US4606906A
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Process of synthesizing mixed BaO-TiO2 based powders for ceramic applications
Assignee: United States Department of Commerce
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Filing: 1984-11-15
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Granted: 1986-08-19
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Expires: 2004-11-15
Abstract
Abstract A process for producing any desired Ba/Ti mixture to be formulated as an amorphous solid which crystallizes at very low temperatures to yield a desired phase or phases is disclosed. The process yields products free of undesirable impurities and allows macroscopic production of certain phases in the baria-titania system, having exceptional high frequency dielectric properties, that were previously unattainable through solid-state high temperature production techniques.
Inventors
- 👤 Joseph J. Ritter
- 👤 Robert S. Roth
- 👤 Taki Negas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:03
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; C04B35/4686; C01P; C01P2002/00; C01P2002/02; C01P2006/00; C01P2006/32; C01P2006/33; C01P2006/36
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
162 words
A process for synthesizing single phase crystalline Ba 2 Ti 9 O 20 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol in a dry atmosphere to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol in a dry atmosphere to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution in a dry atmosphere to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately 2:9; (d) subjecting said mixed barium-titanium alkoxide system to hydrolysis at a reflux temperature of between 70° C. and 90° C. to form a precipitate; (e) separating said precipitate and drying said precipitate; and (f) heating said precipitate at a temperature of between 700° C. and 1100° C. for approximately between 15-20 hours to form a crystalline, single phase of Ba 2 Ti 9 O 20 .
Claim 2
Dependent Claim
162 words
A process for synthesizing single phase crystalline Ba 2 Ti 9 O 20 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol in a dry atmosphere to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol in a dry atmosphere to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution in a dry atmosphere to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately 2:9; (d) subjecting said mixed barium-titanium alkoxide system to hydrolysis at a reflux temperature of between 70° C. and 90° C. to form a precipitate; (e) separating said precipitate and drying said precipitate; and (f) heating said precipitate at a temperature of between 700° C. and 1100° C. for approximately between 15-20 hours to form a crystalline, single phase of Ba 2 Ti 9 O 20 .
Claim 3
Dependent Claim
23 words
The process of claim 1, wherein said mixed barium-titanium alkoxide system is subjected to hydrolysis by adding an ethanol-water solution to said system.
Claim 4
Dependent Claim
31 words
The process of claim 2, wherein said ethanol-water solution contains water in a 10 to 20% excess over that required to hydrolyze all alkoxy groups of said mixed barium-titanium alkoxide solution.
Claim 5
Dependent Claim
12 words
The process of claim 1, wherein said titanium alkoxide is titanium isopropoxide.
Claim 6
Dependent Claim
24 words
The process of claim 1, wherein said first lower alkyl alcohol and said second lower alkyl alcohol have from 1 to 3 carbon atoms.
Claim 7
Dependent Claim
19 words
The process of claim 1, wherein said first lower alkyl alcohol and said second lower alkyl alcohol are ethanol.
Claim 8
Dependent Claim
169 words
A process for synthesizing single phase crystalline Ba 2 Ti 9 O 20 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol in a dry atmosphere to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol in a dry atmosphere to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately 2:9; (d) stirring said mixed barium-titanium alkoxide system to form a precipitate; (e) subjecting said mixed barium-titanium alkoxide system containing said precipitate to hydrolysis at a reflux temperature of between 70° C. and 90° C.; (f) separating said precipitate and drying said precipitate; and (g) heating said precipitate at a temperature of between 700° C. and 1100° C. for between 15 and 20 hours to form a crystalline, single phase of Ba 2 Ti 9 O 20 .
