Barrier oxide film vs. salt layer formation on bismuth in tartaric acid solutions

✍ Scribed by M. Bojinov; I. Kanazirski; A. Girginov

• Book ID: 103065903
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 750 KB
• Volume: 40
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)00378-e

✦ Synopsis

The anodic oxidation of bismuth metal in aqueous tartaric acid solutions is studied using electrochemical and photoelectrochemical techniques. The oxidation process comprises four stages: active anodic dissolution, primary passivation by a semiconductor oxide layer formation, secondary passivation due to salt layer formation at the oxide film/electrolyte interface and further growth of the oxide sublayer by a high-field transport mechanism. The chemical nature of the salt film was determined by ex-situ X-ray diffraction to be very close to normal bismuth tartrate Bi&,H,O&.6H,O.

Electrophysical characteristics of the oxide sublayer point to its identification with Bi,O, .