Thermometric behaviour of cobalt in HNO3 solutions

✍ Scribed by S.M. Abd El Haleem; E.E. Abd El Aal

• Book ID: 104023953
• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 896 KB
• Volume: 204
• Category: Article
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2007.10.065

✦ Synopsis

Cobalt corrodes in dilute HNO 3 solutions according to an autocatalytic mechanism involving the formation of HNO 2 . The rate of metal dissolution increases with the acid concentration.

Passivation of cobalt starts to take place in concentrated HNO 3 solutions due to the formation of a passive oxide film on the metal surface. Addition of inorganic anions, in either neutral or acidic forms, affects the rate of cobalt dissolution and supports the proposed autocatalytic mechanism.