Carbon was used to reduce oxides in spark plasma sintered ZrB₂ ultra‐high temperature ceramics. A thermodynamic model was used to evaluate the reducing reactions to remove B₂O₃ and ZrO₂ from the powder. Powder oxygen content was measured and carbon additions of 0.5 and 0.75 wt% were used. A C–ZrO₂ pseudo binary diagram, ZrO₂–B₂O₃–C pseudo ternaries, and Zr–C–O potential phase diagrams were generated to show how the reactions can be related to an open system experiment in the tube furnace. Scanning transmission electron microscopy identified impurity phases composed of amorphous Zr–B–O with lamellar BN and a Zr–C–O ternary model was calculated under SPS sintering conditions at 1900°C and 6 Pa to understand how oxides can be retained in the microstructure.

中文翻译：

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二硼化锆火花等离子体烧结过程中氧化物碳热还原的热化学模型

碳用于还原火花等离子体烧结ZrB ₂超高温陶瓷中的氧化物。使用热力学模型评估还原反应以从粉末中去除B ₂ O ₃和ZrO ₂。测量粉末的氧含量，并使用0.5和0.75wt％的碳添加量。AC–ZrO ₂伪二进制图，ZrO ₂ –B ₂ O ₃生成了–C伪三元和Zr–C–O电位相图，以显示反应如何与管式炉的开放系统实验相关。扫描透射电子显微镜确定了由无定形Zr–B–O和层状BN组成的杂质相，并在1900°C和6 Pa的SPS烧结条件下计算了Zr–C–O三元模型，以了解氧化物如何保留在微结构中。