Method of producing barium titanate

Patent metadata

Field	Value
Publication number	US-9745204-B2
Application number	US-201514929592-A
Country	US
Kind code	B2
Filing date	Nov 2, 2015
Priority date	May 10, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A method of producing barium titanate that includes making a slurry by dispersing barium titanate powder in a solvent such as ethanol. Then, in a high-pressure vessel, substituting supercritical fluid including carbon dioxide gas, for example, for the solvent in the slurry. Then, separating the barium titanate powder from the supercritical fluid by gasifying the supercritical fluid. Then, performing a heat treatment on the separated barium titanate powders to produce the barium titanate.

First claim

The invention claimed is:

1. A method of producing barium titanate, the method comprising:
making a slurry by dispersing a barium titanate powder in a solvent;
substituting a supercritical fluid for said solvent in said slurry;
separating said barium titanate powder from said supercritical fluid by gasifying said supercritical fluid to produce a separated barium titanate powder; and
performing a heat treatment on said separated barium titanate powder.

2. The method of producing barium titanate according to claim 1 , wherein said solvent includes at least one of ethanol, isopropyl alcohol, and methyl ethyl ketone.

3. The method of producing barium titanate according to claim 2 , wherein said supercritical fluid includes carbon dioxide gas.

4. The method of producing barium titanate according to claim 1 , wherein said supercritical fluid includes carbon dioxide gas.

5. The method of producing barium titanate according to claim 4 , wherein said barium titanate powder is obtained by adding a hydroxide of an alkaline-earth metal element to a titanium oxide slurry containing a titanium oxide powder dispersed in water to cause reaction between said hydroxide and titanium oxide powder.

6. The method of producing barium titanate according to claim 3 , wherein said barium titanate powder is obtained by adding a hydroxide of an alkaline-earth metal element to a titanium oxide slurry containing a titanium oxide powder dispersed in water to cause reaction between said hydroxide and titanium oxide powder.

7. The method of producing barium titanate according to claim 2 , wherein said barium titanate powder is obtained by adding a hydroxide of an alkaline-earth metal element to a titanium oxide slurry containing a titanium oxide powder dispersed in water to cause reaction between said hydroxide and titanium oxide powder.

8. The method of producing barium titanate according to claim 1 , wherein said barium titanate powder is obtained by adding a hydroxide of an alkaline-earth metal element to a titanium oxide slurry containing a titanium oxide powder dispersed in water to cause reaction between said hydroxide and titanium oxide powder.

9. The method of producing barium titanate according to claim 1 , further comprising heating said slurry.

10. The method of producing barium titanate according to claim 9 , further comprising pressurizing said slurry.

11. The method of producing barium titanate according to claim 1 , further comprising pressurizing said slurry.

12. The method of producing barium titanate according to claim 1 , wherein the barium titanate has a particle size from 80 to 150 nm.

Assignees

• Murata Manufacturing Co

Inventors

• Konishi Shinya
• Fujii Kazuya
• Saito Junichi

Classifications

• C04B2235/765

  Tetragonal symmetry · CPC title

• Y02P20/544

  Cross-Sectional Technologies · mapped topic

• C04B2235/762

  Cubic symmetry, e.g. beta-SiC · CPC title

• C04B35/4682

  based on BaTiO3 perovskite phase · CPC title

• C01G23/006 Primary

  Alkaline earth titanates · CPC title