Corrosion behaviors of Ce‐ and Nd‐modified anodic films on aluminum

Abstract

Purpose

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth elements on the corrosion resistance of the anode film.

Design/methodology/approach

The crystalline film was studied by X‐ray diffraction. The methods of scanning electron microscope, energy dispersive X‐ray analysis, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) were used to characterize the properties of the films.

Findings

After rare‐earth element modification, the pores of the porous layer were very evidently smaller, the anodic film was more compact, and the thickness and hardness of the films had increased. The corrosion resistance of the anodic films modified with rare‐earth elements clearly was improved in neutral, acidic, and basic NaCl solutions. Ce showed a better effect than Nd in increasing the corrosion resistance of the films, and the film modified with Ce+Nd showed the highest corrosion resistance. EIS analysis showed that the impedances of both the barrier layer and porous layer of the anodic films increased after modification with the rare‐earth elements, indicating that the anodizing process was affected by the presence of the rare‐earth elements.

Originality/value

The results presented in this paper offer a foundation for further research and application of rare‐earth elements in aluminum anodic oxide films.

Citation

Zheng Li, Q., Zuo, Y., Mao Zhao, J., Ming Tang, Y., Hui Zhao, X. and Ping Xiong, J. (2010), "Corrosion behaviors of Ce‐ and Nd‐modified anodic films on aluminum", Anti-Corrosion Methods and Materials, Vol. 57 No. 5, pp. 238-243. https://doi.org/10.1108/00035591011075878