METHOD FOR CHEMICAL APPLICATION OF STANNIC COATING ONTO PARTS FROM COPPER OR ITS ALLOYS Russian patent published in 2013 - IPC C23C18/18 C23C18/31 

FIELD: metallurgy.

SUBSTANCE: in the method parts of copper or its alloys are treated in a solution containing 6-10 wt % H₂SO₄, 4-8 wt % Na₂Cr₂O₇ and water - balance, for 10-60 min., afterwards flushed with water. Further parts are etched in 18-25% solution of sulfuric or hydrochloric acid, after which parts without preliminary washing are treated in a working aqueous solution, containing sulfuric or hydrochloric acid, thiourea, stannum bichloride dihydrate, previously soaked at 17-30°C for 1-30 days.

EFFECT: method makes it possible to produce high-quality tin coatings with increased corrosion resistance on parts of copper or its alloys.

3 cl, 6 ex