固相反応によるタンタルホウ化物粉末の合成と焼結

概要

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Tantalum boride powders were synthesized by the solid state reaction between tantalum and amorphous boron. Five boride phases (Ta_2B, Ta_3B_2, TaB, Ta_3B_4 and TaB_2) were formed by heat-treatment of the mixed powders at 1000°-1800℃ for 0-120 min. Formation behavior of these borides was dependent on the heat-treatment temperature, in which structurally stable phases formed in order from low to high temperatures. Single phases of TaB_2, TaB and Ta_3B_4 were obtained by the heat-treatment of the mixed powders with corresponding stoichiometric compositions at 800°, 900°and 1800℃, respectively. Sintered compacts of TaB and TaB_<2+x> were prepared by a high-pressure sintering of synthesized TaB and TaB_<2+x> powders at 4 GPa and 1600℃ for 15 min. The bulk density of TaB was 13.51 g/cm^3 (relative density : 95.1%) and the Vickers microhardness was 2550 kg/mm^2. The homogeneous range of the solid solution TaB_<2+x> was 0 <x<0. 55, the density and the microhardness of which increased with increasing amount of boron in solid solutions.
社団法人日本セラミックス協会の論文
1990-03-01