US5096642A — Process for producing a high density ceramic of p…

Claim 1

Independent Claim 229 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is one or more metal elements coordinated with 12 oxygen atoms, and B is one or more metal elements coordinated with 6 oxygen atoms, which comprises: (a) preparing at least one single element solution of a modifiable element containing the entire amount of one of the metal elements constituting the perovskite, and at least one single element solution of a modifying element containing a part of the entire amount of another one of the metal elements constituting the perovskite; (b) forming in a single vessel an intimate precipitate mixture by plural steps of precipitation from said single element solution or solutions; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified oxide powder having primary particles in a substantially monodispersed state; (d) mixing with the modified oxide powder a powder of a compound containing the rest of the entire amount of modifying element and powders of compounds containing the entire amounts of metal elements constituting the perovskite other than the modifiable and modifying elements; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined produce, and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 2

Dependent Claim 229 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is one or more metal elements coordinated with 12 oxygen atoms, and B is one or more metal elements coordinated with 6 oxygen atoms, which comprises: (a) preparing at least one single element solution of a modifiable element containing the entire amount of one of the metal elements constituting the perovskite, and at least one single element solution of a modifying element containing a part of the entire amount of another one of the metal elements constituting the perovskite; (b) forming in a single vessel an intimate precipitate mixture by plural steps of precipitation from said single element solution or solutions; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified oxide powder having primary particles in a substantially monodispersed state; (d) mixing with the modified oxide powder a powder of a compound containing the rest of the entire amount of modifying element and powders of compounds containing the entire amounts of metal elements constituting the perovskite other than the modifiable and modifying elements; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined produce, and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 3

Dependent Claim 21 words

The process according to claim 1, wherein the precipitate is formed by contacting the single element solution with a precipitating solution.

Claim 4

Dependent Claim 31 words

The process according to claim 2, wherein the precipitating solution is selected from the group consisting of solutions of ammonia, ammonium carbonate, sodium hydroxide, oxalic acid, ammonium oxalate and organic amines.

Claim 5

Dependent Claim 52 words

The process according to claim 1, wherein A is selected from the group consisting of Pb, Ba, Ca, Sr, La and Y; and B is selected from the group consisting of Zr, Ti, Mg, Sc, Hf, Th, W, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ni, Cd, Al, Sn, As and Bi.

Claim 6

Dependent Claim 61 words

The process according to claim 1, wherein the modifiable element is Zr, and the modifying element is selected from the group consisting of Ti, Pb, La, Mg, Co, Fe, Zn, Ba, Sr and Ca; and the rest of the constituting elements are selected from the group consisting of La, Ti, Pb, Co, Nb, Fe, Mg, Zn, Ta, Ba, Sr and Ca.

Claim 7

Dependent Claim 223 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is selected from the group consisting of Pb, Ba, Ca, Sr and La; and B is selected from the group consisting of Ti, Zr, Co, Nb, Ta, Fe, Zn and Mg; which comprises: (a) preparing a modifiable element solution containing the entire amount of zirconium required for the perovskite, and at least one single modifying element solution containing a part of the entire amount of one of the metal elements constituting the perovskite other than zirconium; (b) contacting said modifiable element solution and said modifying element solution with a precipitating solution in at least two steps to form an intimate precipitate mixture; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified zirconia powder; (d) mixing with the modified zirconia powder a power of a compound containing the rest of the entire amount of the modifying element and powders of compounds containing the entire amounts of metal elements constituting the perovskite other than zirconium and the modifying element; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined product; and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 8

Dependent Claim 223 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is selected from the group consisting of Pb, Ba, Ca, Sr and La; and B is selected from the group consisting of Ti, Zr, Co, Nb, Ta, Fe, Zn and Mg; which comprises: (a) preparing a modifiable element solution containing the entire amount of zirconium required for the perovskite, and at least one single modifying element solution containing a part of the entire amount of one of the metal elements constituting the perovskite other than zirconium; (b) contacting said modifiable element solution and said modifying element solution with a precipitating solution in at least two steps to form an intimate precipitate mixture; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified zirconia powder; (d) mixing with the modified zirconia powder a power of a compound containing the rest of the entire amount of the modifying element and powders of compounds containing the entire amounts of metal elements constituting the perovskite other than zirconium and the modifying element; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined product; and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 9

