ACIDIC ELECTROLYTE FOR ELECTRODEPOSITION OF GLITTERY TIN-LEAD ALLOY COATINGS Russian patent published in 1998 - IPC

FIELD: metal coatings. SUBSTANCE: electrolyte is composed of (in g/l): tin(II) salt, 12-40; lead(II) salt, 6-25; free acid (HBF₄, HClO₄, H₂SiF₆, C₂HCl₃O₂), 100-300; nonionic surfactant; 37% formaldehyde solution, 5-30 ml/l; glitter-producing composition, containing α,β-unsaturated aldehyde, 0.12- 3.7; high-molecular or unsaturated, or polyatomic alcohol, 0.03-7; and low-molecular alcohol, 1.85-14.84. When borofluoric acid is used as free acid, electrolyte additionally contains boric acid. All organic electrolyte constituents are those used in perfumery and food industry. Electrolyte is characterized by high scattering capacity (more than 60%), wide range of allowable cathode current densities (2-15 A/sq.dm), and alloy deposition rate up to 7 mcm/min (under stationary conditions). Electrochemical stability of electrolyte, when correctly handled, is 1000 Ah/day. EFFECT: improved working characteristics and environmental condition. 2 cl, 1 tbl