Provided is a boron nitride sintered body including boron nitride particles and pores, the boron nitride sintered body having a sheet shape and a thickness of less than 2 mm. Provided is a method for manufacturing a boron nitride sintered body, the method including a sintering step of molding and heating a blend containing a boron carbonitride powder and a sintering aid to obtain a sheet-shaped boron nitride sintered body including boron nitride particles and pores, in which a thickness of the boron nitride sintered body obtained in the sintering step is less than 2 mm.

A silicon nitride sintered body includes a silicon nitride crystal grains and grain boundary phases. Further, when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy the inequalities:

0.8≤ dA/dB≤ 1.2; and

0.8≤ rA/rB≤ 1.2.

In an aspect, a ferrite composition comprises a Ru—Co.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(M′Ru).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M′ is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is −4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the Ru—Co.sub.2Z ferrite.

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 method for producing an article containing silicon carbide as the main constituent includes a plurality of sets of steps of forming a layer of a raw material powder and irradiating the layer with laser light according to three-dimensional model data. The low material powder is a mixture of silicon carbide powder, metallic silicon powder, and carbon powder. The laser light used in the step of irradiation with laser light has a spatial laser power density of 11 J/mm.sup.3 to 50 J/mm.sup.3.

A process of forming a sintered article includes heating a green portion of a tape of polycrystalline ceramic and/or minerals in organic binder at a binder removal zone to a temperature sufficient to pyrolyze the binder; horizontally conveying the portion of tape with organic binder removed from the binder removal zone to a sintering zone; and sintering polycrystalline ceramic and/or minerals of the portion of tape at the sintering zone, wherein the tape simultaneously extends through the removal and sintering zones.

A light emitting device (1) is a light emitting device for use in a photodynamic therapy. The light emitting device includes: a solid-state light-emitting element (2) that emits primary light in which an energy density is 0.5 W/mm.sup.2 or more; and a wavelength converter (3) including a first phosphor (4) that emits first wavelength-converted light (7). The first wavelength-converted light has a light component across at least a whole of a wavelength range of 700 nm or more and less than 800 nm. Energy of fluorescence emitted from the wavelength converter is 100 mW or more. A medical device includes the light emitting device.

The present invention relates to a laminated member including: a glass member having a linear transmittance at a wavelength of 850 nm of 80% or more; a bonding layer including a resin and lying on the glass member; and a Si—SiC member lying on the bonding member, in which the Si—SiC member has an average linear expansion coefficient α at from 20° C. to 200° C. of from 2.85 ppm/° C. to 4.00 ppm/° C.

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.

Provided is a C/C composite having a long life in an environment including a heating process and a cooling process and having less adverse effects on surrounding facilities and the quality of treatment objects. A C/C composite in which, in measurement for open pores by mercury porosimetry, an open porosity for open pores with a radius of not less than 0.4 μm and less than 10 μm in the C/C composite is 2.0% or less.