Abstract: A process for manufacturing a multi-material part by additive manufacturing, includes the following steps: a) a step of providing a pre-treated metal powder comprising grains and an oxidized and porous layer on a surface of the grains; b) a selective laser powder-bed fusion step comprising implementation of steps i) and ii) as follows: i) a step of forming a layer from the pre-treated metal powder; ii) a step of melting by laser the layer, the melting step being carried out under a reactive atmosphere and comprising changing parameters of application of the laser so that at least a first region of the layer is converted so as to lower the electrical conductivity thereof, thus forming a dielectric, and so that at least a second region of the layer is densified without converting it, the at least a first region being formed when the parameters of application of the laser allow a first energy density to be applied to the first region and/or the laser beam to be kept for a first dwell time on the first region, th

Abstract: The invention relates to a process for the manufacture of a metal, ceramic or composite part or of a supported metal, ceramic or composite microstructure by laser irradiation starting from metal oxalates, and also to the part and the microstructure obtained by said process, and to their uses.

Abstract: The invention relates to the use of a material having a spinel ferrite/iron monoxide structure as a sensitive material in the form of a thin film for the bolometric detection of infrared radiation, the chemical composition of said structure, excluding doping agents that may be present, having empirical formula (I): (Fe1?zMz)xO, where x is strictly less than 1 and strictly greater than 0.75. The invention also relates to a bolometric device for infrared radiation detection and infrared imaging, comprising at least one sensor provided with a sensitive element in the form of a thin film as defined above.

Abstract: A process for manufacturing a device comprising at least a support and a component, joined together by at least one braze, includes a brazing operation which is carried out starting from a metal oxalate. Advantageously, it is a silver oxalate or a mixture of silver and copper oxalates, the component and/or the support being covered with a film comprising gold or copper in contact with said braze and the component possibly being a power component.

Abstract: A process for manufacturing a device comprising at least a support and a component, joined together by at least one braze, includes a brazing operation which is carried out starting from a metal oxalate. Advantageously, it is a silver oxalate or a mixture of silver and copper oxalates, the component and/or the support being covered with a film comprising gold or copper in contact with said braze and the component possibly being a power component.

Abstract: The present invention relates to the use as a sensitive material in a thin layer for bolometric detection of infrared radiation, of a material having a spinel ferrite structure of chemical composition, ignoring doping agents if any are present, satisfying empirical formula I: Fe3-(x+y)MxAyO4+?. The invention also provides a bolometric device for detecting infrared radiation or for infrared imaging, and including at least one sensor provided with a sensitive element in the form of a thin layer as defined above.

Abstract: The invention relates to the use of a material having a spinel ferrite/iron monoxide structure as a sensitive material in the form of a thin film for the bolometric detection of infrared radiation, the chemical composition of said structure, excluding doping agents that may be present, having empirical formula (I): (Fe1?zMz)xO, where x is strictly less than 1 and strictly greater than 0.75. The invention also relates to a bolometric device for infrared radiation detection and infrared imaging, comprising at least one sensor provided with a sensitive element in the form of a thin film as defined above.

Abstract: The purpose of the invention is a process for making a solid part designed to form all or part of an anode for the production of aluminium by fused bath electrolysis, containing a cermet formed from at least one metallic oxide such as a mixed oxide with spinel structure, and at least one metallic phase, in which a mixed oxide is used containing a metal R in the form of a cation in its chemical structure, the said metal R being fully or partly reducible by a reduction operation during the manufacturing process, so as to form all or part of the said metallic phase. This process can provide a cermet with a uniform distribution of fine metallic particles.

Abstract: A magneto-optical recording medium has a recording layer and a reflective layer on a substrate. The recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. A manufacturing method comprises the steps of heat treatment in the range of 500-700° C., preferably 600-630° C., after the formation of the recording layer. In the magneto-optical recording and playback device to record and play back data, the wavelength of light for recording data is different from that for reading data, which is preferable for a magneto-optical recording medium comprising a garnet ferrite layer.

Abstract: The present invention relates to the use as a sensitive material in a thin layer for bolometric detection of infrared radiation, of a material having a spinel ferrite structure of chemical composition, ignoring doping agents if any are present, satisfying empirical formula I: Fe3?(x+y)MxAyO4+???(I) The invention also provides a bolometric device for detecting infrared radiation or for infrared imaging, and including at least one sensor provided with a sensitive element in the form of a thin layer as defined above.

Abstract: The purpose of the invention is a process for making a solid part designed to form all or part of an anode for the production of aluminium by fused bath electrolysis, containing a cermet formed from at least one metallic oxide such as a mixed oxide with spinel structure, and at least one metallic phase, in which a mixed oxide is used containing a metal R in the form of a cation in its chemical structure, the said metal R being fully or partly reducible by a reduction operation during the manufacturing process, so as to form all or part of the said metallic phase. This process can provide a cermet with a uniform distribution of fine metallic particles.

