A composition comprises a zirconia powder, in which 55% or more thereof is monoclinic, and a stabilizer capable of suppressing phase transition of zirconia. An average particle diameter of zirconia particles and particles of the stabilizer is 0.06 μm to 0.17 μm. At least a portion of the stabilizer does not form a solid solution with zirconia.

A sintered body includes a solid solution containing cobalt and iron, with the balance being zirconia. The total content of cobalt in terms of CoO and iron in terms of Fe.sub.2O.sub.3 is more than 0.1 wt % and less than 3.0 wt %, and the proportion of cobalt regions larger than 5.5 μm.sup.2 in an elemental map obtained using an electron probe microanalyzer is 25% or less.

The present invention is directed to a method for producing a silicon nitride sintered material, the method including heating a molded article, which contains a silicon nitride powder having a β phase ratio of 80% or more, a dissolved oxygen content of 0.2% by mass or less, and a specific surface area of 5 to 20 m.sup.2/g, and a sintering auxiliary containing a compound having no oxygen bond, and which has an overall oxygen content controlled to be 1 to 15% by mass and an aluminum element overall content controlled to be 800 ppm or less, to a temperature of 1,200 to 1,800° C. in an inert gas atmosphere under a pressure of 0 MPa.Math.G or more and less than 0.1 MPa.Math.G to sinter the silicon nitride.

In the present invention, there can be provided a method for producing a silicon nitride sintered material, which method is advantageous in that a silicon nitride sintered material having high thermal conductivity can be obtained even when using a silicon nitride powder having a high β phase ratio and conducting calcination under normal pressure or substantially normal pressure.

The present invention relates to a SiC composite and a method for manufacturing the same. More particularly, the present invention relates to a slurry composition for ceramic matrix composites which can not only reduce the number of precursor impregnation pyrolysis (PIP) cycles but also be useful in the PIP process to increase hardness, thermal stability, and relative density.

A method of forming a ceramic matrix composite component includes forming a fiber preform, the fiber preform including a plurality of ceramic fiber plies, a non-reduced fiber region having an areal weight, and a reduced fiber region characterized by a reduced areal weight less than the areal weight of the non-reduced fiber region by at least 5 percent. The method further includes selectively applying ceramic particles to the reduced fiber region in such manner as to avoid applying the ceramic particles to the non-reduced fiber region, and subsequently densifying the preform.

A zirconia powder containing a stabilizer, and having a specific surface area of 20 m.sup.2/g or more and 60 m.sup.2/g or less and a particle diameter D.sub.50 of 0.1 μm or more and 0.7 μm or less, in which in a range of 10 nm or more and 200 nm or less in a pore distribution based on a mercury intrusion method, a peak top diameter in a pore volume distribution is 20 nm or more and 85 nm or less, a pore volume is 0.2 ml/g or more and less than 0.5 ml/g, and a pore distribution width is 40 nm or more and 105 nm or less.

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.

A method for producing a lithium-transition metal composite oxide, including steps of: preparing a mixture including a lithium-containing compound and a transition metal compound; obtaining a molded body of the mixture; and sintering the molded bodies in a container having at least one vent hole, to obtain sintered bodies.

A method of additive manufacturing may include disposing a layer of a powder material on a surface of a build platform of an additive manufacturing apparatus. The method may also include placing a compaction platform comprising one or more transducers in contact with an upper surface of the layer of the powder material. The method may additionally include activating at least one transducer of one or more transducers of the compaction platform of the compactor to densify a portion of the layer of the powder material below the at least one transducer while at least the weight of the compaction platform applies a normal force to the layer of the powder material. Related systems for densifying additively manufactured components are also described.

A method includes molding a raw material powder containing a ceramic powder and a thermoplastic resin having a glass transition temperature higher than room temperature into a shape by isostatic pressing and in which a raw material powder slurry is prepared by adding the ceramic powder and the thermoplastic resin to a solvent so that the thermoplastic resin is 2% by weight or more and 40% by weight or less with respect to a total weight of the ceramic powder and the thermoplastic resin, a cast-molded body is to formed by wet-casting the raw material powder slurry into a shape, dried, and subjected to first-stage isostatic press molding at a temperature lower than the glass transition temperature of the thermoplastic resin, then this first-stage press-molded body is heated to the glass transition temperature of the thermoplastic resin or above, and warm isostatic press (WIP) molding is performed.