Oxidation of single crystal PWA 1483 at 950 ℃ in flowing air

摘要

The oxidation behaviour of single crystal PWA 1483 at 950 ℃ was investigated by means of XRD, SEM and EDS. The parabolic oxidation behaviour, as defined by mass gain and the respective oxide layer thicknesses, is characterized by a parabolic rate constant of about 4 × 10~(-6) mg~2/(cm~4 × s) and the formation of a multi-layered oxide scale. An outer scale contains a Ti-bearing thin film composed of TiO_2 and NiTiO_3 but mostly Cr in Cr_2O_3 and (Ni/Co)Cr_2O_4 besides NiTaO_4. This outer scale is connected to a discontinuous layer of Al_2O_3 and an area of γ'-depletion within the base material.