US3637531A
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Method for making ceramic titanate elements and materials therefor
Assignee: Texas Instruments Inc
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Filing: 1970-05-01
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Granted: 1972-01-25
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Expires: 1990-05-01
Abstract
Abstract A method for making ceramic titanate elements and materials therefor, particularly semiconducting lanthanide-doped barium titanate elements having positive temperature coefficients of resistance for use as solid-state sensors or the like, is shown to comprise the steps of dissolving the titanium chelate of triethanolamine with selected alkaline earth salts such as barium acetate and with selected lanthanide salts such as lanthanum acetate in a solvent to form a common solution. Alternatively, tetraisopropyl titanate mixed with lactic acid is combined with selected alkaline earth salts such as barium acetate and with selected lanthanide salts such as lanthanum acetate in a solvent to form a common solution. The solution is then heated, initially to form a semisolid material and thereafter-in an oxidizing or neutral atmosphere-to calcine the semisolid material to form the desired titanate material. The resulting titanate material is then combined with a binder, is pressed into a desired shape, and is fired at high temperature to form the desired ceramic titanate elements.
Inventors
- 👤 Robert C Faxon
- 👤 Robert T Mcgovern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:53
CPC Classifications
C; C01; C01G; C01G23/00; C01G23/003; C01G23/006; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C01P; C01P2002/00; C01P2002/30; C01P2002/34
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
71 words
A method for making a ceramic-forming titanate material comprising the steps of combining an organic titanium compound selected from the group consisting of tetraisopropyl titanate dissolved in an organic acid and titanium chelate of triethanolamine with at least one alkaline earth salt in at least one solvent to form a common solution, heating said common solution to form a semisolid substance, and calcining said substance to form said ceramic-forming titanate material.
Claim 2
Independent Claim
41 words
A method for making a titanate material comprising the steps of dissolving titanium chelate of triethanolamine and at least one alkaline earth salt in at least one solvent to form a gel, and heating said gel to form said titanate material.
Claim 3
Independent Claim
51 words
A method for making a ceramic-forming titanate material comprising the steps of dissolving titanium chelate of triethanolamine and at least one alkaline earth salt in at least one solvent to form a common solution, heating said solution to form a gel, and calcining said gel to form said ceramic-forming titanate material.
Claim 4
Dependent Claim
54 words
A method as set forth in claim 4 wherein said solution is heated at a temperature up to about 80* C. to form said gel, and wherein said gel is heated at a temperature between 600* C. and 1,150* C. for at least 1 hour for calcining said gel to form said titanate material.
Claim 5
Dependent Claim
16 words
A method as set forth in claim 4 wherein said alkaline earth salt comprises barium acetate.
Claim 6
Independent Claim
65 words
A method for making a titanate material for use in forming semiconducting ceramic elements comprising the steps of dissolving titanium chelate of triethanolamine, at least one alkaline earth salt, and at least one lanthanide salt in at least one solvent to form a common solution, heating said solution to form a gel, and heating said gel in an oxidizing atmosphere to form said titanate material.
Claim 7
Independent Claim
90 words
A method for making a barium lanthanum titanate material of perovskite structure having a curie point of approximately 125* C. for use in forming semiconducting ceramic elements comprising the steps of dissolving titanium chelate of triethanolamine, barium acetate, and lanthanum acetate in at least one solvent to form a common solution, heating said solution at a temperature up to about 80* C. to form a gel, and heating said gel in an oxidizing atmosphere at a temperature between 600* C. and 1,150* C. to form said barium lanthanum titanate material.
Claim 8
Dependent Claim
65 words
A method for making semiconducting barium lanthanum titanate element comprising the steps as set forth in claim 8 and comprising the additional steps of adding a binder to said barium lanthanum titanate material, pressing said material to form an intermediate element of selected shape, and firing said intermediate element at a temperature of at least 1,300* C. to form said semiconducting barium lanthanum titanate elements.
Claim 9
Independent Claim
92 words
A method for making a barium strontium lanthanum titanate material having a curie point substantially lower than 125* C. for use in forming semiconducting ceramic elements comprising the steps of combining titanium chelate of triethanolamine, barium acetate, strontium acetate, and lanthanum acetate in at least one solvent to form a common solution, heating said solution at a temperature up to about 80* C. to form a gel, and heating said gel in an oxidizing atmosphere at a temperature between 600* C. and 1,150* C. to form said barium strontium lanthanum titanate material.
