Agence Nationale De Valorisation De La Recherche (Anvar)

Other

Centre National De La Recherche Scientifique

Compagnie Generale D'electricite S.a.

Agence Nationale De Valorization De La Recherche

Paul Hagenmuller

Claude Fouassier

Gerard Demazeau

Michel Pouchard

Michel Pezat

Theophile Plante

Patrick Maestro

Roger Naslain

Alain Levasseur

Jean-Louis Soubeyroux

Bernard Darriet

Abdelmalek Hbika

Bernard Tanguy

Pierre Lamico

Claude E Fouassier

Claude Delmas

Robert Colmet

Josik Portier

Jean-Michel Quenisset

Wen T Fu

Rober Naslain

Jean-Maurice Reau

Bernard Cales

Luminescent mixed borates based on rare earths

A refractory fibrous preform in ceramic material is placed inside an infiltration chamber where it is heated within a reacting gaseous mixture introduced into the chamber and containing at least one gaseous hydrolyzing or oxidizing agent and a volatile hydrolyzable or oxidizable compound of the one element or of each element of which the oxide is a constituent of the matrix of the structure to be produced, in order to obtain by chemical reaction an adhesive deposit of said oxide or oxide constituting said matrix and having a melting point higher than 1750.degree. C.; the values of the overall pressure, of the temperature and of the gas flow rates inside the infiltration chamber are selected to be at a level slightly higher than the minimum values necessary for producing the said chemical reaction, so as to enable the constituents of the gaseous reaction mixture to penetrate to the bottom of the pores in the fibrous preform before having reacted completely such that the pores are densified throughout their length with the adhesive deposit.

Method for producing a refractory composite structure

There is provided an efficient method of storing hydrogen in materials of small mass and small volume. The products of the present invention comprise intimate mixtures (as opposed to alloys) of magnesium and other metals or alloys capable of forming hydrides. The hydrides are selected so that the hydrides have a substantially lower thermal stability than that of magnesium hydride.

Method of storing hydrogen in intimate mixtures of hydrides of magnesium

Process for making a novel ferromagnetic chromium dioxide and rhodium dioxide material in the form of a solid solution Cr.sub.1-x Rh.sub.x O.sub.2 where x is a number between 0 and 0.5. It essentially comprises oxidation, under suitable conditions of temperature and pressure, of hydrated or anhydrous Cr.sub.2 O.sub.3 or of a precursor of Cr.sub.2 O.sub.3, in the presence of (1) an appropriate amount of a compound of rhodium III able to give RhO.sub.2 under reaction conditions and (2) of an oxidizing agent consisting of an oxygenated compound free from metallic cations other than chromium and having, under the reaction conditions, a partial oxygen pressure at least equal to that corresponding, under the same conditions of temperature and pressure, to the equilibria Cr.sub.2 O.sub.3 +1/2O.sub.2 .revreaction.2CrO.sub.2 and Rh.sub.2 O.sub.3 +1/2O.sub.2 .revreaction.2RhO.sub.2 as well as eventually (3) of dilution water and/or of at least an additional doping agent acting as buffer in the reaction medium and/or a conventional modifying agent. The invention is useful for the manufacture of a ferromagnetic material possessing improved magnetic characteristics.

Novel ferromagnetic chromium dioxide and rhodium dioxide material and

The invention relates to the storing of hydrogen in hydrides of metallic alloys. These alloys include besides magnesium an element chosen from the lanthanides and/or element of group IIa of the periodic classification of elements. The magnesium may be, furthermore, possibly substituted among others by a transition metal. These alloys allow the reactivity of the magnesium to be increased in relation to the hydrogen during the hydrogen absorption process as shown by the curves of FIG. 1. Application: supplying hydrogen engines or other hydrogen energy receiving or transforming means with hydrogen.

Process for storing of hydrogen and the use thereof, particularly in

An amorphous cationic conductor of lithium comprising a composition corresponding to the general formula:

Amorphous cationic conductors

A method and apparatus for controlling a heated bath of molten material to obtain controlled solidification, wherein the molten bath is kept in constant rotational movement relative to the solid portion of the material being treated and the mechanical action due to the viscous friction which develops in the bath is detected and thereby controlled, said method being applicable to the floating zone method and the Czochralsky crystal drawing method and being capable of producing ingots of high dimensional regularity.

Controlling the melt temperature during zone refining and Czochralski

Chromium dioxide CrO.sub.2 is prepared by oxidizing hydrated trivalent chromium oxide Cr.sub.2 O.sub.3, xH.sub.2 O, where x is at least 1, at a temperature of at least 350.degree. C and under pressures of at least 2 kilobars. The reaction is carried out in an oxidizing medium, which is a solid or an aqueous liquid solution, essentially constituted by a compound of the formula HXOy, zH.sub.2 O, wherein X represents an atom of chlorine or iodine, y is a positive integer less than or equal to 4, and z is a number which is a function of the dilution of said compound in the solution or a function of the crystallization water in the case of a solid oxidizing agent. The product is useful in any device requiring a compound which is ferromagnetic at a temperature less than 116.degree. C and notably in magnetic tapes.

Process for obtaining chromium dioxide CrO.sub.2

The invention relates to lamelliform oxides of high ionic conductivity which contain monovalent elements inserted between lamellae of oxides of the type (L.sub.x M.sub.1-x) O.sub.2 wherein L is a trivalent element, M is a tetravalent element and x is a number between 0 and 1. Such oxides are useful as solid electrolytes in electrochemical generators or cells.

Solid electrolyte

Growing community of inventors

Talence, France

Paul Hagenmuller