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.

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.

An Al.sub.2O.sub.3 sputtering target having a purity of 99.99 wt % or higher, a relative density of 85% or higher and 95% or less, a volume resistivity of 10×10.sup.14 Ω.Math.cm or less, and a dielectric tangent of 15×10.sup.−4 or more. An object of the present invention is to provide an Al.sub.2O.sub.3 sputtering target having favorable sputtering characteristics, and in particular an Al.sub.2O.sub.3 sputtering target and a production method thereof capable of increasing the deposition rate without having to increase the sputtering power.

A method of forming one or more high temperature co-fired ceramic articles, comprising the steps of:— a) forming a plurality of green compacts, by a process comprising dry pressing a powder comprising ceramic and organic binder to form a green compact; b) disposing a conductor or conductor precursor to at least one surface of at least one of the plurality of green compacts to form at least one patterned green compact; c) assembling the at least one patterned green compact with one or more of the plurality of green compacts or patterned green compacts or both to form a laminated assembly; d) isostatically pressing the laminated assembly to form a pressed laminated assembly; e) firing the pressed laminated assembly at a temperature sufficient to sinter the ceramic layers together.

A honeycomb filter including: a pillar-shaped honeycomb structure having an inflow end face and an outflow end face and including a porous partition wall disposed so as to surround a plurality of cells, the plurality of cells extending from the inflow end face to the outflow end face; inflow side plugging portions disposed at open ends of predetermined cells on the inflow end face side; and outflow side plugging portions disposed at open ends of residual cells on the outflow end face side, wherein the outflow side plugging portions comprise first outflow side plugging portions and second outflow side plugging portions, the plugging length L1 of the first outflow side plugging portions is 10 to 50% of the overall length L0 of the honeycomb structure, and the plugging length L2 of the second outflow side plugging portions is less than 10% of the overall length L0 of the honeycomb structure.

A method of forming one or more high temperature co-fired ceramic articles, comprising the steps of:— a) forming a plurality of green compacts, by a process comprising dry pressing a powder comprising ceramic and organic binder to form a green compact; b) disposing a conductor or conductor precursor to at least one surface of at least one of the plurality of green compacts to form at least one patterned green compact; c) assembling the at least one patterned green compact with one or more of the plurality of green compacts or patterned green compacts or both to form a laminated assembly; d) isostatically pressing the laminated assembly to form a pressed laminated assembly; e) firing the pressed laminated assembly at a temperature sufficient to sinter the ceramic layers together.

Disclosed is a method for fabricating a solid article from a boron carbide powder comprising boron carbide particles that are coated with a titanium compound. Further disclosed herein are the unique advantages of the combined use of titanium and graphite additives in the form of water soluble species to improve intimacy of mixing in the green state. The carbon facilitates sintering, whose concentration is then attenuated in the process of forming very hard, finely dispersed TiB2 phases. The further recognition of the merits of a narrow particle size distribution B4C powder and the use of sintering soak temperatures at the threshold of close porosity which achieve post-HIPed microstructures with average grain sizes approaching the original median particle size. The combination of interdependent factors has led to B.sub.4C-based articles of higher hardness than previously reported.

The present disclosure relates to boron carbide (B.sub.4C) composite material and the method of making and using the boron carbide (B.sub.4C) composite.

Methods of forming ceramic matrix composite structures include joining at least two lamina together to form a flexible ceramic matrix composite structure. Ceramic matrix composite structures include at least one region of reduced inter-laminar bonding at a selected location between lamina thereof. Thermal protection systems include at least one seal comprising a ceramic matrix composite material and have at least one region of reduced inter-laminar bonding at a selected location between lamina used to form the seal. Methods of forming thermal protection systems include providing one or more such seals between adjacent panels of a thermal protection system.

The invention relates to a process of sintering a dental zirconia restoration, the process comprising a first step of heat-treating a porous dental zirconia article with a heating rate of at least 3 K/sec until a temperature level of 75 to 90% of the final sintering temperature is achieved to obtain a partially sintered dental zirconia article, the porous dental zirconia article having a BET surface of 5 to 12 m.sup.2/g and being composed of a 4 mol % yttria stabilized zirconia material and having an alumina content of utmost 0.15 wt. %.