Process for producing a composition which includes perovskite compounds

• US 4,643,984 A
• Filed: 07/23/1985
• Issued: 02/17/1987
• Est. Priority Date: 07/25/1984
• Status: Expired due to Term

• Current Assignee: Sakai Chemical Industry Company Limited
• Original Assignee: Sakai Chemical Industry Company Limited
• Inventors: Aoki, Masashi, Ito, Takeshi, Hidaka, Kazuhisa, Segawa, Kayoko, Rikimaru, Hiroaki, Abe, Kazunobu
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/758,072
• Time in Patent Office: 574 Days
• Field of Search: 423/593, 423/598, 501/134, 501/135, 501/136, 501/137, 501/138, 501/139, 501/1
• US Class Current: 501/134
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 19/00 Compounds of tin
• CPC Class Codes: C01G 21/00 Compounds of lead
• 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 27/006 Compounds containing, besides hafnium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C04B 35/4682 based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/491 based on lead zirconates and lead titanates , e.g. PZT
• CPC Class Codes: C04B 35/493 containing also other lead compounds

Abstract

A process for producing a composition which includes a perovskite compound, the process comprising:

(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;

(b) adding an insolubilizing agent to the resultant reaction mixture to insolubilize water-soluble compounds of the unreacted A group element dissolved in the aqueous medium so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; or

(c) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-soluble compound of the A group element, and then adding to the slurry an insolubilizing agent to insolubilize the water-soluble compound of the A group element so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; and

(d) filtering, washing and drying the resultant mixture to provide the composition which includes the perovskite compound having the desired A/B ratio.

Claims

1. A process for producing a composition which includes a perovskite compound, the process comprising:

(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;

(b) adding an insolubilizing agent to the resultant reaction mixture to insolubilize water-soluble compounds of the unreacted A group element dissolved in the aqueous medium so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio;

or

(c) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-soluble compound of the A group element, and then adding to the slurry an insolubilizing agent to insolubilize the water-soluble compound of the A group element so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; and

(d) filtering, washing and drying the resultant mixture to provide the composition which includes the perovskite compound having the desired A/B ratio.

2. A process for producing a composition which includes a perovskite compound, the process comprising:

(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;

(b) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-insoluble compound of the A group element so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; and

(c) filtering, washing and drying the resultant mixture to provide the composition which includes the perovskite compound having the desired A/B ratio.

3. A process for producing a sintered body which is substantially composed of a perovskite compound of desired atomic ratios, the process comprising:

(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element from the group consisting of Ti;

Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;

(b) adding an insolubilizing agent to the resultant reaction mixture to insolubilize water-soluble compounds of the unreacted A group element dissolved in the aqueous medium so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio;

or

(c) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-soluble compound of the A group element, and then adding to the slurry an insolubilizing agent to insolubilize the water-souble compound of the A group element so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; and

(d) filtering, washing and drying the resultant mixture to provide the composition which includes the perovskite compound having the desired A/B ratio; and

then

(e) sintering the composition at temperatures from about 1100°

C. to about 1300°

C.

5. The process as claimed in claim 3 wherein the composition is mixed with at least one oxide of an element selected from the group consisting of Bi, B, Pb and W, and the mixture was sintered at temperatures from about 900°

C. to about 1100°

C.

4. A process for producing a sintered body which is substantially composed of a perovskite compound of desired atomic ratios, the process comprising:

(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;

(b) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-inoluble compound of the A group element so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio;

(c) filtering, washing and drying the resultant mixture to provide the composition which includes the perovskite compound having the desired A/B ratio; and

(d) sintering the composition at temperatures from about 1100°

C. to about 1300°

C.

6. The process as claimed in claim 4 wherein the composition is mixed with at least one oxide of a element selected from the group consisting of Bi, B, Pb and W, and the mixture was sintered at temperatures from about 900°

C. to about 1100°

C.