A novel approach for preparing electrically conductive alpha/beta SiAlON-TiN composites by spark plasma sintering

Abstract

An effective approach for preparing electrically conductive SiAlON-TiN composites have been developed. Granules of a designed composition of alpha-beta SiAlON were obtained by spray drying and coated with varying amounts of TiO2 powder (0-10 vol%) homogenously by mechanical mixing. Fully dense composites were obtained by spark plasma sintering (SPS) under a pressure of 50 MPa at 1650 degrees C for 5min. According to the scanning electron microscope (SEM) analysis, unique microstructures containing continuously segregated in-situ formed TiN phase in 3D were achieved. Additionally, X-ray diffraction (XRD) studies revealed that all TiO2 was successfully converted to TiN. The resistivity of the alpha-beta SiAlON (1 x 10(11) Omega center dot m) was drastically reduced down to 2 x 10(-4) Omega center dot m at 5 vol % TiO2 addition