter in claims referred to as x) for the ternary system is from 0.025 to 0.15 when the composition molar ratio y (hereinafter in claims referred to as y) for the binary system is 0.25 in the above equation.
Claim 5
Dependent Claim
51 words
The high frequency wave absorbing ceramics according to claim 3, wherein the ternary composition is expressed as (1-x)(1-y)Pb(Fe 1/2 Nb 1/2 )O 3 (1-x)yPb(Fe 2/3 W 1/3 )O 3 xPb(Ni 1/3 Ta 2/3 )O 3 in which x is from 0.025 to 0.13 when y is 0.25 in the above equation.
Claim 6
Dependent Claim
54 words
The high frequency wave absorbing ceramics according to claim 1, wherein the ternary composition is expressed as (1-x)(1-y)Pb(Fe 1/2 Nb 1/2 )O 3 (1-x)yPb(Fe 2/3 W 1/3 )O 3 xPb(Ni 1/3 Ta 2/3 )O 3 in which y is from 0.2 to 0.31 when x is from 0.025 to 0.05 in the above equation.
Claim 7
Dependent Claim
92 words
A high frequency wave absorbing ceramics of a ternary composition consisting essentially of lead iron niobate Pb(Fe 1/2 Nb 1/2 )O 3 , lead iron tungstate Pb(Fe 2/3 W 1/3 )O 3 , and lead nickel tantalate Pb(Ni 1/3 Ta 2/3 )O 3 , the composition ratio in the ternary composition lying in the inside (including the boundary) of a quandrangle A--B--C--D in the ternary phase diagram shown in FIG. 1, and the high frequency wave absorbing ceramics having a dielectric constant of 13,000 or more at a frequency of 1 MHz.
Claim 8
Dependent Claim
92 words
A high frequency wave absorbing ceramics of a ternary composition consisting essentially of lead iron niobate Pb(Fe 1/2 Nb 1/2 )O 3 , lead iron tungstate Pb(Fe 2/3 W 1/3 )O 3 , and lead nickel tantalate Pb(Ni 1/3 Ta 2/3 )O 3 , the composition ratio in the ternary composition lying in the inside (including the boundary) of a quandrangle A--B--C--D in the ternary phase diagram shown in FIG. 1, and the high frequency wave absorbing ceramics having a dielectric constant of 13,000 or more at a frequency of 1 MHz.
Claim 9
Dependent Claim
156 words
The high frequency wave absorbing ceramics according to claim 1, which is prepared by mixing: a powder of lead iron niobate Pb(Fe 1/2 Nb 1/2 )O 3 comprising 4 mol of lead oxide powder (PbO), 1 mol of iron oxide powder (Fe 2 O 3 ) and 1 mol of niobium oxide (Nb 2 O 5 ), a powder of lead iron tungstate Pb(Fe 2/3 W 1/3 )O 3 comprising 3 mol of lead oxide powder (PbO), 1 mol of iron oxide powder (Fe 2 O 3 ) and 1 mol of tungsten oxide powder (WO 3 ) and a powder of lead nickel tantalate Pb(Ni 1/3 Ta 2/3 )O 3 comprising 4 mol of lead oxide powder (PbO), 1 mol of tantalum oxide powder (Ta 2 O 5 ) and 1 mol of nickel oxide powder (NiO), molding the mixture and then sintering the molded mixture at a temperature of from 1,000° to 1,500° C.
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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) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |