Quantitative assessment of local misorientations and pitting corrosion behaviour of pearlitic steel using electron backscattered diffraction and microcapillary techniques

The influence of the grain tolerance angle (GTA) on the microstructural parameters of pearlitic steel is investigated using electron backscattered diffraction. The corrosion behavior of this alloy is then evaluated from local polarisation curves (electrochemical microcell technique) and potentiostatic pulse testing. These results are analyzed according to the specimen microstructure (grain boundaries and grain orientation spread, GOS). It is shown that there is a critical value of the GOS (around 10°) leading to significant decrease of the pitting potential. The influence of the GTA value on the analysis of electrochemical results is also discussed.