Abstract: An alumina powder containing alumina particles, wherein among the alumina particles, an average sphericity of an alumina particle having a projected area equivalent circle diameter of 50 nm or more as determined by microscopy is 0.80 or more, a content ratio of an alumina particle having a particle diameter of 75 ?m or more is 0.05% by mass or less, an average particle diameter of the alumina powder is 0.2 ?m or more and 15 ?m or less, the average particle diameter is a particle diameter measured using a laser light diffraction scattering particle size distribution analyzer, and an amount of water included in the alumina powder measured by a specific measurement method is 30 ppm or more and 500 ppm or less.

Abstract: A semiconductor encapsulation material which exhibits a low viscosity and further improved moldability in encapsulation even when highly loaded with an inorganic filler; an amorphous siliceous powder suitable for the preparation of a resin composition useful as the encapsulation material; and a process for the production of the amorphous siliceous powder. An amorphous siliceous powder having a content of Si and Al of 99.5 mass % or above in terms of oxides, wherein the Al content in the particle size region of 15 ?m to less than 70 ?m is 100 to 30000 ppm in terms of oxides; the Al content in the particle size region of 3 ?m to less than 15 ?m is 100 to 7000 ppm in terms of oxides; and the Al content in the whole particle size region is 100 to 25000 ppm in terms of oxides. It is preferable that the (A)/(B) ratio of the Al content (A) in the particle size region of 15 ?m to less than 70 ?m to the Al content (B) in the particle size region of 3 ?m to less than 15 ?m be 1.0 to 20.

Abstract: A silica powder containing an ultrafine powder in an amount of from 0.1 to 20 mass % and having an average sphericity of at least 0.85, wherein the ultrafine powder has, as the particle size measured by a dynamic light scattering particle size distribution measuring apparatus, an average particle size of from 150 to 250 nm, less than 10 mass % of the ultrafine powder having a particle size of at most 100 nm being less than 10 mass % (not including 0 mass %) and from 10 to 50 mass % of the ultrafine powder having a particle size exceeding 100 nm and not exceeding 150 nm.

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention herein provides ceramic powder which is to be incorporated into rubber or a resin and which can be used as, for instance, a semiconductor-sealing material and for the preparation of a composition excellent in the narrow interstice-filling up property and moldability. The ceramic powder has a multiple peak-frequency type particle size distribution which has at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer, wherein the maximum particle size observed for the first peak falls within the range of from 12 to 30 ?m; that observed for the second peak falls within the range of from 2 to 7 ?m; the content of the particles having a particle size of greater than 7 ?m and less than 12 ?m is not more than 18% (including 0%); and wherein the ratio (F2/F1) of the frequency value F2 of the maximum particle size for the second peak to that F1 of the maximum particle size for the first peak ranges from 0.5 to 1.3.

Abstract: Provided is a semiconductor sealing material in which the contamination rate of conductive foreign matter is extremely low. Further provided are powder comprising spherical silica powder and/or spherical alumina powder suitable for preparing such a semiconductor sealing material, a method for producing the same, and a resin composition. The powder comprises spherical silica powder and/or spherical alumina powder, and when a color reaction test for particles using an aqueous potassium ferricyanide solution under specific conditions is performed for magnetizable particles having a particle size of 45 [mu]m or more, the ratio of the number of particles which develop color to the total number of the magnetizable particles is 20% or less. Such powder can be produced by supplying a specific amount of oxygen gas and/or water vapor to at least one arbitrary site at which the atmospheric temperature is 1600 to 1800 DEG C.

Abstract: The present invention herein provides ceramic powder which is to be incorporated into rubber or a resin and which can be used as, for instance, a semiconductor-sealing material and for the preparation of a composition excellent in the narrow interstice-filling up property and moldability. The ceramic powder has a multiple peak-frequency type particle size distribution which has at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer, wherein the maximum particle size observed for the first peak falls within the range of from 12 to 30 ?m; that observed for the second peak falls within the range of from 2 to 7 ?m; the content of the particles having a particle size of greater than 7 ?m and less than 12 ?m is not more than 18% (including 0%); and wherein the ratio (F2/F1) of the frequency value F2 of the maximum particle size for the second peak to that F1 of the maximum particle size for the first peak ranges from 0.5 to 1.3.

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: To provide an amorphous silica powder suitable for a sealing material for semiconductors having improved HTSL properties and HTOL properties, and a process for its production. An amorphous silica powder containing Al in an amount of from 0.03 to 20 mass % as calculated as Al2O3 measured by atomic absorption spectrophotometry, wherein the average particle size is at most 50 ?m, and when the amorphous silica powder is divided according to the average particle size into two powders, a powder having a particle size smaller than the average particle size has a higher content as calculated as Al2O3 than a powder having a particle size larger than the average particle size.

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention herein provides ceramic powder which is to be incorporated into rubber or a resin and which can be used as, for instance, a semiconductor-sealing material and for the preparation of a composition excellent in the narrow interstice-filling up property and moldability. The ceramic powder has a multiple peak-frequency type particle size distribution which has at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer, wherein the maximum particle size observed for the first peak falls within the range of from 12 to 30 ?m; that observed for the second peak falls within the range of from 2 to 7 ?m; the content of the particles having a particle size of greater than 7 ?m and less than 12 ?m is not more than 18% (including 0%); and wherein the ratio (F2/F1) of the frequency value F2 of the maximum particle size for the second peak to that F1 of the maximum particle size for the first peak ranges from 0.5 to 1.3.

