An ellipsometric study of anodic passivation of nickel in borate buffer solution

✍ Scribed by N. Sato; K. Kudo

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 784 KB
• Volume: 19
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(74)87025-8

✦ Synopsis

Ellipsometric and electrochemical measurements of the anodic passivation and secondary passivation films on nickel in borate buffer solution at pH 8-42 wcrc made. The refcrcnce bare surface, obtained by cathodic reduction of electropolished nickel, gives the optical constants N, = 1.65-3.81 i for nickel. In the passivity region, where a little dissolution of nickel occurs, the surface film has the optical constants N, = 2.7+25 i and the film thickness as estimated by cllipsometry increases linearly with rise Of the potential. Worn 4 to I3 br, which is in fairly good agreement with the coulometrically estimated film thickness.

111 the uxygt-n rvolution region, secondary passivalion occurs with an abrupt increase in both optical constants and thickness of the surface film.

The anodic uassivation of nickel is comuared with that of iron in terms of thickness of the surface film as a function df potential.