Corrosion Behavior of Different Steel Substrates Coupled With Conductive Polymer Under Different Serving Conditions

The corrosion behaviors of stainless steel and nickel-plated carbon steel coupled with conductive polymer were investigated in both hot humid environment and simulated marine environment.The corrosion currents of different steel substrates and conductive polymer in simulated marine environment at room temperature were measured.The corrosion surfaces of different steel couples were observed under a scanning electron microscope (SEM) and chemical compositions were examined by energy dispersive spectrum (EDS) analysis.The corrosion mechanism was discussed.The results showed that the stability of both stainless steel and nickel-plated carbon steel in hot humid environment was excellent and no corrosion happened in the blank test for 360 h while slight corrosion existed in the contact area of coupled steel substrates.In simulated marine environment,the corrosion current of the stainless steel was lower than 100 μA and some directional rod-like particles formed on the surface of the stainless steel,which are mainly caused by oxidative corrosion among different phases.The corrosion current of the nickel-plated carbon steel couples was much greater than that of stainless steel couples and nickel plate cracking resulted in the corrosion of the internal iron because the coated nickel layer was not dense enough.