Effect of dispersants on the physicochemical properties of ultra-fine ZrB2 powder in Sol-gel synthesis

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 ultrafine 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.