Corrosion and creep behavior of a Ni-base alloy in supercritical-carbon dioxide environment at 650 degrees C

Abstract

Creep tests were performed for a nickel-base alloy, Ni-16Cr-9Fe, in air, atmospheric CO2, and supercriticalcarbon dioxide (S-CO2) at 650 degrees C. Creep rupture lives in S-CO2 were shorter compared to air and CO2 environments, and the difference was greater at lower applied stress. Combined effects of applied stress and high pressure caused the formation of thicker oxides, which were subjected to extensive cracking and spallation during creep tests in S-CO2. Cracks were found to propagate through the Aland Ti-rich internal oxides formed at grain boundaries, resulting in reduced creep rupture life in S-CO2 environment.