Kinetics and mechanism of passivation of steel in sodium phosphate solutions

✍ Scribed by V.S. Muralidharan; K.S. Rajagopalan

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 254 KB
• Volume: 23
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(78)80007-3

✦ Synopsis

This paper reports that three current peaks are observed during psssfvabnn ofsteelln NaH,P0, solutions in the pH range of 3 to 5. These are identified as peaks due to growth of phosphate film on theiron surface resulting in passivation of the metal surface, By comparison with anodic oxidation o( silver sulphate to silver oxide it is shown that film growth takes place in the two dimension with instantaneous nucleation . The study of the dependence of the growth of rate constant on pH, phosphate ion and ferrous ion concentrations shows that the rate determining step in the formation of the film is F" .e-Felk'W,,.