FLUX FOR LOW-TEMPERATURE SOLDERING Russian patent published in 2004 - IPC

FIELD: low-temperature soldering of copper and its alloys with use of tin-lead solders.

SUBSTANCE: flux contains next ingredients, mass. %: zinc chloride, 10 - 40; ammonium chloride, 1.0 -4.5; hydroxylamine hydrochloride, 0.05 -1.0; hydrazine chloride, 0.2 -1.0; carbamide, 1.1 -3.0; water, the balance. When flux is heated complex compounds of hydrochloric acid are formed. Said compounds provide intensive destruction of oxide film on surface of parts of copper and brass. Containing in flux surface-active matters provide enhanced wetting of soldered surface with solder and increased area of solder spreading for receiving improved strength of soldered joint. As flux includes increased content of carbamide, its corrosion activity to copper and its alloys is reduced. Flux is sufficiently active even at low temperatures of soldering process. Temperature range of flux activity is 200-400 C.

EFFECT: improved content of flux, enhanced strength of soldered joint.

3 tbl, 1 ex