Comparative analysis of Ti3SiC2 and associated compounds using x-ray diffraction and x-ray photoelectron spectroscopy

摘要

Ti3SiC2 exhibits a unique combination of ceramic and metallic properties suitable for both electrical and mechanical application. With high-temperature stability, high electrical and thermal conductivity and resistance to oxidation, Ti3SiC2 has proven promising as a contact layer for high power SIC semiconductors. However, until recently, synthesis of this material has proven difficult without appreciable quantities (<2 vol%) of impurity phases, namely TiC1-x and Ti5Si3Cx. As such, many properties of this compound are as yet unknown. In this paper, a comparable analysis of Ti3SiC2 and associated compounds, TiC and Ti5Si3Cx has been performed using both x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). Assessing impurity sensitivities for each technique, XRD was shown to readily identify impurities of TiC and Ti5Si3Cx within Ti3SiC2 at <2 wt%. Although XPS could not independently resolve these impurities, its use resulted in the detection of a complex oxide structure on Ti3SiC2. It was speculated that it was composed of mixed C-Ti-C-O and Si-Ti-C-O bond chemistries. In a comparison of TiC, Ti5Si3Cx and Ti3SiC2, differences in oxide states suggest that oxidation is chemically dissimilar for all the three compounds. However, upon etching, the binding energies of Ti3SiC2 and Ti5Si3Cx were shown to be very similar. It may be concluded that a concurrent analysis of both XRD and XPS was essential for identifying the overall surface chemistry of Ti3SiC2. [References: 29]