Electrochemical behavior of 00Cr12Ti with different heat treatments during reactivation process

The electrochemical behavior of 00Cr12Ti with different heat treatments in a 0.1mol·L^-1 H₂SO₄+0.0001mol·L^-1 KSCN solution was investigated by Cu-CuSO₄-16%H₂SO₄ tests,double-loop electrochemical potentiokinetic reactivation(DL-EPR) tests and dynamic electrochemical impedance spectroscopy(DEIS).It was found that specimens treated at 1000℃ for 2h sensitized but specimens treated at 650℃ for 2h did not.The different heat treatments mainly affected the reactivation behavior,but had almost no effect on the activation behavior.During reactivation process,for specimens treated at 1000℃ for 2h,the capacity loop decreased dramatically and then increased gradually,meanwhile it showed a negative value at the low frequency capacitive loop,indicating the breakdown and repair of passive films.For specimens treated at 650℃ for 2h,there were not the breakdown and repair of passive films,meaning that the passive films were stable comparably.After the occurrence of intergranular corrosion,the charge transfer resistance(R_ct)of specimens treated at 1000℃ for 2h is much less than the passive film's resistance(R_p) of specimens treated at 650℃ for 2h due to local corrosion in specimens treated at 1000℃ for 2h.