Studies on synthesis and growth mechanism of high quality sheet cubic diamond crystals under high pressure and high temperature conditions

• High quality sheet cubic diamond crystals were synthesized.
• Sheet cubic diamond crystals had a high growth rate in the radial direction than the axial.
• Finite element method simulated the solvent metal convection field of the growth cell.

This paper reported the synthesis of high quality sheet cubic diamond crystals by temperature gradient method under high pressure and high temperature conditions with FeNi alloy as solvent catalyst. The growth mechanisms were discussed by finite element simulation. The synthetic sheet cubic diamond crystals had a higher growth rate in radial direction than that in axial direction. Raman spectrum and Fourier transform infrared spectrum indicated that synthesized sheet cubic diamonds had fewer crystal lattice distortions and nitrogen impurities. Finite element simulations indicated that the solvent metal convection field in the radial direction was stronger than that in the axial direction. A mechanism of sheet cubic diamond crystal growth was proposed and discussed.