Nano-structures of Aluminum Nitride and a method of producing nano-structures of Aluminum Nitride from nut shells comprising milling agricultural nuts into a fine nut powder, milling nanocrystalline Al.sub.2O.sub.3 into a powder, mixing, pressing the fine nut powder and the powder of nanocrystalline Al.sub.2O.sub.3, heating the pellet, maintaining the temperature of the pellet at about 1400° C., cooling the pellet, eliminating the residual carbon, and forming nano-structures of AlN. An Aluminum Nitride (AlN) product made from the steps of preparing powders of agricultural nuts using ball milling, preparing powders of nanocrystalline Al.sub.2O.sub.3, mixing the powders of agricultural nuts and the powders of nanocrystalline Al.sub.2O.sub.3 forming a homogenous sample powder of agricultural nuts and Al.sub.2O.sub.3, pressurizing, pyrolizing the disk, and reacting the disk and the nitrogen atmosphere and forming AlN.

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 μm, 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.

Nano-structures of Aluminum Nitride and a method of producing nano-structures of Aluminum Nitride from nut shells comprising milling agricultural nuts into a fine nut powder, milling nanocrystalline Al.sub.2O.sub.3 into a powder, mixing, pressing the fine nut powder and the powder of nanocrystalline Al.sub.2O.sub.3, heating the pellet, maintaining the temperature of the pellet at about 1400° C., cooling the pellet, eliminating the residual carbon, and forming nano-structures of AlN. An Aluminum Nitride (AlN) product made from the steps of preparing powders of agricultural nuts using ball milling, preparing powders of nanocrystalline Al.sub.2O.sub.3, mixing the powders of agricultural nuts and the powders of nanocrystalline Al.sub.2O.sub.3 forming a homogenous sample powder of agricultural nuts and Al.sub.2O.sub.3, pressurizing, pyrolyzing the disk, and reacting the disk and the nitrogen atmosphere and forming AlN.

An aluminum nitride particle including at least a first truncated six-sided pyramid (1-a) and a second truncated six-sided pyramid (1-b), the aluminum nitride particle having a shape such that a lower base (3) of the first truncated six-sided pyramid (1-a) and a lower base (3) of the second truncated six-sided pyramid (1-b) face each other, the first truncated six-sided pyramid (1-a) and the second truncated six-sided pyramid (1-b) each having an upper base (2) with an area S1 of not less than 60 μm.sup.2 and not more than 4800 μm.sup.2, and each having a ratio (S1/S2) of the area S1 to an area S2 of the lower base (3) being not less than 0.5 and less than 1, the first truncated six-sided pyramid (1-a) and the second truncated six-sided pyramid (1-b) respectively having a height h1 and a height h2 each being not less than 5 μm and not more than 20 μm.

An aluminum nitride particle including at least a first truncated six-sided pyramid (1-a) and a second truncated six-sided pyramid (1-b), the aluminum nitride particle having a shape such that a lower base (3) of the first truncated six-sided pyramid (1-a) and a lower base (3) of the second truncated six-sided pyramid (1-b) face each other, the first truncated six-sided pyramid (1-a) and the second truncated six-sided pyramid (1-b) each having an upper base (2) with an area Si of not less than 60 μm.sup.2 and not more than 4800 μm.sup.2, and each having a ratio (S1/S2) of the area Si to an area S2 of the lower base (3) being not less than 0.5 and less than 1, the first truncated six-sided pyramid (1-a) and the second truncated six-sided pyramid (1-b) respectively having a height h1 and a height h2 each being not less than 5 μm and not more than 20 μm.

An aluminum nitride particle including: a plurality of planes randomly arranged in a surface of the particle, the plurality of planes forming an obtuse ridge part or an obtuse valley part in the surface of the particle, the plurality of planes being observable in a scanning electron micrograph with 500 times magnification; wherein the particle has a longer diameter L of 20 to 200 μm; a ratio L/D of the longer diameter L (unit: μm) to a shorter diameter D (unit: μm) of the particle is 1 to 1.25; and the plurality of planes comprise a first plane, wherein an area S (unit: μm.sup.2) of the first plane satisfies S/L≥1.0 μm.

Aluminum nitride particles which are excellent in high thermal conductivity and useful as a filler for a heat dissipating material and which have good fluidity for improving the fillability, that is, spherical AlN particles containing Zr atoms with respect to Al atoms in an amount of a molar ratio Zr/Al=4.0×10.sup.−4 to 4.2×10.sup.−2, having an AlN conversion rate of 70.0% or more, and having a circularity of 0.85 to 1.00.

A filler composition is excellent in heat dissipation. A silicone resin composition includes the filler composition. A heat dissipation element is made by molding the silicone resin composition. More specifically, the filler composition has a filler (A1) having an average particle diameter of 0.3-1.0 μm, a filler (A2) having an average particle diameter of 3-15 μm, and a filler (A3) having an average particle diameter of 35-140 μm, wherein the filler (A1), the filler (A2) and the filler (A3) are one or more kinds selected from alumina, magnesia, AlN covered alumina, AlN and SN.

Aluminum nitride particles used as a material of an aluminum nitride sintered compact are disclosed. The aluminum nitride particles may have a same crystal orientation. The aluminum nitride particles each have an aspect ratio of 3 or more, a plate-like shape, a planar length of 0.6 μm or more and 20 μm or less, and a thickness length of 0.05 μm or more and 2 μm or less.

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 μm, 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.