Investigation of corrosion protection of steel by polyaniline films

Adhesion of Polyaniline on Metallic Surfaces

“…However, for AISI 304 coated with PAni, the corrosion potential variation (E corr  0.295 V) is greater than that of the uncoated surface. This change can be justified, as described by Santos Junior et al (Santos et al (Santos et al, 1998)), as the attack of the species in the electrolyte, passing through the polymer layer, forming a passivation layer and interrupting the corrosion process. Fig.…”

“…Many studies have reported the use of conducting polymers as coatings (Bernard et al, 1999;Santos et al, 1998;Talman et al, 2002). Particularly, PAni has been extensively used due to its ability to protect metals against aqueous corrosion (Santos et al, 1998;DeBerry, 1985).…”

“…Particularly, PAni has been extensively used due to its ability to protect metals against aqueous corrosion (Santos et al, 1998;DeBerry, 1985). PAni can be obtained by either chemical or electrochemical oxidation of aniline (Trivedi, D.C., 1997).…”

“…The advantage of PAni was its effective use in acidic environments. According to different authors (Dominis et al, 2003;Cook et al, 2004), at least three different configurations of PAni used as a corrosion protector have been reported: coatings alone, such as solution cast PAni films formed or electrochemically synthesized (Santos et al, 1998;Huerta-Vilca et al, 2003b, 2004aFahlman et al, 1997), coatings as primer with a conventional polymer topcoat (Dominis et al, 2003;Talo et al, 1997), and PAni blended with a conventional polymer coating or polymer coatings containing PAni as an additive (Galkowski et al, 2005;Samui et al, 2003;Sathiyanarayanan et al, 2009). Kinlen et al (Kinlen et al, 1997) and other authors Oliveira et al, 2009) observed that the electrochemically produced conducting polymers, as PAni, shift the corrosion potential (E corr ) of the metal to the passive region, maintaining a protective oxide layer on the metal and minimizing the rate of metal dissolution (Eq.…”

“…The authors concluded that PAni in emeraldine base form protected mild steel in acidic and near neutral environments via inhibition of the active corrosion process rather than by anodic protection in the form of passivation. Santos et al (Santos et al, 1998) showed the capability of PAni in the emeraldine oxidation state to protect carbon steel and stainless steel against corrosion, in 3% NaCl aqueous solutions saturated with air. The authors related that the polymeric film is strongly adherent to the metallic substrate studied (carbon and stainless steel).…”