Patent US3637532A successfully refreshed from Google Patents.
US3637532A
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Sintered cold-conductor resistor body and method for its production
Assignee: Siemens AG
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Filing: 1969-08-01
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Granted: 1972-01-25
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Expires: 1989-08-01
Abstract
Abstract Positive temperature coefficient resistor materials composed of doped ferroelectric substances such as barium titanate, the materials including at least two discrete crystalline phases, one composed of a material having a Curie temperature above and the other composed of a material having a Curie temperature below the Curie temperature of the composite, the composite having a substantially improved load quotient.
Inventors
- 👤 Emil Ramisch
- 👤 Werner Schwan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:51
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; H01C7/023; H01C7/025; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; H01B; H01B1/00; H01B1/06; H01B1/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
260 words
An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered n-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula MeIIMeIVO3 wherein MeII is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and MeIV is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, said body having n-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature of at least 120* C., and the other phase consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature which differs from that of the first phase by at least 20* C., at least one of said phases being a substituted barium titanate, the substituted barium titanate containing from 2 to 48 mol percent of an element selected from the group consisting of calcium and strontium in substitution for the corresponding amount of barium.
Claim 2
Dependent Claim
260 words
An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered n-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula MeIIMeIVO3 wherein MeII is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and MeIV is at least one tetravalent metal selected from the group consisting of titanium tin and zirconium, said body having n-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the grOup consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature of at least 120* C., and the other phase consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature which differs from that of the first phase by at least 20* C., at least one of said phases being a substituted barium titanate, the substituted barium titanate containing from 1 to 15 mol percent of a metal selected from the group consisting of tin and zirconium in substitution for the corresponding amount of titanium.
Claim 3
Dependent Claim
288 words
An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered n-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula MeIIMeIVO3 wherein MeII is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and MeIV is at least one tetravalent selected from the group consisting of titanium, tin and zirconium, said body having n-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature of at least 120* C., and the other phase consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature which differs from that of the first phase by at least 20* C., at least one of said phases being a substituted barium titanate, the substituted barium titanate containing from 2 to 48 mol percent of an element selected from the group consisting of calcium and strontium in substitution for the corresponding amount of barium and also containing from 1 to 15 mol percent of a metal selected from the group consisting of tin and zirconium in substitution for the corresponding amount of titanium.
Claim 4
Dependent Claim
249 words
An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered n-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula MeIIMeIVO3 wherein MeII is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and MeIV is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, said body having n-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature of at least 120* C., and the other phase consisting of a barium titanate lattice containing one of said dopants and having a Curie temperature which differs fRom that of the first phase by at least 20* C., at least one of said phases being a substituted barium titanate, the substituted barium titanate containing from 1 to 30 mol percent lead in substitution for the corresponding amount of barium.
Claim 5
Dependent Claim
92 words
The resistor of claim 1 wherein both of said phases are substituted barium titanate, one of which contains from 1 to 30 mol percent lead in substitution for the corresponding amount of barium, and the other of which contains from 2 to 48 mol percent of an element selected from the group consisting of calcium and strontium in substitution for the corresponding amount of barium, and from 1 to 15 mol percent of a metal selected from the group consisting of tin and zirconium in substitution for the corresponding amount of lead.
Claim 6
Dependent Claim
53 words
The resistor of claim 2 in which one phase has the formula BaO.1.01(TiO2) containing 0.086 mol percent Sb2O3 as a dopant and having a Curie temperature of 120* C. and the other phase has the formula (BaO.855SrO.145).(Ti0.977SnO.035)O3 containing 0.124 mol percent Sb2O3 as a dopant and has a Curie temperature of 40* C.
Claim 7
Dependent Claim
59 words
The resistor of claim 5 in which one phase has the formula BaO.1.01(TiO2) containing 0.086 mol percent Sb2O3 as a dopant and has a Curie temperature of 120* C. and the other phase consists of doped substituted barium titanate having the formula (BaO.843PbO.157)O.1.015(TiO2) containing 0.086 mol percent Sb2O3 as a dopant and has a Curie temperature of 180* C.
Claim 8
Dependent Claim
65 words
The resistor of claim 6 in which one phase is a doped substituted barium titanate having the formula (BaO.855SrO.145).(TiO.977SnO.035)O3 containing 0.124 mol percent Sb2O3 as a dopant and having a Curie temperature of 40* C. and the other phase is a doped substituted barium titanate having the formula (BaO.843PbO.157)O.1.015(TiO2) containing 0.086 mol percent Sb2O3 as a dopant and having a Curie temperature of 180* C.
Claim 9
Independent Claim
204 words
A method for producing an electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm cm. and below, and having a load quotient on the order of 20 to 30 percent, which comprises first forming a plurality of compositions each having the empirical formula MeIIMeIVO3 wherein MeII is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead, and MeIV is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, each composition having n-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten, and rare earth metals, the Curie temperatures of said compositions differing by at least 20* C., heating each of said compositions individually at temperatures up to 1,100* C. to produce a perowskite structure in each, mixing the resulting compositions in substantially equal amounts by weight, shaping the resulting mixture, and sintering the resulting shaped mixture for about 1 hour at a temperature between 1,300* and 1,380* C.
Claim 10
Dependent Claim
24 words
The method of claim 10 in which said mixing takes place in a liquid medium which is inert toward the ingredients of the mixture.
Claim 11
Dependent Claim
16 words
The method of claim 10 in which said mixing takes place in the dry state. >
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |