Title: Dielectric composite materials and method for preparing

Abstract

The invention allows the fabrication of small, dense beads of dielectric materials with selected compositions, which are incorporated into a polymeric matrix for use in capacitors, filters, and the like. A porous, generally spherical bead of hydrous metal oxide containing titanium or zirconium is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead may be washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) at elevated temperature and pressure to convert the bead into a mixed hydrous titanium- or zirconium-alkaline earth oxide while retaining the generally spherical shape. Alternatively, the gel bead may be made by coprecipitation. This mixed oxide bead is then washed, dried and calcined to produce the desired (BaTiO.sub.3, PbTiO.sub.3, SrZrO.sub.3) structure. The sintered beads are incorporated into a selected polymer matrix. The resulting dielectric composite material may be electrically "poled" if desired.

Inventors:

Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.; Felten, John J.

Issue Date:

Tue Jul 29 00:00:00 EDT 2003

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1174424

Patent Number(s):

6600645

Application Number:

10/256,843

Assignee:

UT-Battelle, LLC (Oak Ridge, TN)

Patent Classifications (CPCs):

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01G - COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01P - INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

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C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01G - COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F

C01G23/003 - {Titanates
C01G23/006 - {Alkaline earth titanates}
C01G23/0536 - {by hydrolysing chloride-containing salts}

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01P - INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

C01P2004/60 - Particles characterised by their size
C01P2004/61 - Micrometer sized, i.e. from 1-100 micrometer

C - CHEMISTRY C04 - CEMENTS C04B - LIME, MAGNESIA

C04B2235/02 - Composition of constituents of the starting material or of secondary phases of the final product
C04B2235/3215 - Barium oxides or oxide-forming salts thereof
C04B2235/3224 - Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
C04B2235/3232 - Titanium oxides or titanates, e.g. rutile or anatase
C04B2235/3236 - Alkaline earth titanates
C04B2235/3296 - Lead oxides, plumbates or oxide forming salts thereof, e.g. silver plumbate
C04B2235/44 - Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
C04B2235/449 - Organic acids, e.g. EDTA, citrate, acetate, oxalate
C04B2235/528 - Spheres
C04B2235/79 - Non-stoichiometric products, e.g. perovskites
C04B2235/94 - Products characterised by their shape
C04B35/462 - based on titanates
C04B35/468 - based on barium titanates
C04B35/472 - based on lead titanates
C04B35/6281 - {Alkaline earth metal oxides}
C04B35/62886 - {by wet chemical techniques}

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01G - CAPACITORS

H01G4/206 - {inorganic and synthetic material}

H - ELECTRICITY H05 - ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR H05K - PRINTED CIRCUITS

H05K1/162 - {incorporating printed capacitors}

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DOE Contract Number:  

AC05-00OR22725

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE