Process for Production of Powder of Perovskite Compound

• US 20080044344A1
• Filed: 02/09/2005
• Published: 02/21/2008
• Est. Priority Date: 08/13/2004
• Status: Active Grant

• Current Assignee: Sakai Chemical Industry Company Limited
• Original Assignee: Sakai Chemical Industry Company Limited
• Inventors: Ikeda, Yoshiaki, Hidaka, Kazuhisa, Shikida, Takashi, Ogama, Shinji
• Granted Patent: US 9,005,568 B2
• Time in Patent Office: Days
• US Class Current: 423/598
• CPC Class Codes: C01G 23/003 Titanates C01G23/001 takes precedence
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01G 25/00 Compounds of zirconium
• CPC Class Codes: C01G 25/006 Compounds containing, besides zirconium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 27/00 Compounds of hafnium
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3205 Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/3249 containing also titanium oxide or titanates, e.g. lead zirconate titanate (PZT)
• CPC Class Codes: C04B 2235/441 Alkoxides, e.g. methoxide, tert-butoxide
• CPC Class Codes: C04B 2235/449 Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5472 Bimodal, multi-modal or multi-fraction
• CPC Class Codes: C04B 2235/5481 : Monomodal
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/724 : Halogenide content
• CPC Class Codes: C04B 2235/768 : Perovskite structure ABO3
• CPC Class Codes: C04B 35/465 : based on alkaline earth metal titanates
• CPC Class Codes: C04B 35/4682 : based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/47 : based on strontium titanates
• CPC Class Codes: C04B 35/48 : based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/49 : containing also titanium oxides or titanates
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: H01B 3/12 : ceramics

Abstract

The invention provides a process for production of powder of perovskite compound which comprises: the first step for obtaining an aggregate of perovskite compound which comprises at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and Pb and at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, and which is represented by the general formula
ABO₃ wherein A is at least one A group element and B is at least one B group element; and the second step for heating the aggregate of perovskite compound obtained in the first step in a solvent at a temperature in a range from 30° C. to 500° C. whereby disintegrating the aggregate. The process makes it unnecessary to resort to a conventional mechanical crushing means or to make use of impact caused by milling media or airflow, but it makes possible to obtain a powder of perovskite compound which is not contaminated with impurities derived from milling media or chipping particles but has a high purity and a narrow particle size distribution.

Claims

1. A process for production of powder of perovskite compound which comprises:

the first step for obtaining an aggregate of perovskite compound which comprises at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and Pb and at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, and which is represented by the general formula

ABO₃

wherein A is at least one A group element and B is at least one B group element; and

the second step for heating the aggregate of perovskite compound obtained in the first step in a solvent at a temperature in a range from 30°

C. to 500°

C., whereby disintegrating the aggregate.

2. The process according to claim 1 in which, in the first step, a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and Pb and an oxide and/or a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn is subjected to hydrothermal treatment at a temperature in the range of 100-300°

C. in the presence of an aqueous solvent, and the obtained reaction product is heated at a temperature in the range of 100-1400°

C. to obtain an aggregate of perovskite compound.

3. The process according to claim 1 in which, in the first step, a mixture of an oxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and/or a compound to produce the oxide when it is heated and an oxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn and/or a compound to produce the oxide when it is heated is heated at a temperature in the range of 600-1400°

C. to obtain an aggregate of perovskite compound.

4. The process according to claim 1 in which, in the first step, a double salt is prepared using a water soluble salt of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, a water soluble salt of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn and at least one organic acid salt selected from the group consisting of an oxalic acid and a citric acid, and then the double salt is heated at a temperature in the range of 400-1400°

C. to obtain an aggregate of perovskite compound.

5. The process according to claim 1 in which, in the first step, a mixture of an alkoxide and/or a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and an alkoxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn is hydrolyzed, and then the resultant reaction product is heated at a temperature in the range of 100-1400°

C. to obtain an aggregate of perovskite compound.

6. The process according to claim 1 in which, in the first step, a mixture of a sol of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba and a sol of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn is gelled, and then the resultant reaction product is heated at a temperature in the range of 100-1400°

C. to obtain an aggregate of perovskite compound.

7. The process according to any one of claims 1 to 6 in which, in the first step, an aggregate of perovskite compound containing an additive to promote or suppress the growth of particle of perovskite compound.

8. The process according to any one of claims 1 to 7 in which, in the second step, an aggregate of perovskite compound is heated in a solvent containing an acid or a base.