Abstract: A semiconductor encapsulation material which exhibits a low viscosity and further improved moldability in encapsulation even when highly loaded with an inorganic filler; an amorphous siliceous powder suitable for the preparation of a resin composition useful as the encapsulation material; and a process for the production of the amorphous siliceous powder. An amorphous siliceous powder having a content of Si and Al of 99.5 mass % or above in terms of oxides, wherein the Al content in the particle size region of 15 ?m to less than 70 ?m is 100 to 30000 ppm in terms of oxides; the Al content in the particle size region of 3 ?m to less than 15 ?m is 100 to 7000 ppm in terms of oxides; and the Al content in the whole particle size region is 100 to 25000 ppm in terms of oxides. It is preferable that the (A)/(B) ratio of the Al content (A) in the particle size region of 15 ?m to less than 70 ?m to the Al content (B) in the particle size region of 3 ?m to less than 15 ?m be 1.0 to 20.

Abstract: To provide an amorphous silica powder suitable for a sealing material for semiconductors having improved HTSL properties and HTOL properties, and a process for its production. An amorphous silica powder containing Al in an amount of from 0.03 to 20 mass % as calculated as Al2O3 measured by atomic absorption spectrophotometry, wherein the average particle size is at most 50 ?m, and when the amorphous silica powder is divided according to the average particle size into two powders, a powder having a particle size smaller than the average particle size has a higher content as calculated as Al2O3 than a powder having a particle size larger than the average particle size.

Abstract: The present invention herein provides fine inorganic hollow powder having a high hollowness rate, which can be incorporated into, for instance, a low dielectric rubber or resin composition. The inorganic hollow powder has an average hollowness rate of higher than 70% by volume and an average particle size ranging from 3 to 20 ?m and the powder preferably has an average hollowness rate ranging from 75 to 85% by volume, an average particle size ranging from 5 to 15 ?m, a maximum particle size of not more than 25 ?m, a specific surface area of not more than 10 m2/g, an average sphericity degree of not less than 0.90 and a purity of not less than 99% by mass.

Abstract: Inorganic hollow powder is provided having a high purity, an enhanced fineness and a high hollowness. Specifically, inorganic hollow powder is provided having an average particle diameter of 1 to 5 ?m, the maximum particle diameter of 20 ?m or less, a particle size distribution standard deviation of 3 ?m or less, and an average hollowness of 35 to 70 vol %. The inorganic hollow powder is obtained, for instance, by supplying, via an inorganic feed material powder supply pipe at a discharge rate of 80 m/s or more, inorganic raw material powder having a specific surface area of 500 m2/g or more and an average particle diameter of 7 ?m or less, into a flame formed by a burner comprising at least a triple pipe portion sequentially arranged with, in order from outside, a combustion supporting gas supply pipe, a combustible gas supply pipe and the inorganic feed material powder supply pipe.

Abstract: To provide a silica powder which is excellent in flowability and packing properties and which is less likely to form a flash, a process for its production, and a composition having it incorporated in at least one of a rubber and a resin, particularly a sealing material. A silica powder containing an ultrafine powder in an amount of from 0.1 to 20 mass % and having an average sphericity of at least 0.85, wherein the ultrafine powder has, as the particle size measured by a dynamic light scattering particle size distribution measuring apparatus, an average particle size of from 150 to 250 nm, a content of particles having a particle size of at most 100 nm being less than 10 mass % (not including 0 mass %) and a content of particles having a particle size exceeding 100 nm and not exceeding 150 nm being from 10 to 50 mass %. A process for producing a silica powder, which comprises spraying a silica powder material to a high temperature zone of at least 1,750° C.

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention herein provides ceramic powder which is to be incorporated into rubber or a resin and which can be used as, for instance, a semiconductor-sealing material and for the preparation of a composition excellent in the narrow interstice-filling up property and moldability. The ceramic powder has a multiple peak-frequency type particle size distribution which has at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer, wherein the maximum particle size observed for the first peak falls within the range of from 12 to 30 ?m; that observed for the second peak falls within the range of from 2 to 7 ?m; the content of the particles having a particle size of greater than 7 ?m and less than 12 ?m is not more than 18% (including 0%); and wherein the ratio (F2/F1) of the frequency value F2 of the maximum particle size for the second peak to that F1 of the maximum particle size for the first peak ranges from 0.5 to 1.3.

Abstract: An electromagnetic relay is provided which enables a coating process with a coating agent even after being mounted on a printed circuit board having undergone reflow heating by preventing invasion of water while maintaining air permeability. A main body making up the electromagnetic relay includes an electrical contact portion, electromagnetic driving portion and molded resin base and is covered with the molded resin cover. One or more through holes are formed by applying laser beam from a rear side of the molded resin cover. A spot diameter of each through hole on a surface of an outside of the molded resin cover is 0.1 ?m to 10 ?m. Instead of the molded resin cover, through-holes each having a size of 0.1 ?m to 10 ?m may be formed by applying the laser beam to the molded resin base.

Abstract: The present invention herein provides fine inorganic hollow powder having a high hollowness rate, which can be incorporated into, for instance, a low dielectric rubber or resin composition. The inorganic hollow powder has an average hollowness rate of higher than 70% by volume and an average particle size ranging from 3 to 20 ?m and the powder preferably has an average hollowness rate ranging from 75 to 85% by volume, an average particle size ranging from 5 to 15 ?m, a maximum particle size of not more than 25 ?m, a specific surface area of not more than 10 m2/g, an average sphericity degree of not less than 0.90 and a purity of not less than 99% by mass.