Process of synthesizing mixed BaO-TiO.sub.2 based powders for ceramic applications
First Claim
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1. A process for synthesizing single phase crystalline Ba2 Ti9 O20 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 Ba2 Ti9 O20.
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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.
36 Citations
18 Claims
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1. A process for synthesizing single phase crystalline Ba2 Ti9 O20 powders comprising the steps of:
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(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 Ba2 Ti9 O20. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A process for synthesizing single phase crystalline Ba2 Ti9 O20 powders comprising the steps of:
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(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 Ba2 Ti9 O20. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A process for synthesizing single phase crystalline BaTi5 O11 powders comprising the steps of:
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(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 BaTi5 O11. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification