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: 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: The electrolysis cell according to the invention is concerned with the preparation of Zr or Hf by electrolysis, from a molten mixture of alkali metal or alkaline earth chlorides and fluorides.It comprises a graphite collector which defines the anodic space and which is extended at the lower end below the level of the electrolyte by a metal wall made of metal to be deposited or coated with said metal.The wall may advantageously be made in the form of a porous diaphragm.

Abstract: The apparatus and the process according to the invention concern the preparation of titanium by electrolysis in a bath of molten halides.The apparatus comprises a porous diaphragm which is disposed around a feed cathode permitting partial reduction of the TiCl.sub.4 introduced into the electrolyte.The intensity of the current which passes through the feed cathode is so regulated as to maintain a low but non-zero voltage drop, across the diaphragm which is insulated with respect to the feed cathode.

Abstract: The process according to the invention concerns the production of polyvalent metals such as titanium by electrolysis of molten halides.It comprises controlling the permeability of the diaphragm which separates the anolyte from the catholyte, by causing growth or re-dissolution of a deposit of the metal to be produced.The process is applied in particular to the production of titanium by electrolysis from TiCl.sub.4.

Abstract: The process which is the subject of this invention concerns the preparation of titanium by electrolysis from a bath of molten halides.It comprises effecting partial reduction of the TiCl.sub.4 which is used as the starting material in a separate reaction vessel, and then directly feeding the electrolyzing apparatus by means of titanium halides with a valency of less than 3. The partial reduction of the TiCl.sub.4 is effected by means of divided titanium or another metal such as Na.

Abstract: The invention relates to a master alloy intended for the preparation of zirconium-base alloys and more particularly for the preparation of alloys such as those known as zircaloy 2 and zircaloy 4 useful for nuclear applications.This master alloy contains, by weight, from about 50 to 85% of Sn; 5 to 30% of Zr; 0 to 20% of Fe; and 0 to 20% Cr, with the combined Fe+Cr content being about 3 to 30%.This master alloy enables zirconium alloys to be produced in which the tin is distributed homogeneously.

Abstract: A method for treating zirconium and zirconium alloys, in particular the zirconium alloys used in nuclear reactors which are water cooled, as a structural or casing material for fuels. The method consists in dissolving or maintaining a solid solution of the majority of carbon contained in these alloys by thermal or thermo-mechanical treatments carried out in the .alpha. + .beta. range or if necessary in the .beta. range followed by a rolling in .alpha. phase if necessary. The products obtained have a highly improved mechanical resistance under heat, in particular with regard to resistance to creep; they are particularly suitable for constructing casing tubes for fuels in water cooled nuclear reactors having a better resistance to distortion in relation to time.