Effect of molybdenum and tungsten polyoxometalates on the composition of surface layers and electrochemical behavior of stainless steel in sulfuric acid

Autor: S.S. Veselyi, Yu. E. Pronin, L. P. Kazansky, E.M. Sokolova
Rok vydání: 2013
Předmět:
Zdroj: International Journal of Corrosion and Scale Inhibition. 2:067-081
ISSN: 2305-6894
DOI: 10.17675/2305-6894-2013-2-1-067-081
Popis: The composition and thickness of the surface layers formed on ferrite steel at various applied potentials in pure 1 N H2SO4 and in the presence of polyoxometalate (POM) anions ( in cationic composition are observed near the passivation potential. At anodic potentials the surface oxide layer is enriched by chromium oxide. The thickness of this layer does not exceed 2-3 nm. If polymolybdate or polytungstate anions are added to sulfuric acid, they are located mostly in the uppermost oxide layer. The anodic currents decrease notably with an increase in POM concentration. At the passivation potential the oxide layer thickness exceeds 3-4 nm and it is substantially enriched by molybdenum. On the samples kept for 1 h in 1 N H2SO4, a protective layer is formed in the presence of POM and an after-affect is achieved. This layer remains stable upon transfer into pure 1 N H2SO4, especially in the case of
Databáze: OpenAIRE