Abstract:In this work, hot corrosion behavior of Ni-20Cr-18W based superalloys at 900℃ has been investigated.
The alloy corroded in 75% Na2SO4 +25% NaCl mixture molten salt has been analyzed by optical microscope, X
-ray diffraction, scanning electronic microscope and energy sispersive X-ray analysis. Results show that the Ni-20Cr
-18W based superalloy represents basic dissolution model. The corrosion front goes ahead as a plane into the matrix
of alloy without selective corrosion behavior. Most of outcomes in the outer corrosion layer are NiO and Ni3S2. The alloy
surface loses protective oxide layer and the outcomes increase the corrosion rate. The high thermal corrosion rate of
alloy can be ascribed to the tungsten element and the corrosion between second phase particles and matrix.
