The potential excellent properties of TiAl-based alloys could be brought into play to more extent in the application as high-temperature
structure materials if their
high-temperature oxidation resistance can be further improved. Pack siliconizing is one of convenient and effective methods in improving their oxidation resistances. In this paper, the long-term cyclic oxidation test was performed on siliconized
TiAl-based alloy specimens and the oxidation kinetics was analyzed. The results show that the oxidation process usually consists of three stages before crack and spallation of the surface layer,which are the parabolic, the linear and the quadratic stages. The higher the siliconation temperature or the longer the siliconization time is, the longer the parabolic stage is, and the better the oxidation resistance becomes. For the specimen that was siliconized at 1250℃ for 2h, however, only the parabolic region appeared during the whole cyclic oxidation test at 900℃ up to 1000 h. The weight gain is less than 0.3 mg·cm -2 after cyclic oxidation at 900℃ for 1000h,and the corresponding parabolic oxidation rate constant, K_p is about 6.03×10 -5mg2/(cm4h). The excellent oxidation resistance is attributed to the formation of a composite coating with a stable Ti_5Si_3-based layer and a dense Al_2O_3-based layer.