Preparation Of Tantalum Carbide In Graphite Substrate

Graphite material is an important conductive material and structural materials in today’s industry. It can be used in mechinery, electronic industry, chemistry, metallurgy, nuclear, aerospace industry and other fields with its excellent performance. However, the porous structure makes the graphite can be oxidized easily. Generally, the places of holes and cracks in graphite are more susceptible to oxidation than other places. This drawback severely limits the application of graphite materials. So, it is very important to prevent the oxidation of graphite under oxidized condition. Tantalum carbide is characterized by high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock, and excellent oxidation resistance and corrosion resistance, which makes it very attractive for anti-ablation application as one of the most premising throat materials among transition metal carbides. So, the oxidation resistance of graphite can be enhanced through preparing tantalum carbide in graphite.In this paper, tantalum carbide was prepared in graphite substrate based on the electrochemical reduction of Ta2O5in a fused eutectic mixture of NaCl-CaCl2. The influence of the content of Ta2O5in liquid was studied and the liquid was vibrated by ultrasonic. The influence of the density of graphite and the roughness of the surface of graphite on the effect of liquid infiltration was studied. The influence of electrolyzing voltage, electrolyzing time and electrolyzing temperature on the composition of products were studied in this paper. X-ray diffraction and energy-dispersive X-ray spectra were used to analyze the phase and chemical composition of products systematically. The distribution of tantalum carbide in graphite was characterized by SEM.The reasonable content of the Ta2O5in liquid was6.00g per100ml; The effect of liquid infiltration can be enhanced when the liquid was vibrated by ultrasonic; The Ta2O5can be penetrated into the graphite more easily when more porous graphite was used; Compared with the smooth graphite, a larger amount of tantalum carbide could be prepared on the surface of the rough graphite; The reasonable condition to prepare TaC on graphite was electrolyzing for4.5h at2.3V in molten NaCl-CaCl2under800℃; The TaC can be prepared at the surface and the crack of the graphite.