Naslov
Investigations of the Mechanism of Corrosion Inhibition by Polyaniline -PANI-Coated Stainless Steel in Sulfuric Acid Solution

Autori
Gašparac, Rahela ; Martin, C.R.

Izvornik
Journal of The Electrochemical Society (0013-4651) 148 (2001), 4; B138-B145

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
stainless steel; polyaniline (PANI); sulphuric acid; corrosion; inhibition

Sažetak
The objective of this work was to elucidate the mechanism by which polyaniline (PANI) films passivate stainless steel surfaces in highly corrosive H2SO4 solution. A variety of experimental methods including measurements of the open circuit potential, Auger depth profiling, and the scanning reference electrode technique (SRET) was used. These studies have shown that passivation is achieved because the oxidized and protically-doped emeraldine-salt form of PANI holds the potential of the underlying stainless steel electrode in the passive region. Because of this electrostatic mechanism of corrosion inhibition, the entire stainless steel surface does not have to be coated with PANI in order to achieve passivation. Auger depth profiling experiments show that, in analogy to the case of a bare stainless steel surface whose potential is potentiostatically maintained in the passive region, the stainless-steel surface beneath the PANI-film is enriched in Cr after exposure to the H2SO4 solution. Finally, SRET was used to explore passivation of the stainless steel in regions exposed to solution by pinholes intentionally cut through the PANI film. SRET shows that the PANI film surrounding the pinhole can heal the stainless steel in the pinhole region.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

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