The corrosion resistances of two types of stainless steels 304L, AL6XN and two types of nickel base alloys Inconel 718 and
Alloy 671 were studied in the simulation environment of
supercritical water oxidation (SCWO) system for recycling of waste plastics. The morphology of corrosion surfaces was inspected by scanning electron microscope (SEM). The results show that the order from high to low corrosion rates is 304L, AL6XN, Inconel 718, Alloy 671 after exposing in deionized pure water or 0.1 mol/L sodium chloride solution for 96 h at 320℃ and its saturated vapor pressure. Two nickel base alloys show better resistance of general corrosion, while serious pits are found on the Inconel 718 samples. Only the Alloy 671 shows very excellent corrosion resistance in the testing conditions. The chemical compositions of the surfaces of Inconel 718 and Alloy 671 after experiments were examined by EDXS and XPS. And the results demonstrate that severe dealloying of Ni occurs on the Inconel 718, while chromium oxide film on the surface of Alloy 671 plays excellent protecting role. Alloy 671 can be considered as the candidate fabrication material of SCWO vessel.