Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, D-95440, Bayreuth, Germany.
Bayerisches Geoinstitut, University of Bayreuth, D-95440, Bayreuth, Germany.
Sci Rep. 2017 Aug 21;7(1):8969. doi: 10.1038/s41598-017-09012-8.
Boron carbide is a ceramic material with unique properties widely used in numerous, including armor, applications. Its mechanical properties, mechanism of compression, and limits of stability are of both scientific and practical value. Here, we report the behavior of the stoichiometric boron carbide BC studied on single crystals up to 68 GPa. As revealed by synchrotron X-ray diffraction, BC maintains its crystal structure and does not undergo phase transitions. Accurate measurements of the unit cell and B icosahedra volumes as a function of pressure led to conclusion that they reduce similarly upon compression that is typical for covalently bonded solids. A comparison of the compressional behavior of BC with that of α-B, γ-B, and BC showed that it is determined by the types of bonding involved in the course of compression. Neither 'molecular-like' nor 'inversed molecular-like' solid behavior upon compression was detected that closes a long-standing scientific dispute.
碳化硼是一种具有独特性能的陶瓷材料，广泛应用于许多领域，包括装甲。它的力学性能、压缩机制和稳定性极限具有科学和实际价值。在这里，我们报告了在 68GPa 以下的单晶上研究的化学计量比碳化硼 BC 的行为。同步辐射 X 射线衍射表明，BC 保持其晶体结构，不发生相变。对单元胞和 B 二十面体体积随压力的精确测量得出结论，它们在压缩过程中以典型的共价结合固体的方式相似地减小。BC 的压缩行为与 α-B、γ-B 和 BC 的比较表明，它取决于压缩过程中涉及的键合类型。在压缩过程中既没有检测到“分子样”也没有检测到“反分子样”固体行为，这解决了一个长期存在的科学争议。
