US4548741A
Expired / Lapsed
US
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Method for doping tin oxide
Assignee: EIDP Inc
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Filing: 1983-01-24
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Granted: 1985-10-22
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Expires: 2003-01-24
Abstract
Abstract The invention is directed primarily to a method of doping tin oxide with Ta 2 O 5 and/or Nb 2 O 5 using pyrochlore-related compounds derived from the system SnO-SnO 2 -Ta 2 O 5 -Nb 2 O 5 for use in thick film resistor compositions. The invention is also directed to thick film resistors containing the above-described pyrochlore-related compounds and to various compositions and methods for making such thick film resistors.
Inventors
- 👤 Jacob Hormadaly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:32
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/06; H01C; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/06533; H01C7/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
119 words
The method of making a conductive phase for resistors containing a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, which comprises firing in a nonoxidizing atmosphere an admixture of finely divided particles of SnO, SnO 2 and metal pentoxide selected from the group consisting of Ta 2 O 5 , Nb 2 O 5 and mixtures thereof, at a temperature of at least 900° C., the mole ratio of SnO to metal pentoxide being 1.4-3.0, the SnO 2 being in stoichiometric excess of the SnO and metal pentoxide and comprising 20-95% by weight of the total oxides.
Claim 2
Independent Claim
119 words
The method of making a conductive phase for resistors containing a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, which comprises firing in a nonoxidizing atmosphere an admixture of finely divided particles of SnO, SnO 2 and metal pentoxide selected from the group consisting of Ta 2 O 5 , Nb 2 O 5 and mixtures thereof, at a temperature of at least 900° C., the mole ratio of SnO to metal pentoxide being 1.4-3.0, the SnO 2 being in stoichiometric excess of the SnO and metal pentoxide and comprising 20-95% by weight of the total oxides.
Claim 3
Dependent Claim
46 words
A screen-printable thick film resistor composition comprising a dispersion in organic medium of finely divided particles of an admixture of conductive phase made by the method of claim 1 and inorganic binder, the inorganic binder being 5-45% by weight of the solids content of the dispersion.
Claim 4
Dependent Claim
123 words
The screen-printable composition of claim 2 in which the inorganic binder is a Bi-, Cd- and Pb-free frit comprising by mole % 10-50% SiO 2 , 20-60% B 2 O 3 , 10-35% BaO, 0-20% CaO, 0-15% MgO, 0-15% NiO, 0-15% Al 2 O 3 , 0-5% SnO 2 , 0-7% ZrO 2 and 0-5% of a metal fluoride in which the metal is selected from the group consisting of alkali metals, alkaline earth metals and nickel, the mole ratio ##EQU5## is 0.8-4, the total of BaO, CaO, MgO, NiO and CaF 2 is 15-50 mole % and the total of Al 2 O 3 , B 2 O 3 , SiO 2 , SnO 2 and ZrO 2 is 50-85 mole %.
Claim 5
Dependent Claim
40 words
The screen-printable composition of claim 3 which contains 0-5% by weight basis binder solids of finely divided particles of a metal fluoride in which the metal is selected from the group consisting of alkali metals, alkaline earth metals and nickel.
Claim 6
Dependent Claim
48 words
A resistor comprising a patterned thin layer of the dispersion of any of the compositions of claims 2 and 4 or mixtures thereof which has been dried and fired in a nonoxidizing atmosphere to effect volatilization of the organic medium and liquid phase sintering of the inorganic binder.
Claim 7
Dependent Claim
97 words
The method of making a resistor element comprising the sequential steps of: (a) forming a dispersion in organic medium of finely divided particles of conductive phase made by the method of claim 1 and inorganic binder, the inorganic binder being 5-45% by weight of the solids content of the dispersion; (b) forming a patterned thin layer of the dispersion of step (a); (c) drying the layer of step (b); and (d) firing the dried layer of step (c) in a nonoxidizing atmosphere to effect volatilization of the organic medium and liquid phase sintering of the inorganic binder.
Claim 8
Dependent Claim
30 words
The method of claim 6 in which the dispersion also contains finely divided particles of SnO 2 in an amount 10-90% by weight basis conductive phase and SnO 2 .
Claim 9
Dependent Claim
61 words
A composition for the preparation of a conductive phase comprising an admixture of finely divided particles of (a) 5-95% by weight of a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, and (b) 95-5% by weight SnO 2 .
Claim 10
Dependent Claim
61 words
A composition for the preparation of a conductive phase comprising an admixture of finely divided particles of (a) 5-95% by weight of a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, and (b) 95-5% by weight SnO 2 .
