Baths for bright cobalt alloy electrodeposition - contg. tin and/or zinc ions and amine brightener

摘要

Baths for electrodeposition of bright Co/Sn or Co/Zn alloys contain Co and Sn and/or Zn ions and a brightener of formula NR1R2R3 (I) (where R1 is 1-6C alkyl or hydroxyalkyl; R2 and R3 are H or 1-6C alkyl, hydroxyalkyl or aminoalkyl). (I) is pref. triethanolamine, N-(2-aminoethyl) ethanolamine, tris(hydroxymethyl aminomethane, triisopropylamine, monoethanolamine or N-methyldiethanolamine. Baths for Co/Sn deposition pref. contain 0.5-5 g/l Co ions, 0.5-5 g/l Sn ions, 1-20 ml/l (I) and 1-50 g/l gluconate or glucoheptonate. Baths for Co/Zn deposition pref. contain 0.5-10 g/l Co ions, 0.5-20 g/l Zn ions, 1-20 ml/l (I) and 1-100 g/l gluconate or glucoheptonate. The Sn ions are pref. stannous ions and the bath is pref. free of NH4 ions. The baths produce chrome-like deposits which can be rendered resistant to high-temp. discoloration and fingerprint retention by passivation with H3PO4/CrO3.