GB624304A - Improvements in or relating to the production of magnesium base alloys - Google Patents

Abstract

A process for the production of magnesium base alloys containing zirconium comprises producing a molten mixture or compound salt containing zirconium chloride or bromide and one or more chlorides of sodium and potassium to form at least some proportion of a double salt, forming this mixture or compound salt into lumps which are broken into pieces of convenient size or forming the mixture or compound salt into suitable small pieces, p bringing such pieces into contact with molten magnesium or a molten magnesium base alloy and agitating the melt to effect solution of the zirconium in the magnesium. The mixture may include one or more halides not reducible by magnesium and/or one or more reducible halides of a permissible alloying element, i.e. of an element which does not form high melting point compounds with zirconium, e.g. zinc or cadmium. This mixture may have a melting point below 300 DEG C. When no alkaline earth metal chlorides are present the mixture may contain up to 50 per cent of zirconium fluoride. The mixture may be made by adding a solid mixture of zirconium chloride and potassium and/or sodium chloride to a molten pool of a mixture of halide salts which are inert to magnesium and has a low melting temperature or range. The mixture may contain at least 30 per cent zirconium chloride, at least 25 per cent zirconium fluoride and at least 10 per cent of another halide not reducible by magnesium. Specific mixtures referred to contain: (a) approximately 75 per cent zirconium chloride and 25 per cent sodium chloride; (b) 45 per cent zirconium chloride, 35 per cent zirconium fluoride, 20 per cent sodium chloride. Specifications 511,137, 511,482, 533,264 and 26438/39 (as open to inspection under Sect. 91) are referred to.