| 摘要 |
<p>Cyanide-free aq. Ag electroplating bath, contg. dissolved Ag cpds., thiosulphate and organic N cpds. and opt. conventional bath additives, contains aromatic heterocycles (I) with N atom(s) in the heterocyclic ring system and a mol. wt. of at least 100. The plating has improved grain structure and brightness. In an example, the bath contains 40 g./l. AgCl, 190 g./l. Na2S3O3 and 0.1 g./l. 1,10-phenanthroline and had a pH of 10. Plating was carried out at 25 degrees C., a current density of 0.8 A/dm.2 and 0.6 V. Bright silver plating with a hardness HB 0.015 of 160 kp/mm.2 was obtd.</p> |
