A comparative study on combustion synthesis of Ta-B compounds

作者：Yeh C L^*; Wang H J

来源：Ceramics International, 2011, 37(5): 1569-1573.

DOI：10.1016/j.ceramint.2011.01.024

• Tantalum boride
• Self-propagating high-temperature synthesis (SHS)
• Activation energy
• X-ray diffraction

A comparative study on the preparation of various tantalum borides (including Ta(2)B, Ta(3)B(2), TaB, Ta(5)B(6), Ta(3)B(4), and TaB(2)) in the Ta-B system was experimentally conducted by self-propagating high-temperature synthesis (SHS) from the elemental powder compacts of their corresponding stoichiometries. Both combustion temperature and reaction front velocity increased and then decreased with increasing boron content in the powder mixture. The fastest flame front with a reaction temperature of 1732 degrees C and a propagation rate of 11.2 mm/s was observed in the sample of Ta:B = 1:1. The combustion temperature (1205 degrees C) and flame-front velocity (3.82 mm/s) for the powder compact of Ta:B = 2:1 were the lowest. According to the XRD analysis, single-phase TaB and TaB(2) were produced from the samples of Ta:B = 1:1 and 1:2, respectively. However, multiphase products were synthesized from the samples of other stoichiometries. In the final products from Ta-rich samples of Ta:B = 2:1 and 3:2, two boride phases, Ta(2)B and TaB, along with a large amount of residual Ta were detected. The products yielded from boron-rich reactants of Ta:B = 5:6 and 3:4 were composed of TaB, Ta(3)B(4), and TaB(2). Based upon the temperature dependence of combustion wave velocity, the activation energies associated with the formation of TaB and TaB(2) by solid state combustion were determined to be 131.1 and 181.4 kJ/mol, respectively.

• 出版日期2011-7