Corrosion Behavior of Ni-based Alloys in H₂S/CO₂ Environment

The pitting corrosion behavior of two Ni-based corrosion resistant alloys,G3 and Incoloy 825,were investigated in FeCl3 solution by polarization curves and immersion testing.The high temperature corrosion behavior of the alloys in NaCl solution containing H2S/CO2 was studied using high temperature high pressure autoclave.The scanning electron microscopy(SEM) and energy disperse spectroscopy(EDS) were used to analyze the microstructure and composition of the samples.The results showed that the pitting-resistance of G3 was superior to that of Incoloy 825,and the critical pitting temperature of G3 was higher than 50 ℃.The corrosion behaviors of the two alloys were different,i.e.,G3 had anodic passivation area and higher pitting potential.With the increase of experimental temperature the corrosion degree of the two alloys increased and some pits appeared on the surface of Incoloy 825.