The corrosion behavior of 17-4 stainless steel in a stainless steel-carbon steel galvanic couple

In this work, the corrosion behavior of 17-4 stainless steel in a stainless steel (17-4) and carbon steel (C110) galvanic couple was investigated using electrochemical methods including open circuit potential, galvanic potential, electrochemical impedance spectroscopy and Mott-Schottky curves. The results show that the corrosion resistance of 17-4 stainless steel decreases, although it is generally considered that stainless steel acting as the cathode in this kind of galvanic couple should be protected. This can be attributed to that the passive film on the 17-4 stainless steel is destabilized by the cathodic polarization in this galvanic couple. Consequently, a decrease in corrosion resistance of 17-4 stainless steel can be found.