Oxidation behavior, microstructure and mechanism of YAl3C3 at 1500 °C in air up to 30 hours

Abstract

YAl3C3 has the potential to be a single phase ultra-high temperature ceramic with good oxidation resistance in a wide temperature range. In this work, the isothermal oxidation behavior of YAl3C3 has been investigated at 1500 °C in air up to 30 h. The oxidation kinetics of YAl3C3 approximately follows a parabolic law. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and Raman spectroscopy were used to characterize the oxide scale. The results show that the oxide scales exhibit a three-layer structure, mostly consisting of an outer layer of well-mixed Y3Al5O12 and Al2O3, along with a middle lamellar structure with periodic distribution of Y3Al5O12 and Y3Al5O12+Al2O3 sublayers due to the regulation of the interfacial oxygen partial pressure as well as an inner carbon-rich amorphous layer.