An aspect of the present invention provides a semi-cured product composite containing: a porous body; and a semi-cured product of a thermally curable composition impregnated in the porous body, wherein the thermally curable composition contains an epoxy compound and a cyanate compound, and an equivalent ratio of an epoxy group of the epoxy compound to a cyanate group of the cyanate compound in the thermally curable composition is 1.0 or more.

Compositions comprising preceramic resins and fumed alumina are described. The compositions can also include fillers, such as silicon carbide whiskers or zirconium diboride particles. The compositions can be used as three-dimensional printable inks for preparing ceramic composites, e.g., composites having complex geometry. Inclusion of fumed alumina as a rheology modifier in the composition can provide improved printing properties for the inks compared to preceramic resin inks that do not include fumed alumina.

A cubic boron nitride sintered material includes: more than or equal to 20 volume % and less than 80 volume % of cubic boron nitride grains; and more than 20 volume % and less than or equal to 80 volume % of a binder phase, and when a carbon content is measured from a cubic boron nitride grain into the binder phase in a direction perpendicular to an interface between the cubic boron nitride grain and the binder phase using TEM-EDX, a first region having a carbon content larger than an average value of a carbon content of the binder phase exists, the interface exists in the first region, and a length of the first region is more than or equal to 0.1 nm and less than or equal to 10 nm.

A method for forming an abrasive article via an additive manufacturing technique including forming a layer of powder material comprising a precursor bond material and abrasive particles, compacting at least a portion of the layer to form a compacted layer, binding at least a portion of the compacted layer and repeating the steps of forming, compacting and binding to form a green body abrasive article.

Provided is a boron nitride sintered body including boron nitride particles and pores, in which an average pore diameter of the pores is less than 2 μm. Provided is a method for manufacturing a boron nitride sintered body, the method including: a nitriding step of firing a boron carbide powder in a nitrogen pressurized atmosphere to obtain a fired product containing boron carbonitride; and a sintering step of molding and heating a blend containing the fired product and a sintering aid to obtain the boron nitride sintered body including boron nitride particles and pores, in which the sintering aid contains boron oxide and calcium carbonate, and the blend contains 1 to 20 parts by mass of a boron compound and a calcium compound in total with respect to 100 parts by mass of the fired product.

Provided is a boron nitride sintered body including boron nitride particles and pores, in which a compressive elastic modulus is 1 GPa or more. Provided is a method for manufacturing a boron nitride sintered body, the method including: a nitriding step of firing a boron carbide powder in a nitrogen atmosphere to obtain a fired product containing boron carbonitride; and a sintering step of molding and heating a blend containing the fired product and a sintering aid to obtain the boron nitride sintered body including boron nitride particles and pores, in which the sintering aid contains a boron compound and a calcium compound, and the blend contains 1 to 20 parts by mass of the boron compound and the calcium compound in total with respect to 100 parts by mass of the fired product.

A cBN sinter comprising cubic boron nitride grains and a binder phase, the binder phase comprising Ti.sub.2CN and Co.sub.2B, wherein the ratio I.sub.Ti2CN/I.sub.Co2B of a peak intensity I.sub.Ti2CN assigned to Ti.sub.2CN appearing at 2θ = 41.9° to 42.2° to a peak intensity I.sub.TiAl3 assigned to Co.sub.2B appearing at 2θ = 45.7° to 45.9° is in a range of 0.5 and 2.0 in an XRD measurement.

Provided is a method for manufacturing a composite body, the method including: a nitriding step of firing a boron carbide powder in a nitrogen atmosphere to obtain a fired product containing boron carbonitride; a sintering step of molding and heating a blend containing the fired product and a sintering aid to obtain a boron nitride sintered body including boron nitride particles and pores; and an impregnating step of impregnating the boron nitride sintered body with a resin composition, the composite body having the boron nitride sintered body and a resin filled in at least some of the pores of the boron nitride sintered body.

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.