Abstract: A method for producing pellets of sintered material, comprising: a) forming calibrated pre-compacts by first uniaxial pressing of equal portions powder at a first threshold below the maximum green density threshold of the powder; b) providing a pressing tool set comprising a die having a plurality of cavities and pressure pistons; c) placing the pre-compacts in the cavities with first and second sintered boron nitride disks, having a thickness in the millimetre range and a density >=90%; d) forming calibrated compacts by second uniaxial pressing of the pre-compacts using the pressure pistons at a second threshold greater than the first threshold, which is less than or equal to the maximum green density of the powder; e) forming sintered compacts by applying pressure and a pulsed current to the pressing tool set to bring about a rapid rise in temperature according to a temperature-, pressure- and duration-controlled SPS sintering cycle.

Abstract: A method for manufacturing a porous fuel comprising uranium, optionally plutonium and at least one minor actinide is provided. The method may comprise the following successive steps: a) a step for compacting as pellets a mixture of powders comprising uranium oxide, optionally plutonium oxide and at least one oxide of a minor actinide, at least one portion of the uranium oxide being in the form of triuranium octaoxide U3O8, the other portion being in the form of uranium dioxide UO2; b) a step for reducing at least one portion of the triuranium octaoxide U3O8 into uranium dioxide UO2.

Abstract: A method for manufacturing a porous fuel comprising uranium, optionally plutonium and at least one minor actinide is provided. The method may comprise the following successive steps: a) a step for compacting as pellets a mixture of powders comprising uranium oxide, optionally plutonium oxide and at least one oxide of a minor actinide, at least one portion of the uranium oxide being in the form of triuranium octaoxide U3O8, the other portion being in the form of uranium dioxide UO2; b) a step for reducing at least one portion of the triuranium octaoxide U3O8 into uranium dioxide UO2.

Abstract: Process for the preparation of a ceramic wherein: 50% to 75% by weight of a compound intended to form a conductive phase, and 25% to 50% by weight of one or more materials allowing the formation of insulating phases composed of silicon nitride and modified silicon oxynitride are mixed in a receptacle containing a liquid after a thermal treatment leading to sintering of the ceramic; this mixture is subjected to grinding, drying and sieving operations; this mixture is pressed; and this mixture is sintered so as to obtain a ceramic with a porosity of between 0 and 30%. The sintering is carried out under a pressure of at least 50 bar of a gas which is inert towards the constituents of the mixture. Ceramic thus obtained and spark plug comprising it.

Abstract: Method for manufacturing a high-energy, low-voltage ignition plug comprising a ceramic material between its electrodes: there is mixed, in a container containing a liquid, from 50 to 75% of a compound which is intended to form a conductive phase and from 25 to 50% of one or more materials which allow the formation of phases of yttrium garnet after thermal processing; operations are carried out for pulverizing, drying and sieving the admixture; the admixture is pressed or injected into a mould; sintering is carried out so as to obtain a ceramic material having porosity of between 0 and 30%; the ceramic material is used in order to constitute the material located between the electrodes of a high-energy, low-voltage ignition plug. Ignition plug manufactured in that manner.

Abstract: Process for the preparation of a ceramic wherein: 50% to 75% by weight of a compound intended to form a conductive phase, and 25 % to 50% by weight of one or more materials allowing the formation of insulating phases composed of silicon nitride and modified silicon oxynitride are mixed in a receptacle containing a liquid after a thermal treatment leading to sintering of the ceramic; this mixture is subjected to grinding, drying and sieving operations; this mixture is pressed; and this mixture is sintered so as to obtain a ceramic with a porosity of between 0 and 30%. The sintering is carried out under a pressure of at least 50 bar of a gas which is inert towards the constituents of the mixture. Ceramic thus obtained and spark plug comprising it.

Abstract: Method for preparing a semi-conductive ceramic material, wherein: in a receptacle containing a liquid, there are mixed from 30 to 90% of a conductive phase based on Z1-xMxCrO3 for 0?×?0.3, with Z being an element of the lanthanide group or a mixture of elements of this type, and M being calcium, strontium, magnesium, aluminum, titanium, yttrium or a mixture of two or more of these elements; from 8 to 60% of an insulating phase based on fine grains of alumina or tabular alumina or mullite or a mixture of two or more of these compounds; and from 0 to 10% of sintering additives; operations are carried out for milling, drying and sieving this mixture; this mixture is pressed; and this mixture is sintered in order to obtain a ceramic material having a porosity less than or equal to 25%.

Abstract: Method for manufacturing a high-energy, low-voltage ignition plug comprising a ceramic material between its electrodes: there is mixed, in a container containing a liquid, from 50 to 75% of a compound which is intended to form a conductive phase and from 25 to 50% of one or more materials which allow the formation of phases of yttrium garnet after thermal processing; operations are carried out for pulverising, drying and sieving the admixture; the admixture is pressed or injected into a mould; sintering is carried out so as to obtain a ceramic material having porosity of between 0 and 30%; the ceramic material is used in order to constitute the material located between the electrodes of a high-energy, low-voltage ignition plug. Ignition plug manufactured in that manner.

Abstract: Method for preparing a semi-conductive ceramic material, wherein: in a receptacle containing a liquid, there are mixed from 30 to 90% of a conductive phase based on Z1-xMxCrO3 for 0?X?0.3, with Z being an element of the lanthanide group or a mixture of elements of this type, and M being calcium, strontium, magnesium, aluminum, titanium, yttrium or a mixture of two or more of these elements; from 8 to 60% of an insulating phase based on fine grains of alumina or tabular alumina or mullite or a mixture of two or more of these compounds; and from 0 to 10% of sintering additives; operations are carried out for milling, drying and sieving this mixture; this mixture is pressed; and this mixture is sintered in order to obtain a ceramic material having a porosity less than or equal to 25%.