Current and potential relations for the cathodic protection of steel in salt water

A laboratory i nvestigation was made pertai ni ng to the cathodic protection of steel specim ens that were exposed for 60 days to both stagnant and aerated ci ty water, to wh ich was added 3 percent by weight of sodium chloride.Major consideration was given to the significa nce of potential as a criterion for protection.Optimum protection was achieved when specimens were con trolled at -0.77 volt w ith reference to the saturated calomel half cell.Al though a good degree of protection was obtained at controlled pote ntials more noble than -0.77 volt, that is, at the potentials associated with the breaks in cathodic polarization curves, this Jesser d egree of protection could not be obtained at lower mean current densiti es.