GB758088A - Improvements in or relating to jointing metals by soldering - Google Patents

Abstract

A soldering flux for use in making a joint having an aluminium or aluminium alloy component comprises potassium chloride 10-70 per cent, lithium chloride 8-70 per cent, sodium chloride 0,25-19 per cent, zinc chloride 0,5-40 per cent and lithium fluoride 0,25-20 per cent. It may also include caesium chloride and rubidium chloride which separately or together may replace lithium chloride in part up to 40 per cent, cadmium chloride 0-20 per cent (alternatively the cadmium chloride may replace zinc chloride with a maximum or 20 per cent of cadmium chloride), stannous chloride, lead chloride and/or antimony tri-chloride 0-10 per cent, and cryolite, which may be used up to a maximum of 15 per cent either as additional to, or in part replacement of, the lithium fluoride. There may also be added to the flux 0,5-10 per cent of potassium, sodium or zinc fluoride or halides of one or more of the following elements: magnesium, barium, calcium, copper, nickel, silver, iron, bismuth and manganese. In addition one or more of the metal chlorides in the flux composition may be replaced by the corresponding bromides or iodides in amount up to 60 per cent potassium chloride, 60 per cent lithium chloride, 15 per cent sodium chloride and 35 per cent zinc chloride. The flux may be applied as a paste to the parts to be jointed or may be applied by means of the solder rod which has been coated by dipping the heated rod into the powdered flux. Metals and alloys which may be thus jointed to aluminium or aluminium alloys include the precious metals, nickel-silver alloys, copper, copper-base alloys and steel.