热处理气氛对生成纳米碳化钽的影响及机理
Effect of Heat Treatment Atmospheres on Formation of TaC Nano-powdersand and Its Mechanism
马明亮, 沈卫平, 王青云, 葛昌纯
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作者单位:(北京科技大学 核材料研究所 特种陶瓷粉末冶金研究室, 北京 100083)
中文关键字:碳化钽(TaC); 纳米粉末; 热处理气氛; 生成温度; 比表面积
英文关键字:TaC; nano-powder; heat treatment atmospheres; formation temperature; BET
中文摘要:在真空、氢气和氩气气氛中,使用液相先躯体法制备得到纳米碳化钽(TaC)粉末,并使用XRD、TEM、比表面积分析仪分析了在不同热处理气氛中得到的产物的物相、显微形貌及比表面积。通过对产物的对比和分析,说明热处理气氛对生成纳米TaC的影响,并对其机理进行探讨。在真空中,气体产物CO被排到炉外,从而加速生成TaC的反应,使之在1300 ℃时生成比表面积为28 m2/g、平均粒径约50 nm、略有团聚的TaC。在氢气中,CH4作为碳气相迁移的载体加速反应进行,使之在1300 ℃时生成比表面积为12 m2/g,平均粒径约100 nm、略有团聚的TaC。在氩气中,没有促进反应进行的因素,在1400 ℃时才可生成比表面积为61 m2/g,平均粒径约50 nm、分散较好的TaC。
英文摘要:TaC nano-powder were prepared in different heat treatment atmospheres by liquid precursor method. The phase composition, microstructure and BET of samples prepared in different heat treatment atmospheres were characterized by XRD, TEM and specific surface area analyzer, respectively. The effects of heat treatment atmospheres on formation of TaC nano-powder and its mechanism were discussed. In vacuum, the gas product CO was deflated, which can accelerate the reaction to form slightly agglomerated TaC particles (28 m2/g (BET), 50 nm) at 1300 ℃. In hydrogen, CH4 as a carrier gas migrating carbon to accelerate the reaction to form larger TaC particles (12 m2/g (BET), ~100 nm) at 1300 ℃. In the argon gas, there is no factor to accelerate the reaction so that separated TaC particles (61 m2/g (BET), 50 nm) can be fabricated at 1400 ℃.