Comparative effect of (1 1 1) and (1 1 0) crystallographic orientation on the passive behavior of low alloy steels in bicarbonate solution

Highlights: • Low alloy steels with (1 1 1) texture and (1 1 0) texture were prepared by ATP. • (1 1 0) texture shows anodic-passivation, but (1 1 1) texture causes self-passivation. • The existence of (1 1 1) planes is beneficial for Fe₃O₄ inner layer film formed. • The pitting originates from (1 1 0) planes but developed into other planes. In this work, low alloy steels with different textures were prepared by advanced thermo-mechanical processes (ATP). The microstructures, passive performance, and chloride-ion pitting behaviors were characterized by electron backscatter diffraction (EBSD), electrochemical measurements, X-ray photoelectron spectroscopy (XPS), and auger electron spectroscopy (AES). The results indicate that crystallographic orientation has an important influence on passive performance and pitting resistance in bicarbonate solution. Low alloy steels with (1 1 0) texture would undergo an active dissolution and passive process, while the (1 1 1) texture showed a self-passive behavior. Moreover, the existence of (1 1 1) texture improves the pitting resistance compared with the (1 1 0) texture.