Abstract
An instrument (Fig. 1 & 2), which is composed of several external plastic tubes, a circulating pump, a head tank, current-supplying anodes and corresponding inner metallic tubes as specimen, was developed to investigate the effect of cathodic current on the polarization of inner surface of metallic tubes for heat exchangers. Some test results on bare steel tubes and epoxy-coated steel tubes in artificial sea water were graphed as shown in Fig. 3-8 & 9, which told the promising performance of coated pipe, and some doubts on application of famous Michalke's Equation in the case of bare steel tube.
