Transition Metal Borides Via Carbothermal Synthesis: II. Zirconium Diboride T. Şimşek1, M. Barış2, B. Çelebi 3, S. A. Tuncel3, O. Yılmaz2, Y. Yalçınoğlu2, M. Bilen2 ([email protected], [email protected]) 1 Department of Physics Engineering, Hacettepe University, Ankara, Turkey 2 Eti Maden Works General Management, Ankara, Turkey 3 Division of Nanotechnology, Hacettepe University, Ankara, Turkey Zirconium diboride particles were produced via carbothermal reduction of zirconium dioxide (ZrO2) and boron oxide (B2O3) and carbon (C) in graphite crucible under argon atmosphere. Different initial reaction mixtures were prepared with different molar proportions of the ingredients. In these preparations the molar ratio of ZrO2/B2O3 was changed while keeping the molar concentration of carbon was constant. The powder mixture with a certain initial composition was put into hardened steel vial with the steel balls. The powder was mixed for 2 hours at 300 rpm. Following to ball-milling, the resulting powder was put into a graphite crucible. The temperature was increased with a rate of 10oC per minute to the reaction temperature. The reaction was performed at the temperatures of 1700 o C and 1750oC. The powders were analysed by XRD. 1700 ˚C 1750 ˚C Figure 1. XRD spectra of ZrB2 samples obtained with different mole ratios of ZrO2/B2O3 at different temperatures. Lower reaction temperatures provided crystalline samples also containing ZrO2. The results indicated that crystalline phases obtained with different temperatures and ZrO2/B2O3 ratios dominantly contained ZrB2. ZrB with very low concentration was also detected in the samples. ZrB2 samples with the highest purity was obtained at the reaction temperature of 1750oC. References 1) Balcı, O., Ağaoğulları, D., Duman, İ., Öveçoğlu, M. L., “Carbothermal production of ZrB2–ZrO2 ceramic powders from ZrO2–B2O3/B system by high-energy ball milling and annealing assisted process”, Ceramics International, 38, (2012) 2201-2207. 2. Guo, W.M., Zhang, Z., G.J., “Reaction Processes and Characterization of ZrB2 Powder Prepared by Boro/Carbothermal Reduction of ZrO2 in Vacuum”, J. Am. Ceram. Soc., 92, (2009) 264–267.