Effect of pretreatment potentials on pit generation of Incoloy 800

Pit generation of Incoloy 800 in 3.5%NaCl solution has been analysed on the basis of a stochastic theory. A parallel combination of several processes was found to be included in the pit generation at a constant potential. The number of the processes and their pit generation rates altered depending on the pretreatment potential as well as the potential applied during pit generation. The increase of the pretreatment potential caused to decrease the number of the process and also the rate of pit generation. The critical pitting potential which does not depend on the pretreatment potential and the potential sweep velocity can be determined when the pretreatment potential is more noble than -0.10 V. (author)