Electrochemical behaviour of N80 steel in CO_2 environment at high temperature and pressure conditions

摘要

This study investigates the scale formation behaviour of N80 steel in CO2 environment at different temperatures and immersion time by in-situ electrochemical and surface analysis techniques. It shows that the temperature and immersion time have significant influence on electrochemical behaviour, which is due to the different scales formed on N80 steel surface. The scales formed at 60 degrees C and 90 degrees C are mainly corrosion products. At 120 degrees C and 150 degrees C, the scale consists of CaCO3. The formation of CaCO3 inhibits the corrosion and the formation of FeCO3. CaCO3, formed in 150 degrees C, is aragonite, which provides better protection to substrate for its compact structure.