Abstract: The isothermal oxidation behavior of a cast Ni-base superalloy K52 at 900 ℃, which compared with Ni-base superalloy ЧC104-Bи, was investigated. The bases of the experiment and theory were provided for designing and applying superalloy K52. The results indicate that oxidation kinetics obeyed parabolic law for the two kinds of superalloys. The resistance oxidation belongs to Ⅰgrade for K52 and ЧC104-Bи superalloys at 900 ℃.The scales on the surface were determined by X-ray diffraction, scanning electron microscopy(SEM), and EPMA equipped with an EDAX unit. The results show that oxidation scales of K52 superalloy is similar to that of ЧC104-Bи one, and the oxidation scales consisted of three parts: which the external layer without protective discrete is mainly formed with TiO₂, and a protective continuous compact Cr₂O₃ layer with a certain amount of NiCr₂O₄ is intermediate layer, as well as the internal layer is mainly Al₂O₃ with a small amount of TiO₂. The oxidation resistance of the superalloy K52 is superior to that of the superalloy ЧC104-Bи.

Key words: Cast Ni-base superalloy K52, High temperature oxidation, Oxidation kinetics, Oxidation film