Naslov
PANI layers of different degrees of protonation in corrosion protection of stainless steel

Autori
Kraljić Roković, Marijana ; Kalić, Marijana ; Duić, Ljerka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts, 57th Annual Meeting of the International Society of Electrochemistry / - , 2006

Skup
57th Annual Meeting of the International Society of Electrochemistry

Mjesto i datum
Edinburgh, Ujedinjeno Kraljevstvo, 27.08.2006. - 01.09.2006

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
polyaniline; deprotonation; stainless steel; corrosion protection

Sažetak
It has been shown that PANI can be effective in corrosion protection of steel [1] and of some other metals like copper [2] and aluminium [3]. In corrosion protection different states of polyaniline were tested, mostly protonated emeraldine, but also emeraldine base was used. There are speculations about protecting properties of PANI base. Good protecting properties with PANI base were obtained in some papers [2], while in other [4] it was reported that PANI base does not offer corrosion protection. In this work the aim was to study protecting properties of PANI layers of different degrees of protonation in 0.1 mol dm-3 NaCl solution. Methods of testing, used in this work, were open circuit potential monitoring and Electrochemical impedance spectroscopy. Different degree of PANI protonation was obtained by keeping the layer during one day in different solutions, like 3 mol dm-3 phosphoric acid solution (pH=0.4), or in buffer solutions (pH=4.3, pH=7.8). Depending on a degree of protonation different protecting properties were obtained. Corrosion protection of stainless steel with PANI layer, in solutions containing chloride ion, is not based on the previously proposed electrochemical mechanism [5]. In this case PANI imposes a physical barrier for the diffusion of chloride ions through the layer. The best protecting properties, in solution containing Cl-, were obtained with the layer kept before testing during one day in buffer solution of pH=7.8 where a complete deprotonation was obtained. It was shown that better corrosion protection is not a consequence of the improved oxide quality but of deprotonation that is followed by a change of a polymer structure. [1] M. Kraljić, Z. Mandić, Lj. Duić, Corr. Sci. 45 (2003) 181. [2] V. Brusic, M. Angelopoulos, T. Graham: J. Electrochem. Soc. 144 (1997) 436. [3] R. Racicot, R. Brown, S.C. Yang: Synth. Met. 85 (1997) 1263. [4] W.S. Araujo, I.C.P. Margarit, M. Ferreira, O.R. Mattoso, P. Lima Neto, Electrochim. Acta. 46 (2001) 1307. [5] B. Wessling: Synth. Met. 85 (1997) 1313.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Kemijsko inženjerstvo

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