Naslov
Passivity of Copper and Copper-Nickel Electrodes in the Presence of Benzotriazole

Autori
Metikoš-Huković, Mirjana ; Babić, Ranko ; Lončar, Mirjana

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

Izvornik
: Korrosionsschutz durch elektrochemische Oberflächenmodifizierung, Kurzreferate / W.Plieth - : Deutsche Gesellschaft für chemisches Apparatewesen (DECHEMA), 1997

Skup
3. Electrochemisches Grundlagensymposium in Verbindung mit dem 2. Kurt-Schwabe -Symposium

Mjesto i datum
Dresden, Njemačka, 17.04.1997. - 19.04.1997

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
copper; Cu-10Ni; benzotriazole (BTA); corrosion inhibition; passivity; impedance spectroscopy; cyclic voltammetry; photopolarization; Raman spectroscopy

Sažetak
The electrochemical behavior of copper and copper alloys have been the subject of our interest for a long period of time. The aim of the present work is to investigate the inhibitive properties of benzotriazole (BTA) on the corrosion properties of copper and copper-nickel alloy (90Cu10Ni) in an acetate buffer solution, pH 5.8. Experimental: An investigation was performed by using cyclic voltammetry, photopolarization measurements, impedance spectroscopy and Raman spectroscopy methods. The electrochemical set up consisted of an EGG&PAR Potentiostat/Galvanostat Model 273 and an EGG&PAR Lock-in Amplifier Model 5301A, controlled with a PC. The incident light of a tungsten-halogen lamp was chopped by using a modified Brookdeal 9479 variable-frequency modulated light. Results and discussion: All methods applied showed a strong influence of BTA on the electrochemical behavior of the investigated electrodes in an acetate buffer, pH 5.8. Generally, the similar influence of BTA was observed on both electrodes. At lower inhibitor concentration a chemisorbed monolayer of BTA was formed. Adsorption of BTA on both electrodes follows the Langmuir adsorption isotherm, with a relatively high Gibbs adsorption energy (approx. -37 kJmol^-1). Polarization and especially impedance measurements showed that the inhibitory action of BTA is strongly expressed at the inhibitor concentration above 1 mM, due to the formation of the thick polymeric layer on the electrode surface. Cyclic voltammetry measurements clearly confirmed a duplex structure of the surface film on the both electrodes. Photopolarization measurements performed in-situ, showed that a nonstoichiometric structure of the inner oxide layer (p-type conductivity on Cu and n-type conductivity on Cu-Ni alloy) becomes stoichiometric in the presence of BTA, due to formation of the polymeric complex: nCu_(s) + nBTA^-_(aq) --> (Cu(I)BTA)_n_(s) + ne^- , which significantly decreases the rate of charge transfer at the electrode/solution interface. Electric and dielectric properties of the inhibitory layer have been determined by impedance spectroscopy and its structure by Raman spectroscopy.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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