Dependent Claim 261 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is one or more metal elements coordinated with 12 oxygen atoms, B is one or more metal elements coordinated with 6 oxygen atoms, which comprises: (a) preparing at least two solutions including at least one mixed solution obtained by mixing, in optional proportions, at least one single element solution of a modifiable element containing the entire amount of one of the metal elements constituting the perovskite, and at least one single element solution of a modified element containing a part of the entire amount of another one of the metal elements constituting the perovskite; (b) forming separately in separate vessels precipitates from said at least two single element solutions or from said at least two solutions including at least one mixed solution and mixing the precipitates to obtain an intimate precipitate mixture; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified oxide powder having primary particles in a substantially monodispersed state; (d) mixing with the modified oxide powder a powder of a compound containing the rest of the entire amount of the modifying element and powders and compounds containing the entire amounts of metal elements constituting the perovskite other than the modifiable and modifying elements; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined products, and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 10

Dependent Claim 261 words

A process for producing a high density ceramic of perovskite having the formula: ABO.sub.3 wherein A is one or more metal elements coordinated with 12 oxygen atoms, B is one or more metal elements coordinated with 6 oxygen atoms, which comprises: (a) preparing at least two solutions including at least one mixed solution obtained by mixing, in optional proportions, at least one single element solution of a modifiable element containing the entire amount of one of the metal elements constituting the perovskite, and at least one single element solution of a modified element containing a part of the entire amount of another one of the metal elements constituting the perovskite; (b) forming separately in separate vessels precipitates from said at least two single element solutions or from said at least two solutions including at least one mixed solution and mixing the precipitates to obtain an intimate precipitate mixture; (c) washing, drying and calcining the intimate precipitate mixture at a temperature of from 400° C. to 1400° C. to obtain a modified oxide powder having primary particles in a substantially monodispersed state; (d) mixing with the modified oxide powder a powder of a compound containing the rest of the entire amount of the modifying element and powders and compounds containing the entire amounts of metal elements constituting the perovskite other than the modifiable and modifying elements; (e) calcining the powder mixture at a temperature of from 400° C. to 1400° C.; and (f) compacting the calcined products, and sintering the compacted product at a temperature of from 700° C. to 1700° C.

Claim 11

Dependent Claim 21 words

The process according to claim 7, wherein the precipitates are formed by contacting said at least two solutions with precipitating solution.

Claim 12

Dependent Claim 31 words

The process according to claim 8, wherein the precipitating solutions are selected from the group consisting of solutions of ammonia, ammonium carbonate, sodium hydroxide, oxalic acid, ammonium oxalate and organic amines.

Claim 13

Dependent Claim 15 words

The process according to claim 7, wherein each solution is an aqueous or alcohol solution.

Claim 14

Dependent Claim 51 words

The process according to claim 7, wherein A selected from the group consisting of Pb, Ba, Ca Sr, La and Y; and B is selected from the group consisting of Zr, Ti, Mg, Sc, Hf, Th, W, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ni, Cd, Al, Sn, As and Bi.

Claim 15

Dependent Claim 60 words

The process according to claim 7, wherein the modifiable element is Zr, the modifying element is selected from the group consisting of Ti, Pb, La, Mg, Cr, Fe, Zn, Ba, Sr and Ca; and the rest of the constituting elements are selected from the group consisting of La, Tr, Pb, Co, Nb, Fe, Mg, Zn, Ta, Ba, Sr and Ca.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-03-17	1995-09-16	1996-03-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-03-17	1999-09-16	2000-03-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-03-17	2003-09-16	2004-03-17	$7700.00	Window Closed / Lapsed

Process for producing a high density ceramic of perovskite

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