Abstract: This invention relates to magneto-optical recording media such as magneto-optical disks and cards, manufacturing methods of the medium and a magneto-optical recording and playback device to record and play back data using the magneto-optical recording media. The magneto-optical recording medium of the present invention has a recording layer and a reflective layer on a substrate, and the recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. The manufacturing method of the present invention comprises the steps of heat treatment in the range of 500-700° C., preferably 600-630° C., after the formation of the recording layer.

Abstract: The present invention relates to a method of recording data in digital form on a write-once read-many optical medium comprising a sensitive film based on a metal oxide of the oxidizable spinel type. Regions of the sensitive film are heated, locally and in succession, under conditions allowing oxidation of the oxidizable metal ions of the oxide. In the optical medium thus recorded, the virgin regions, which are not modified by the write operation, are oxidizable and change color after heat treatment in an oxidizing atmosphere.

Abstract: This invention relates to magneto-optical recording media such as magneto-optical disks and cards, manufacturing methods of the medium and a magneto-optical recording and playback device to record and play back data using the magnetic-optical recording media. The magneto-optical recording medium has a recording layer and a reflective layer on a substrate, and the recording layer has a layered structure in which at least on spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. The manufacturing method comprises the steps of heat treatment after the formation of the recording layer. In the magneto-optical recording and playback device to record and playback data, the wavelength of light for recording data is different from that for reading data, which is preferable for a magneto-optical recording medium comprising a garnet ferrite layer.

Abstract: This invention relates to magneto-optical recording media such as magneto-optical disks and cards, manufacturing methods of the medium and a magneto-optical recording and playback device to record and play back data using the magneto-optical recording media. The magneto-optical recording medium of the present invention has a recording layer and a reflective layer on a substrate, and the recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. The manufacturing method of the present invention comprises the steps of heat treatment in the range of 500-700° C., preferably 600-630° C., after the formation of the recording layer.

Abstract: The invention relates to a method of preparing metal powder comprising: preparing a simple or mixed oxalate of one or more metals formed of particles with needle-like morphology having a mean acicularity ratio (length/diameter) of from 4 to 20, and a length of from 5 to 10 microns and converting said oxalate to metal or metal alloy powder by reducing treatment with gaseous hydrogen. The conversion of said oxalate can be carried out by decomposing said oxalate, in air, to an oxide and then reducing said oxide to metal or metal alloy. The metal is chosen from among the rare earth metals and the transition metals, preferably from among iron, cobalt, and nickel. The method is particularly suitable for making iron powder metal having a spongy and filament-like microstructure which makes it suitable for use in heating composition for thermo-piles. In addition, the invention relates to metal compacts unstoved or annealed which are obtained by applying compaction pressure to the powders according to the invention.

Abstract: Composite material for magnetooptic recording, comprising a thin layer deposited on a non-magnetic solid substrate. The said thin layer is a polycrystalline layer consisting of microcrystals having a structure of a vacant-site spinel ferrite, based on iron, cobalt and transition metals. By virtue of a particular process for producing the thin layers, enabling especially the size of the crystallites to be increased, it is possible to optimize the magnetic and magnetooptic properties and to obtain thin layers having, for example, a remanent Faraday rotation and a coercive field which are greater, respectively, than 1 degree per micron for the Faraday rotation and 1000 Oe for the coercive field.

Abstract: Composite material for magnetooptic recording, comprising a thin layer deposited on a non-magnetic solid substrate. The said thin layer is a polycrystalline layer consisting of microcrystals having a structure of a vacant-site spinel ferrite, based on iron, cobalt and transition metals. By virtue of a particular process for producing the thin layers, enabling especially the size of the crystallites to be increased, it is possible to optimize the magnetic and magnetooptic properties and to obtain thin layers having, for example, a remanent Faraday rotation and a coercive field which are greater, respectively, than 1 degree per micron for the Faraday rotation and 1000 Oe for the coercive field.

Abstract: Particulate magnetic oxide compositions based on iron oxide (III) and oxide of at least one bivalent metal selected among cobalt, iron, copper, zinc, magnesium, nickel, manganese and cadmium, characterized in that said compositions contain additionally in the form of an oxide from 0.2 to 5% by weight calculated on the total weight at least one additive or substituent selected among alkali metals, alkaline-earth metals, boron, the elements of columns 3, 4 and 5 of the periodical classification of elements having a molecular mass higher than 26, the transition metals 3d and 4d other than those already mentioned, and the rare earths, with the proviso that when an alkali metal or tin is present, at least another additive or substituent is also present, and in that said compositions have a structure of the lanucar spinel type; the preparation and application thereof are also disclosed.

Abstract: The disclosed particulate composition of simple or mixed oxalate of ferromagnetic metals is characterized in that it is provided in the form of needle-shaped particles having a length comprised between 0.05 and 0.5 micrometer, with a proportion higher than 60% of particles having a length equal to the average length .+-.0.1 .mu.m. and an acicular ratio higher than 3, said average length being comprised between 0.15 and 0.35 .mu.m; its preparation and its application are also disclosed.