GB440764A - Process for the electrolytic manufacture of borides - Google Patents

Abstract

440,764. Electrolytic production of metallic borides. SOC. D'ELECTROCHIMIE, D'ELECTRO-METALLURGIE, ET DES ACIERIES ELECTRIQUES D'UGINE, 10, Rue du General Foy, Paris, and ANDRIEUX, J. L., 11, Rue Cornelie Gemond, Grenoble, both in France. March 18, 1935, No. 8446. Convention date, March 17, 1934. [Class 41] Borides are obtained by electrolysis of a fused bath containing boric anhydride or borax, the oxide of the metal whose boride is to be prepared, and a chloride of this metal or of a more electro-positive metal. In the production of alkaline earth or rare earth metal borides, the bath may consist of the borate and chloride of the metal. In the production of borides of other metals, the bath may consist of borates and chlorides of alkali, alkaline earth or rare earth metals together with an oxide or salt of the metal whose boride is to be prepared. For the production of calcium boride, the bath is made up in the proportions 3B2O3, CaO, 7CaCl2. This is electrolyzed at 950‹ C. with current density 50-100 amps. per sq. dem. with a carbon cathode forming the cell lining and a carbon anode. The lower part of the electrolyte containing crystals of calcium boride is drawn off from time to time, and constituents added to the bath to maintain its composition constant. The density of the bath may be maintained below that of the boride by addition of chloride. For the production of titanium boride a mixture of boric anhydride, lime and calcium chloride in the above proportions is prepared and 10 per cent by weight of titanium oxide is added to the mixture. The oxide may be replaced by the carbonate or a halide or by an oxygenated salt of an alkali or alkaline earth metal in which the metal whose oxide is replaced forms part of the acidic radicle. A process in which a fluoride instead of a chloride is employed in the mixture is referred to.