Abstract: A The invention discloses an assembly consisting of a head (1, 1′, 200) and an overcap (30, 30′, 30″, 300), the head having a cylindrical neck provided with a helical screw thread (21), the overcap having a cylindrical skirt (31) provided with a thread (36) matching the neck thread (21). The overcap carries an axial plate (33) radially flexible and circumferentially rigid. The neck base (10) is provided with at least an opening stop (12), and at least a closure stop (11), of lesser height. When the overcap (30) is screwed on the head for mounting the assembly, the free end of the axial plate is urged into contact with a first wall (14) of the opening stop (12) and the axial plate whereof the free end is urged by a centrifugal motion, is elastically deformed then, folds down towards the neck in a space between the opening (12) and closure (11) stops, its displacement being thereby restricted.

Abstract: This invention relates to a process for identifying the external surface or surfaces of an Al alloy of a homogeneous or composite material by electrochemical means. This method involves forming an anodic layer, in situ, on the products to be identified, by electrolysis under predetermined conditions and following or plotting the development of the voltage U at the terminals of the electrolyzer as a function of time t during an intentiostatic test. The shape and relative position of curves U=f(t), thus obtained, allows the various alloys tested to be identified from a comparison of the derived curve from a curve U=f(t) derived from a known sample. The present method has advantages over the earlier methods of marking in that it provides: non-destructive method employable in situ on products which may have large dimensions (coils, plates, sheets, etc.); almost instantaneous identification; high reliability; and is simple and economic to use.

Abstract: The invention concerns a metal alloy with large lattice spacings (>than 1 nm), and consisting essentially of, by weight: at least one element selected from a group A consisting of Al, Zn and Cu, total group A elements being 44-92%; at least one element selected from a group B consisting of Ag, Ga and Au, total group B elements being 0-46%, with % group A+group B=88-92%, and ##EQU1## a group C element which is Li in an amount of 7.2-12%; at least one element selected from a group D consisting of Mg, K, Na, and Ca, total group D elements being 0-12%, with % group C+% group D=8-12%, ##EQU2## and % group A+% group B+% group C+% group D=100%; said alloy additionally comprising elemental impurities in an amount of less than 1% each and less than 5% total, based on the total weight of the alloy.

Abstract: The invention relates to an accurate method of quantitative analysis by the quantitative determination of the mean atomic number of phases containing two light elements or one light element combined with heavy elements using a scanning microscope connected to an image analyser of the intensity of the back-scattered electrons. This method of quantitative analysis by the quantitative determination of the mean atomic number (Z.sub.1) with a precision of .+-.0.1 unit of an unknown phase present in the plane micrographic section of a sample, containing either two light elements (3.ltoreq.Z.ltoreq.11) or at least one heavy element (Z>12) and a single light element (3.ltoreq.Z.ltoreq.

Abstract: The invention relates to a process for obtaining crystals of intermetallic compounds, in particular isolated monocrystals, by cooling alloys in the molten state.The process involves using an alloy in the molten state which has a composition such that the first phase to crystallize during its solidification corresponds to the compound to be isolated, cooling it slowly by subjecting it to cyclic stirring and thermal cycling without attaining the temperature at which another solid phase appears then abruptly expelling the residual liquid.The process is used for obtaining large monophase primary crystals of compounds which melt congruently or incongruently, in particular compounds having symmetry of order 5 known as "quasi-crystals".

Abstract: The invention relates to a process for producing transition metal powders by electrolysis in melted salt baths. This process is characterized in that electrolysis is performed in such a way that the deposition voltage of the transition metal is 0.1 to 0.4V below that of the alkali metal or alkaline earth metal which it is the easiest to reduce.It is used in the production of powders having dimensions between a few fractions of a micron and approximately 200 microns from metals belonging to groups IVb, Vb and VIb of the periodic classification of metals, such as e.g. titanium, zirconium and hafnium.

Abstract: A process for the manufacture of a rough-shaped, cold-rolled cladding tube of "Zircaloy 2" or "Zircaloy 4", in which(a) an ingot of the alloy is transformed by hot working and the bar obtained is cut up into billets,(b) the bar or the billet is then immersed from the .beta. range,(c) at least one billet which has thus been immersed is extruded in the .alpha. range,(d) the rough shape extruded is cold-rolled and heat-treated to give rise to a cold-rolled, rough-shaped cladding tube,wherein the hot working is first carried out in the .beta. range with a cross-sectional reduction ratio of at least 1.5 and then in the .alpha. range with a cross-sectional reduction ratio of at least 3, is disclosed.

Abstract: A closed apparatus of potential fluidization type, for conveying powder materials in a dense bed from a storage region (31) to at least one region to be fed therewith, comprising a storage tank (48) for storing the powder material, referred to as a reserve container, which comprises between the two regions at least one horizontal conveyor (33) formed by a lower duct (35) for a flow of gas, an upper duct (36) for a flow of the powder material and the gas, between which ducts is disposed a porous wall (34), and at least one conduit (38) for feeding gas to the lower duct, which makes it possible to establish a pressure Pf that creates a dense potential-fluidization bed of the powder material that fills the conveyor, by virtue of the presence of at least one balancing column (39), the filling height (56) of which balances the pressure Pf of the potential-fluidization gas, the improvement wherein the closed storage tank or reserve container (48) of the region to be supplied with material, being provided with an in

Abstract: This invention relates to a cell for producing a metal by electrolyzing halides in a molten salt bath. It consists of using one cathode in the form of a basket, simultaneously passing a current I.sub.1 between this cathode and an anode in such a manner as to carry out a first deposit of crude metal in the basket and a current I.sub.2 between the said basket and complimentary cathodes for depositing the final metal thereon. The cell consists of a central anodic system, a tubular cathodic basket surrounding the anode and a series of cathodes surrounding this basket, a positioning which cathodes can be reversed in relation to the basket.

