Tartaric-sulphuric acid anodized clad AA2024-T3 post-treated in Ce-containing solutions at different temperatures: Corrosion behaviour and Ce ions distribution

Author(s)

Prada Ramirez, Oscar Mauricio ^[1] ; Queiroz, Fernanda Martins ^{[1, 2]} ; Tunes, Matheus Araujo ^[3] ; Antunes, Renato Altobelli ^[4] ; Rodrigues, Cleber Lima ^[5] ; Lanzutti, Alex ^[6] ; Pogatscher, Stefan ^[3] ; Olivier, Marie-Georges ^{[7, 8]} ; De Melo, Hercilio Gomes ^[1]

Affiliation

^[1] Escola Politecn Univ Sao Paulo, Av Prof Mello de Moraes 2463, Sao Paulo, SP - Brazil

^[2] Escola & Fac Tecnol SENAI Suico Brasileira Paulo, R Bento Branco Andrade Filho 379, Sao Paulo, SP - Brazil

^[3] Univ Leoben, Chair Nonferrous Met, 18 Franz Josef Str, A-8700 Leoben - Austria

^[4] Univ Fed ABC, Av Dos Estados 5001, Santo Andre, SP - Brazil

^[5] Univ Sao Paulo, Inst Fis, Rua Matao, Trav R 187, Sao Paulo, SP - Brazil

^[6] Univ Udine, Polytech Dept Engn & Architecture, Via Cotonificio 108, I-33100 Udine - Italy

^[7] Univ Mons, Serv Sci Mat, Pl Parc 23, B-7000 Mons - Belgium

^[8] Mat Nova Asbl, Ave Copern 1, B-7000 Mons - Belgium

• Document type: Journal article
• Source: Applied Surface Science; v. 534, DEC 30 2020.
• Web of Science Citations: 1

Abstract

The effect of temperature of a Ce-H2O2 post-treatment on the corrosion resistance of clad AA2024-T3 anodized in tartaric-sulfuric acid as well as the distribution of Ce oxyhydroxides in the anodized layer was investigated. Electrochemical impedance spectroscopy tests showed that samples post-treated at moderate temperatures (up to 50 degrees C) presented more stable and slightly higher impedance modulus than untreated ones. Increasing the posttreatment temperature to 75 degrees C decreased the corrosion resistance, likely due to damaging of the porous and barrier layer protective properties, as indicated by electric equivalent circuit fitting. Scanning electron microscopy characterization showed that Ce oxyhydroxides deposition (3 + and 4 + oxidation states as determined by X-ray photoelectron spectroscopy) was enhanced with increasing post-treatment temperature, and that pores were not blocked. Glow Discharge Optical Emission Spectrometry and Rutherford Backscattering Spectrometry analyses indicated local enrichment of Ce species at the bottom of the pores, whereas scanning transmission electron microscopy confirmed the presence of Ce-containing nanoparticles stuck to the pore's walls. Analyses of corroded samples showed increased amounts of Ce oxyhydroxides on the surface and that Ce species remained inside the pores, indicating that the post-treatment protocol successfully and durably incorporated Ce ions within the structure of the anodized layer. (AU)

• FAPESP's process: 18/01096-5 - Corrosion study of the alloy AA2024-T3 anodized in TSA and protected with Ce ions and an hybrid sol-gel coating
• Grantee: Hercílio Gomes de Melo
• Support Opportunities: Regular Research Grants