| 摘要 |
1484575 Electro-depositing tin-nickel alloy NASGLO INTERNATIONAL CORP 6 Aug 1974 [20 Aug 1973 24 June 1974] 34566/74 Headings C7A and C7B An alloy comprising 0À001-0À30 wt. per cent Ni, the balance Sn, useful as an electric contact; to replace conventional Au or Ni coatings; or to restore the appearance of Ag, is electro-plated from an aqueous bath comprising either a) Ni sulphate or sulphamate, a corresponding Sn salt and sulphuric, sulphamic or benzene sulphonic acid or b) Ni and Sn fluoborates and fluoboric acid; the bath having a pH no higher than 1, the Sn salt having a concentration at least 7À49 g/l, and the wt. ratio of the Ni and Sn salts being at least 0À20:1. A brightener may be added e.g. gelatine, 1-benzoyl acetone or N-benzyltrimethylammonium bromide or hydroxide. Non-corrodible and/or non-passivating anodes are used e.g. Ni, Pt or Pt on Ti; a mixture of Sn and Ni anodes is possible. Metallic or metallized substrates are referred to. Optimum conditions include an anodic c.d. below 25 asf, a temperature of 20-30‹C and an anode area double that of the cathode. |
