A study on sintered TiO 2 and TiO 2 /SiC composites synthesized through chemical reaction based solution method

Abstract

TiO₂ and TiO₂/SiC composites are synthesized through chemical route followed by solid-state sintering at 1450℃. The X-ray diffraction pattern shows the peaks of TiO₂ and SiC for the compositional ratio up to 60:40 whereas no peak corresponding to TiO₂ has been observed for the SiC percentage of 50 and 60. It is confirmed from the micro-Raman and Fourier transform infrared spectra that TiO₂ has got diffused into the SiC surfaces and interfaces in the composites having higher percentages of SiC. Maximum hardness has been observed for the TiO₂ and SiC composition of 50:50. No optical transition has been observed for the composites with TiO₂: SiC ratio equal to or below 1.5. The increase in absorption percentages with increasing concentration of SiC indicates that these composites can be utilized as photo-catalytic active material in visible light. The electrical resistivity measurements clearly show the increase in conductivity with increase in SiC percentage up to 50% in TiO₂/SiC composites. All these TiO₂/SiC composites are found to have carrier concentration in the order of 10¹⁶–10¹⁸/cm³ at room temperature and hence can be proven as good ceramic semiconductors. It is observed that the insulating nature of TiO₂ gets transformed to the semiconducting nature by the addition of SiC. The electrical, mechanical and optical properties are also found to be strongly dependent on the SiC percentages.