A SiC powder containing 70% by mass or more of a β-SiC, wherein in a volume-based cumulative particle size distribution measured by a laser diffraction method, a D50 is 8 to 35 μm and a D10 is 5 μm or more.

A method for making ceramic composites via sintering a mixture of alumina and oil fly ash. The alumina is in the form of nanoparticles and/or microparticles. The oil fly ash may be treated with an acid prior to the sintering. The composite may comprise graphite carbon derived from oil fly ash dispersed in an alumina matrix. The density, mechanical performance (e.g. Vickers hardness, fracture toughness), and thermal properties (e.g. thermal expansion, thermal conductivity) of the ceramic composites prepared by the method are also specified.

A Cr—Si sintered body contains Cr and Si. The Cr—Si sintered body contains a crystalline CrSi.sub.2 phase and a crystalline Si phase. A content of the Si phase in the Cr—Si sintered body is 40% by mass or more. A relative density of the Cr—Si sintered body relative to a true density of the Cr—Si sintered body is 95% or more. The CrSi.sub.2 phase has an average crystal grain size of 40 μm or less, and the Si phase has an average crystal grain size of 30 μm or less. A total content of impurities in the Cr—Si sintered body is 200 ppm by mass or less, and the impurities are composed of at least one element selected from the group consisting of Mn, Fe, Mg, Ca, Sr, and Ba.

Disclosed is a cordierite sintered body comprising from 90 to 98% by volume of a cordierite crystal phase as measured using x ray diffraction, SEM and image processing methods wherein the cordierite sintered body has at least one surface comprising pores having a diameter of from 0.1 to 5 um as measured using SEM and image processing methods. The cordierite sintered body has a Young's modulus of about 125 GPa or greater, and volumetric porosity of less than about 4%. Methods of making the cordierite sintered body are also disclosed.

An alumina sintered body having a low dielectric loss tangent and a method for manufacturing the alumina sintered body are provided. An alumina sintered body contains Al.sub.2O.sub.3 99.50 mass % or more, and 99.95 mass % or less and sodium and silicon, wherein at a surface layer A in any given cross-section and a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer A is smaller than the concentration ratio of sodium to silicon at the central portion B.

Provided according to embodiments of the invention are varistor ceramic formulations that include zinc oxide (ZnO). In particular, varistor ceramic formulations of the invention may include dopants including an alkali metal compound, an alkaline earth compound, an oxide of boron, an oxide of aluminum, or a combination thereof. Varistor ceramic formulations may also include other metal oxides. Also provided according to embodiments of the invention are varistor ceramic materials formed by sintering a varistor ceramic formulation according to an embodiment of the invention. Further provided are varistors formed from such ceramic materials and methods of making such materials.

A low-cost, durable silicon carbide member for a plasma processing apparatus. The silicon carbide member for a plasma processing apparatus can be obtained by processing a sintered body which is produced with a method in which metal impurity is reduced to more than 20 ppm and 70 ppm or less, and an α-structure silicon carbide power having an average particle diameter of 0.3 to 3 μm and including 50 ppm or less of an Al impurity is mixed with 0.5 to 5 weight parts of a B.sub.4C sintering aid, or with a sintering aid comprising Al.sub.2O.sub.3 and Y.sub.2O.sub.3 with total amount of 3 to 15 weight parts, and then a mixture of the α-structure silicon carbide power with the sintering aid is sintered in an argon atmosphere furnace or a high-frequency induction heating furnace.

A sputtering target which is made of a magnesium oxide sintered body having a purity of not less than 99.99% or not less than 99.995% by mass %, a relative density of not less than 98%, and an average grain size of not more than 8 μm. The average grain size of the sputtering target is preferably not more than 5 μm, more preferably not more than 2 μm. A sputtered film having an excellent insulation resistance and an excellent homogeneity can be obtained by using the sputtering target.

(Problem) In conventional method for producing artificial graphite, in order to obtain a product having excellent crystallinity, it was necessary to mold a filler and a binder and then repeat impregnation, carbonization and graphitization, and since carbonization and graphitization proceeded by a solid phase reaction, a period of time of as long as 2 to 3 months was required for the production and cost was high and further, a large size structure in the shape of column and cylinder could not be produced. In addition, nanocarbon materials such as carbon nanotube, carbon nanofiber and carbon nanohorn could not be produced. (Means to solve) A properly pre-baked filler is sealed in a graphite vessel and is subsequently subjected to hot isostatic pressing (HIP) treatment, thereby allowing gases such as hydrocarbon and hydrogen to be generated from the filler and precipitating vapor-phase-grown graphite around and inside the filler using the generated gases as a source material, and thereby, an integrated structure of carbide of the filler and the vapor-phase-grown graphite is produced. In addition, nanocarbon materials are produced selectively and efficiently by adding a catalyst or adjusting the HIP treating temperature.

A highly purified diatomite composition may include greater than or equal to 90% silica, from about 0.5% to about 5% of a calcium-containing compound, and less than or equal to about 2% total of aluminum-containing oxides and iron-containing oxides. A method of making a highly purified diatomite composition may include providing a diatomite comprising at least 5% of a calcium-containing compound, calcining the diatomite, and acid washing the calcined diatomite. The calcined, acid-washed diatomite may include less than or equal to about 1% total of extractable aluminum-containing oxides and iron-containing oxides, and less than or equal to about 5% of the calcium-containing compound. The acid washing may include an acid selected from the group consisting of sulfuric acid (H.sub.2SO.sub.4), hydrochloric acid (HCl), and nitric acid (HNO.sub.3). The method may not include a flotation step.