The Penn State Research Foundation

The Perkin-Elmer Corporation

Dennis Tool Company

Dennis Tool Corporation

Dinesh K Agrawal

Rustum N Roy

Jiping Cheng

Mahlon D Dennis

Balasubramaniam Vaidhyanathan

Christopher Yi Fang

Paul D Gigl

Thomas R Shrout

Shalva Gedevanishvili

Paul D Gigil

Vladimir S Stubican

Yogesh Mehrotra

Ronnen A Roy

Herbert A McKinstry

A method of microwave synthesis of phosphors includes a microwave furnace having a microwave chamber; providing starting material in the microwave chamber; and subjecting the starting material to microwaves, whereby the starting material is synthesized into phosphors. An insulation package for use in microwave synthesis is disclosed that includes an insulator having an opening therein, wherein the opening is substantially symmetrically disposed in relation to a central axis of the insulator, and wherein the opening is adapted to receive starting material. A susceptor configuration may be positioned within the cavity, wherein the insulator, the cavity, and the susceptor configuration are substantially symmetrically disposed in relation to an axis of rotation of the insulation package. A microwave furnace for continuous microwave synthesis of phosphors is also disclosed.

Method and apparatus for microwave phosphor synthesis

An apparatus ( ) for the development of transparent alumina ceramics using microwave energy at the frequency between 0.915 and 2.45 GHz inclusive in hydrogen atmosphere at ambient pressure comprises an enclosed, insulated chamber ( ) to retain a workpiece ( ) for the application of microwave energy. The chamber comprises a TE single mode or a multimode microwave cavity into which is mounted a quartz tube ( ). An insulation material ( ), transparent to microwave energy, is positioned within the quartz tube. A port ( ) for the introduction of hydrogen penetrates the cavity so that the microwave sintering of the workpiece is performed in an ultra-pure hydrogen atmosphere. The workpiece is preferably mounted on a refractory ceramic such as alumina tube for the microwave sintering process. A method, preferably using the apparatus, develops transparent alumina ceramics and single crystal sapphire.

Method and apparatus for the preparation of transparent alumina ceramics by microwave sintering

A process for sintering green powder metal, metal alloy or metal composition parts employing microwave energy is described.

Process for sintering powder metal components

Certain embodiments relate to a process for forming a multilayer electrical device. The process includes providing a multilayer structure including layers of a dielectric material and an electrode material. The electrode material may include at least one material selected from the group consisting of nickel and copper. A variety of dielectric materials may be used, such as barium titanate. The method also includes sintering the dielectric material by heating the structure using microwaves in an industrial nitrogen atmosphere, which contains an oxygen partial pressure of 10 to 10 atm.

Microwave sintering of multilayer dielectrics with base metal electrodes

A method of heating an article with microwave energy is described in which a thin layer of highly microwave absorbent powdered material is provided around at least a portion of a container made of microwave transparent material. The article to be heated is placed at a position within the container where the article is adjacent the thin layer of highly microwave absorbent powdered material, and microwave energy is applied to the container.

Microwave processing using highly microwave absorbing powdered material layers

Embodiments include a process including providing a microwave radiation source and a processing chamber. The process includes generating a region of pure magnetic field from the microwave radiation in the processing chamber. A region of pure electric field from the microwave radiation is also generated. A material is positioned in the region of pure magnetic field while no portion of the material is positioned in the region of pure electric field, and the material is heated in the region of pure magnetic field. The heating may be conducted to sinter the material. The material may includes a metal.

Microwave processing in pure H fields and pure E fields

The present disclosure is directed to a method of converting green particles to form finished particles. The apparatus used for sintering incorporates an elongate hollow tube, an insulative sleeve there about to define an elevated temperature zone, and a microwave generator coupled through a wave guide into a microwave cavity incorporated the tube. The particles are moved through the tube at a controlled rate to assure adequate exposure to the microwave radiation. Another form sintered a solid part in a cavity or mold.

Process and apparatus for the preparation of particulate or solid parts

This disclosure sets forth a method and apparatus for microwave processing of green work pieces. Typically, individual green work pieces are formed in a small mold cavity crucible, and individual crucibles are then indexed into and out of a tube for a controlled transit time along the tube. The tube extends in one embodiment through a preheater and then into the microwave cavity, the preheater providing an initial heating step to change the rate of absorption of microwave energy so that microwave sintering is accomplished in the cavity.

Method and apparatus for transporting green work pieces through a

Crystalline solid solutions and diphasic mixtures having a composition of Ca.sub.1-x M.sub.x Zr.sub.4 P.sub.6 O.sub.24, where M is Ba and/or Sr and X is between about 0.25 and 0.75, have been produced which display both low anisotropy and near zero bulk thermal expansion behavior.

Low expansion ceramic

A low expansion ceramic composition is represented by the formula Ca.sub.0.5 Ti.sub.2 P.sub.3 O.sub.12 in which up to 100 percent of the Ca is replaced by one or more of the other alkaline earth metals and alkali metals, the alkali metals being selected from the group consisting of Na, Li, K and combinations thereof and substituted in the ratio of two units of alkali metal for each unit of Ca replaced. Up to 100 percent of the Ti is replaced by one or more members selected from the group consisting of Zr, Sn, Nb, Ta and Cr. For each unit of Cr replacement an approximately equal unit of alkali metal is added. For each unit of Nb and/or Ta replacement an approximately equal unit of Na and/or K replaces a unit of Ca. Up to 100 percent of the P may be replaced by Si and/or S. The total of the amounts of Ca, other alkaline earth metals, Li, K, Ti, Sn, Nb, Ta and Cr is greater then zero. Preferably up to 100 percent of the Ca is replaced by Na, and up to 100 percent of the Ti is replaced by Zr or NaCr. The ceramic composition is especially suitable for optically reflecting films.

Low expansion ceramic material

The present invention is directed to a method of manufacturing low thermal expansion modified cordierite compositions which are especially useful in the manufacture of mirrors for high temperature applications, said method comprising the steps of: providing, on a molecular basis, a mixture of about 2 moles magnesium oxide, 2 moles aluminum oxide, and about 5 moles divided between silicon dioxide and germanium oxide; blending said materials; milling the mixture until finely divided and thoroughly mixed; forming said mixture into a desired shape; gradually heating the shape to a temperature at which reactive sintering occurs and a cordierite type structure is formed; gradually cooling the structure; and hot compacting the structure to consolidate the sintered body to very nearly 100 percent of theoretical density.

Growing community of inventors

State College, PA, United States of America

Dinesh K Agrawal