Inhibitor Evaluation by the Pearson Null Bridge^★

A Pearson null bridge was built in order to determine its usefulness in the evaluation of corrosion inhibitors. Eight compounds and three commercial inhibitors were tested using steel in aqueous sodium sulfate solution as the corrosion system. The materials used had all been studied by various other means, thereby permitting comparison of previous results with those obtained by this method. As an estimate, this procedure gave about 70 percent correlation with other methods, as far as inhibiting mechanisms are concerned. This is on the basis of qualitative classification only. As a quantitative tool, the bridge in its present form appears to be considerably less useful.