A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2.

Disclosed is a ceramic composition comprising a plurality of at least semi-coherent particles with an average diameter ranging from 1 nm to 50 nm included within a matrix, wherein the matrix comprises one metal carbonate salt, metal oxide or metalloid oxide, the particles and the matrix share at least one metal element and the metal element is 10% to 80% of the total content of said matrix, and the composition has a lattice mismatch of less than 5%. Disclosed are also an article and methods for making the ceramic composition of the present invention.

A multilayer ceramic electronic component includes: a ceramic body including a dielectric layer having a main component represented by (Ba.sub.1-xCa.sub.x)(Ti.sub.1-y)(Zr, Sn, Hf).sub.y)O.sub.3 (where, 0≤x≤1, 0≤y≤0.5), and having a plurality of grains and grain boundaries disposed between the plurality of grains, and including first and second internal electrodes alternately stacked with the dielectric layer interposed therebetween; a first external electrode; and a second external electrode, wherein the dielectric layer includes a triple point in contact with three grain boundaries and a secondary phase of Si disposed inside the triple point, wherein a dispersion of an Si content at an interface between the dielectric layer and the internal electrode may be 1% by weight or less.

Disclosed is a ceramic composition comprising a plurality of at least semi-coherent particles with an average diameter ranging from 1 nm to 50 nm included within a matrix, wherein the matrix comprises one metal carbonate salt, metal oxide or metalloid oxide, the particles and the matrix share at least one metal element and the metal element is 10% to 80% of the total content of said matrix, and the composition has a lattice mismatch of less than 5%. Disclosed are also an article and methods for making the ceramic composition of the present invention.

Provided is a method for preparing a graphene-copper calcium titanate CCTO based ceramic composite dielectric material, which includes: dissolving metal ion sources in respective solvents to obtain respective solutions, and mixing the solutions evenly to obtain a precursor collosol of the CCTO based ceramic; allowing the precursor collosol of the CCTO based ceramic to stand for aging, followed by adding a graphene oxide dispersion to mix with the precursor collosol evenly, drying the resulting mixture to obtain dry precursor powders of the graphene-CCTO based ceramic, which are then grinded into fine powders, followed by irradiating by a low-power laser to obtain graphene-CCTO based ceramic composite powders; and compacting and molding the graphene-CCTO based ceramic composite powders, followed by catalytic synthesis with a high-power laser to obtain the graphene-CCTO based ceramic composite dielectric material.

A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2

A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2.

A copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of an aluminum nitride, wherein, the copper member and the ceramic member are bonded to each other, and a Mg solid solution layer is provided between the copper member and the ceramic member and contains Mg in a state of a solid solution in a Cu primary phase.

A Cr:YAG sintered body including Al, Y, Cr, Ca, Mg, Si, and O, and component contents in the sintered body satisfying conditional expressions of 1) to 3) below, provided in the Conditional expression, each chemical symbol represents a component content (atppm).

|(Y+Ca)/(Al+Cr+Si+Mg)−0.6|<0.001;  1)

0≤(Ca+Mg)−(Cr+Si)≤50 atppm; and  2)

50≤Si≤500 atppm  3)

The embodiment of the present invention is to provide a Cr:YAG sintered body which exhibits high transparency and has a high Cr.sup.4+ conversion ratio, and its production method.

A stacked structure includes a first structure formed of a composite sintered body that contains AlN and MgAl.sub.2O.sub.4 as main phases, and a second structure formed of a ceramic sintered body and stacked on and bonded to the first structure. A difference in linear thermal expansion coefficient between the first structure and the second structure is less than or equal to 0.3 ppm/K.