Boride-based ultra-high temperature ceramics have been extensively utilized as high temperature thermal protection materials due to its excellent physical and mechanical properties. Yet, the synthesis of boride-based ceramic powder with high purity, ultra-fine structure and excellent dispersity remains a great challenge to reach. In this work, zirconium diboride (ZrB₂) ultra-high temperature ceramic powder with high purity and ultra-fine structure (size of hundreds of nanometers) was prepared by carbothermal reaction combined with sol-gel method. Various dispersants including oleic acid (OA), polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) were employed during the preparation procedure to tune the physicochemical properties of the resultant ZrB₂. According to the X-ray diffraction and microscopy characterizations, it was revealed that the OA turned up as the most effective dispersant to obtain the ZrB₂ powder with hundreds-nanometer-scale and high purity. Besides, the thermogravimetry-differential thermal analysis and Fourier transformed infrared spectroscopy analysis were performed, unveiling the function of OA in enhancing the dispersity of the ZrB₂. Such a work on the effect of dispersant on the preparation of ultra-high temperature ceramic powder could shed some important light for the development of high temperature resistant materials.

硼化物基超高温陶瓷由于其优异的物理和机械性能而被广泛用作高温热保护材料。然而，合成具有高纯度，超细结构和优异分散性的硼化物基陶瓷粉末仍然是一个巨大的挑战。通过碳热反应结合溶胶-凝胶法制备了高纯度，超细结构（尺寸为数百纳米）的二硼化锆（ZrB ₂）超高温陶瓷粉。在制备过程中使用了各种分散剂，包括油酸（OA），聚乙二醇（PEG）和聚乙烯吡咯烷酮（PVP），以调节所得ZrB ₂的理化性质。。根据X射线衍射和显微镜表征，发现OA成为获得数百纳米级高纯度ZrB ₂粉末的最有效分散剂。此外，还进行了热重差示热分析和傅立叶变换红外光谱分析，揭示了OA在增强ZrB ₂分散性中的作用。这种有关分散剂对制备超高温陶瓷粉的作用的工作为开发耐高温材料提供了重要的启示。