An aluminum nitride granular powder is constituted by aluminum nitride sintered granules, the aluminum nitride granular powder having a maximum peak diameter of 30 m to 200 m in a volume-based particle diameter distribution obtained from maximum lengths of the aluminum nitride sintered granules measured with use of a dry particle image analyzer, with regard to the aluminum nitride sintered granules each of which has a particle diameter of not less than 30% of the maximum peak diameter, a ratio of the number of particles having an HS roundness value of 0.5 to 0.8 as measured with use of the dry particle image analyzer being not less than 15% relative to the aluminum nitride sintered granules each having the particle diameter.

An aluminum nitride granular powder is constituted by aluminum nitride sintered granules, the aluminum nitride granular powder having a maximum peak diameter of 30 m to 200 m in a volume-based particle diameter distribution obtained from maximum lengths of the aluminum nitride sintered granules measured with use of a dry particle image analyzer, with regard to the aluminum nitride sintered granules each of which has a particle diameter of not less than 30% of the maximum peak diameter, a ratio of the number of particles having an HS roundness value of 0.5 to 0.8 as measured with use of the dry particle image analyzer being not less than 15% relative to the aluminum nitride sintered granules each having the particle diameter.

Boron nitride powder according to an embodiment includes a core and a shell surrounding the outside of the core, wherein the core includes at least one metal material of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn or at least one ceramic material of Al2O3, ZrO2, ZnO, MgO, SiC, AlN, Si3N4, and SiO2, wherein the shell comprises boron nitride.

A method of producing a hydrophobic porous alumina by: i) providing a slurry comprising an alumina compound, the slurry having a pH equal to or greater than 7; ii) adding an organic composition comprising carboxylic acids with alkyl hydrocarbon chains having a carbon length less than 14 to the slurry to form an acidic modified slurry; the acidic modified slurry having a pH of between 3 and less than 7; iii) hydrothermally aging the acidic modified slurry to form a hydrothermally aged slurry; and iv) drying the hydrothermally aged slurry.

A solid composite material combining: an inorganic pigment in the form of discrete particles each comprising a colored core and a coating adapted to allow light to pass through and a matrix based on metalloid or metal oxide, said matrix being adapted to allow light to pass through.

A bright pigment of the present invention is a bright pigment including flaky particles and a metal oxide layer covering each surface of the flaky particles. The metal oxide layer has a thickness variation coefficient (standard deviation of thickness of the metal oxide layer/average thickness of the metal oxide layer) of 20% or less. The bright pigment preferably contains a sodium component, and the sodium component is Na.sub.2O. The content of Na.sub.2O in the flaky particles is 3% by mass or more and less than 9.5% by mass. The bright pigment preferably has a specific surface area of 5.0 m.sup.2/g or less.

A bright pigment of the present invention is a bright pigment including flaky particles and a metal oxide layer covering each surface of the flaky particles. The metal oxide layer has a thickness variation coefficient (standard deviation of thickness of the metal oxide layer/average thickness of the metal oxide layer) of 20% or less. The bright pigment preferably contains a sodium component, and the sodium component is Na.sub.2O. The content of Na.sub.2O in the flaky particles is 3% by mass or more and less than 9.5% by mass. The bright pigment preferably has a specific surface area of 5.0 m.sup.2/g or less.

A sealing sheet is provided which is used for sealing of a semiconductor chip embedded in a substrate or a semiconductor chip on a pressure sensitive adhesive sheet in a method of manufacturing a semiconductor device. The method includes a treatment step using an alkaline solution. The sealing sheet includes at least an adhesive layer having curability. The adhesive layer is formed of an adhesive composition that contains a thermoset resin, a thermoplastic resin, and an inorganic filler. The inorganic filler is surface-treated with a surface treatment agent having a minimum coverage area of less than 550 m.sup.2/g. With the sealing sheet, blisters in plating are less likely to occur.

Milling methods that use grinding media particles formed of a ceramic material having an interlamellar spacing of less than 1250 nm.

Core particles produced in situ or introduced as preformed core particles are coated with a layer of carbon. Non-carbon as well as some carbon-based core materials can be utilized. The resulting carbon coated particles can find applications in rubber products, for instance as reinforcement for tire components.