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

The electrochemical behavior of 00Cr12Ti with different heat treatments in a 0.1 mol·L^-1 H₂SO₄+0.0001 mol·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°C for 2 h sensitized but specimens treated at 650°C for 2 h 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°C for 2 h, 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°C for 2 h, 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°C for 2 h is much less than the passive film's resistance (R_p) of specimens treated at 650°C for 2 h due to local corrosion in specimens treated at 1000°C for 2 h.