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US5032559A
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Method of preparing barium, titanium, zirconium oxide ferroelectric ceramic compositions
Assignee: Osram Sylvania Inc
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Filing: 1990-05-21
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Granted: 1991-07-16
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Expires: 2010-05-21
Abstract
Abstract A procedure used to prepare Ba(Ti 1-x ),Zr x )O 3 compositions wherein 0<x<0.25 having a more completely randomized distribution of Ti and Zr atoms on the TiO 2 sublattice of barium titanate is described. In accordance with the present invention there is provided a method for preparing barium titanium zirconium oxide ferroelectic ceramic. The present method comprises mixing tetraalkyl titanate and alkyl zirconate in appropriate amounts to produce (Ti 1-x Zr x )alkoxide wherein 0<x<0.25; reacting (Ti 1-x Zr x ) alkoxide wherein 0<x<0.25 to form (Ti 1-x Zr x )O 2 wherein 0<x<0.25 admixing (Ti 1-x Zr x )O 2 with BaCO 3 , said BaCO 3 being added in a molar ratio greater than 1 relative to (Ti 1-x Zr x )O 2 ; heating the admixture for a period of time and at a temperature sufficient to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x<0.25. The improved randomization of the Ti and Zr atom distributions results in a ferroelectric ceramic material having squarer electrical polarization hysteresis loops and higher remanent polarization values than can be obtained from conventionally prepared materials of similar composition.
Inventors
- 👤 Robert T. McSweeney
- 👤 Karlene Zuk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:13
CPC Classifications
C; C01; C01G; C01G25/00; C01G25/006; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2002/76; C01P2004/00; C01P2004/60; C01P2004/61; C01P2004/80; C01P2006/00; C01P2006/12; C01P2006/42; C01P2006/60
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
140 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method comprising: (a) reacting tetraalkyl titanate and tetraalkyl zirconate in appropriate amounts to produce (Ti 1-x Zr x )-alkoxide wherein 021 x≦0.25; (b) reacting said (Ti 1-x Zr x )-alkoxide to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with a BaO precursor, said BaO precursor, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU1## having a value greater than 1; and (d) heating the admixture for a period of time and at a sufficient temperature to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
Claim 2
Independent Claim
140 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method comprising: (a) reacting tetraalkyl titanate and tetraalkyl zirconate in appropriate amounts to produce (Ti 1-x Zr x )-alkoxide wherein 021 x≦0.25; (b) reacting said (Ti 1-x Zr x )-alkoxide to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with a BaO precursor, said BaO precursor, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU1## having a value greater than 1; and (d) heating the admixture for a period of time and at a sufficient temperature to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
Claim 3
Dependent Claim
83 words
A method in accordance with claim 1 wherein said step of reacting said (Ti 1-x Zr x )-alkoxide to form TiZrO 4 and (Ti 1-s Zr s )O 2 comprises: hydrolyzing said (Ti 1-x Zr x )-alkoxide to form a precipitate; isolating said precipitate; and heating said precipitate for a sufficient period of time and at a sufficient temperature to form TiZrO 4 and (Ti 1-s Zr s )O 2 wherein s is the solubility limit for ZrO 2 in TiO 2 .
Claim 4
Dependent Claim
32 words
A method in accordance with claim 2 wherein said tetraalkyl titanate includes alkyl groups which are straight, branched, or cyclic alkyl groups having from 1 to 12 carbon atoms per alkyl group.
Claim 5
Dependent Claim
21 words
A method in accordance with claim 3 wherein said alkyl groups have from 2 to 8 carbon atoms per alkyl group.
Claim 6
Dependent Claim
21 words
A method in accordance with claim 9 wherein said alkyl groups have from 4 to 6 carbon atoms per alkyl group.
Claim 7
Dependent Claim
32 words
A method in accordance with claim 2 wherein said tetraalkyl zirconate includes alkyl groups which are straight, branched, or cyclic alkyl groups having from 1 to 12 carbon atoms per alkyl group.
Claim 8
Dependent Claim
21 words
A method in accordance with claim 6 wherein said alkyl groups have from 2 to 8 carbon atoms per alkyl group.
