Synthesis of anodic films in the presence of aniline and TiO(2) nanoparticles on AA2024-T3 aluminium alloy

• Published in: Thin solid films Vol. 517; no. 24; pp. 6742 - 6746
• Main Authors: Zubillaga, O, Cano, F J, Azkarate, I, Molchan, I S, Thompson, G E, Skeldon, P
• Format: Journal Article
• Language: English
• Published: 30-10-2009
• ISSN: 0040-6090
• DOI: 10.1016/j.tsf.2009.05.039

Coatings, comprising an inner porous anodic alumina film and an outer polyaniline/TiO(2) nanoparticle layer, were electrochemically synthesised on an AA2024-T3 aluminium alloy by single-step, anodic polarisation in an oxalic acid-based electrolyte. The morphology and composition of the coatings were examined by TEM, SEM and XPS, with the size and zeta-potential of the TiO(2) nanoparticles in the oxalic acid solution also measured. Observation of the growth of the coating during of anodic polarisation revealed that a distinct, two-layered coating is formed from the early stages of polarisation, with the anodic film forming at a constant rate and the outer layer developing at a rate that decreases markedly with times beyond about 30 min. Nanoparticles, agglomerated in the electrolyte, migrate to the anode due to the negative zeta-potential and form the nanoparticle-containing layer at the surface of anodic film. Such particles are not incorporated in the pores due to agglomeration and disordered film porosity at the outer layer of the anodic film.