The effect of subsurface degradation on tribocorrosion behaviors of Inconel 690 in 3.5% sodium chloride

The fretting corrosion behaviors of Inconel 690 under different electrochemical polarization condition in 3.5% sodium chloride were investigated. The results indicated that the degradation mechanism of subsurface microstructure, which strongly depended on polarization condition, played significant influence on fretting corrosion behaviors. In cathodic polarization condition (CPC), oxidation was suppressed. Tribologically transformed structure (TTS) was stripped by plowing, thereafter mixed with the transferred material to form the wear debris layer (WDL). In anodic polarization condition (APC), oxidation was promoted. TTS and WDL were directly dissolved into solution by oxidation. Therefore, the wear mechanism in CPC is mainly abrasive wear, but is abrasive wear and oxidation in APC. Correspondingly, the wear volume in CPC is smaller than that in APC.