GB745456A - Improvements in or relating to method of fluxing and flux compositions - Google Patents

Abstract

A flux composition comprises (1) at least one halide of Zn, Cd, Sn, Sb, Bi and Pb; (2) at least one salt of semicarbazide, hydrazine, hydrocarbon substituted hydrazines and heterocyclic substituted hydrazines, and (3) at least one of: salts of ammonia, salts of quaternary alkyl-ammonium bases, hydroxylamine, alkylamines, arylamines, aralkylamines, alicyclicamines and saturated cyclic amines, compounds of the formula R1R2R3R4NX, when R1, R2, R3 and R4 are methyl or ethyl and X is a halogen, and aliphatic carboxylic amides having 1-6 carbon atoms. The first component may be stannous, zinc, cadmium or lead chloride or bromide, antimony or bismuth trichloride or tribromide, zinc or cadmium dihydrazine chloride or bromide, zinc or cadmium ammonium chloride or bromide or 3, 5, 5-trimethylpyrazidine zinc chloride; fluorides and iodides may also be used. The second component may be hydrazine monohydro-chloride or monohydrobromide, semicarbazide hydrochloride, hydrobromide, hydrofluoride or phosphate, a double chloride of hydrazine and Zn, Cd, Sn or Sb, 3, 5, 5-trimethylpyrazoline hydrochloride or hydrobromide or 3, 5, 5-trimethylpyrazoline zinc chloride. Also mentioned are salts of the formula R5 R6 N=NR7R8 where R5, R6, R7 and R8 are alkyl, aryl, aralkyl or cycloalkyl radicals e.g. methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, phenyl, benzyl, phenylethyl, ortho-, meta- or para-tolyl, xylyl, ethylphenyl, cyclopentyl and cyclohexyl, and of pentamethylene and hexamethylene hydrazine, acetone hydrazone and 2-pyridyl hydrazine as well as hydrazine dihydrofluoride, dihydroiodide, formate, phosphate, hypophosphate, acetate and abietate and trihydrazine dihydroiodide. The third component may be ammonium chloride, bromide, fluoride, carbonate or phosphate, zinc or cadmium ammonium chloride or bromide, hydroxylamine hydrochloride or hydrobromide, salts of mono-, di- and tri-methylamine, methylethylamine, triethylamine, mono- and di-isopropylamine, aniline, benzylamine, phenylethylamine, cyclohexylamine, ethylene diamine, piperidine, morpholine and quaternary ammonium, or formamide, acetamide, propionamide or dimethyl or diethyl formamide. The flux, which may be used for soldering aluminium, may be applied in liquid, paste or powder form, melted dissolved in water, alcohols, glycols, ketones or the methyl or ethyl esters of acetic acid.