A microwave heating apparatus according to the present disclosure includes a housing, a drum unit disposed rotatably on the housing and into which heating target substance and gas are introduced, and at least one heating unit heating the drum unit by applying microwaves to the drum unit. With a microwave heating apparatus and a method for manufacturing an aluminum nitride using the same of the present disclosure, an aluminum nitride may be manufactured at a lower temperature than that of conventional methods, thereby reducing manufacturing time. Additionally, a microwave heating apparatus according to the present disclosure may significantly reduce power consumption compared to an electric heating apparatus.

To provide an aluminum nitride particle having a hexagonal columnar barrel part and bowl-like projection parts at both ends of the columnar part, wherein the long diameter (D) of the barrel part is 10 to 250 ?m, the ratio (L.sub.1/D) of the distance (L.sub.1) between the apexes of the two projection pars to the long diameter (D) of the barrel part is 0.7 to 1.3, and the percentage of the length or thickness (L.sub.2) of the barrel part to the distance (L.sub.1) between the apexes of the two projection parts is 10 to 60%. The aluminum nitride particle can provide high heat conductivity and excellent electric insulation to a resin when it is filled into the resin.

A method of making Aluminum Nitride (AlN) from nut shells comprising preparing powders of agricultural nuts, preparing powders of nanocrystalline Al.sub.2O.sub.3, mixing the powders and thereby forming a homogenous sample powder of agricultural nuts and Al.sub.2O.sub.3, pressurizing the homogenous sample powder into a disk, heat treating or pyrolyzing the disk in a nitrogen atmosphere, reacting the disk and the nitrogen atmosphere and forming AlN, and wherein the AlN is nano-structured AlN and in a pure form and in the wurtzite phase of AlN. A method of producing Aluminum Nitride comprising milling nuts into a powder, milling a powder of nanocrystalline Al.sub.2O.sub.3, mixing, pressing into a pellet, providing nitrogen, heating, and forming AlN. An Aluminum Nitride product from preparing powders of nuts and Al.sub.2O.sub.3, mixing, and forming a powder, pressurizing into a disk, pyrolyzing in nitrogen, and forming AlN.

A method for preparing a spherical aluminum nitride granule includes (A) providing an aluminum oxide powder and a resin, followed by dissolving the aluminum oxide powder and the resin in a solvent to form a mixed slurry; (B) performing spray drying on the mixed slurry to form a spherical granule; (C) performing carbonization on the spherical granule in an inert atmosphere to form a carbonized spherical granule; (D) performing carbothermic reduction on the carbonized spherical granule in a nitrogen atmosphere to form a spherical aluminum nitride granule; (E) performing a densification sintering thermal treatment continuously on the spherical aluminum nitride granule in a nitrogen atmosphere; and (F) performing decarbonization on the densified spherical aluminum nitride granule in a nitrogen atmosphere to form densified spherical aluminum nitride sintered particles of tens of micrometers. Accordingly, the manufacturing process is simple and energy-saving.

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.

The present invention provides, as an aluminum nitride powder excellent in the water resistance, an aluminum nitride powder subjected to a surface treatment with a predetermined organic compound. The present invention also provides a resin composition including the aluminum nitride powder and a resin, and a thermal conductive molded article obtained by molding the resin composition.

The present invention provides, as an aluminum nitride powder excellent in the water resistance, an aluminum nitride powder subjected to a surface treatment with a predetermined organic compound. The present invention also provides a resin composition including the aluminum nitride powder and a resin, and a thermal conductive molded article obtained by molding the resin composition.

An aluminum nitride powder preparation method, comprises uniformly mixing aluminum with a nitrogen source, carbon source, and halide to form a mixed powder, which is then subject to a high-temperature direct nitridation reaction in a nitrogen-containing gas atmosphere and finally carbon removal in the atmosphere to form a high-purity aluminum nitride powder. The carbon source is mixed with the aluminum powder to form a separator to avoid the problem of melting and agglomeration of aluminum powder. The nitrogen source is mixed into the aluminum powder, and when the nitrogen source is thermally decomposed and the generated gas escapes, numerous pores can be created in the mixed powder, so that the external nitrogen-containing gas atmosphere can easily enter the mixed powder to react with aluminum, thereby improving the nitridation efficiency of aluminum powder.

Provided is an aluminum nitride powder useful as a raw material when an aluminum nitride sintered body excellent as an insulating high thermal conductive member is manufactured, particularly, by press molding. An aluminum nitride powder includes particles having a sphericity of 0.8 or more, in which a median size D.sub.50 obtained by a laser diffraction method is 0.5 to 1.5 m, a ratio D.sub.90/D.sub.50 of a particle size D.sub.90 corresponding to a cumulative undersize distribution of 90% to the D.sub.50 is 2.2 or less, a BET specific surface area is 2 to 4 m.sup.2/g, and a total oxygen concentration is 0.6 to 1.2% by mass.