Provided is a boron nitride sintered body including: a plurality of coarse particles each having a length of 20 μm or more; and fine particles smaller than the plurality of coarse particles, in which, when viewed in a cross-section, the plurality of coarse particles intersect with each other. Provided is a method for manufacturing a boron nitride sintered body, the method including: a raw material preparation step of firing a mixture containing boron carbonitride and a boron compound in a nitrogen atmosphere to obtain lump boron nitride having an average particle diameter of 10 to 200 μm; and a sintering step of molding and heating a blend containing the lump boron nitride and a sintering aid to obtain a boron nitride sintered body including coarse particles each having a length of 20 μm or more in a cross-section and fine particles smaller than the coarse particles.

Provided is a boron nitride sintered body having a porous structure, the boron nitride sintered body including a lump particle formed by aggregation of primary particles of boron nitride and having a particle diameter of 15 μm or more. Provided is a method for manufacturing a boron nitride sintered body, the method including: a nitriding step of firing a raw material powder containing boron carbide in an atmosphere containing nitrogen to obtain a fired product including lump particles each having a core part with primary particles of boron carbonitride aggregated and a shell part surrounding the core part; and a firing step of molding and heating a blend containing the fired product including lump particles and a sintering aid to obtain the boron nitride sintered body having a porous structure and including lump particles of boron nitride.

A vermiculite core for a vehicle may include vermiculite and pearlstone, an aluminum component for the vehicle may be manufactured using the vermiculite core including the vermiculite and the pearlstone, and a method for manufacturing the vermiculite core for the vehicle may include mixing the vermiculite and the pearlstone, injecting a mixture of the vermiculite and the pearlstone into a mold, and pressing the mixture using a presser.

A dielectric composition is provided. The dielectric composition includes: a main component made of: a first complex oxide expressed by a chemical formula {K(Ba.sub.1-xSr.sub.x).sub.2Nb.sub.5O.sub.15}; and a second complex oxide expressed by a chemical formula that differs the chemical formula of the first complex oxide. The second complex oxide is a complex oxide expressed by one of chemical formulae: {(Ca.sub.1-ySr.sub.y)(Zr.sub.1-zTi.sub.z)O.sub.3}; {Ba(Ti.sub.1-uZr.sub.u)O.sub.3}; {(Ca.sub.1-vSr.sub.v)TiSiO.sub.5}; and {(Ba.sub.1-wRe.sub.2w/3)Nb.sub.2O.sub.6}, x satisfies 0.35≦x≦0.75, and a satisfies 0.25≦a≦0.75 when a molar ratio between the first and second complex oxides is defined by a:b in an order and a+b=1.00.

Disclosed is a rapid, reproducible solution-based method to synthesize solid sodium ion-conductive materials. The method includes: (a) forming an aqueous mixture of (i) at least one sodium salt, and (ii) at least one metal oxide; (b) adding at least one phosphorous precursor as a neutralizing agent into the mixture; (c) concentrating the mixture to form a paste; (d) calcining or removing liquid from the paste to form a solid; and (e) sintering the solid at a high temperature to form a dense, non-porous, sodium ion-conductive material. Solid sodium ion-conductive materials have electrochemical applications, including use as solid electrolytes for batteries.

The invention relates to α/β-sialon-based materials. The invention particularly relates to α/β-sialon-based materials that have an improved sintering activity and impart high edge strength to the sintered molded articles made of said materials.

Provided are a barium titanate-based piezoelectric ceramics having satisfactory piezoelectric performance and a satisfactory mechanical quality factor (Q.sub.m), and a piezoelectric element using the same. Specifically provided are a piezoelectric ceramics, including: crystal particles; and a grain boundary between the crystal particles, in which the crystal particles each include barium titanate having a perovskite-type structure and manganese at 0.04% by mass or more and 0.20% by mass or less in terms of a metal with respect to the barium titanate, and the grain boundary includes at least one compound selected from the group consisting of Ba.sub.4Ti.sub.12O.sub.27 and Ba.sub.6Ti.sub.17O.sub.40, and a piezoelectric element using the same.

There are provided a composite perovskite powder, a preparation method thereof, and a paste composition for an internal electrode having the same, the composite perovskite powder capable of preventing ions from being eluted from an aqueous system at the time of synthesis while being ultra-atomized, such that when the composite perovskite powder is used as an inhibitor powder for an internal electrode, sintering properties of the internal electrode may be deteriorated, and sintering properties of a dielectric material may be increased; accordingly, connectivity of the internal electrode may be improved, and permittivity and reliability of a multilayer ceramic capacitor (MLCC) may be increased.

A titanium-containing calcium hexaaluminate material and preparation method thereof is disclosed. The technical solution is: using 60˜80 wt % alumina micro powder, 5˜20 wt % calcium-containing micro powder, 10˜20 wt % titania micro powder and 1˜10 wt % manganese oxide micro powder as raw materials, blending the raw materials evenly in a planetary ball mill to obtain a blend, machine pressing the blend at 100˜200 MPa to obtain a green body, drying the green body at 110˜200° C. for 12˜36 h, and incubating the dried green body at 1500˜1800° C. for 1˜8 h to obtain the titanium-containing calcium hexaaluminate material. The present disclosure has low cost and simple process, and the prepared titanium-containing calcium hexaaluminate material has the characteristics of good chemical stability, high thermal shock resistance and strong melt resistance to titanium-aluminum alloy.

An insulator composition includes Al.sub.2O.sub.3 having a particle size of 120 to 500 nm. The insulator composition has a strength of 400 to 740 MPa and a particle size of 1 μm or less.