METHOD FOR HOT-DIP TINNING PRINTED CIRCUIT BOARD Russian patent published in 2003 - IPC

FIELD: tin plating. SUBSTANCE: method involves preparing surface and application of sublayer followed by application of tin-containing alloy and protective layer. Flux containing the following components is used as a sublayer, wt.-%: acid (as measured for anhydrous acid), 1.5-3.5; laprol 2502-OZH, 42.0-58.0; distilled water, the balance. The solution containing the following components is sued as a protective layer, wt.-%: sodium hydroxide, 3.0-4.0; potassium hydroxide, 5.5-8.5; ortho-phosphoric acid, 68.0- 82.0; colophony, 4.0-4.0; potassium hypophosphite, 0.05-0.15; distilled water, the balance. Invention provides enhancement of strength and quality of soldered joint. Invention can be used in radio engineering and microelectronic industry for tinplating soldering outlets of semiconductive devices and printed circuit boards. EFFECT: improved tinplating method. 3 cl, 1 tbl, 1 ex