Claim 9
Dependent Claim
169 words
A process for synthesizing single phase crystalline Ba 2 Ti 9 O 20 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol in a dry atmosphere to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol in a dry atmosphere to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately 2:9; (d) stirring said mixed barium-titanium alkoxide system to form a precipitate; (e) subjecting said mixed barium-titanium alkoxide system containing said precipitate to hydrolysis at a reflux temperature of between 70° C. and 90° C.; (f) separating said precipitate and drying said precipitate; and (g) heating said precipitate at a temperature of between 700° C. and 1100° C. for between 15 and 20 hours to form a crystalline, single phase of Ba 2 Ti 9 O 20 .
Claim 10
Dependent Claim
26 words
The process of claim 7, wherein said mixed barium-titanium alkoxide system containing said precipitate is subjected to hydrolysis by adding an ethanol-water solution to said system.
Claim 11
Dependent Claim
31 words
The process of claim 8, wherein said ethanol-water solution contains water in a 10 to 20% excess over that required to hydrolyze all alkoxy groups of said mixed barium-titanium alkoxide solution.
Claim 12
Dependent Claim
12 words
The process of claim 7, wherein said titanium alkoxide is titanium isopropoxide.
Claim 13
Dependent Claim
24 words
The process of claim 7, wherein said first lower alkyl alcohol and said second lower alkyl alcohol have from 1 to 3 carbon atoms.
Claim 14
Dependent Claim
18 words
The process of claim 7, wherein said first lower alkyl alcohol and second lower alkyl alcohol are ethanol.
Claim 15
Dependent Claim
189 words
A process for synthesizing single phase crystalline BaTi 5 O 11 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately one to five; (d) stirring said mixed barium-titanium alkoxide system to form a first precipitate; (e) heating said mixed barium-titanium alkoxide system containing said first precipitate at a reflux temperature of between 70° C. and 90° C. for between 15-20 hours to dissolve said first precipitate and form a second precipitate; (f) subjecting said mixed barium-titanium alkoxide system containing said second precipitate to hydrolysis to form a precursor; (g) separating and drying said second precipitate; and (h) calcining said precipitate at between 700° C. and 1100° C. for a period of between 15 and 20 hours to form a crystalline, single phase of BaTi 5 O 11 .
Claim 16
Dependent Claim
189 words
A process for synthesizing single phase crystalline BaTi 5 O 11 powders comprising the steps of: (a) dissolving barium oxide in a first lower alkyl alcohol to form a barium alkoxide solution; (b) dissolving a titanium alkoxide in a second lower alkyl alcohol to form a titanium alkoxide solution; (c) combining said barium alkoxide solution and said titanium alkoxide solution to form a mixed barium-titanium alkoxide system wherein the molar ratio of barium to titanium in said mixed system is approximately one to five; (d) stirring said mixed barium-titanium alkoxide system to form a first precipitate; (e) heating said mixed barium-titanium alkoxide system containing said first precipitate at a reflux temperature of between 70° C. and 90° C. for between 15-20 hours to dissolve said first precipitate and form a second precipitate; (f) subjecting said mixed barium-titanium alkoxide system containing said second precipitate to hydrolysis to form a precursor; (g) separating and drying said second precipitate; and (h) calcining said precipitate at between 700° C. and 1100° C. for a period of between 15 and 20 hours to form a crystalline, single phase of BaTi 5 O 11 .
Claim 17
Dependent Claim
27 words
The process of claim 13, wherein said mixed barium-titanium alkoxide system containing said second precipitate is subjected to hydrolysis by adding an ethanol-water solution to said system.
Claim 18
Dependent Claim
31 words
The process of claim 13, wherein said ethanol-water solution contains water in a 10 to 20% excess over that required to hydrolyze all alkoxy groups of said mixed barium-titanium alkoxide solution.
Claim 19
Dependent Claim
12 words
The process of claim 13, wherein said titanium alkoxide is titanium isopropoxide.
Claim 20
Dependent Claim
24 words
The process of claim 13, wherein said first lower alkyl alcohol and said second lower alkyl alcohol have from 1 to 3 carbon atoms.
Claim 21
Dependent Claim
19 words
The process of claim 13, wherein said first lower alkyl alcohol and said second lower alkyl alcohol are ethanol.
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