US4853199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing crystalline complex perovskite compounds
Assignee: Panasonic Holdings Corp
•
Filing: 1988-01-07
•
Granted: 1989-08-01
•
Expires: 2008-01-07
Abstract
Abstract A method for producing crystalline complex perovskite compounds from starting compounds of at least one metal such as Ca, Ba or Sr, at least one metal such as Mg, Zn, Ni or Co and at least one metal such as Ta or Ni. The respective compounds are selected from oxides, hydroxides, hydrous oxides, and water-soluble organic compounds and inorganic salts of the respective metals. The water-soluble organic compounds and inorganic salts are capable of yielding metal oxides, hydroxides and hydrous oxides by hydrolysis. These starting compounds are heated at certain temperatures in an alkaline aqueous solution to obtain the perovskite compound at significantly low reaction temperatures of at least 95° C. Prior to the heating, the starting compounds may be treated in the alkaline aqueous solution at temperatures lower than 95° C. to form a uniformly mixed amorphous phase of the compounds and then heated.
Inventors
- 👤 Osamu Inoue
- 👤 Syunichiro Kawashima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:18
CPC Classifications
C; C01; C01G; C01G35/00; C01G35/006; C01G33/00; C01G33/006; C01P; C01P2002/00; C01P2002/02; C01P2002/30; C01P2002/34; C01P2002/60; C01P2004/00; C01P2004/60; C01P2004/62
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
242 words
A method of producing a fine powder, crystalline complex perovskite compound of the formula A(B.sub.1/3 C.sub.2/3)O.sub.3, wherein A represents at least one divalent metal selected from the group consisting of Ca, Sr and Ba, B represents at least one metal selected from the group consisting of Mg, Zn, Co and Ni, and C represents at least one pentavalent metal selected from the group consisting of Ta and Nb, the method comprising providing a proportion of at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals A, at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals B, and at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals C, provided that the watersoluble inorganic salts and organic compounds of the respective metals are, respectively, capable of yielding oxides, hydroxide and hydrous oxides of the metals by hydrolysis, said member which are not water soluble having a size of one micrometer or less, the proportion of said members being such as to effect formation of said perovskite compound; and reacting the selected members in an alkaline aqueous solution at a temperature of 140° C. or lower, said temperature being sufficient to cause the members to convert into the fine powder, crystalline complex perovskite compound.
Claim 2
Independent Claim
242 words
A method of producing a fine powder, crystalline complex perovskite compound of the formula A(B.sub.1/3 C.sub.2/3)O.sub.3, wherein A represents at least one divalent metal selected from the group consisting of Ca, Sr and Ba, B represents at least one metal selected from the group consisting of Mg, Zn, Co and Ni, and C represents at least one pentavalent metal selected from the group consisting of Ta and Nb, the method comprising providing a proportion of at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals A, at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals B, and at least one member selected from the group consisting of oxides, hydroxides, hydrous oxides, water-soluble inorganic salts and organic compounds of the metals C, provided that the watersoluble inorganic salts and organic compounds of the respective metals are, respectively, capable of yielding oxides, hydroxide and hydrous oxides of the metals by hydrolysis, said member which are not water soluble having a size of one micrometer or less, the proportion of said members being such as to effect formation of said perovskite compound; and reacting the selected members in an alkaline aqueous solution at a temperature of 140° C. or lower, said temperature being sufficient to cause the members to convert into the fine powder, crystalline complex perovskite compound.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein said crystalline complex perovskite compound is Sr(Mg 1/3 Nb 2/3 )O 3 .
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein said crystalline complex perovskite compound is Ba(Mg 1/3 Ta 2/3 )O 3 .
Claim 5
Dependent Claim
20 words
A method according to claim 1, wherein said crystalline complex perovskite compound is Ba(Zn 1/3 Ta 2/3 )O 3 .
Claim 6
Dependent Claim
21 words
A method according to claim 1, wherein said alkaline aqueous solution is a solution of a hydroxide of the metal A.
Claim 7
Dependent Claim
20 words
A method according to claim 5, wherein the solution of a hydroxide of the metal A is a saturated solution.
Claim 8
Dependent Claim
19 words
A method according to claim 1, wherein said alkaline aqueous solution is a solution of an alkali metal hydroxide.
Claim 9
Dependent Claim
18 words
A method according to claim 1, wherein said alkaline aqueous solution has a pH not lower than 12.
Claim 10
Dependent Claim
14 words
A method according to claim 1, wherein the temperature is higher than 95° C.
Claim 11
Dependent Claim
25 words
A method according to claim 1, wherein the temperature is higher than 110° C. and the reaction is effected in a closed system under pressure.
Claim 12
Dependent Claim
29 words
A method according to claim 1, wherein the reaction is effected in a system using a reflux condenser so that the water in the alkaline aqueous solution is recycled.
Claim 13
Dependent Claim
36 words
A method according to claim 1, further comprising heating the alkaline aqueous solution to dryness when at least one of the selected members is soluble in water and is used to make the alkaline aqueous solution.
Claim 14
Dependent Claim
18 words
A method according to claim 1, further comprising separating the obtained perovskite compound from the alkaline aqueous solution.
Claim 15
Dependent Claim
17 words
A method according got claim 1, wherein the reaction is effected in a CO 2 gas-free atmosphere.
Claim 16
Dependent Claim
71 words
A method according to claim 1, wherein the reaction is effected by a procedure which comprises treating the selected members in an alkaline aqueous solution at a temperature lower than 95° C. to form a uniformly mixed amorphous powder, and heating the amorphous powder in the alkaline aqueous solution or in coexistence therewith at a temperature not lower than 95° C. to convert the powder into a crystalline complex perovskite compound.
Claim 17
Dependent Claim
19 words
A method according to claim 15, wherein the amorphous powder is heated at a temperature higher than 110° C.
Claim 18
Dependent Claim
26 words
A method according to claim 15, wherein prior to the heating, the amorphous powder is removed from the solution but kept wetted, and is subsequently heated.
Claim 19
Dependent Claim
17 words
A method according to claim 15, wherein the amorphous powder is heated in the alkaline aqueous solution.
Claim 20
Dependent Claim
14 words
A method according to claim 15, wherein the amorphous powder is heated to dryness.
References Cited (Backward Citations)
US3464785A
Cited
JPS5556063A
Cited
US4675123A
Cited
JPS5626726A
Cited
JPS5782119A
Cited
JPS582220A
Cited
JPS58199717A
Cited
US4487842A
Cited
JPS5939716A
Cited
JPS61158821A
Cited
JPH0610303A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |