Effect of surface treatments on the localized corrosion resistance of the AA2198-T8 aluminum lithium alloy welded by FSW process

Author(s)

Machado, Caruline de S. C. ; Klumpp, Rafael E. ; Ayusso, Victor H. ; Donatus, Uyime ; Milagre, Mariana X. ; Araujo, Joao V. de S. ; Machado, Glauson A. F. ; Costa, I.

• Document type: Journal article
• Source: SURFACE AND INTERFACE ANALYSIS; v. 51, n. 12, p. 9-pg., 2019-12-01.

Abstract

In this work, the effect of eight types of surface treatments on the corrosion resistance of friction stir welded samples of an AA2198-T8 Al-Cu-Li alloy were tested and compared in an attempt to find suitable alternatives to toxic and carcinogenic hexavalent chromium treatments. All the samples were anodized and subjected to different post-anodizing treatments. The post-anodizing treatments were (1) hydrothermal treatment in Ce (NO3)(3) 6H(2)O solution; (2) hydrothermal treatment in Ce (NO3)(3) 6H(2)O solution with H2O2; (3) hydrothermal treatment in boiling water; (4) hexavalent chromium conversion coating; and (5) immersion in BTSE (bis-1,2-(triethoxysilyl) ethane. The corrosion resistance of the treated samples was evaluated by immersion tests in sodium chloride solution (0.1 mol L-1 NaCl) and electrochemical impedance spectroscopy (EIS) of the friction stir weldment. The results showed that among the alternative treatments, the Ce-containing solutions presented the best corrosion resistance, especially when used without peroxide. (AU)

• FAPESP's process: 17/03095-3 - Investigation on corrosion susceptibility of Al-Cu-Li alloys by friction stir welding (FSW) through scanning vibrating electrode technique (SVET)
• Grantee: Uyime Donatus
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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 Opportunities: Research Projects - Thematic Grants