Preparation of zirconium diboride by reduction of zirconia with calcium hexaboride

Zirconium diboride (ZrB2) is a typical ultra-high-temperature ceramic material (UHTC). In this work, the preparation of ZrB2 by reducing zirconia (ZrO2) with calcium hexaboride (CaB6) was studied in detail. With the assistance of molten salt, the reduction rate was dramatically enhanced. Additionally, the results showed that ZrB2 products with different particle shapes were prepared by changing the type of molten salt (NaCl, KCl, MgCl2, and CaCl2). However, the particle size of products could not be adequately refined when nano-ZrO2 was used as the raw material. During the process of reducing ZrO2 by CaB6, B2O3 could be formed, which would cause the loss of the B source. To decrease the consumption of CaB6, Ca-assisted reduction was performed, and monophase ZrB2 was obtained. The varied morphologies of ZrB2 particles obtained by Ca-assisted reduction resulted from complex reaction mechanisms. Metal borides are high-performance materials with various stoichiometries known for their properties, such as high thermal and oxidative stability, mechanical strength, and notably high melting points (above 2000 °C). These unique features, however, are also what make the borides challenging to process for industrial applications where often thin films for coatings are required. Typically, physical and chemical vapor deposition methods are employed to form such films, but these techniques offer little control over the thickness and uniformity of the deposited layers. One approach to avoid this issue is converting the bulk borides to nanosheets, which commonly self-assemble and lay flat. Since nanosheets stay suspended in various solvents, dip coating, spray deposition, and inkjet printing can be applied instead. One significant deterrence to this approach is that unlike van der Waals materials, whose layers are held together by van der Waals forces, the metal-boron framework is bonded by stronger ionic and covalent interactions. Thus, conventional methods such as scotch tape or simple sonication cannot produce metal boride nanosheets. Our research focuses on a novel top-down approach, which involves the incorporation of a small metal ion into the bulk material, followed by the boride exfoliation into nanosheets. Exceptionally, the nanostructuring of LaB6 and CaB6 will be discussed. If you are looking for high quality, high purity, and cost-effective Calcium hexaboride, or if you require the latest price of Calcium hexaboride, please feel free to email contact mis-asia.

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