Supercritical-CO2 corrosion behavior of alumina- and chromia-forming heat resistant alloys with Ti

Abstract

Short-term corrosion behavior of the alumina- and chromia-forming Fe-Ni-based heat resistant alloys with Ti for gamma'-Ni-3(Al,Ti) precipitation were evaluated in supercritical-CO2 (sCO(2)) environment at 650 degrees C and 20 MPa for 457 h. The corrosion test showed development of thinner oxides with some occasional Fe-rich oxide nodules in alumina-forming alloy A (16Cr-4.5Al-3Ti). However, chromia-forming alloy C (20Cr-2Al-2Ti) exhibited several occurrences of Fe-rich oxide nodules and spallation of thinner oxides. Meanwhile, the pre-oxidation treatment resulted in improved corrosion resistance in sCO(2) environment by preventing the Fe-rich oxide nodule formation and oxide spallation, especially for alloy A with formation of alpha-Al2O3.