Research On Synthesis And Properties Of Titanium Carbide By High Temperature And Pressure

Due to its excellent physical and chemical properties, transition metal compounds have attracted people’s attention, especially, transition metal carbides and borides have a wild application in many fields by virtue of its high hardness, abrasion resistance, electrical conductivity and thermal conductivity, good chemical stability. Titanium carbide is one of the most widely used materials in transition metal carbides. There are many methods of synthesis of TiC, such as carbon thermal reduction method, direct carbonation method, chemical deposition method, high temperature self propagating synthesis etc., but there are problems such as long reaction time, harsh reaction conditions and the low purity limiting the application of TiC materials.Synthesis of transition metal carbide by high pressure and high temperature metho d(HPHT) has its unique feature. HPHT method can drastically reduce the reaction tim e, increase the purity and relative density. Furthermore, new physical phenomenon ma y appear when HPHT method is applied. In this paper, we successfully synthesize TiC1-x using the SPD-6x600 T six cubic press, with high purity graphite powder and titanium powder as raw material. The high temperature provided by the press can make the titanium element reach the melting state, so that the raw material is fully mixed, and the reaction is accelerated. High pressure can reduce the distance between atoms effectively and shorten the reaction time to improve the synthesis efficiency. In the end, the pure phase TiC body materials are synthesized quickly and cleanly.TiC body materials whose high density reach more than 94% are synthesized with high purity titanium and graphite powders as raw materials, in a molar ratio of 1:1 mixture, with 5.2 GPa pressure provided by cubic compressor, while temperature is at 1800 to 2100 degrees Celsius and holding for 5 to 30 minutes. It is found that temperature and raw material ratio affect largely on product by further using the X-ray polycrystalline diffraction(XRD) on the sample composition analysis and by scanning electron microscopy(SEM), transmission electron microscopy(TEM), and energy dispersive(EDS) on the synthesis of micro morphology and internal structure. Using the micro hardness tester for the synthesis of TiC for Vivtorinox hardness testing, the measured convergence of Vivtorinox hardness is 27.6 GPa, which shows that it has a high hardness. The resistivity of the composite is tested through the method of van der Fort method, and the room temperature resistivity is obtained at the order of 10-6 Ω.m which indicates that it has excellent electrical conductivity. Finally, by TG-DTA, the oxidation resistance of TiC is measured at about 500 ℃, which shows that it has strong antioxidant activity.Finally, in order to further explain the nature of the synthesis of TiC materials, we stimulate the mechanical and electronic properties of TiC by the electronic structure, compact layout, reagan, electronic density of states and electronic analysis using the first principles of density functional theory.