Abstract:
The invention relates to a method for preparing a powder of an alloy based on uranium and molybdenum in a metastable gamma phase, which comprises: a) putting at least one first reagent selected from uranium oxides and mixtures thereof, uranium fluorides and mixtures thereof, into contact with a second reagent consisting in molybdenum and a third reagent consisting in a reducing metal, the first, second and third reagents being in a divided form; b) reacting the reagents at a temperature>=the melting temperature of the third reagent and under an inert atmosphere, whereby this reaction leads to the formation of the alloy comprising uranium and molybdenum in the form of a powder, for which the particles are covered with a reducing metal oxide or fluoride layer; c) cooling the so formed powder at a rate at least equal to 450° C./hour; and d) removing the reducing metal oxide or fluoride layer which covers the particles of the powder of the alloy comprising uranium and molybdenum. It also relates to a method for manufacturing a nuclear fuel implementing this method. Applications: Manufacturing of nuclear fuels, notably for MTRs.
Abstract:
A method is provided for manufacturing a moving part capable of providing a liquid seal. The method comprises the steps of: firstly forming the part from sintered steel; and secondly forming a layer of Fe 3 O 4 on an un-ground surface of the part to provide a surface finish that is capable of providing a liquid seal.
Abstract:
An object of the present invention is to provide a method for producing a surface-modified rare earth metal-based sintered magnet having extremely excellent corrosion resistance even in an environment with fluctuating temperature and humidity and also having excellent magnetic characteristics. The method for producing a surface-modified rare earth metal-based sintered magnet of the present invention as a means for achieving the object is characterized by comprising a step of subjecting a rare earth metal-based sintered magnet to a heat treatment at 200°C to 600°C in an atmosphere having an oxygen partial pressure of 1 × 10 3 Pa to 1 × 10 5 Pa and a water vapor partial pressure of 45 Pa or less with the ratio between the oxygen partial pressure and the water vapor partial pressure (oxygen partial pressure/water vapor partial pressure) being 450 to 20000.
Abstract:
The present invention concerns a process for the manufacture of soft magnetic composite components comprising the steps of : die compacting a powder composition comprising a mixture of soft magnetic, iron or iron-based powder, the core particles of which are surrounded by an electrically insulating, inorganic coating, and an organic lubricant in an amount of 0.05 to 1.5 % by weight of the composition, said organic lubricant being free from metal and having a temperature of vaporisation less than the decomposition temperature of the coating; ejecting the compacted body from the die; heating the compacted body in a non reducing atmosphere to a temperature above the vaporisation temperature of the lubricant and below the decomposition temperature of the inorganic coating for removing the lubricant from the compacted body, and subjecting the obtained body to heat treatment at a temperature between 3000C and 600°C in water vapour. The invention also concerns soft magnetic composite components having a transverse rupture strength of at least 100 MPa, a permeability of at least 700 and a core loss at 1 Tesla and 400 Hz of at most 70W/kg.
Abstract:
A method for producing a metal powder which comprises effecting a plasma discharge in water between an electrode of an elemental metal and a counter electrode to generate a metal ion vapor and contacting the metal ion vapor with water to thereby convert the metal ion vapor to a powder; and an apparatus for producing a metal powder which comprises a power source for high voltage high current discharge, a device for supplying an electrode of a metal such as titanium, a high voltage discharge device having an electrode of a metal such as titanium and a counter electrode, a device for vibrating or sliding anelectrode, a water tank, a water inlet, an outlet and a discharge pump for discharging a dispersion of a metal such as titanium, and a device for separating and recovering a powder of a metal such as titanium. The method and the apparatus allows the production of a metal powder having high purity and being uniform in the shape and size of particles, at a low cost.
Abstract:
A method for making a sintered porous metal plate comprises the steps of: a slurry preparation step for preparing a foamable slurry containing metal powder; a shaping step for shaping the foamable slurry into a plate article; a foaming step for foaming the plate article; and a drying step for drying the plate article after foaming. Further, an apparatus for making a sintered porous metal plate comprises a slurry preparation section for preparing a foamable slurry containing at least metal powder, a foaming agent and a liquid medium; a shaping section for shaping the foamable slurry fed from the slurry preparation section into a plate article; a foaming section for foaming the plate article of the foamable slurry; and a drying section for drying the cellular article; and these section are integrated in series by a transfer section.
Abstract:
A porous metallic body that has a three-dimensional reticular skeleton structure wholly constituted of a powdery metallic sinter with a porosity of 10-60 % and that has a total porosity of 80-99 %. The specific surface are thereof is as large as, for example, 300-11,000 cm2/cm3. This body can be reinforced with reinforcing plates and is suitable as an electrode of an alkaline secondary battery capable of attaining a long service life and a large capacity of active materials which can be contained. The metallic body is produced by molding a foamable slurry containing a metallic powder, drying the molded slurry preferably after foaming, and sintering the same.
Abstract:
The invention relates to a binder system, characterized in that the binder system consists of: (a) 30 to 95 per cent by weight of a water-soluble polyethylene glycol (PEG), and (b) 70 to 5 per cent by weight of a polyvinyl butyral (PVB). The invention also relates to a method for producing a product by means of PIM or powder extrusion using the binder system according to the invention, in which, in order to remove the binder system from a green product, firstly at least 70% of the PEG is removed by means of a solvent which substantially comprises water, and holding the product at a temperature in a range from 10 to 40°C for 8 to 100 hours.