High-pressure synthesis, characterization, and equation of state of cubic C-BN solid solutions

Phase transition in BCx system under high-pressure and high-temperature: Synthesis of cubic dense BC3 nanostructured phase

“…HPHT by Knitle et al 47 and later confirmed by Solozhenko et al 48 . In their studies, the cubic structure of the BC 2 N phases obtained under HPHT conditions was deduced using synchrotron…”

“…x-ray diffraction 47,48 and from the positions of the Raman peaks that were close to diamond 47,49 .…”

Predicting new superhard phases

“…Considerable efforts have also been devoted to the synthesis and modeling of ternary B-C-N materials. Following the typical expectation that most of the superhard materials are insulators or semiconductors, since the metallic component has negative effect on hardness, different combinations of B, C, and N can be proposed for the search of novel isoelectronic structures with that of diamond, while the following simple rule [55] [4][5][6][7][8]. Diamond-like BC 2 N (cBC 2 N) has gained extensive attention and the reported hardness is in the range of 62-76 GPa, much higher than that of cBN.…”

“…The lightest element that could produce three-dimensional structure, beryllium, has been often neglected to synthesize superhard materials, perhaps because it is toxic and may require specialized high-pressure equipment [3]. Following this route, great experimental progress is achieved with the successful synthesis of cBC x N [4][5][6][7][8], B 2 CN [9], cBC 5 [10], boron suboxide (e.g., B 6 O) [11], γ-B 28 [12][13][14], B 4 C [15], boron subnitride (e.g., B 13 N 2 ) [16], and so on. Except for B2CN, they have been experimentally reported as superhard materials.…”

“…These compounds possess ultrahigh bulk moduli (428 GPa for IrN 2 [20]) comparable with those of the traditional superhard materials. Though there exists extensive debates [26,27], ReB 2 and WB 4 have been claimed to be superhard [24,25,29].…”