Characterisation of amorphous silica in air-oxidised Ti 3SiC 2 at 500–1000 °C using secondary-ion mass spectrometry, nuclear magnetic resonance and transmission electron microscopy

Abstract

In this paper we have described the use of secondary-ion mass spectrometry (SIMS), solid state 29Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti 3SiC 2 oxidised at 500–1000 °C. The formation of amorphous SiO 2 and growth of crystalline TiO 2 with temperature was monitored using dynamic SIMS and synchrotron radiation diffraction. A duplex structure with an outer TiO 2-rich layer and an inner mixed layer of SiO 2 and TiO 2 was observed. Results of NMR and TEM verified for the first time the direct evidence of amorphous silica formation during the oxidation of Ti 3SiC 2 at the temperature range 500–1000 °C.