Abstract
The effect of additions of bromides and iodides to sea water on the corrosion of copper has been investigated. Tests were carried out in solutions containing Kl or KBr at concentrations from 10−l to 10−5 mol/l, and various alkyl halides at concentrations from 10−3 mol/l up to saturation (approx. 10−l mol/l).
The inhibiting efficiency of KI varies with concentration, having a peak value (approx. 75% after 360 h immersion) at 10−2 mol/l. Inhibition is due to the formation of a layer of CuI on the copper surface. Alkyl iodides have a lower inhibitive efficiency than KI and this efficiency decreases the longer the period of immersion. The mechanism of inhibition is similar to that observed for KI.
KBr has an inhibitive efficiency of 50–60% at a concentration of 10−l mol/l, but corrosion is actually accelerated at concentrations below 10−3 mol/l. The inhibiting effect is due to the action of KBr in reducing the concentration of O2 in the corrosive solution, and not to the formaiion of a protective layer of CuBr. The action of alkyl bromides is always deleterious.
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