Synthesis of fine zirconium carbide powder with carbon nanofibers
The article presents the results of studying the process of fine zirconium carbide powder synthesis and analyzing its characteristics and properties. Zirconium carbide was prepared by zirconium reduction by nanofibrous carbon in a resistance furnace with a graphite heater. The presence of zirconium carbide in the samples was found by X-ray analysis. The content of zirconium and impurities were found by X-ray fluorescence analysis, the total carbon concentration was determined by burning the sample in an oxygen flow followed by the determination of CO 2. The morphology and particle size were determined by scanning electron microscopy. According to the results of local energy dispersive X-ray microanalysis the samples were presented predominantly by zirconium and carbon. A specific surface area, pore volume and diameter wee determined by the BET method. The density of the samples was found. The sedimentation analysis was carried out. Thermal stability was studied by a simultaneous thermal analysis in oxygen during heating to a temperature of 1100 °C. The corrosion resistance of the resulting carbide in sulfuric acid was also studied. The optimal parameters of the zirconium carbide synthesis were a 60-minute exposure at temperatures from 2000 to 2100 °C. The resulting materials were presented by a single phase - zirconium carbide with an impurity content of about 3 %. It consisted of aggregated particles with a size less than 20 microns. The specific surface of the material ranged from 1.3 to 1.8 m 2/g. The oxidation of zirconium carbide began at 480 °C, the process ended at 800 °C. Carbide decomposition was negligible under exposure in a sulfuric acid solution at room temperature. Thus, the corrosion resistance of the resulting material can be compared with a coarse material (40…50 microns) powder with a similar compound.