Method of manufacturing powdered barium titanate

• US 4,859,448 A
• Filed: 06/20/1988
• Issued: 08/22/1989
• Est. Priority Date: 11/25/1987
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Klee, Mareike K., Brand, Hans-Wolfgang
• Primary Examiner(s): Stoll, Robert L.
• Application Number:
  US07/209,450
• Time in Patent Office: 428 Days
• Field of Search: 501/137, 423/598, 423/635, 423/610
• US Class Current: 423/598
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/76 by a space-group or by other symmetry indications
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer

Abstract

A method of manufacturing powdered barium titanate, in which titanium dioxide is made to react with barium hydroxide, excluding CO₂ at a temperature in the range from 60° to 95° C., amorphous titanium dioxide having a water content of ≈0.5 mol. being made to react with excess barium hydroxide in water, and being dried after removing the excess barium ions.

Claims

1. A method of manufacturing powdered barium titanate powder, said method comprising the steps:

(a) refluxing at a temperature of between 70°

C.-95°

C. an aqueous suspension of an amorphous titanium dioxide power having a bound water content of ≃

0.5 mol and barium hydroxide in excess while excluding CO₂ to thereby form barium titanate,

(b) removing barium titanate powder from the suspension,

(c) removing excess barium ions from the barium titanate power and,

(d) then drying the barium titanate powder.

2. A method of claim 1 wherein the amorphous titanium dioxide powder is manufactured by hydrolyzing a titanium alcoholate by adding deionized water to a solution of a titanium alcholate to thereby precipitate out an amorphous titanium dioxide power having a bound water content of ≃

0.5 mol, separating said titanium dioxide powder from said solution, washing said titanium dioxide powder with a washing solution, separating the washing solution from said titanium dioxide powder and, without drying, employing said titanium dioxide powder in said method.

3. The method of claim 1 wherein Ba(OH)₂.8H₂ O is used as the supply of the barium hydroxide.

4. The method of claim 2 wherein the solution of the titanium alcoholate is a solution of titanium tetraethoxide in m-xylol.