Ta-C化合反应生成TaC的过程

Conversion Process of TaC by Combination Reaction of Ta with C

研究了Ta-C化合反应生成TaC的过程。热力学计算结果表明,Ta-C反应受动力学过程控制,反应初期易生成中间相的Ta2C。动力学分析结果表明,Ta-C反应过程符合缩核反应模型,C的扩散为反应的控制步骤。首先,C向Ta中扩散形成间隙固溶体,进一步转变为Ta2C相,C过量时最终形成TaC。树脂炭和热解炭与Ta粉经1800℃反应后,均生成晶粒细小、结晶度高、呈多边形状的致密TaC层。炭纤维和Ta粉2300℃热处理实验表明,由于发生了C向Ta中扩散而生成TaC。

The conversion process of TaC by combination reaction of Ta with C was studied. The calculated thermodynamic results showed that the reaction was governed by kinetic process, and Ta2C was easily formed at first. The kinetic analysis showed the conversion process of the reaction can meet the needs of the model of condensation reaction and the diffusion of C is the controlling step of the reaction. First, interstitial solid solution was formed, then Ta2C and finally TaC when C content was excessive. The dense TaC layers produced by the reaction of resin carbon and pyrolitic carbon with Ta powder at 1800℃ were formed, presenting fine particles with high crystallization and polygonized shape. The heat treatment experiments of carbon fiber with Ta powder at 2300℃ prove that TaC was formed by diffusion of C into Ta.