| In order to study the thermal corrosion behaviors of DSM11 Ni-base superalloy, corrosion tests were conducted on the alloy
coated with 5%NaCl+95%Na 2 SO 4 mixed salt films at 650, 750, and 850 ℃. The surface morphology, phase composition, distribution of ele?
ments and corrosion layer, and corrosion mechanism of the alloy after 200 hours corrosion were analyzed using metallographic microscopy
(OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results show that with
the increase of temperature, corrosion status on the surface of the superalloy gradually becomes serious, corrosion products become compli?
cated, the loss of mass gradually increases and the thickness of the corrosion layer gradually increases. The corrosion layer of the superalloy
can be divided into three layers, the outer and middle layers are multilayer oxides, and the inner layer is composed of granular oxides and
sulfides, the intrusions of O and S indicate that the superalloy has obvious internal oxidation and internal sulfuration. At three temperatures,
a continuous and stable Al 2 O 3 protective layer is formed on the alloy surface, which inhibits the thermal corrosion reaction and effectively
protects the matrix, indicating that the alloy has a certain thermal corrosion resistance. |