Claim 9
Dependent Claim
21 words
A method in accordance with claim 7 wherein said alkyl groups have from 4 to 6 carbon atoms per alkyl group.
Claim 10
Dependent Claim
24 words
A method in accordance with claim 2 wherein said precipitate is heated at a temperature of from about 500° C. to about 1300620 C.
Claim 11
Dependent Claim
24 words
A method in accordance with claim 2 wherein said precipitate is heated at a temperature of from about 700° C. to about 1100620 C.
Claim 12
Dependent Claim
56 words
A method in accordance with claim 2 wherein said step of heating the admixture of said (Ti 1-s Zr s )O 2 , TiZrO 4 , and BaO precursor to produce Ba(Ti 1-s Zr s )O 3 wherein 0<x≦0.25 is carried out at a temperature in the range of from about 1000° to about 1400° C.
Claim 13
Dependent Claim
18 words
A method in accordance with claim 11 wherein the temperature if from about 1200° to about 1280° C.
Claim 14
Dependent Claim
27 words
A method in accordance with claim 1 wherein said BaO precursor is selected from the group consisting of barium carbonate, barium nitrate, barium chloride, and barium acetate.
Claim 15
Dependent Claim
14 words
A method in accordance with claim 13 wherein said BaO precursor is barium carbonate.
Claim 16
Dependent Claim
14 words
A method in accordance with claim 13 wherein said BaO precursor is barium nitrate.
Claim 17
Dependent Claim
14 words
A method in accordance with claim 13 wherein said BaO precursor is barium chloride.
Claim 18
Dependent Claim
14 words
A method in accordance with claim 13 wherein said BaO precursor is barium acetate.
Claim 19
Independent Claim
129 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method comprising: (a) preparing (Ti 1-x Zr x )-alkoxide wherein 0<x≦0.25; (b) reacting said (Ti 1-x Zr x )-alkoxide to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with a BaO precursor, said BaO precursor, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU2## having a value greater than 1; and (d) heating the admixture for a period of time and at a sufficient temperature to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
Claim 20
Independent Claim
129 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method comprising: (a) preparing (Ti 1-x Zr x )-alkoxide wherein 0<x≦0.25; (b) reacting said (Ti 1-x Zr x )-alkoxide to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with a BaO precursor, said BaO precursor, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU2## having a value greater than 1; and (d) heating the admixture for a period of time and at a sufficient temperature to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
Claim 21
Independent Claim
186 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method consisting of the steps: (a) reacting tetrabutyl titanate and n-butyl zirconate in appropriate amounts to produce (Ti 1-x Zr x )-alkoxide wherein 0<x≦0.25; (b) hydrolyzing said (Ti 1-x Zr x )-alkoxide to form a slurry; (c) drying said slurry to obtain a precipitate; (d) calcining said precipitate at a temperature in the range of from about 700° C. to about 1100° C. for a sufficient period of time to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with barium carbonate, said barium carbonate, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU3## having a value greater than 1; and (d) heating the admixture for a period of time and at a temperature of from about 1200° C. to about 1280° C. to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
Claim 22
Independent Claim
186 words
A method for preparing a barium titanium zirconium oxide ferroelectric ceramic composition, said method consisting of the steps: (a) reacting tetrabutyl titanate and n-butyl zirconate in appropriate amounts to produce (Ti 1-x Zr x )-alkoxide wherein 0<x≦0.25; (b) hydrolyzing said (Ti 1-x Zr x )-alkoxide to form a slurry; (c) drying said slurry to obtain a precipitate; (d) calcining said precipitate at a temperature in the range of from about 700° C. to about 1100° C. for a sufficient period of time to form a two phase mixture of TiZrO 4 and (Ti 1-s Zr s )O 2 , wherein s is the solubility limit for ZrO 2 in TiO 2 ; (c) admixing said (Ti 1-s Zr s )O 2 and TiZrO 4 with barium carbonate, said barium carbonate, (Ti 1-s Zr s )O 2 and TiZrO 4 being present in a molar ratio of ##EQU3## having a value greater than 1; and (d) heating the admixture for a period of time and at a temperature of from about 1200° C. to about 1280° C. to produce Ba(Ti 1-x Zr x )O 3 wherein 0<x≦0.25.
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