非シアン銀めっきの密着性に及ぽす電極近傍pH変化の影響 [in Japanese] Influence of pH Changes near Electrode on Adhesion in Cyanide-Free Silver Deposition [in Japanese]
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I<sub>2</sub> concentration in a potassium iodide silver plating solution increases with time in the lower pH range. Which decreases cathode current efficiency in silver deposition, making it necessary to control pH between 4.5 and 5.0. Silver deposits become less adhesive with increasing pH. We studied the effects of pH near electrode surfaces on silver deposit adhesion.<br>We found the following:<br>(1) The pH value near the cathode surface was much greater than that of bulk solution during electrodeposition without a buffer. The addition of KH<sub>2</sub>PO<sub>4</sub> as a buffer markedly reduced the pH change near the electrode.<br>(2) Silver deposit adhesion to undercoated nickel surfaces was improved by adding KH<sub>2</sub>PO<sub>4</sub>.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 49(2), 201-204, 1998-02-01
The Surface Finishing Society of Japan