PREPARATION METHOD OF PARTS FOR SOLDERING Russian patent published in 2015 - IPC B23K1/20 B23K103/10 C23C18/36 

FIELD: heating.

SUBSTANCE: oxide film is removed from the surface of parts and a nickel coating 5-7 mcm thick is applied at the temperature of 85-90°C from a solution of the following composition, g/l: nickel chloride 20-25, sodium hypophosphite 15-20, thiocarbamide 0.001, boric acid 5-15, and hydroxy propionic acid 35-45. Then, water washing, drying, heating to the temperature of 500±10°C in vacuum, exposure at the same temperature during 10-20 minutes and further cooling is performed. Heating and cooling rate is 10-15°C per minute.

EFFECT: method allows obtaining quality formation of a soldered seam and protection of a soldered item against corrosion under operating conditions of a heat exchanger due to good adhesion of a coating to a substrate so that solder metal wetting of the substrate and its uniform flowing ability at soldering of heat exchangers is performed.

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