Claim 10
Independent Claim
109 words
A method for making semiconducting ceramic titanate elements comprising the steps of dissolving titanium chelate of triethanolamine and at least one alkaline earth salt in at least one solvent to form a common solution, heating said solution to form a gel, heating said gel in an oxidizing atmosphere to form a titanate material, combining said titanate material with an aqueous solution of a lanthanide salt and a binder material to form slurry, drying said slurry to form a lanthanide-doped binder mixture, pressing said binder mixture to form an intermediate element of selected shape, and firing said intermediate element at an elevated temperature to form said semiconducting ceramic titanate element.
Claim 11
Dependent Claim
16 words
A method as set forth in claim 11 wherein said alkaline earth salt comprises barium acetate.
Claim 12
Dependent Claim
22 words
A method as set forth in claim 11 wherein said alkaline earth salt comprises a mixture of barium acetate and strontium acetate.
Claim 13
Dependent Claim
15 words
A method as set forth in claim 11 wherein said lanthanide salt comprises lanthanum acetate.
Claim 14
Independent Claim
65 words
A method for making a titanate material comprising the steps of dissolving tetraisopropyl titanate with an organic acid selected from the group consisting of acetic acid and water-soluble alphahydroxy acids and with at least one alkaline earth salt in a solvent to form a common solution, and heating said solution to form a foamlike substance and to calcine said substance to form said titanate material.
Claim 15
Independent Claim
50 words
A method for making a ceramic-forming titanate material comprising the steps of dissolving tetraisopropyl titanate in a lactic acid solution and adding at least one alkaline earth salt to said solution, heating said solution to form a foamlike substance, and calcining said foamlike substance to form said ceramic-forming titanate material.
Claim 16
Dependent Claim
43 words
A method as set forth in claim 16 wherein said solution is heated at a temperature between 600* C. and 1,150* C. for at least 1 hour for forming said foamlike substance and for calcining said foamlike substance to form said titanate material.
Claim 17
Dependent Claim
16 words
A method as set forth in claim 16 wherein said alkaline earth salt comprises barium acetate.
Claim 18
Independent Claim
72 words
A method for making a titanate material for use in forming semiconducting ceramic elements comprising the steps of dissolving tetraisopropyl titanate in an aqueous lactic acid solution and adding at least one alkaline earth salt and at least one lanthanide salt in said solution to form a common solution, heating said common solution to form a foamlike substance, and heating said foamlike substance in an oxidizing atmosphere to form said titanate material.
Claim 19
Independent Claim
83 words
A method for making a barium lanthanum titanate material of perovskite structure having a curie point of approximately 125* C. for use in forming semiconducting ceramic elements comprising the steps of dissolving tetraisopropyl titAnate in an aqueous lactic acid solution and adding barium acetate and lanthanum acetate therein to form a common solution, heating said common solution at a temperature between 600* C. and 1,150* C. to form a foamlike substance and to calcine said substance to form said barium lanthanum titanate material.
Claim 20
Dependent Claim
66 words
A method for making a semiconducting barium lanthanum titanate element comprising the steps as set forth in claim 20 and comprising the additional steps of adding a binder to said barium lanthanum titanate material, pressing said material to form an intermediate element of selected shape, and firing said intermediate element at a temperature of at least 1,300* C. to form said semiconducting barium lanthanum titanate elements.
Claim 21
Independent Claim
86 words
A method for making a barium strontium lanthanum titanate material having a curie point substantially lower than 125* C. for use in forming semiconducting ceramic elements comprising the steps of combining tetraisopropyl titanate dissolved in lactic acid with barium acetate, strontium acetate, and lanthanum acetate in at least one solvent to form a common solution, heating said solution at a temperature between 600* C. and 1, 150* C. to form a foamlike substance and to calcine said substance to form said barium strontium lanthanum titanate material.
Claim 22
Independent Claim
111 words
A method for making semiconducting ceramic titanate elements comprising the steps of dissolving tetraisopropyl titanate in an aqueous solution of lactic acid, adding at least one alkaline earth salt to said solution, heating said solution in an oxidizing atmosphere to form a foamlike substance and to calcine said substance to form a titanate material, combining said titanate material with an aqueous solution of a lanthanide salt and a binder material to form a slurry, drying said slurry to form a lanthanide-doped binder mixture, pressing said binder mixture to form an intermediate element of selected shape, and firing said intermediate element at an elevated temperature to form said semiconducting ceramic titanate element.
Claim 23
Dependent Claim
16 words
A method as set forth in claim 23 wherein said alkaline earth salt comprises barium acetate.
Claim 24
Dependent Claim
22 words
A method as set forth in claim 23 wherein said alkaline earth salt comprises a mixture of barium acetate and strontium acetate.
Claim 25
Dependent Claim
15 words
A method as set forth in claim 23 wherein said lanthanide salt comprises lanthanum acetate.
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 |