抄録
Niobium disilicide (NbSi2) layers were applied on γ-TiAl specimens to enhance their oxidation resistance at 1050 °C. The NbSi2 layers were prepared by joining thin Nb foils to γ-TiAl surfaces, and siliconizing the Nb/γ-TiAl using molten salts. The coatings and their oxidation behavior were characterized using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy techniques. Isothermal oxidation tests showed that oxidation resistance of the uncoated γ-TiAl at 1050 °C in air was inadequate for prolonged exposure and scale spallation occurred, causing severe oxidation of γ-TiAl at high temperature. NbSi2 coatings were formed and adhered firmly to the underlying γ-TiAl. Oxidation of the NbSi2-coated γ-TiAI (NbSi2/Nb/γ-TiAl) at 1050 °C in air showed improved oxidation resistance at exposure time of 10 h. The NbSi2 coatings provided good intrinsic oxidation resistance at 1050 °C in air for prolonged oxidation exposure, and showed potential use in protecting γ-TiAl at high-temperature applications.
