A first object of the present invention is to provide a surface-modified inorganic nitride having excellent dispersibility. Furthermore, a second object of the present invention is to provide a composition, a thermally conductive material, and a device with a thermally conductive layer which contain the surface-modified inorganic nitride. The surface-modified inorganic nitride of the present invention includes an inorganic nitride, and a compound which is represented by General Formula (I) and is adsorbed onto a surface of the inorganic nitride. ##STR00001## In General Formula (1), n represents an integer of 3 or greater. X represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Y represents a single bond, O, CO, COO, OCO, S, CS, NR.sup.A, N?N, or a divalent unsaturated hydrocarbon group. R.sup.A represents a hydrogen atom or an alkyl group. R.sup.1 and R.sup.2 each independently represent a substituent. Here, at least one of R.sup.1 or R.sup.2 represents a monovalent organic group containing a specific functional group selected from the group A of specific functional groups. In General Formula (1), a plurality of X's may be the same as or different from each other. Moreover, a plurality of Y's may be the same as or different from each other.

A method of producing ceramic wafer includes a forming step and processing step. The processing step includes forming positioning notch or positioning, flat edge and edge profile, which avoids the ceramic wafers to have processing defect during cutting, grinding, and polishing, for increasing yield. The ceramic particles for producing ceramic wafer include nitride ceramic powder, oxide ceramic powder, and nitride ceramic powder. The ceramic wafer has low dielectric constant, insulation, and excellent heat dissipation, which can be applied for the need of semiconductor process, producing electric product and semiconductor equipment.

A method of producing ceramic wafer includes a forming step and processing step. The processing step includes forming positioning notch or positioning, flat edge and edge profile, which avoids the ceramic wafers to have processing defect during cutting, grinding, and polishing, for increasing yield. The ceramic particles for producing ceramic wafer include nitride ceramic powder, oxide ceramic powder, and nitride ceramic powder. The ceramic wafer has low dielectric constant, insulation, and excellent heat dissipation, which can be applied for the need of semiconductor process, producing electric product and semiconductor equipment.

A method for effectively removing minute impurities of 1 ?m or less in size that are present on a surface of an aluminum nitride single-crystal substrate without etching the surface includes scrubbing a surface of an aluminum nitride single-crystal substrate using a polymer compound material having lower hardness than an aluminum nitride single crystal, and an alkali aqueous solution having 0.01-1 mass % concentration of potassium hydroxide or sodium hydroxide, the alkali aqueous solution being absorbed in the polymer compound material.

The present invention relates to a method of manufacturing aluminum nitride and aluminum nitride prepared by the same. Pure aluminum powder having a median particle size (D50) of 1.52 m was heated to a temperature in a range of 595 C.900 C. in a nitrogen containing atmosphere comprising nitrogen and argon gases, at atmospheric pressure for one hour to obtain aluminum nitride with a degree of nitridation exceeding 93%. According to the present invention aluminum nitride may be produced with high yield using a simple and inexpensive one-step heating method in a relatively short period of time.

Thermal energy storage (TES) systems based on metal hydride pairs using new class of high efficiency materials are evaluated. The use of low temperature metal cost effective material such hydrides NaAlH4 and Na3AlH6 became possible. In order to obtain high efficiency at reasonable cost high temperature materials were altered by the addition of materials to form reversible alloys and hydrides. The compounds were cycled to determine stability of hydrogen capacity over extended number of cycling. A thermal energy storage system based on two metal hydride pairs such as CaAl/CaH2/Al:NaAlH.sub.4, Ca.sub.2Si/CaH.sub.2/Si:Na.sub.3AlH.sub.6 and NaMgH.sub.2FSi/Mg2SiNaF:Na.sub.3AlH.sub.6 allows low cost and high efficiency performance.

Thermal energy storage (TES) systems based on metal hydride pairs using new class of high efficiency materials are evaluated. The use of low temperature metal cost effective material such hydrides NaAlH4 and Na3AlH6 became possible. In order to obtain high efficiency at reasonable cost high temperature materials were altered by the addition of materials to form reversible alloys and hydrides. The compounds were cycled to determine stability of hydrogen capacity over extended number of cycling. A thermal energy storage system based on two metal hydride pairs such as CaAl/CaH2/Al:NaAlH.sub.4, Ca.sub.2Si/CaH.sub.2/Si:Na.sub.3AlH.sub.6 and NaMgH.sub.2FSi/Mg2SiNaF:Na.sub.3AlH.sub.6 allows low cost and high efficiency performance.

The present invention provides method for producing a spherical aluminum nitride powder. In an embodiment, the method comprises mixing an Al precursor and a flux in a solvent to produce a mixed solution, spray-drying the mixed solution to form a spray-dried powder, mixing the spray-dried powder and a carbon-based material to form a mixture, heat treating the mixture in a nitrogen atmosphere to form a heat-treated compound, and decarbonizing the heat-treated compound in an air atmosphere, wherein the flux is at least one selected from the group consisting of Cu.sub.2O, TiO.sub.2, Bi.sub.2O.sub.3, and CuO, or a mixture of at least one selected from the group consisting of Cu.sub.2O, TiO.sub.2, Bi.sub.2O.sub.3, and CuO and at least one selected from the group consisting of CaF.sub.2 and Y.sub.2O.sub.3.

The present invention provides method for producing a spherical aluminum nitride powder. In an embodiment, the method comprises mixing an Al precursor and a flux in a solvent to produce a mixed solution, spray-drying the mixed solution to form a spray-dried powder, mixing the spray-dried powder and a carbon-based material to form a mixture, heat treating the mixture in a nitrogen atmosphere to form a heat-treated compound, and decarbonizing the heat-treated compound in an air atmosphere, wherein the flux is at least one selected from the group consisting of Cu.sub.2O, TiO.sub.2, Bi.sub.2O.sub.3, and CuO, or a mixture of at least one selected from the group consisting of Cu.sub.2O, TiO.sub.2, Bi.sub.2O.sub.3, and CuO and at least one selected from the group consisting of CaF.sub.2 and Y.sub.2O.sub.3.

In a first step of a method for producing a transparent AlN sintered body, first, a formed body is prepared by forming a mixture obtained by mixing a sintering aid with an AlN raw-material powder containing a plate-like AlN powder whose plate surface is a c-plane and which has an aspect ratio of 3 or more. At this time, the mixture is formed such that the plate surface of the plate-like AlN powder is disposed along a surface of the formed body. In a second step, an oriented AlN sintered body is obtained by subjecting the formed body to hot-press sintering in a non-oxidizing atmosphere while applying a pressure to the surface of the formed body. In a third step, a transparent AlN sintered body is obtained by sintering the oriented AlN sintered body at normal pressure in a non-oxidizing atmosphere to remove a component derived from the sintering aid.