EFFECT OF VELOCITY ON THE CORROSION BEHAVIOUR OF Al-Mg 3 IN NORTH SEA WATER.

Experiments conducted in a PVC loop showed that the rate of corrosion of Al-Mg 3 is increased to 9. 0 mils per year at a velocity of 1. 6 m/s in North Sea Water. The details of the PVC loop are described. The behavior of oxygen is time dependent and smaller concentrations of oxygen are found to be more beneficial. A concentration of 4. 0 ppm appears optimum. The optimum effect of inhibition by 50 ppm K//2CrO//4 and 100 ppm NaHCO//3 has been confirmed by electrochemical methods. Pitting and grain boundary attack appear to be the main localized forms of attack. Pitting frequency decreases with increased pH between 6. 5-8. 0. The PVC loop appears to be a good tool for biofouling corrosion and preliminary normal temperature studies prior to the high temperature loop studies.