Corrosion Behavior and Passive Film Composition of Alloy 825 in High Temperature and High H2S-CO2 Containing Environment
Zhe Feng, Xuehua Fan, Zhu Wang, Yong Yu, Lijuan Chen, Yanxia Du, Lei Dong
Abstract
The effect of high temperature on corrosion behavior and passive film composition of Ni-based alloy 825 in H 2 S-containing environment was investigated by Confocal Laser Microscope (CLM), Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), and X-ray Photoelectron Spectroscopy (XPS). The experiment was carried out at 150 and 230°C in NaCl solution. The partial pressure of H 2 S was set to 1.2 MPa and CO 2 was set to 3.2 MPa. The results showed that Ni-based alloy 825 presented good general corrosion resistance. Pitting corrosion was likely to occur at 230°C because of Cr depleted in the passive film. NiS appeared at high temperature and is damaging to protectiveness of passive film.