Investigation of the fireside corrosion of a new wrought Ni-Fe-Cr-based alloy in advanced ultra-supercritical steam boilers

The gas-phase and coal ash-related fireside corrosion behavior of a new type of Ni-Fe-Cr based superalloy GH984G and two other contrast alloys were investigated for its application under advanced ultra-supercritical (A-USC) conditions. Results showed that the oxidation activation energy of the three alloys at 600–780 °C in the flue gas environment can be ranked from large to small: C-HRA-1>GH984G>Alloy 625. In the coal ash environment, GH984G and C-HRA-1 exhibited satisfactory corrosion resistance, while Alloy 625 had weaker corrosion resistance due to the presence of molybdenum. The corrosion mechanism of GH984G and the influence of constituent elements were elucidated.