Sodium alkenyl or alkynyl salt use in metal electroplating bath to bind halogen - useful for preventing toxic halogen gas emission, esp. from zinc@, nickel@ or copper@ plating bath e.g. fluorine@, chlorine@, bromine@ or iodine@ at inert anode

摘要

Na vinyl sulphonate (IA), Na allyl sulphonate (IB), K vinyl acetate (IC), Na propyne sulphonate (ID), diethylpropynyl ammonium chloride (IF), dimethyl propynyl ammonium H sulphate (IG), butyn-1,4-diol (IG) or Na alpha-hyroxypropyne sulphonate (IH) is used as additive in metal electroplating baths. (I) are pref. added in concns. of 0.01-10 g/l. The baths and an inert anode are used in a liq.-tight housing, pref. of ion exchange material or plastics. USE/ADVANTAGE - (I) are used in Zn, Ni or Cu plating baths (claimed). They prevent the generation of toxic halogen gases (esp. F2, Cl2, Br2 or I2) at an inert anode. In an example, a plating bath had an anolyte of 5 g/l H2SO4; and a catholyte of 370 g/l NiSO4.6H2O, 40 g.l NiCl2.6H2O, 40 g/l H3BO3, 8 g/l NaCl and 1 g/l brightener ('Stratolus C'; RTM). An inert anode surrounded by a membrane to reduce the Ni content was used, as Ni contents of over 90 g/l reduce levelling. Operation was stopped after a few min. because of a strong Cl2 odour. If 245 mg/l (IA) were added to the anolyte, the odour disappeared immediately and the effect was maintained for several hrs., after which more (IA) was added. It did not interfere with the process.