Nanolayered Diamond Sintered Compact Obtained by Direct Conversion from Highly Oriented Graphite under High Pressure and High Temperature

Table 1

Synthesis conditions and experimental results.

𝑃 (GPa)	𝑇 (°C)	𝑡 (min)	Phases	Optical appearance
15	2300	20	C-dia, H-dia*	Transparent
15	1800	20	Gr, H-dia, C-dia	Opaque
15	1300	20	Gr, H-dia, C-dia	Opaque
15	1000	20	Gr, H-dia, C-dia	Opaque

Gr: graphite, H-dia: Hexagonal diamond, C-dia: cubic diamond, *: trace amount.