The inhibiting action of some tetrazole derivatives on the copper corr
osion in chloride solutions has been studied. Experiments have been ca
rried on OFHC copper in 0.1 M NaCl solutions with the following tetraz
ole derivatives at the 10(-3) M concentration: tetrazole (T), 5-mercap
to-1-methyl-tetrazole (SMc-1Me-T), 5-mercapto(Na salt)-1-methyl-tetraz
ole (5NaMc-1Me-T), 5-mercapto-1-acetic acid(Na salt)-tetrazole (5Mc-1A
c-T), 5-mercapto-1-phenyl-tetrazole (5Mc-1Ph-T), 5-phenyl-tetrazole (5
Ph-T) and 5-amino-tetrazole (5NH(2)-T) in the range of pH from 4 to 8
and at temperatures of 40 and 80 degrees C. Some inhibitors have been
studied from 10(-5) to 6 x 10(-3) M. Cathodic and anodic polarisation
curves were recorded after 1 h of immersion. Polarisation resistances
measurements have been made as a function of the time in the 300 h exp
eriment. The weight loss measurements have confirmed the electrochemic
al trend. The prefilming action of some tetrazole derivatives has been
evaluated. The interaction between the organic molecules and the meta
l surface has been studied by means of FTIR reflection spectra. All th
e inhibitors, except the 5Mc-1Ac-T which stimulates the corrosion, sho
w an inhibiting efficiency from 50 to 99%. In every case the inhibitin
g efficiency increases with increasing pH value. 5Mc-1Ph-T and 5Ph-T s
how the better protective characteristics. Copyright (C) 1996 Elsevier
Science Ltd