Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9697414 | Diamond and Related Materials | 2005 | 4 Pages |
Abstract
Carbonado-like polycrystalline diamond was synthesized in the non-metallic B4C-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 B4C 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 B4C-graphite-liquid and B4C-diamond-liquid eutectic temperatures. The presence of a volatile component, boric acid, in the starting B4C-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.
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Authors
E.A. Ekimov, V.A. Sidorov, R.A. Sadykov, N.N. Mel'nik, S. Gierlotka, A. Presz,