Claim 11
Dependent Claim
106 words
A composition for the preparation of a conductive phase containing a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, comprising an admixture of finely divided particles of SnO, SnO 2 and a metal pentoxide selected from the group consisting of Ta 2 O 5 , Nb 2 O 5 and mixtures thereof. The mole ratio of SnO to metal pentoxide being 1.4-3.0, the SnO 2 being in stoichiometric excess of the SnO and metal pentoxide and comprising 5-95% by weight of the total oxides.
Claim 12
Dependent Claim
106 words
A composition for the preparation of a conductive phase containing a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, comprising an admixture of finely divided particles of SnO, SnO 2 and a metal pentoxide selected from the group consisting of Ta 2 O 5 , Nb 2 O 5 and mixtures thereof. The mole ratio of SnO to metal pentoxide being 1.4-3.0, the SnO 2 being in stoichiometric excess of the SnO and metal pentoxide and comprising 5-95% by weight of the total oxides.
Claim 13
Dependent Claim
34 words
A conductive phase for the preparation of thick film resistors comprising finely divided particles of the composition of claim 9 which have been fired in a nonoxidizing atmosphere at a temperature of 500°-1100° C.
Claim 14
Independent Claim
69 words
The method of making a conductive phase for resistors which comprises firing in a nonoxidizing atmosphere an admixture of finely divided particles of SnO 2 and a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, the amount of SnO 2 being 20-95% by weight of the admixture.
Claim 15
Independent Claim
69 words
The method of making a conductive phase for resistors which comprises firing in a nonoxidizing atmosphere an admixture of finely divided particles of SnO 2 and a pyrochlore-related compound corresponding to the formula Sn.sub.2-x.sup.2+ Ta.sub.y.sbsb.3 Nb.sub.y.sbsb.2 Sn.sub.y.sbsb.1.sup.4+ O.sub.7-x-y.sbsb.1.sub./2 wherein x=0-0.55 y 3 =0-2 y 2 =0-2 y 1 =0-0.5 and y 1 +y 2 +y 3 =2, the amount of SnO 2 being 20-95% by weight of the admixture.
Claim 16
Dependent Claim
34 words
A conductive phase for the preparation of thick film resistors comprising finely divided particles of the composition of claim 8 which have been fired in a nonoxidizing atmosphere at a temperature of 500°-1100° C.
Claim 17
Dependent Claim
46 words
A screen-printable thick film resistor composition comprising a dispersion in organic medium of finely divided particles of an admixture of conductive phase made by the method of claim 11 and inorganic binder, the inorganic binder being 5-45% by weight of the solids content of the dispersion.
Claim 18
Dependent Claim
123 words
The screen-printable composition of claim 13 in which the inorganic binder is a Bi-, Cd- and Pb-free frit comprising by mole % 10-50% SiO 2 , 20-60% B 2 O 3 , 10-35% BaO, 0-20% CaO, 0-15% MgO, 0-15% NiO, 0-15% Al 2 O 3 , 0-5% SnO 2 , 0-7% ZrO 2 and 0-5% of a metal fluoride in which the metal is selected from the group consisting of alkali metals, alkaline earth metals and nickel, the mole ratio ##EQU6## is 0.8-4, the total of BaO, CaO, MgO, NiO and CaF 2 is 15-50 mole % and the total of Al 2 O 3 , B 2 O 3 ; SiO 2 , SnO 2 and ZrO 2 is 50-85 mole %.
Claim 19
Dependent Claim
40 words
The screen-printable composition of claim 14 which contains 0-5% by weight basis binder solids of finely divided particles of a metal fluoride in which the metal is selected from the group consisting of alkali metals, alkaline earth metals and nickel.
Claim 20
Dependent Claim
97 words
The method of making a resistor element comprising the sequential steps of: (a) forming a dispersion in organic medium of finely divided particles of conductive phase made by the method of claim 3 and inorganic binder, the inorganic binder being 5-45% by weight of the solids content of the dispersion; (b) forming a patterned thin layer of the dispersion of step (a); (c) drying the layer of step (b); and (d) firing the dried layer of step (c) in a nonoxidizing atmosphere to effect volatilization of the organic medium and liquid phase sintering of the inorganic binder.
Claim 21
Dependent Claim
30 words
The method of claim 16 in which the dispersion also contains finely divided particles of SnO 2 in an amount 10-90% by weight basis conductive phase and SnO 2 .
Claim 22
Dependent Claim
46 words
A resistor comprising a patterned thin layer of the dispersion of the compositions of claims 14 or 15 or mixtures thereof which has been dried and fired in a nonoxidizing atmosphere to effect volatilization of the organic medium and liquid phase sintering of the inorganic binder.
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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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |