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.

Polycrystalline diamond cutters for rotary drill bits and methods of making the same are disclosed. A polycrystalline diamond compact includes a polycrystalline diamond body having a working surface, an interface surface, and a perimeter surface. The polycrystalline diamond compact also includes a substrate bonded to the polycrystalline diamond body along the interface surface. A non-diamond volume fraction of the polycrystalline diamond body is greater at the interface surface than at the working surface.

Brake disks with integrated heat sink are provided. Brake disk includes a fiber-reinforced composite material and an encapsulated heat sink material impregnated into the fiber-reinforced composite material. The encapsulated heat sink material comprises a heat sink material encapsulated within a silicon-containing encapsulation layer. Methods for manufacturing the brake disk with integrated heat sink and methods for producing the encapsulated heat sink material are also provided.

A polycrystalline sintered ceramic material of very low electrical resistivity includes by mass more than 95% silicon carbide (SiC), less than 1.5% silicon in another form than SiC, less than 2.5% carbon in another form than SiC, less than 1% oxygen (O), less than 0.5% aluminum (Al), less than 0.5% of the elements Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, less than 0.5% alkali elements, less than 0.5% alkaline earth, between 0.1 and 1.5% nitrogen (N), the other elements forming the complement to 100%, wherein the grains of the above material have a median equivalent diameter of between 0.5 and 5 micrometers, the mass ratio of SiC alpha (?)/SiC beta (?) is less than 0.1, and the total porosity represents less than 15% by volume of the material.

A process for preparing alloy products is described using a self-sustaining or self-propagating SHS-type combustion process with point-source ignition, preferably a laser, in a pressurized vessel. Binary, ternary and quaternary alloys can be formed with control over polycrystalline structure and bandgap. Methods to tune the bandgap and the alloys formed are described. The alloy products may be doped. Preferably sulfides, tellurides or selenides are formed. Cooling during reaction takes place.

The present invention relates to a method of manufacturing a ceramic article (3) from a metal or metal matrix composite preform (1) provided by 3D-printing or by 3D-weaving. The preform (1) is placed in a heating chamber (2), and a predetermined time-temperature profile is applied in order to controllably react the preform (1) with a gas introduced into the heating chamber (2). The metal, the gas and the time-temperature profile are chosen so as to induce a metal-gas reaction resulting in at least a part of the preform (1) transforming into a ceramic. Preferred embodiments of the invention comprises a first oxidation stage involving a metal-gas reaction in order to form a supporting oxide layer (5) at the surface of the metal, followed by a second stage in which the heating chamber (2) is heated to a temperature above the melting point of the metal to increase the kinetics of the chemical reaction. The invention also relates to a number of advantageous uses of a ceramic article manufactured as described.

Brake disks with integrated heat sink are provided. Brake disk includes a fiber-reinforced composite material and an encapsulated heat sink material impregnated into the fiber-reinforced composite material. The encapsulated heat sink material comprises a heat sink material encapsulated within a silicon-containing encapsulation layer. Methods for manufacturing the brake disk with integrated heat sink and methods for producing the encapsulated heat sink material are also provided.

A method for manufacturing a magnesium-based thermoelectric conversion material of the present invention includes a raw material-forming step of forming a raw material for sintering by adding silicon oxide in an amount within a range equal to or greater than 0.5 mol % and equal to or smaller than 13.0 mol % to a magnesium-based compound, and a sintering step of heating the raw material for sintering at a temperature within a range equal to or higher than 750 C. and equal to or lower than 950 C. while applying pressure equal to or higher than 10 MPa to the raw material for sintering so as to form a sintered substance.

A method for producing MnZn ferrite comprising Fe, Mn and Zn as main components, and Ca, Si and Co, and at least one selected from the group consisting of Ta, Nb and Zr as sub-components, comprising a step of molding a raw material powder for the MnZn ferrite to obtain a green body, and a step of sintering the green body; the sintering step comprising a temperature-elevating step, a high-temperature-keeping step, and a cooling step; the cooling step including a slow cooling step of cooling in a temperature range of 1100 C. to 1250 C. at a cooling speed of 0 C./hour to 20 C./hour for 1 hours to 20 hours, and a cooling speed before and after the slow cooling step being higher than 20 C./hour; the MnZn ferrite having a volume resistivity of 8.5 .Math.m or more at room temperature, an average crystal grain size of 7 m to 15 m, and core loss of 420 kW/m.sup.3 or less between 23 C. and 140 C. at a frequency of 100 kHz and an exciting magnetic flux density of 200 mT.

The present invention relates to a method of producing porous alpha-SiC containing shaped body and porous alpha-SiC containing shaped body produced by that method. The porous alpha-SiC containing shaped body shows a characteristic microstructure providing a high degree of mechanical stability.