Abstract: The present invention relates to a process for improving the purity of transition metals produced by electrolysis of halides thereof in a bath of molten salts in a tank having a metal internal wall.The process is characterised in that a cathodic potential with respect to the anode of the cell is permanently imposed on the tank.It finds application in the production of metals such as in particular titanium, zirconium, hafnium, vanadium, niobium and tantalum, with a low proportion of oxygen and foreign metal elements.

Abstract: A process for measuring the potential of an indicator electrode of a transition metal, which dips into a bath of molten chlorides disposed in an electrolytic cell relative to a reference electrode. It is characterized by introducing into the bath an amount of alkali metal and/or alkaline earth fluorides such that the molar ratio of the fluorine contained in the bath to the amount of dissolved transitions metal is between 4 and 8.

Abstract: This invention relates to an electrolysis process and cell for producing a metal by electrolyzing halides in a molten salt bath. It consists of using one cathode in the form of a basket, simultaneously passing a current I.sub.1 between this cathode and the anode in such a manner as to carry out a first deposit of crude metal in the basket and a current I.sub.2 between the said basket and the complimentary cathodes for depositing the final metal thereon. The cell consists of a central anodic system, a tubular cathodic basket surrounding the anode and a series of cathodes surrounding this basket, a positioning which can be reversed in relation to the basket. The invention finds its application in the continuous production of good quality refractory metal with a suitable material and electric yield.

Abstract: This invention relates to a process for obtaining extruded semifinished products from high resistance aluminum alloy powder.It is characterized in that there is used particularly a powder of an aluminum-lithium alloy obtained by atomization in a neutral gas. This powder is loaded in a jacket of aluminum alloy of the 5000 type, then hot degassed under a pressure less than the atmospheric pressure; after sealing of the jacket, the unit is subjected to hot inverted extrusion and heat treated in the ambient air.The plated composite semifinished product thus obtained exhibits a very high resistance and finds its application particularly in the aeronautical industry.

Abstract: The present invention relates to a process for purifying metals, such as aluminum, by segregation, wherein, by controlled cooling in the upper part of a volume of liquid metal to be purified, which is contained in a crucible and disposed in a furnace, small crystals are caused to form, the crystals falling towards the bottom of the container under the force of gravity. The small crystals are compacted so as to cause the formation of a compact layer of large purified crystals.This process is distinguished from the known processes in that, to enhance the purification effect, the thermal flux is so adjusted as to completely and progressively re-melt the lower part of the mass of large crystals which are formed, with the re-melting action being propagated upwardly so as permanently to maintain a layer of large crystals which separates the re-melted liquid entirely disposed in the lower part from the remaining mother liquor.

Abstract: A process for the purification of solutions containing sodium or potassium carbonate, sulphate, hydroxide or hydrogen carbonate, and mainly at least one of the metals belonging to the group formed by vanadium, uranium or molybdenum, in the form of sodium or potassium salts, and inorganic and/or organic impurities, wherein the above-mentioned solutions are completely or partially caustified by the addition of an adequate amount of lime, whereby a first precipitate essentially containing calcium carbonate is separated, and the separated liquor is concentrated by evaporation until the hydroxide content is at most equal to 50%, to cause the production of a second precipitate which essentially comprises sodium or potassium sulphate, then, after separation thereof, a hydroxide-rich liquor is collected.This process is more particularly adapted for treatments of liquors resulting from the alkaline attach of vanadiferous and uraniferous ores.

Abstract: A process for treating a hydrometallurgical suspension resulting from the acid attack on an ore containing at least one metal element to be put to use, and non-attackable mineral materials, a fraction of which is formed of clays, comprising extracting the useful metal element which has gone into solution in the attack operation, by means of an organic solvent belonging to the group of alkyl phosphates, which is characterized by introducing a condensed mineral phosphate into the ore attack medium, for the purpose of limiting the losses due to adsorption of the organic extraction solvent by the clays.The process applies more particularly to uraniferous, molybdeniferous, vanadiferous and cobaltiferous ores.

Abstract: The present invention relates to a process of segregation for producing metals such as aluminum in a very high state of purity in respect of eutectic elements. The process comprises adding to a metal which is already very pure, at least one eutectic element, in a hypoeutectic amount, to ensure efficiency of the segregation operation. The added element or elements must be capable of being easily eliminated in the segregation operation, and it must not create difficulties in regard to the use envisaged for the metal.This process can be used in particular for the production, with a suitable yield, of aluminum containing less than 10 ppm of iron and silicon, and intended in particular for the manufacture of high and medium voltage capacitors.

Abstract: A process and apparatus for controlling the rate of introduction and the content of alumina to a tank for the production of aluminium by the electrolysis of dissolved alumina in a cryolite-base bath, the upper part of which forms a solidified crust, and wherein the alumina content is maintained within a narrow range, of between 1% and 3.5%, wherein the alumina is introduced directly into the molten cryolite bath by way of at least one opening which is kept open in the solidified crust and the rate at which the alumina is introduced is modulated relative to variations in the internal resistance of the tank during predetermined periods of time, with alternation of the cycles of introducing alumina at a slower rate and at a faster rate than the rate corresponding to normal consumption within the tank.