Abstract: A method for changing the color of a diamond. The method comprises placing the diamond in a substrate holder in a chemical vapor deposition (CVD) equipment. The CVD equipment is maintained at pressures near or below atmospheric pressure. A mixture of gases including hydrogen is introduced inside the CVD equipment. The introduced mixture of gases is energized by using microwave radiation to heat the diamond to temperatures above 1400° C. Then, the diamond is maintained at temperatures above 1400° C. for few seconds to few hours.

Abstract: We disclose a colorless composition comprising metal particles (e.g., silver nanoparticles) and water, wherein said particles comprise an interior of elemental metal (e.g., silver) and an exterior of metal oxide (e.g., one or more silver oxide(s)), wherein the metal nanoparticles are present in the water at a level of about 5-40 ppm, and wherein the composition manifests significant antimicrobial properties. Methods of use of the composition are described. The composition can be incorporated into a hydrogel with essentially no loss of antimicrobial properties. Various metal-containing compositions with unexpected biological efficacy are also disclosed.

Abstract: Multimode and single mode microwave energy is used to improve the extraction of metals from chalcogenide minerals. In one process microwave energy is used to comminute the mineral after which the mineral is reacted with acid in the presence of microwave energy. Following treatment the mineral is removed and the extracted metal is recovered from the acid. In another process chalcogenide minerals are exposed to the magnetic field maximum or the electrical field maximum of a single mode electromagnetic energy. This treatment causes a phase separation between metals and silicates within the mineral leaving metal rich regions from which the metal can be readily recovered by traditional methods.

Abstract: An apparatus (10) 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 (14) to retain a workpiece (12) for the application of microwave energy. The chamber comprises a TE103 single mode or a multimode microwave cavity into which is mounted a quartz tube (18). An insulation material (20), transparent to microwave energy, is positioned within the quartz tube. A port (28) 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.

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

Abstract: An apparatus (10) 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 (14) to retain a workpiece (12) for the application of microwave energy. The chamber comprises a TE103 single mode or a multimode microwave cavity into which is mounted a quartz tube (18). An insulation material (20), transparent to microwave energy, is positioned within the quartz tube. A port (28) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention relates generally to methods for the synthesis of various solids such as diamonds, diamonds films, boron nitride and other similar materials. This invention specifically relates to utilizing novel sources of reaction species (e.g., in the case of diamond formation, novel sources of carbon and/or hydrogen and/or seeds) for the manufacture of various materials and the use of such materials for various commercial purposes.

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

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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Compositionally triphasic nanocomposite gel is made by mixing two or more sols of ceramic precursor oxides. Such gel is then dried and ground to a fine powder which is pressed into compact bodies. The compact bodies are thereafter fired in a sintering oven at from 1100.degree. C. to 1400.degree. C. and, aided by the heat of reaction of the two or more nono gel powders, the (heterogeneous) mixture of such powders crystallizes into a homogeneous crystalline ceramic of .alpha.-cordierite at up to 100% of theoretical density. Thus, novel method of manufacture and novel ceramic end-product are provided.

Abstract: Ceramic oxide diphasic xerogels of structurally dissimilar phases (crystalline and amorphous, semicrystalline or noncrystalline) but compositionally similar phases will be converted to crystalline ceramic oxide products having enhanced densification when subjected to substantially lower sintering temperature.

Abstract: Cesium can be selectively recovered from a nuclear waste solution containing cesium together with other metal ions by contact with a modified phlogopite which is a hydrated, sodium phlogopite mica. Once the cesium has entered the modified phlogopite it is fixed and can be safely stored for long periods of time.

Abstract: 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.

Abstract: 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.