Cabot Corporation

Sridhar Venigalla

Jeffrey A Kerchner

David M Reed

Dorran L Schultz

Stephen A Costantino

Ricky W Kitchell

Stephen J Krause

Heather L Enman

Robert A Hard

Kathleen A Thrush

Methods to at least partially reduce a niobium oxide are described wherein the process includes mixing the niobium oxide and niobium powder to form a powder mixture that is then heat treated to form heat treated particles which then undergo reacting in an atmosphere which permits the transfer of oxygen atoms from the niobium oxide to the niobium powder, and at a temperature and for a time sufficient to form an oxygen reduced niobium oxide. Oxygen reduced niobium oxides having high porosity are also described as well as capacitors containing anodes made from the oxygen reduced niobium oxides.

Methods of making a niobium metal oxide and oxygen reduced niobium oxides

NbTaO powder wherein x is 0.1 to 0.5 is described. Further, this powder, as well as niobium suboxide powders, can be doped with at least one dopant oxide. Pressed bodies of the powder, sintered bodies, capacitor anodes, and capacitors are also described.

High voltage niobium oxides and capacitors containing same

A method to passivate a metal or metal oxide or metal suboxide powder, especially a valve metal powder such as tantalum or niobium and the passivated powders formed therefrom are described. The method includes passivating a starting powder with a gas having at least 25 wt. % oxygen present. Passivation is preferably achieved without performing any evacuation steps. Capacitors made from the passivated powders are also described.

Passivation of tantalum and other metal powders using oxygen

Valve metal suboxides having a primary suboxide phase and optionally a secondary suboxide phase, a valve metal phase, and/or at least one tertiary suboxide phase can be present in varying amounts. Also disclosed is anodes and capacitors containing the valve metal suboxides of the present invention. Also, a method to prepare a valve metal suboxide is further described which includes granulating one or more of the starting materials individually or together and/or granulating the final product.

Phase formation of oxygen reduced valve metal oxides and granulation methods

The invention provides a method for producing barium titanate-based particulate compositions. The method includes a heat treatment step, separate from a sintering step, that involves treating a barium titanate-based particulate composition at a temperature between about 700&deg; C. and about 1150&deg; C. to increase average particle size. The increased average particle size can improve the electrical properties (i.e., dielectric constant and dissipation factor) of the heat-treated composition as compared to the composition prior to heat treating. The heat-treated composition may be further processed, for example, by producing a dispersion which may be cast and sintered to form a dielectric layer in electronic components including MLCCs.

Production of dielectric particles

The invention provides dielectric compositions and methods of forming the same. The dielectric compositions may be used to form dielectric layers in electronic devices such as multilayer ceramic capacitors (MLCCs) and, in particular, MLCCs which include base metal electrodes. The dielectric compositions include a barium titanate-based material and several dopants. The type and concentration of each dopant is selected to provide the dielectric composition with desirable electrical properties including a stable capacitance over a temperature range, a low dissipation factor, and a high capacitance. Preferably, MLCCs including dielectric layers formed with the composition satisfy X7R and/or X5R requirements.

Dielectric compositions and methods to form the same

Coated barium titanate-based particles and a process to coat the particles are provided. The coating includes a dopant metal compound that is insoluble in water under alkaline conditions. The dopant metal in the coating is selected from the group of metals which form oxides or hydroxides that are soluble in water under alkaline conditions such as tungsten, molybdenum, vanadium, and chromium. The process involves precipitating the insoluble compound from an aqueous medium as a coating on surfaces of barium titanate-based particles. The coated barium titanate-based particles may be further processed, for example, to form dielectric materials which may be used in many electronic applications such as in MLCCs applications.

Coated barium titanate-based particles and process

Barium titanate-based particles having a coating comprising an oxide, hydrous oxide, hydroxide or organic acid salt of a metal other than barium or titanium, wherein at least 90 percent of said particles have a particle size less than 0.9 micrometer when said particles are dispersed by high shear mixing, useful in the fabrication of thin, fine-grained dielectric layers for multilayer ceramic capacitors with high breakdown voltage.

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Macungie, PA, United States of America

Sridhar Venigalla