The present invention discloses a dielectric ceramic formula enabling one to obtain a multilayer ceramic capacitor by alternatively stacking the ceramic dielectric layers and base metal internal electrodes. The dielectric ceramic composition comprises a primary ingredient:

[(Na.sub.1-xK.sub.x).sub.sA.sub.1-s].sub.m[(Nb.sub.1-yTa.sub.y).sub.uB1.sub.vB2.sub.w)]O.sub.3

wherein:
A is at least one selected from the alkaline-earth element group of Mg, Ca, Sr, and Ba;
B1 is at least one selected from the group of Ti, Zr, Hf and Sn;
B2 is at least one selected from transition metal elements;
and wherein:
x, y, s, u, v, and w are molar fractions of respective elements, and m is the molar ratio of [(Na.sub.1-xK.sub.x).sub.sA.sub.1-s] and [(Nb.sub.1-yTa.sub.y).sub.uB1.sub.vB2.sub.w)]. They are in the following respective range:
0.93≤m≤1.07;
0.7≤s≤1.0;
0.00≤x≤0.05; 0.00≤y≤0.65;
0.7≤u≤1.0; 0.0≤v≤0.3; 0.001≤w≤0.100;
a first sub-component composes of at least one selected from the rare-earth compound,
wherein the rare-earth element is no more than 10 mol % parts with respect to the main component; and
a second sub-component composes a compound with low melting temperature to assist the ceramic sintering process, said frit, which is Li free and could be at least one selected from fluorides, silicates, borides, and oxides. The content of frit is within the range of 0.01 mol % to 15.00 mol % parts with respect to the main component.

(i) a step of disposing a powder that includes an absorber absorbing light of a wavelength included in a laser beam to be irradiated and silicon dioxide as a main component; (ii) a step of sintering or melting and solidifying the powder by irradiating the powder with a laser beam; and (iii) a step of heat-treating a shaped object formed by repeating the steps (i) and (ii) at 1470° C. or more and less than 1730° C.

Provided is a cubic boron nitride sintered body including more than or equal to 85 volume percent and less than 100 volume percent of cubic boron nitride particles, and a remainder of a binder, wherein the binder contains WC, Co, and an Al compound, the binder contains W.sub.2Co.sub.21B.sub.6, and, when I.sub.A represents an X-ray diffraction intensity of a (111) plane of the cubic boron nitride particles, I.sub.B represents an X-ray diffraction intensity of a (100) plane of the WC, and I.sub.C represents an X-ray diffraction intensity of a (420) plane of the W.sub.2Co.sub.21B.sub.6, a ratio I.sub.C/I.sub.A of the I.sub.C to the I.sub.A is more than 0 and less than 0.10, and a ratio I.sub.C/I.sub.B of the I.sub.C to the I.sub.B is more than 0 and less than 0.40.

Method for manufacturing a composite material part includes injecting a slurry containing a refractory ceramic particle powder into a fibrous texture, draining the liquid from the slurry that passed through the fibrous texture and retaining the refractory ceramic particle powder inside said texture so as to obtain a fibrous preform loaded with refractory ceramic particles, and demoulding of the fibrous preform. The method includes, after demoulding the fibrous preform, checking the compliance of the demoulded fibrous preform. If the preform is noncompliant, the method also includes, before a sintering, immersing the demoulded fibrous preform in a bath of a liquid suitable for decompacting the refractory ceramic particles present in the fibrous preform, and additionally injecting a slurry containing a refractory ceramic particle powder into the fibrous preform present in the mould cavity.

A method may include depositing a sacrificial support material on or adjacent to a build surface. The sacrificial support material may be configured to support a continuous reinforcement material during an additive manufacturing technique. The method also may include extruding the continuous reinforcement material from an additive manufacturing device such that at least a portion of the continuous reinforcement material contacts and is supported by the sacrificial support material; and removing the sacrificial support material to result in a feature defined at least in part by the continuous reinforcement material at the absence of sacrificial support material.

Disclosed is a modified preceramic polymer having a polymer backbone consisting of silicon or a combination of silicon and carbon; and a pendant modifier bonded to the backbone wherein the modifier includes silicon, boron, aluminum, a transition metal, a refractory metal, or a combination thereof. The modified preceramic polymer can be used to form a ceramic matrix composite.

A method and apparatus for producing AlN whiskers includes reduced incorporation of metal particles, an AlN whisker body, AlN whiskers, a resin molded body, and a method for producing the resin molded body. The method for producing AlN whiskers includes heating an Al-containing material in a material accommodation unit to thereby generate Al gas; and introducing the Al gas into a reaction chamber through a communication portion while introducing nitrogen gas into the reaction chamber through a gas inlet port, to thereby grow AlN whiskers on the surface of an Al.sub.2O.sub.3 substrate placed in the reaction chamber.

A fuel assembly for a nuclear reactor, a fuel rod of the fuel assembly, and a ceramic nuclear fuel pellet of the fuel rod are disclosed. The fuel pellet includes a first fissile material of UB.sub.2, The boron of the UB.sub.2 is enriched to have a concentration of the isotope .sup.11B that is higher than for natural B.

A method for the preparation of a dense HfC(Si)—HfB.sub.2 composite ceramic. hafnium oxide powders, nano-sized carbon black and silicon hexaboride powders are mixed in a molar ratio of (1-10):(1-20):(1-5) to obtain a powder mixture. The powder mixture is subjected to ball milling, dried and transferred to a graphite mold for spark plasma sintering. In this way, an in-situ carbon-boron reduction reaction and the sintering densification are completed in one step, and the obtained HfC(Si)—HfB.sub.2 composite ceramic has a density of 94.0%-100% and uniformly dispersed grains.

The present invention relates to a process for preparing a composite, ultra-refractory, fibre-reinforced ceramic material obtained through the infiltration of carbon and/or silicon carbide fibres with a ceramic suspension comprising yttrium, lanthanum and/or scandium compounds, and the subsequent densification of the composite. The fibre-reinforced UHTC compounds obtained by the process can be used for making items intended for use in extreme temperature and pressure conditions.