Electrosynthesized polyaniline for the corrosion protection of aluminum alloy 2024-T3

Abstract

Filmes de polianilina aderentes a liga de alumínio 2024-T3 foram preparados por eletrodeposição a partir de soluções de ácido oxálico contendo anilina. O método mais apropriado para preparar filmes de proteção contra a corrosão foi uma deposição galvanostática sucessiva de 500 segundos. Com este tipo de filme, o potencial de circuito aberto do metal protegido deslocou de aproximadamente 0,065 V vs. ECS em comparação a liga não protegida. Coberturas de polianilina podem ser consideradas como candidatas para proteger ligas de alumínio com alto teor de cobre (3 -5%) evitando o par galvânico entre o cobre redepositado na superfície e o seio da liga. A performance dos filmes de polianilina foi verificada com testes de imersão de até 2,5 meses. O resultado observado foi bom com a formação de alguns óxidos de alumínio devido a permeação de eletrólito e assim, para otimizar a performance de coberturas protetoras estas devem conter uma camada superior isolante.Adherent polyaniline films on aluminum alloy 2024-T3 have been prepared by electrodeposition from aniline containing oxalic acid solution. The most appropriate method to prepare protective films was a successive galvanostatic deposition of 500 seconds. With this type of film, the open circuit potential of the coating shifted around 0.065V vs. SCE compared to the uncoated alloy. The polyaniline coatings can be considered as candidates to protect copper-rich (3 -5%) aluminum alloys by avoiding the galvanic couple between re-deposited copper on the surface and the bulk alloy. The performance of the polyaniline films was verified by immersion tests up to 2.5 months. It was good with formation of some aluminum oxides due to electrolyte permeation so, in order to optimize the performance a coating formulation would content an isolation topcoat.

Adhesion of Polyaniline on Metallic Surfaces

“…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.…”

Advanced anti corrosive properties of poly(aniline-co-o-toluidine)/flyash composite coatings

“…In recent years, a number of intrinsically conducting polymers (ICPs) like polyaniline (PANI), and polypyrrole (PPy) have been used as corrosion inhibitors or corrosion resistant coatings [1][2][3][4][5][6][7][8][9]. Corrosion resistant coatings of these ICPs are deposited chemically or electrochemically on metal surface.…”

Corrosion protection of AA-7075 aluminum alloy surface by poly(o-methoxyaniline)

“…Thus, in some cases the deposition of PAni by casting solution is the more viable method, in some cases. Despite this, fewer reports describe the deposition of polyanilines (PAni and POMA) on aluminum alloys, such as AA-7075-T6 [22][23][24][25][26].…”