The compound carbide of refractory metal had great potential applications in ultra-high temperature, biomedical and nuclear fields. In the present study, a novel method composed of vacuum carbothermal reduction followed by calcium treatment was proposed to synthesize single-phase compound carbide. It was found that the required temperature for the formation of single-phase Ta₄HfC₅ solid solution in liquid calcium was above 1573 K. Meanwhile, the single-phase binary carbides (NbTaC₂), ternary carbides (TiNbTaC₃, ZrNbTaC₃), quaternary carbides (TiHfNbTaC₄, ZrHfNbTaC₄), pentanary carbides (TiZrHfNbTaC₅) and hexanary carbides (TiZrHfVNbTaC₆) were also synthesized by the current method. The formation mechanism of the single-phase compound carbide was discussed and two parameters T_SS (based on the mixing enthalpy change and mixing entropy change) and δ_a (based on the difference of lattice parameter) were proposed for predicting the formation ability of solid solution. It was found that the necessary conditions for formation of solid solution by current method were T_SS < 1800 K and δ_a < 3.2%. In addition, when the value of T_SS was lower than 5.5 × 10³·ln(1/δ_a)-19 × 10³, the single-phase compound carbides could be easily synthesized.

难熔金属复合碳化物在超高温，生物医学和核领域具有广阔的应用前景。在本研究中，提出了一种新的方法，该方法由真空碳热还原然后钙处理组成，以合成单相复合碳化物。发现在液体钙中形成单相Ta ₄ HfC ₅固溶体所需的温度高于1573K。同时，单相二元碳化物（NbTaC ₂），三元碳化物（TiNbTaC ₃，ZrNbTaC ₃） ，四元碳化物（TiHfNbTaC ₄，ZrHfNbTaC ₄），五元碳化物（TiZrHfNbTaC ₅）和六价碳化物（TiZrHfVNbTaC ₆）也通过当前方法合成。讨论了单相复合碳化物的形成机理和两个参数Ť _SS（基于混合焓变和混合熵变化）和Δ_一个（基于晶格参数的差异）提出了用于预测的固体形成的能力解决方案。据发现，通过当前的方法用于形成固溶体的必要条件为Ť _SS  <1800 K和δ_一个 <3.2％。另外，当的值Ť _SS低于5.5×10 ³ ·LN（1 / δ_一个）-19×10 ³，很容易合成单相碳化物。