ON THE PROTECTIVE ACTION OF 1,2,3-BENZOTRIAZOLE DERIVATIVE FILMS AGAINST COPPER CORROSION

The inhibiting effects of 1,2,3-benzotriazole (BTA), 5-methyl-BTA (C1- BTA), 5-butyl-BTA (C4-BTA), 5-hexyl-BTA (C6-BTA) and 5-dodecyl-BTA (C1 2-BTA) films on the corrosion of copper in 3.5% NaCl (pH=7 and 2.5) an d 0.1 m NaClO4 (pH=7) were evaluated from polarization curves and EIS spectra. The characteristics of the inhibitor films were investigated by means of wetting tests and XPS analysis. The tested compounds (almo st insoluble C12-BTA excepted) produce films able to inhibit the oxyge n reduction process depending on the alkyl chain length, but only C6-B TA film succeeds in hindering the copper oxidation reaction, even in a cid NaCl. The protective action expecially exerted by the C6-BTA film should be related to the hydrophobic effect of the alkyl chain, rather than to an electron releasing inductive stabilisation effect. (C) 199 7 Elsevier Science Ltd.