1. A novel route to superhard nanocrystalline cubic boron nitride: Emulsion detonation and high-pressure high-temperature transformation-assisted consolidation
- Author
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Richard A. Haber, Igor Petrusha, Myroslav Karpets, Chawon Hwang, Dexin Zhao, Kelvin Y. Xie, Sergey Dub, Viktoer Moshchil, Semyon Ponomaryov, Metin Örnek, and Tatiana Prikhna
- Subjects
010302 applied physics ,Materials science ,Consolidation (soil) ,Detonation ,Nucleation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nanocrystalline material ,Grain growth ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Boron nitride ,0103 physical sciences ,Emulsion ,Vickers hardness test ,Materials Chemistry ,Ceramics and Composites ,0210 nano-technology - Abstract
Synthesizing bulk nanocrystalline materials is challenging since grain growth should be suppressed whereas densification promoted. Here, we demonstrate a novel route to synthesize superhard bulk nanocrystalline cubic boron nitride (cBN), which combines the use of emulsion detonation and high-pressure high-temperature transformation-assisted consolidation. The emulsion detonation process activates BN to possess unique structure and chemistry, i.e. wurtzitic BN nanograins in hexagonal BN matrix with enhanced structural disordering and oxygen impurity, a combination that enhances the nucleation rate of cBN and its densification leading to the formation of bulk nanocrystalline cBN at reduced conditions. The cBN, synthesized at 7.5 GPa and 1800 °C, displayed Vickers hardness values of 50−62 GPa for 5−20 N loads. The findings in the study suggest a feasible solution to synthesize bulk nanocrystalline cBN in a more scalable way, while also providing design insights on how to refine grain growth while enhancing densification to synthesize bulk nanocrystalline materials.
- Published
- 2021