Method for producing barium titanate-based powder, and multilayer ceramic capacitor

Patent metadata

Field	Value
Publication number	US-10315928-B2
Application number	US-201514934420-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Nov 17, 2014
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A method for producing a barium titanate-based powder that includes mixing a titanium compound and a barium compound together with water and chlorine to prepare a slurry, and temporarily firing the mixture of the titanium compound and the barium compound which is contained in the slurry to provide a barium titanate-based powder. The chlorine in the slurry is in the form of chlorine ions in a ratio of 230 to 1100 wt ppm based on the amount of the barium titanate-based powder to be synthesized.

First claim

What is claimed is:

1. A method for producing a barium titanate-based powder, the method comprising:
mixing a titanium compound and a barium compound together with water and chlorine to prepare a first slurry, the chlorine being in the form of chlorine ions in a ratio of 230 to 1100 wt ppm based on an amount of the barium titanate-based powder to be produced;
firing the mixture of the titanium compound and the barium compound contained in the first slurry to produce the barium titanate-based powder;
dispersing the produced barium titanate-based powder in a second slurry; and
removing chlorine contained in or on the barium titanate-based powder obtained after the firing of the mixture of the titanium compound and the barium compound contained in the first slurry and after dispersing the produced barium titanate-based powder in the second slurry.

2. The method for producing a barium titanate-based powder according to claim 1 , wherein the chlorine is added as ammonium chloride to form the first slurry.

3. The method for producing a barium titanate-based powder according to claim 1 , wherein the titanium compound is titanium dioxide.

4. The method for producing a barium titanate-based powder according to claim 3 , wherein the titanium dioxide comprises grains having a specific surface area of 30 to 50 m 2 /g.

5. The method for producing a barium titanate-based powder according to claim 1 , wherein the barium compound is barium carbonate.

6. The method for producing a barium titanate-based powder according to claim 5 , wherein the barium carbonate comprises grains having a specific surface area of 10 to 30 m 2 /g.

7. The method for producing a barium titanate-based powder according to claim 1 , further comprising drying the first slurry before the firing is carried out.

8. The method for producing a barium titanate-based powder according to claim 7 , wherein the drying is carried out at 100 to 200° C. for 12 to 36 hours.

9. The method for producing a barium titanate-based powder according to claim 1 , wherein the firing is carried out at 800 to 1100° C. for 1 to 5 hours.

10. The method for producing a barium titanate-based powder according to claim 1 , wherein the chlorine contained in or on the barium titanate-based powder is removed until a content of the chlorine contained in or on the barium titanate-based powder is reduced to 100 wt ppm or less.

11. The method for producing a barium titanate-based powder according to claim 1 , wherein the chlorine is removed by passing the second slurry in which the produced barium titanate-based powder is dispersed through an ion exchange resin.

12. The method for producing a barium titanate-based powder according to claim 1 , wherein the chlorine is removed with the use of an ion exchange resin.

13. A multilayer ceramic capacitor which is produced using the barium titanate-based powder obtained by the method according to claim 1 .

Assignees

• Murata Manufacturing Co

Inventors

• Ajichi Hiroko
• Nakagawa Toshiharu
• Wang Wenjun
• Nakae Sanae
• Tachibana Norikazu

Classifications

• C01P2002/74

  by peak-intensities or a ratio thereof only · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B2235/3418

  Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint · CPC title

• C04B35/4682

  based on BaTiO3 perovskite phase · CPC title

• C04B2235/3215

  Barium oxides or oxide-forming salts thereof · CPC title