Characterisation of amorphous silica in air-oxidised Ti3SiC2 at 500-1000 °C using secondary-ion mass spectrometry, nuclear magnetic resonance and transmission electron microscopy

In this paper we have described the use of secondary-ion mass spectrometry (SIMS), solid state Si-29 magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti3SiC2 oxidised at 500-1000 degrees C. The formation of amorphous SiO2 and growth of crystalline TiO2 with temperature was monitored using dynamic SIMS and synchrotron radiation diffraction. A duplex structure with an outer TiO2-rich layer and an inner mixed layer of SiO2 and TiO2 was observed. Results of NMR and TEM verified for the first time the direct evidence of amorphous silica formation during the oxidation of Ti3SiC2 at the temperature range 500-1000 degrees C. (C) 2010 Elsevier B.V. All rights reserved