Effect of the Temperature on the CO₂-Corrosion of Ni₃Al

摘要

Carbon dioxide (CO2) corrosion of pipeline steels and equipment has been considered one of the mostsevere problems in the oil and gas industry. Carbon steels are commonly used for different purposes,because of its competitive cost. However, carbon steel is not the most corrosion resistant material formany environments. The low corrosion resistance of carbon steel is due to its inability to grow aprotective oxide layer on its surface that protects it from the aggressiveness of the surroundingenvironment. It has been demonstrated that carbon steel can be safely operated in very corrosiveservice conditions if a corrosion control system is properly designed and implemented. However, whenthese safety precautions fail the consequences can be catastrophic. As a result, it is necessary toconsider employing materials with greater corrosion resistance. In this logic intermetallic materials canbe a feasible option. In this study the corrosion behavior of a Ni3Al intermetallic alloy and 1018 carbonsteel was investigated. Corrosion performance of both materials was evaluated by electrochemical testsby polarization curves, rest potential measurements, and linear polarization resistance. Corrosion testswere carried out in 3% NaCl-diesel mixture saturated with CO2 in a temperature gap from 30 to 80 C.Results showed that the Ni3Al has both a nobler behavior and higher corrosion resistance than carbonsteel. On the other hand, corrosion rate of carbon steel is limited by mass transfer and in case of theNi3Al intermetallic alloy, corrosion rate is limited for its passivity.