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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

EIS investigation of a Ce-based posttreatment step on the corrosion behaviour of Alclad AA2024 anodized in TSA

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Prada Ramirez, Oscar Mauricio [1] ; Queiroz, Fernanda Martins [1] ; Terada, Maysa [2] ; Donatus, Uyime [3] ; Costa, Isolda [3] ; Olivier, Marie-Georges [4, 5] ; de Melo, Hercilio Gomes [1]
Total Authors: 7
[1] Univ Sao Paulo, Escola Politecn, Av Prof Mello Moraes, BR-2463 Sao Paulo, SP - Brazil
[2] CNPEM, Lab Nacl Nanotecnol, LnNano, Rua Giuseppe Maximo Scolfaro, Campinas, SP - Brazil
[3] CNEN, IPEN, SP, Sao Paulo, SP - Brazil
[4] Univ Mons, Serv Sci Mat, Mons - Belgium
[5] Mat Nova Asbl, Mons - Belgium
Total Affiliations: 5
Document type: Journal article
Source: SURFACE AND INTERFACE ANALYSIS; v. 51, n. 12, SI, p. 1260-1275, DEC 2019.
Web of Science Citations: 0

In the aircraft industry, anodizing and posttreatment steps use Cr (VI) compounds, which, despite offering good corrosion resistance and self-healing properties, are highly toxic and carcinogenic. Ce compounds are recognized as efficient corrosion inhibitors for Al alloys, and several works report self-healing ability for these chemicals. In this investigation, the corrosion resistance of Alclad AA2024-T3 alloy anodized in tartaric-sulphuric acid (TSA) bath and posttreated in a solution comprising cerium nitrate without and with hydrogen peroxide was evaluated. The purpose is to investigate the potentiality of using hydrothermal treatment in Ce nitrate solution as candidate to replace Cr (VI) posttreatment. The aim is to provide a posttreatment step which, while improving the corrosion resistance, does not plug the mouths of the pores maintaining the adhesion properties of the porous anodic layer. Microstructural characterization was carried out by SEM-EDS whereas corrosion resistance was evaluated by EIS. The surface analysis showed that the posttreatments, all performed at 50 degrees C, kept the open structure of the pores. EIS analysis showed that the posttreatments performed in the H2O2 solution for short immersion times were the most effective in improving the corrosion resistance of the samples, whereas electrical equivalent circuit (EEC) fitting of the data indicated sealing of the porous layer during the immersion of the different samples in the test solution. SEM-EDS analysis of the samples posttreated in the H2O2 containing solution, prior and after the corrosion test, showed the presence of Ce oxy-hydroxide randomly deposited on the sample surface, indicating that Ce could be incorporated/stored in the anodic 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 type: Regular Research Grants
FAPESP's process: 13/13235-6 - Investigation on the localized corrosion and the fatigue corrosion resistance of high strength aluminum alloys joined by friction stir welding (FSW)
Grantee:Isolda Costa
Support type: Research Projects - Thematic Grants