Preparation of barium titanate or strontium titanate having a mean diameter of less than 10 nanometers

• US 20030215384A1
• Filed: 05/12/2003
• Published: 11/20/2003
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Sterzel, Hans-Josef
• Granted Patent: US 7,223,378 B2
• Time in Patent Office: Days
• 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 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• 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 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/44 Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
• CPC Class Codes: C04B 2235/441 Alkoxides, e.g. methoxide, tert-butoxide
• CPC Class Codes: C04B 2235/5454 nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/549 the particle size being expressed by crystallite size or primary particle size
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/761 Unit-cell parameters, e.g. lattice constants
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/79 Non-stoichiometric products, e.g. perovskites (ABO3) with an A/B-ratio other than 1
• CPC Class Codes: C04B 35/6264 Mixing media, e.g. organic solvents
• CPC Class Codes: C04B 35/62655 Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: H01G 4/1227 based on alkaline earth titanates

Abstract

Process for preparing barium titanate or strontium titanate by reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C₁-C₈-alcohol or a glycol ether at from 50 to 150° C.

Claims

1. A process for preparing barium titanate or strontium titanate, which comprises reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C₁-C₈-alcohol or a glycol ether at from 50 to 150°

C.

2. A process for preparing barium titanate or strontium titanate as claimed in claim 1, wherein the mean diameter of the barium titanate or strontium titanate particles is less than 10 nm.

3. A process for preparing barium titanate or strontium titanate as claimed in claim 1 or 2, wherein the barium hydroxide hydrate or strontium hydroxide hydrate used is the octahydrate.

4. A process for preparing barium titanate or strontium titanate as claimed in any of claims 1, 2 and 3, wherein mixtures of barium hydroxide or strontium hydroxide and its octahydrate are used.

5. Barium titanate or strontium titanate prepared as claimed in any of claims 1, 2, 3 and 4, wherein the barium titanate or strontium titanate particles have a mean diameter of less than 10 nm.

6. The use of barium titanate or strontium titanate prepared as claimed in any of claims 1, 2, 3 and 4 as a dielectric.

7. The use of barium titanate or strontium titanate prepared as claimed in any of claims 1, 2, 3 and 4 as dielectric in capacitors.