METHOD OF PREPARING OF ALUMINIUM ALLOY SURFACE BEFORE STANNIC COATING APPLICATION Russian patent published in 1994 - IPC

FIELD: electroplating. SUBSTANCE: method involves defatting for 1-3 min at 50-60 C in the liquid containing, g/l: sodium hydroxide 35-45; ethylenediaminetetraacetic acid disodium salt (Trilon B) 6-15, and sodium perchlorate 2-4. Treatment is carried out in solution containing, g/l: hydrazine hydrochloride 250-270 and derivatives of diantipyrylmethane monohydrate 0.8-1.0 following by treatment for 5-15 s at 20-30 C in solution containing, g/l: potassium pyrophosphate 190-220 and hydrazine hydrochloride 2-4. EFFECT: improved method of alloy surface preparing. 1 tbl