The present invention provides a polyvinyl acetal resin which leaves less fine undissolved matter when dissolved in an organic solvent and thus can improve productivity particularly when used as a binder for a ceramic green sheet, and which can also provide a ceramic green sheet having excellent toughness and enables production of a highly reliable multilayer ceramic capacitor. Provided is a polyvinyl acetal resin having: a wavenumber A (cm.sup.−1) of a peak within a range of 3,100 to 3,700 cm.sup.−1 in an IR absorption spectrum measured using an infrared spectrophotometer; and a hydroxy group content (mol %), the wavenumber A of the peak and the hydroxy group content satisfying relations of the following formulas (1) and (2):

[(3,470−A)/Hydroxy group content]≤5.5  (1)

(3,470−A)≤185  (2)

wherein A is a wavenumber which is lower than 3,470 cm.sup.−1 and at which a transmittance a (%) satisfying [100−(100−X)/2] is exhibited, where X (%) is a minimum transmittance of the peak within the wavenumber range of 3,100 to 3,700 cm.sup.−1.

A method of preparing a woven fabric material for use in a ceramic matrix composite includes passing a desized woven fabric tape having a first inter-filament spacing through a dispersal module configured to transform the desized woven fabric tape into a dispersed woven fabric tape having a second inter-filament spacing greater than the first inter-filament spacing. The dispersal module includes a first charging element with a charged surface and disposed to apply an electric charge to the desized woven fabric tape. The method further includes applying a polymer binder to the dispersed woven fabric tape to create a stabilized woven fabric tape having the second inter-filament spacing.

A method of preparing a woven ceramic fabric for use in a ceramic matrix composite includes transforming a woven fabric sheet having a first tow architecture into a separated woven fabric sheet having a second tow architecture, the first tow architecture including a plurality of warp tows and a plurality of weft tows, and the second tow architecture including a plurality of warp subtows and/or a plurality of weft subtows. Transforming the woven fabric sheet includes separating at least some of the plurality of warp tows and/or the plurality of weft tows into a greater number of corresponding warp subtows and/or weft subtows, respectively, such that second tow architecture includes more warp subtows and/or weft subtows than the first tow architecture comprises warp tows and weft tows, and wherein each of the warp subtows and/or weft subtows includes fewer filaments than corresponding warp tow and/or weft tow. Each of the plurality of warp subtows and/or weft subtows is spaced apart from the closest adjacent warp subtow and/or weft subtow, respectively, a distance of 25 to 230 microns.

A method of preparing a woven fabric material for use in a ceramic matrix composite includes securing a woven fabric tape in tension across a roller, the roller having an outer surface with a plurality of spiked protrusions extending radially therefrom, each of the plurality of spiked protrusions having a diameter between 10 microns and 500 microns. The method further includes passing the woven fabric along the roller, such that the roller rotates with the passing of the woven fabric tape, thereby impinging the spiked protrusions into the woven fabric tape, and separating filaments within tows of the woven fabric tape by penetration of at least one of the spiked protrusions into the woven fabric tape, such that filaments within various tows of the woven fabric tape are pushed apart to form a separated woven fabric tape with a greater number of tows per unit area than the woven fabric tape.

Provided is at least any of a layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. There is provided a layered body having a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer.

A ceramic composite and a method of preparing the same are provided. The method of preparing the ceramic composite includes mixing an aluminum slag and a carbon accelerator to obtain a mixture and reacting the mixture at a temperature equal to or greater than 1600° C. in a nitrogen atmosphere to obtain a ceramic composite. The aluminum slag includes aluminum, oxygen, nitrogen, and magnesium. The weight ratio of the oxygen to the aluminum is 0.6 to 2. The weight ratio of the nitrogen to the aluminum is 0.1 to 1.2. The weight ratio of the magnesium to the aluminum is 0.04 to 0.2. The ceramic composite includes aluminum nitride accounting for at least 90 wt % of the ceramic composite.

There is provided at least any of a layered body which has a change in color tone and in which it is unnecessary to select a colorant and the content of the colorant in consideration of a difference in the sintering behavior between layers, a precursor thereof, or a method for producing these. Provided is a layered body which has a structure, in which two or more layers containing stabilizer-containing zirconia and a colorant are layered, and in which types and contents of the colorants contained in the layers are equal to each other, the layered body including at least: a first layer containing a colorant and zirconia which has a stabilizer content of higher than or equal to 3.3 mol %; and a second layer containing a colorant and zirconia which has a stabilizer content different from that of the zirconia contained in the first layer.

A grain-grade zirconia toughened alumina ceramic substrate and a method for preparing the same. The ceramic substrate is prepared from alumina power (main phase) and zirconia powder (secondary phase) in a binary azeotrope of anhydrous ethanol and butanone in the presence of magnesia-alumina spinel powder (as sintering aid), phosphate ester (as dispersant), polyvinyl butyral (as binder) and dibutyl phthalate (as plasticizer). In a mixture of the alumina power and the zirconia powder, a volume percentage of the alumina power is 82.44-96.7%, and a volume percentage of the zirconia powder is 3.30-17.56%. The magnesia-alumina spinel powder is 0.1-4.0% by weight of the mixture of the alumina power and the zirconia powder. A particle size ratio of the alumina powder to the zirconia powder is 2.415-4.444.

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 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.