Corrosion behaviour of the 2098-T351 Al–Cu–Li alloy after different surface treatments

ABSTRACT

The effect of different surface treatments on the corrosion resistance of the AA2098 Al–Cu–Li alloy has been investigated. Surface characterization was performed using 3D optical profilometry, energy dispersive X-ray spectroscopy and scanning electron microscopy. The corrosion resistance of the 2098 alloy after the surface treatments was investigated in 0.1 mol L⁻¹ NaCl solution by electrochemical techniques and microscopy. Corrosion results showed that the untreated and the chemically etched surfaces were more active than the mechanically abraded and mechanically polished surfaces owing to differences in the nature of the native oxides formed after the surface treatments. Corrosion rate and mode were also affected by how close the exposed surface was to the mid-thickness region of the AA2098-T351 plate relative to the actual top surface (before polishing). This is associated with the variation in the volume fraction and distribution of the T1 phase as the mid-thickness region of the AA2098-T351 plate is approached.

KEYWORDS:

• Al alloys
• localized corrosion
• surface characterization

Acknowledgements

The authors acknowledge CNPq-PIBIC for the grants of Wanessa G. Barboza and FAPESP for financial support (2013/12323-6) and the grant of R. Silva (Proc. 2018/06880-6). Acknowledgements are also owing to the Polytechnic School of São Paulo University (PMT/USP), Dr Hercilio G. de Melo, for the LEIS analysis and to Dr Antonello Astarita from the University of Naples for providing the 2098-T351 Al–Cu–Li alloy material.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of a continuing study.

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico; Fundação de Amparo ã Pesquisa do Estado de São Paulo [grant number 2013/12323-6; 2018/06880-6].