ピロリン酸ィオンーグリシン混合配位子浴からのスズーこッケル合金電析に及ぼすピロリン酸イオンの影響

摘要

We investigated the effects of pyrophosphate ions on tin-nickel alloy deposition from pyrophosphate-glycine complex baths. The potential -current density curves for the alloy deposition were measured using a rotating-disk electrode system and the cathodic current for each metal deposition was evaluated quantitatively based on the polarization curves. Pyrophosphate ions promoted the dissolution of both tin ions and nickel ions in the alloy baths. Addition of pyrophosphate ions, however, polarized the reduction potential for metal deposition in the baths containing either tin ions or nickel ions. On the other hand, the inhibition effect caused by addition of pyrophosphate ions was weakened greatly in the tin-nickel alloy deposition from the baths having mixed ligand complexes consisted of pyrophosphate ions and glycine, which might indicate that tin ions facilitated nickel deposition and nickel ions also did tin deposition.%スズーこッケル合金電析物は，食塩水の電気分解に際して低い水素過電圧を示すことから，活性陰極として20年近く利用されてきた。また，この合金皮膜は高い耐食性と光沢性を有しているので，近年クロムめつきの代替めつきとしても注目されている。スズーこッケル合金電析物浴には，塩酸酸性浴,フッ化物浴,ケィフッ化物浴,そしてアルカリ性のピロリン酸塩浴およびピ口リン酸イオンーグリシン混合浴がある。