INVESTIGATION ON CORRSION BEHAVIOR OF NIOBIUM CONTAINING STEEL IN SEAWATER BY AC IMPEDANCE TECHNIQUE

In present work,variation of open circuit potential of niobium steel and carbon steel in seawater at ambient temperature with time was studied.The AC impedance spectra of the interface between steels and the seawater by different time were measured.The results show that:(1)The charge transfer resistances of niobium steels in sea water exhibited a tendency to become higher and higher with time,which implied that corrosion products of niobium steel were much compact than those of carbon steel;(2)The corrosion potential of niobium steel increased gradually with increasing corrosion period,while carbon steel remained constant.Therefore the corrosion resistance of the niobium micro-alloyed steel is better than that of the carbon steel.