Anodic growth of passive films on tin

✍ Scribed by Tor Hurlen

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 239 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)e0173-w

✦ Synopsis

The title subject is studied by galvanostatic E-t curves on 20 h stabilized passive tin electrodes in weakly alkaline phosphate solution (pH9.5) at 25°C. These curves generally exhibit a small initial superpolarization ascribed to transient changes in the surface density of kinks (s) by the current density (J) applied. Obedience is found to the Cabrera-Mott equation for irreversible metal ion transfer from kink sites in the metal surface and to the oxide film. For the steady-growth kink density and the ion transfer valence., it is found that d log s/d log j = 0.5 and n = 2, respectively. No space-charge effect is seen in passive films growing at rates up to 100 PA cm -' (the highest current applied).