Abstract—

Based on analysis of phase diagram data and thermodynamic modeling, we have evaluated the optimal temperature ranges of the processes underlying the preparation of B₄C–TiB₂ and B₄C–ZrB₂ composite powders via boron carbide reactions in the presence of excess boron carbide: 2MO₂ + (n + 1)B₄C + 3C = 2MB₂ + 4CO + nB₄C (M = Ti, Zr). The values of n have been taken so as to obtain composite powders with the following compositions (mol %): 90B₄C–10MB₂ (n = 19), 80B₄C–20MB₂ (n = 9), 75B₄C–25MB₂ (n = 7), and 70B₄C–30MB₂ (n = 5.67). We have found temperatures that ensure the preparation of composite powders with tailored composition at various CO pressures. At a CO pressure of 0.0773 MPa, these temperatures for both reactions are 1816 K (~1540°C), independent of the composition of the synthesized powders. The eutectic temperature in the B₄C–TiB₂ system is ~2200°C and that in the B₄C–ZrB₂ system is ~2280°C. Thus, at a nearly atmospheric pressure in the reactor, the optimal synthesis temperature of B₄C–TiB₂ composite powder lies in the range 1540–2200°C and that of B₄C–ZrB₂ composite powder lies in the range 1540–2280°C. Such powders are potentially attractive for the fabrication of ceramics with improved performance parameters.

中文翻译：

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适于合成B 4 C–TiB 2和B 4 C–ZrB 2粉末复合材料的温度范围的评估

摘要—

基于相图数据分析和热力学模型，我们评估了在过量硼存在下通过碳化硼反应制备B ₄ C–TiB ₂和B ₄ C–ZrB ₂复合粉末的基础工艺的最佳温度范围碳化物：2MO ₂ +（n + 1）B ₄ C + 3C = 2MB ₂ + 4CO + n B ₄ C（M = Ti，Zr）。取n值以获得具有以下组成（mol％）的复合粉末：90B ₄ C–10MB ₂（n = 19），80B ₄C–20MB ₂（n = 9），75B ₄ C–25MB ₂（n = 7）和70B ₄ C–30MB ₂（n = 5.67）。我们发现温度可确保在各种CO压力下制备具有定制成分的复合粉末。在0.0773 MPa的CO压力下，两个反应的温度均为1816 K（〜1540°C），与合成粉末的组成无关。B ₄ C–TiB ₂系统中的共晶温度为〜2200°C，而B ₄ C–ZrB _2中的共晶温度为〜2200°C系统温度约为2280°C。因此，在反应器中接近大气压的情况下，B ₄ C–TiB ₂复合粉末的最佳合成温度为1540–2200°C，B ₄ C–ZrB ₂复合粉末的最佳合成温度为1540–2 2280℃。这样的粉末对于制造具有改善的性能参数的陶瓷具有潜在的吸引力。