Inhibition of sea water corrosion by chromate addition

Effect of chromate addition in sea water in inhibiting corrosion of mild steel was studied. Results indicated that the addition of 50 ppm of K2CrO4 was effective to considerably lower the corrosion rate although the pitting corrosion occurred even at 10,000 ppm of chromate concentration. At higher concentrations of chromate corrosion potential moved towards more noble direction and considerable amount of polarisation of both anode and cathode potentials corresponding to a lower value of corrosion current was effected. (Shri D.K. Khan, Scientist and D.K. Basu, Senior Laboratory Assistant, NML Marine Corrosion Research Station, Digha, Shri K.P. Mukherjee, Scientist, National Metallurgical Laboratory)