Effects of Hydrostatic Pressure on the Corrosion of Copper in Sea Water

Abstract

A study has been made of the effect of hydrostatic pressure, ranging from 1 to 300 atm. (0·102 to 30·6 N.mm⁻²) on the corrosion of copper in sea water at pH 7·8 and at a temperature of 10°c. The experimental technique ensured that the content of dissolved oxygen in the sea water was virtually constant over the pressure range, at a value of 7·0 ppm. The same test series was also carried out in a 3·5% NaCl solution.

The weight loss of the copper was found to increase with increase in pressure, both in sea water and in NaCl, and reached a maximum at a pressure of 150 atm. (∼15 N.mm⁻²) in both solutions. The increased pressure has no influence on the anodic dissolution process for copper, but accelerates the cathodic process. Protective films adhering to the corroded surfaces are identical for the two solutions at ambient pressure. However, at higher pressures adherent corrosion products form only in NaCl solutions. These products were found to be the same as those formed at ambient pressure.