Abstract: Provided are: spherical crystalline silica particles which ensure higher productivity and lower production costs than conventional ones, contain plenty of quartz having high thermal conductivity, have high fluidity, high dispersibility, high filling property, and low abrasion property, and are also applicable to semiconductor field; and a method for producing the spherical crystalline silica particles. The crystalline silica particles are characterized in that with respect to the total mass of the particles, the content of a crystal phase is at least 90 mass % and the content of a quartz crystal is at least 70 mass %. In addition, at least one kind of alkali metals may be contained in an amount of 0.4-5 mass % in terms of oxides, with respect to the total mass of the particles. Furthermore, at least one kind of alkaline earth metals may be contained in an amount of 1-5 mass % in terms of oxides, with respect to the total mass of the particles.

Abstract: The purpose of the present invention is to provide: silica particles of which the maximum particle diameter can be minimized and which can achieve proper fluidability that cannot be achieved by the conventional techniques; and silica spherical particles which, when used as a filler for a heat-dissipating sheet, can achieve excellent heat conductivity and flexibility. Silica spherical particles characterized in that, when particles each having a size of 5 ?m or more and imaged by an optical measurement are observed, the particle diameter of each of the particles, which is determined from the image, satisfies the following requirements. Requirements: D99?29 ?m, and 10 ?m?Dmode<D99, and D99/Dmode?1.5, and Dmode?20 ?m.

Abstract: Provided are: spherical crystalline silica particles which ensure higher productivity and lower production costs than conventional ones, contain plenty of quartz having high thermal conductivity, have high fluidity, high dispersibility, high filling property, and low abrasion property, and are also applicable to semiconductor field; and a method for producing the spherical crystalline silica particles. The crystalline silica particles are characterized in that with respect to the total mass of the particles, the content of a crystal phase is at least 90 mass % and the content of a quartz crystal is at least 70 mass %. In addition, at least one kind of alkali metals may be contained in an amount of 0.4-5 mass % in terms of oxides, with respect to the total mass of the particles. Furthermore, at least one kind of alkaline earth metals may be contained in an amount of 1-5 mass % in terms of oxides, with respect to the total mass of the particles.

Abstract: The present invention addresses the problem of providing: spherical eucryptite particles which have higher circularity than in the prior art, have a large negative thermal expansion and a high thermal conductivity, have high flowability, dispersibility, and filling capability, and are also applicable in the field of semiconductors; and a method for producing the spherical eucryptite particles. As a means for solving the problem, the present invention provides: the method for producing the spherical eucryptite particles characterized by heat treating, at 600 to 1100° C., spherical particles which have been thermally sprayed with a feedstock powder that includes 45 to 55 mol % of SiO2, 20 to 30 mol % of Al2O3, and 20 to 30 mol % of Li2O, and obtaining spherical particles that include 89% or more of a eucryptite crystalline phase; and the spherical eucryptite particles obtained by this method.

Abstract: Spherical crystalline silica particles having a higher productivity, lower production cost, higher coefficient of thermal expansion, higher heat transmission rate, higher fluidity, higher dispersability, higher fill factor, low abrasiveness, and higher purity compared with the past and able to be applied in the semiconductor field and a process of production of the same are provided. Spherical crystalline silica particles containing 400 to 5000 ppm of aluminum and containing 80% or more of crystal phases are provided.

Abstract: Spherical crystalline silica particles having a higher productivity, lower production cost, higher coefficient of thermal expansion, higher heat transmission rate, higher fluidity, higher dispersability, higher fill factor, low abrasiveness, and higher purity compared with the past and able to be applied in the semiconductor field and a process of production of the same are provided. Spherical crystalline silica particles containing 400 to 5000 ppm of aluminum and containing 80% or more of crystal phases are provided.