無電解めっき法を用いたFe基板へのSn高含有（＞30 at.%）Ni-Sn薄膜の作製（2）

～錯化剤および浴の安定化に関する検討～

抄録

Electroless deposition of nickel-tin（Ni-Sn）layers on iron（Fe）substrates from baths containing sodium hypophosphite（NaH₂PO₂）as a reducing agent was examined. In a bath containing both sodium citrate（Na₃C₆H₅O₇）and sodium gluconate（HOCH₂ （CHOH）₄COONa）as com plexing agents, the Ni-Sn layer having 1 μm thickness and atomic Sn content of 30-40 at.% was formed. The bath stability was maintained until the 10th deposition process. Optimizing the concentration ratios of sodium citrate to sodium gluconate and to sodium stannate（Na₂SnO₃）was important to ascertain the Ni-Sn layer properties for this study. The main component of the Ni-Sn layer was found to be Ni_1.5Sn. A small amount of the Ni layer was included in the layer. Results confirmed that the Ni-Sn layer formed from the optimized bath with NaH₂PO₂/ Na₃C₆H₅O₇/ HOCH₂ （CHOH）₄COONa had nearly perfect chemical resistance properties against hydrogen peroxide and sodium hydroxide aqueous solutions.