A SiC based sinterable powder mixture comprising, by dried weight of said powder: a) a mineral content comprising—silicon carbide (SiC) particles, —mineral boron compound particles, the powder comprising at least 50% by weight of SiC and the total mineral content of the powder being at least 90% by weight, b) at least a water insoluble carbon-containing source, in particular a carbon containing resin, the powder comprising at least 1% by weight, and preferably less than 10% by weight, of said water insoluble carbon-containing source, wherein the average particle size of said sinterable powder is comprised between 0.5 to 2.0 micrometers.

A manufacturing method of a ring-shaped element for an etcher, comprises a granulation operation comprising i) a slurry manufacturing process of preparing a slurry by mixing a raw material including boron carbide, a sinterability enhancer with a solvent; and ii) a granulation process of drying the slurry to prepare granulated raw material; a molding operation of manufacturing a green body by molding the granulated raw material; a sintering operation of carbonizing and sintering the green body to manufacture a sintered body; a shape operation of shaping the sintered body to a ring-shaped element for an etcher. The sinterability enhancer comprises one selected from the group consisting of carbon, boron oxide and combinations thereof.

A grain-grade zirconia toughened alumina ceramic substrate and a method for preparing the same. The ceramic substrate is prepared from alumina power (main phase) and zirconia powder (secondary phase) in a binary azeotrope of anhydrous ethanol and butanone in the presence of magnesia-alumina spinel powder (as sintering aid), phosphate ester (as dispersant), polyvinyl butyral (as binder) and dibutyl phthalate (as plasticizer). In a mixture of the alumina power and the zirconia powder, a volume percentage of the alumina power is 82.44-96.7%, and a volume percentage of the zirconia powder is 3.30-17.56%. The magnesia-alumina spinel powder is 0.1-4.0% by weight of the mixture of the alumina power and the zirconia powder. A particle size ratio of the alumina powder to the zirconia powder is 2.415-4.444.

The present invention is directed to a method for producing a silicon nitride sintered material, the method including heating a molded article, which contains a silicon nitride powder having a β phase ratio of 80% or more, a dissolved oxygen content of 0.2% by mass or less, and a specific surface area of 5 to 20 m.sup.2/g, and a sintering auxiliary containing a compound having no oxygen bond, and which has an overall oxygen content controlled to be 1 to 15% by mass and an aluminum element overall content controlled to be 800 ppm or less, to a temperature of 1,200 to 1,800° C. in an inert gas atmosphere under a pressure of 0 MPa.Math.G or more and less than 0.1 MPa.Math.G to sinter the silicon nitride.

In the present invention, there can be provided a method for producing a silicon nitride sintered material, which method is advantageous in that a silicon nitride sintered material having high thermal conductivity can be obtained even when using a silicon nitride powder having a high β phase ratio and conducting calcination under normal pressure or substantially normal pressure.

The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of ΔL.sub.c>ΔL.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is ΔL.sub.c and the sintering shrinkage of the silicon carbide matrix is ΔL.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.

A ceramic composite can include a first ceramic phase and a second ceramic phase. The first ceramic phase can include a silicon carbide. The second phase can include a boron carbide. In an embodiment, the silicon carbide in the first ceramic phase can have a grain size in a range of 0.8 to 200 microns. The first phase, the second phase, or both can further include a carbon. In another embodiment, at least one of the first ceramic phase and the second ceramic phase can have a median minimum width of at least 5 microns.

A sintered bead with the following crystal phases, in percentages by mass based on crystal phases: 25%≤zircon, or “Z.sub.1”, ≤94%; 4%≤stabilized zirconia+stabilized hafnia, or “Z.sub.2”, ≤61%; monoclinic zirconia+monoclinic hafnia, or “Z.sub.3”≤50%; corundum≤57%; crystal phases other than Z.sub.1, Z.sub.2, Z.sub.3 and corundum<10%; the following chemical composition, in percentages by mass based on oxides: 33%≤ZrO.sub.2+HfO.sub.2, or “Z.sub.4”≤83.4%; HfO.sub.2≤2%; 10.6%≤SiO.sub.2≤34.7%; Al.sub.2O.sub.3≤50%; 0%≤Y.sub.2O.sub.3, or “Z.sub.5”; 0%≤CeO.sub.2, or “Z.sub.6”; 0.3%≤CeO.sub.2+Y.sub.2O.sub.3≤19%, provided that (1) CeO.sub.2+3.76*Y.sub.2O.sub.3≥0.128*Z, and (2) CeO.sub.2+1.3*Y.sub.2O.sub.3≤0.318*Z, with Z=Z.sub.4+Z.sub.5+Z.sub.6−(0.67*Z.sub.1*(Z.sub.4+Z.sub.5+Z.sub.6)/(0.67*Z.sub.1+Z.sub.2+Z.sub.3)); MgO≤5%; CaO≤2%; oxides other than ZrO.sub.2, HfO.sub.2, SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, CeO.sub.2 and Y.sub.2O.sub.3<5.0%.

Ultra-high temperature carbide (UHTC) foams and methods of fabricating and using the same are provided. The UHTC foams are produced in a three-step process, including UHTC slurry preparation, freeze-drying, and spark plasma sintering (SPS). The fabrication methods allow for the production of any kind of single- or multi-component UHTC foam, while also providing flexibility in the shape and size of the UHTC foams to produce near-net-shape components.

A Li.sub.3Mg.sub.2SbO.sub.6-based microwave dielectric ceramic material easy to sinter and with high Q value, and a preparation method thereof are disclosed. A chemical formula of the material is Li.sub.3(Mg.sub.1-xZn.sub.x).sub.2SbO.sub.6, wherein 0.02≤x≤0.08. The preparation method includes: 1) mixing and ball-milling Sb.sub.2O.sub.3 and Li.sub.2CO.sub.3 according to a chemical ratio and then drying, and conducting pre-sintering to obtain a Li.sub.3SbO.sub.4 phase; and 2) mixing and ball-milling MgO, ZnO and Li.sub.3SbO.sub.4 powder according a chemical ratio of Li.sub.3(Mg.sub.1-xZn.sub.x).sub.2SbO.sub.6 and then drying, conducting granulation and sieving after adding an adhesive, pressing into a cylindrical body, and sintering the cylindrical body into ceramic in the air at 1325° C. and under normal pressure, wherein a dielectric constant is 7.2-8.5, a quality factor is 51844-97719 GHz, and a temperature coefficient of resonance frequency is −14-1 ppm/° C.

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.