Early corrosion properties of titanium alloys, Ni-based alloys and stainless steel in supercritical water oxidation of sewage sludge

Abstract Supercritical water oxidation (SCWO) can efficiently and harmlessly dispose sewage sludge, while corrosion phenomena lead to rapid shutdown and/or failure of expensive process equipments in a supercritical system. The behavior titanium alloys, Ni-based alloys stainless steel exposed sludge at 450 °C, 26 MPa for 60 h was investigated by means gravimetry, scanning electron microscopy, energy dispersive X-ray spectroscopy diffraction. 316 SS (stainless steel) showed the highest rate, TA10 had lowest rate. oxide scale on surface contained magnetite FeCr 2 O 4 , Cr 3 NiCr were main components layer Inconel 600. Among them, mainly existed inner layers 600, respectively. lack resulted severe pitting poor resistance.