Analysis of the Temperature Influence on Galvanic Corrosion and Mathematical Model

The general and galvanic corrosion of high strength steel (980), high strength steel (907) and high strength steel (921A) in seawater at elevated temperatures has been analyzed using electrochemical measurements and a zero-resistance ammeter (ZRA). After the tests, the surface morphologies of the samples have been detected by SEM. Results show galvanic corrosion behavior of 980/907/921A fulfill the mixed potential theory, 921A acts as the anode and both 980 and 907 act as the cathodes. These results using ZRA have been compared with results estimated from the polarization curves according to the mixed potential theory (imposed potential measurements). The effect of temperature on the galvanic corrosion estimated using both types of measurements are basically in agreement, since temperature increases the galvanic current density of the pair in both cases. The galvanic current density with increasing temperature is estimated by the exponential function.