Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/tmm.00603002
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

EFEITO DE MOLÉCULAS AUTO-ORGANIZÁVEIS NA RESISTÊNCIA À CORROSÃO DA LIGA AA2024-T3

EFFECT OF SELF-ASSEMBLING MOLECULES ON THE CORROSION RESISTANCE OF THE AA2024-T3 ALLOY

Souza, Solange de; Yoshikawa, Daniel Sierra; Assis, Sérgio Luiz de; Santos, Wagner Izaltino A. dos; Costa, Isolda

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Resumo

Revestimentos baseados em moléculas auto-organizáveis (SAM) vêm sendo estudados como possíveis substitutos aos revestimentos de conversão de cromato para proteção contra corrosão em ligas de alumínio. Neste trabalho é investigada a influência de moléculas auto-organizáveis, do grupo dos alcanos difosfonatos, na resistência à corrosão da liga AA2024-T3 utilizando as técnicas de espectroscopia de impedância eletroquímica, polarização potenciodinâmica, ensaios acelerados de corrosão e microscopia eletrônica de varredura. Os resultados mostram que o tratamento da superfície da liga AA2024-T3 com SAM causou o ataque corrosivo e diminuiu sua resistência à corrosão. O tratamento da superfície com solução à base de cromo (VI) também causou ataque na liga e também diminuiu a sua resistência à corrosão. O tratamento que resulta em melhor resistência à corrosão da liga consiste no crescimento e selagem do óxido de alumínio.

Palavras-chave

Moléculas auto-organizáveis, AA2024-T3, Cromatização

Abstract

Coatings based on self-assembling molecules (SAM) have been studied as possible substitutes to the chromate conversion coatings for corrosion protection of aluminium alloys. In this work, the influence of alkane diphosphonates self-assembling molecules on the corrosion resistance of the AA2024-T3 aluminium alloy is investigated. The corrosion investigation is carried out by electrochemical impedance spectroscopy, potentiodynamic polarization techniques, accelerated corrosion experiments and scanning electron microscopy technique. Results show that the surface treatment with self-assembling molecules decreased the corrosion resistance of the alloy due to the corrosive attack of the SAM solution to the alloy surface. The solution used for passivation with chromium (VI) also caused the attack of the alloy surface, leading to slight decreases in the corrosion resistance. The surface treatment that produced the best corrosion resistance is associated with the growth and sealing of the surface oxide.

Keywords

Self-assembling molecules, AA2024-T3, Chromatizing

Referências

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