| 摘要 |
<p>Cyanide-free aq. Ag electroplating bath, contg. dissolved Ag cpds., thiosulphate, opt. organic N cpds. and opt. conventional additives, also contains dissolved Sb cpds. (I), pref. in an amt. of 0.1-5, esp. 0.1-2 g. Sb/l. The bath pref. also contains dissolved aromatic heterocycles (II) with N atom(s) in the heterocyclic ring system and a mol. wt. of at least 100. The plating obtd. is hard, e.g. with a Vickers hardness of 220-250 kp./mm.2, and can also be brighter. The bath is stable and regulation is simple. In an example, the bath contained 45 g./l. AgCl, 240 g./l. Na2S2O3, 20 g./l. Na4P2O7, 0.5 g./l. Sb as glycerol complex and 0.1 g./l. wetting agent and had a pH of 10. Plating was carried out at 20 degrees C. and a current density of 0.5 A/dm.2.</p> |
