Abstract: The invention relates to ceramic materials usable as tritium producing material in a thermonuclear fusion reactor. These materials are constituted by lithium zirconate substituted by copper in the form of solid solutions of the type Li.sub.2 ZrO.sub.3.

Abstract: This invention relates to a process for the preparation of lithium aluminosilicate or gamma lithium aluminate ceramics having a controlled microstructure and stoichiometry.According to this process, mixing takes place accompanied by stirring in a short chain anhydrous alcohol of an unpolymerized liquid aluminium alkoxide and optionally a silicon alkoxide with a hydrated or unhydrated lithium hydroxide, followed by the addition of water in order to hydrolyze the mixture and obtain, after drying, beta LiAlO.sub.2 powder.This powder can be directly compacted and then sintered at temperatures of 800.degree. to 1150.degree. C. without prior calcination giving a gamma lithium aluminate ceramic with a controlled stoichiometry and microstructure (grains of 0.1 to 10 .mu.m).

Abstract: Ceramic compositions based on yttrium oxide contain a minor amount of a titanium oxide and are readily sintered into dense ceramic shaped articles well adopted for metallurgical applications.

Abstract: The present invention relates to a ceramic based on yttrium oxide and titanium oxide. This ceramic has a light transmission percentage of at least 20% in a wavelength range between 0.5 and 8 .mu.m.It also relates to a sintering process for obtaining said ceramic.

Abstract: A process for the production of, in particular, ceramic parts having a cavity by press molding or pressing sealed sheaths.The core used for defining the cavity and preventing subsequent machining operations is initially more voluminous than the desired cavity and has an adequate ductility to allow partial extrusion during pressing. This avoids often excessive mechanical stresses, which can lead to a bursting or shattering of the densified part when the sheath is removed. This process has, application to the hot isostatic pressing of fragile materials.

Abstract: The invention relates to a process for shaping a material by isostatic compression at a temperature of at least 1300.degree. C. of a powder of said material in a tight sheath.The sheath is made from titanium or a titanium alloy and is internally coated with tantalum in such a way that the sheath can be embrittled during hot isostatic compression, by the diffusion of tantalum into the titanium or titanium alloy, in the presence of oxygen. In general, the titanium sheath is coated with tantalum by spraying in the presence of oxygen.The use of such a sheath makes it possible to avoid the operation of eliminating the sheath chemically or mechanically conventionally necessary in such processes.

Abstract: A process for the surface treatment of a part wherein it comprises subjecting the surface of said part in an inert atmosphere to the action of a hot gaseous arc plasma, and followed by the immediate cooling of the thus treated surface by projecting on to the same a cooling liquid at a temperature close to its saturation point which is a temperature whose variation from the saturation temperature does not exceed 15.degree. C.

Abstract: Process and apparatus for confining the pollution of an isostatic pressing enclosure.At the end of an isostatic pressing operation, a glove box is sealingly fixed above the enclosure, the plug is removed from the latter and deposited within the glove box, after which the sampling and inspection operations necessary for detecting any contamination are performed.Application to the compression of radioactive waste by isostatic pressing.

Abstract: The invention relates to a process for the production of porous products of boron or boron compounds.This process comprises the following stages:(1) suspending the boron powder in a solution of an alkali metal salt, hydroxide and/or oxide,(2) then separating the powder from the suspension liquid by settling,(3) drying the thus separated powder to obtain an agglomerated powder, and(4) subjecting the thus obtained agglomerated powder to at least two heat treatments performed at different temperatures, the final stage of the heat treatment being performed at a temperature of 1500.degree. to 2200.degree. C. and the first stage being performed at a temperature below that of the final stage.The heat treatment can be performed in three stages, as shown in the attached graph.

Abstract: The invention relates to a process and an apparatus for coating a member by plasma spraying.According to the invention, the pressure and composition of the atmosphere prevailing in the enclosure in which the operation takes place are constantly checked. The temperature of the member is regulated with the aid of a cooling system and the relative displacements of the member, the gun and the cooling system are automatically controlled.Application to the deposition of protective coatings on metal members or on composite materials.