US5145540A
Expired / Lapsed
US
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Ceramic composition of matter and its use
Assignee: Hoechst AG
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Filing: 1990-10-23
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Granted: 1992-09-08
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Expires: 2010-10-23
Abstract
Abstract A ceramic composition of matter which is sinterable at low temperatures is composed of a) 40 to 90% by weight of a finely disperse, high-melting oxidic material and b) 10 to 60% by weight of a finely disperse glass having a softening point of 500 DEG to 850 DEG C., a coefficient of thermal expansion (=CTE) of 2 to 5x10-6 K-1 (measured in the interval from 0 DEG to 400 DEG C.) and a dielectric constant of less than 5 (measured at 106 Hz and 20 DEG C.). The finely disperse oxidic material is composed of a mixture of MgO, Al2O3 and SiO2 in an Al2O3/MgO weight ratio of 1.8-4 with an SiO2 weight fraction of 42-65% by weight or an equivalent quantity of corresponding oxide precursors which, on heating, decompose to give these oxides. The MgO or the MgO precursor has a mean grain size of 0.05 to 3 mu m and the SiO2 or the SiO2 precursor has a mean grain size of 2 to 20 mu m. The composition sinters at 900 DEG -1100 DEG C. and is suitable for producing substrates or metallized housings.
Inventors
- 👤 Paul Foley
- 👤 Rainer Buckpesch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:18
CPC Classifications
C; C03; C03C; C03C14/00; C03C14/004; H; H01; H01B; H01B3/00; H01B3/02; H01B3/08; H01B3/085; H01B3/12; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H10; H10W; H10W70/00; H10W70/60; H10W70/67; H10W70/69; H10W70/692; H10W99/00; C03C2214/00; C03C2214/04; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
170 words
A ceramic composition of matter, which is sinterable at low temperatures, comprising a) 40 to 90% by weight of a finely dispersed, high-melting oxidic material and b) 10 to 60% by weight of a finely dispersed glass having a softening point of 500° to 850° C., a coefficient of thermal expansion of 2 to 5×10 -6 K -1 measured in the interval from 0° to 400° C., and a dielectric constant of less than 5 measured at 10 6 Hz and 20° C., wherein the finely dispersed oxidic material comprises MgO, Al 2 O 3 and SiO 2 in an Al 2 O 3 /MgO weight ratio of 1.8-4 with an SiO 2 weight fraction of 42-65% by weight, or an equivalent quantity of corresponding oxide precursors which, on heating, decompose to give these oxides, and the MgO or the MgO precursor has a mean grain size of 0.05 to 3μm, and the SiO 2 or the SiO 2 precursor has a mean grain size of 2 to 20 μm.
Claim 2
Dependent Claim
170 words
A ceramic composition of matter, which is sinterable at low temperatures, comprising a) 40 to 90% by weight of a finely dispersed, high-melting oxidic material and b) 10 to 60% by weight of a finely dispersed glass having a softening point of 500° to 850° C., a coefficient of thermal expansion of 2 to 5×10 -6 K -1 measured in the interval from 0° to 400° C., and a dielectric constant of less than 5 measured at 10 6 Hz and 20° C., wherein the finely dispersed oxidic material comprises MgO, Al 2 O 3 and SiO 2 in an Al 2 O 3 /MgO weight ratio of 1.8-4 with an SiO 2 weight fraction of 42-65% by weight, or an equivalent quantity of corresponding oxide precursors which, on heating, decompose to give these oxides, and the MgO or the MgO precursor has a mean grain size of 0.05 to 3μm, and the SiO 2 or the SiO 2 precursor has a mean grain size of 2 to 20 μm.
Claim 3
Dependent Claim
17 words
A composition as claimed in claim 1, wherein the finely dispersed glass used is a borosilicate glass.
Claim 4
Dependent Claim
18 words
A composition as claimed in claim 1, wherein the finely dispersed glass used is a lithium borosilicate glass.
Claim 5
Dependent Claim
21 words
A composition as claimed in claim 1, wherein a glass is used which is free of zinc oxide and lead oxide.
Claim 6
Dependent Claim
47 words
A green ceramic sheet of 0.1 to 2 mm thickness, containing 5 to 20% by weight of organic components and 80 to 95% by weight of a finely dispersed, sinterable ceramic intermediate, wherein the ceramic intermediate is the ceramic composition of matter as claimed in claim 1.
Claim 7
Dependent Claim
57 words
A process for producing a glass-ceramic substrate, which comprises mixing the composition as claimed in claim 1 with organic auxiliaries, shaping the mixture to give a thin stratiform molding, slowly heating the green molding until the organic auxiliaries have been removed, and then sintering at a temperature from 900° to 1100° C., especially 900° to 1000° C.
Claim 8
Dependent Claim
20 words
A process according to claim 6 wherein the sintering is conducted at a temperature of from 900° to 1000° C.
Claim 9
Dependent Claim
118 words
A process for producing a multi-layer housing from glass ceramics, which comprises preparing at least 2 ceramic green sheets as claimed in claim 5, generating a stratiform geometrical structure on the surface of at least two of said green sheets with the use of a metallization paste which contains metal powder, binder and a solvent, stacking up the individual green sheets to form a sandwich structure, laminating the green sheets together, heating the laminate in order to remove the organic constituents and then further heating to a temperature of 900°-1100° C., so that the ceramic intermediate sinters together to give a glass ceramic and the metal particles of the paste sinter together to give an electrically conductive track.
Claim 10
Dependent Claim
22 words
The process as claimed in claim 8, wherein a metallization paste is used, the metal fraction of which sinters at 800°-1000° 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) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |