Abstract
Carbonado-like polycrystalline diamond was synthesized in the non-metallic B 4C–graphite system at a high pressure of 8–9 GPa and very high temperatures, about 2600–2800 K. The Vickers hardness of the polycrystalline diamond containing less than 5 mass% of B 4C was 70–120 GPa at the indenter load 4.9 N. The experimental evidence suggests that the graphite-to-diamond transformation starts in the temperature range between the B 4C–graphite–liquid and B 4C–diamond–liquid eutectic temperatures. The presence of a volatile component, boric acid, in the starting B 4C–graphite system breaks the polycrystalline microstructure of the diamond material leading to the formation of separate diamond microcrystals. In addition, we demonstrate that the toroid-type high-pressure chamber can be used for experiments at the temperature up to 2800–3100 K.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
