Corrosion Behavior of X65 Steel in CO₂ Acidic Solution at Different Temperature

X65 steel specimens were tested in an acidic solution containing CO2 with a pressure of 1 MPa at 60-150 ℃ for 72 h in an autoclave.XRD,EPMA,SEM and weight-loss methods were used to analyze the corrosion products and corrosion rates.The results showed that the corrosion rates at 60 ℃,90 ℃,120 ℃ and 150 ℃ were 10.97,3.70,8.37 and 18.97 mm·a-1 respectively.Protective films of FeCO3 were not generated at 60 ℃ resulting in serious corrosion.Fine and compact protective films of FeCO3 were formed at 90 ℃ and reduced the corrosion rate markedly.The FeCO3 films were relatively fine but scattered at 120 ℃ and were coarse and loose at 150 ℃ and thus increased the corrosion rate.