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.

Multifunctional Boron Nitride nanotube-Boron Nitride (BN—BN) nanocomposites for energy transducers, thermal conductors, anti-penetrator/wear resistance coatings, and radiation hardened materials for harsh environments. An all boron-nitride structured BN—BN composite is synthesized. A boron nitride containing precursor is synthesized, then mixed with boron nitride nanotubes (BNNTs) to produce a composite solution which is used to make green bodies of different forms including, for example, fibers, mats, films, and plates. The green bodies are pyrolized to facilitate transformation into BN—BN composite ceramics. The pyrolysis temperature, pressure, atmosphere and time are controlled to produce a desired BN crystalline structure. The wholly BN structured materials exhibit excellent thermal stability, high thermal conductivity, piezoelectricity as well as enhanced toughness, hardness, and radiation shielding properties. By substituting with other elements into the original structure of the nanotubes and/or matrix, new nanocomposites (i.e., BCN, BCSiN ceramics) which possess excellent hardness, tailored photonic bandgap and photoluminescence, result.

A method of manufacturing polycrystalline abrasive elements consisting of micron, sub-micron or nano-sized ultrahard abrasives dispersed in micron, sub-micron or nano-sized matrix materials. A plurality of ultrahard abrasive particles having vitreophilic surfaces are coated with a matrix precursor material in a refined colloidal process and then treated to render them suitable for sintering. The matrix precursor material can be converted to an oxide, nitride, carbide, oxynitride, oxycarbide, or carbonitride, or an elemental form thereof. The coated ultrahard abrasive particles are consolidated and sintered at a pressure and temperature at which they are crystallographically or thermodynamically stable.

A sintered body containing polycrystalline grains of a metal oxynitride containing at least two metal elements, wherein Ba and at least one metal element of a crystal phase of the sintered body are contained in a triple point that is not a void between the polycrystalline grains. A method for producing the sintered body includes sintering a mixture of at least a metal oxynitride as a main component and a sintering aid containing cyanamide in an atmosphere containing nitrogen or a rare gas or in a reduced-pressure atmosphere of 10 Pa or less while applying a mechanical pressure with a retention time at a maximum heating temperature during the sintering set to 1 minute to 10 minutes.

The present invention provides titanium nitride-reinforced zirconia toughened alumina (ZTA) ceramic powder and a preparation method thereof, and belongs to the technical field of ceramic materials. The preparation method provided in the present invention includes the following steps: mixing an aluminum salt, a zirconium salt, a yttrium salt, and a titanium salt with water to obtain a mixed aqueous solution, where the aluminum salt, the zirconium salt, the yttrium salt, and the titanium salt are water-soluble inorganic salts; mixing the obtained mixed aqueous solution and an alkaline precipitant for precipitation, to obtain hydroxide precipitate powder; successively conducting first calcination and second calcination on the obtained hydroxide precipitate powder, to obtain oxide solid solution powder; and subjecting the obtained oxide solid solution powder to selective nitridation reaction, to obtain titanium nitride-reinforced ZTA ceramic powder.

The present invention provides an Al.sub.2O.sub.3—ZrO.sub.2—Y.sub.2O.sub.3—TiN nanocomposite ceramic powder and a preparation method thereof, and belongs to the field of ceramic materials. In the ceramic powder provided by the present invention, a molar ratio of Zr:Al:Y:Ti is (30-70):(10-30):(0.4-1):(5-20). The nanocomposite ceramic powder provided by the present invention is good in dispersibility, and does not generate agglomeration, and the mechanical properties of a ceramic material obtained after sintering of the nanocomposite ceramic powder provided by the present invention are better. Proved by results of embodiments, the hardness of a ceramic material obtained by sintering of the nanocomposite ceramic powder provided by the present invention is 28-35 GPa, and abrasion ratio is 4500-6000:1.

The present invention provides a gallium nitride sintered body and a gallium nitride molded article which have high density and low oxygen content without using a special apparatus. According to the first embodiment, a gallium nitride sintered body, which is characterized by having density of 2.5 g/cm.sup.3 to less than 5.0 g/cm.sup.3 and an intensity ratio of the gallium oxide peak of the (002) plane to the gallium nitride peak of the (002) plane of less than 3%, which is determined by X-ray diffraction analysis, can be obtained. According to the second embodiment, a metal gallium-impregnated gallium nitride molded article, which is characterized by comprising a gallium nitride phase and a metal gallium phase that exist as separate phases and having a molar ratio, Ga/(Ga+N), of 55% to 80%, can be obtained.

Disclosed are a high-entropy nitride ceramic fiber, and a preparation method and use thereof. The high-entropy ceramic fiber comprises Ti, Hf, Ta, Nb, and Mo; the high-entropy nitride ceramic fiber presents single crystal phase, and each of the elements are uniformly distributed at molecular level. The preparation method of the high-entropy ceramic fiber comprises: mixing a high-entropy ceramic precursor comprising the target metal elements, a spinning aid, and a solvent uniformly to prepare a precursor spinning solution, followed by working procedures of spinning, pyrolyzation, and nitriding to prepare the high-entropy nitride ceramic fiber. The high-entropy nitride ceramic fiber can be used in photocatalysis process of carbon dioxide to prepare methane.

Provided are gallium nitride particles that have a low oxygen content and a high moldability and allow a gallium nitride sputtering target having a high density and a high strength to be produced. By causing a mixed powder of gallium oxide and gallium nitride to react at a temperature of 1000-1100° C. such that an ammonia reaction amount per hour is 1 or more times (by mole) an amount of gallium charged, gallium nitride particles are obtained of which an oxygen content is 1 atm % or less, an average particle size of primary particles is 5 μm or more, and a particle size of a range of 10 area % from smallest particles of a particle size distribution (10% particle size) is 3 μm or less.

A method for manufacturing a multilayer electronic component having an element body in which a functional part and a conductor part are laminated. The green multilayer body 11 is formed on the temporary holding film 62 formed on the release substrate. The green multilayer body 11 is formed by repeating the first step forming a green functional part using the first ink containing the functional particles and the second step forming the green conductor part using the second ink containing the conductive particles. The temporary holding film 62 has conductivity.