Low Temperature Synthesis Of TiC\TiN\TiCN Nanaocrystallites Via Chemical Metathesis Route

Binary compounds of titanium nitride (TiN) and titanium carbide (TiC) attract considerable interests because of high melting point and thermal conductivity, extreme hardness, good oxidation and wear resistance, and low electrical resistivity, moreover, ternary titanium carbonitride (TiCN) concurrently possess the merits of TiN and TiC, and has some more excellent properties, which make them wide applications in mechanical, electrical , tribological and high-performance ceramic fields. Therefore, much effort has been devoted to preparing these promising materials. However, these methods available for the synthesis of TiCYTiNYTiCN should carried out at high temperature or high pressure with complicated manipulation. Thus search a facile, economical synthesis route to achieve these important materials has significant theoretical and practical meanings.In this paper, TiC\TiN\TiCN nanocrystals were successfully prepared at low temperature via chemical metathesis method. Wherein the route takes the high temperature and high pressure autoclave as reaction vessel. And these nanocrystals were characterized by X-ray powder diffraction, transmission electron microscopy, high resolution transmission electron microscopy and X-ray photoemission spectra, respectively.Polyhedral hollow TiC nanocrystallites with 40nm in diameter were synthesized by the reaction of TiCl4 and CaC2 at 500 for 8h. To the best of our knowledge, this is the first time to observe such kind of nanostructure. Herein CaC2 acted not only as reagent, but also as template for hollow polyhedron.TiN nanocrystals were successfully prepared through the reaction of TiCl4 and NaNH2 at 300. this is also the first time to report the synthesis of nanocystalline TiN synthesized at such a low temperature with NaNH2 as nitrogen source. Apart from spherical particles with an average size of 10nm, a certain quantity of extremely long straight rods can be easily observed.Ternary TiCN nanocrystallites with an average size of 66nm were successfullyobtained at low temperature (450) using TiCU, CaC2 and NaN3 as source materials. Furthermore, TiCN nanocrystals were synthesized at 420 for 8h using TiCU, CCl4 and NaN3 via chemical metathesis method.