Naslov
EIS study of passive oxide films on aluminium in citric acid solutions

Autori
Šeruga, Marijan ; Hasenay, Damir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / 55th Annual Meeting of the International Society of Electrochemistry / - Solun : International Society of Electrochemistry, 2004

Skup
55th Annual Meeting of the International Society of Electrochemistry

Mjesto i datum
Solun, Grčka, 19.09.2004. - 24.09.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
aluminium; oxide films; electrochemical impedance spectroscopy EIS; citric acid

Sažetak
The influence of anodising time and pH value of solutions on the properties of passive oxide films potentiostatically formed at 1.0 V on aluminium (Al) in 0.05 M citric acid solutions (pH = 5-7), were investigated by the means of potentiostatic controlled current-time transients and electrochemical impedance spectroscopy (EIS) techniques. Electrochemical measurements were performed using a potentiostat PAR M273A and Lock-In Amplifier 5210, controlled by computer. From the impedance spectra of potentiostatically formed oxide films it is evident that the system shows at high frequencies capacitive behaviour and at low frequencies inductive behaviour. The capacitive behaviour can be related to the growth and dielectric properties of oxide barrier layer, while the inductive behaviour is probably due to the relaxation processes of adsorbed species at the oxide/solution interface. It is observed that during the anodising up to 1-2 h reciprocal capacitance (which is proportional to the thickness of oxide film) increase, after which the oxide film reaches the constant value of C-1 (constant film thickness). This behaviour suggests that subsequent ordering of the structure of anodic oxide films and/or surface coordination processes takes place during prolonged anodising. It is evident that the properties of oxide films depend on pH values of citric acid solutions. The higher pH values of solutions (pH = 7) stimulate formation of thicker and more resistive oxide film and at the same time decrease the influence of relaxation processes on the total impedance of the system.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA