CHARACTERIZATION OF NANOPOROUS ALUMINUM OXIDE LAYERS OBTAINED BY CONTROLLED ANODIC OXIDATION

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-12-6 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 61, 43-50 pp, DOI: 10.5593/sgem2017/61/S24.006

ABSTRACT

The properties of aluminum and its alloy make them to be the first choice as manufacturing materials for different equipments and accessories. The light weight, high strength and improved corrosion resistance recommend aluminum and its alloy to be used specially in transportation and construction industries.
The native aluminum oxide film formed after exposure in air presents voids and cracks and the exposure aluminum parts to corrosive environments which lead to the degradation and reducing their lifetime.
In order to improve the properties of aluminum and its alloys, different surface treatment methods have been developed. Between treatment methods the most used and inexpensive is considered to be the controlled anodic oxidation process.
The aim of present paper is to characterize the corrosion behavior and morphological properties of the nanoporous aluminum oxide layer obtained by controlled anodic oxidation. The ex-situ and in-situ characterization methods were used, such as: scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS), open circuit potential (OCP), linear polarization (RP) and cyclic voltammetry (CV).
The results show that the controlled anodic oxidation of aluminum and its alloys increases the thickness of nanoporous aluminum oxide film, which leads to the increasing of the polarization resistance and the decreasing of corrosion rate.

Keywords: aluminum alloys, anodic oxidation, surface treatment, corrosion resistance