Synthesis of column-shaped diamond under HTHP

In this paper diamond monocrystals were synthesized using the new Fe-based type catalyst A and normal common catalyst respectively in a SPD6×1200 high-pressure and high-temperature apparatus.The result indicated that the diamond crystals synthesized using common catalyst show a yellow color and integrity morphology.Most of crystal is transparency.The grain size of synthesized crystal is relatively uniform and normal crystal size is 0.3 mm.Diamond crystals synthesized using catalyst A shown green color and stripe morphology.The crystal size is 0.5mm to 0.7mm.This two type crystals were observed under scanning electronic microscopy (SEM).It shown that the surface of former crystal is smooth,but the"V"shape defect can be seen on the surface of the latter.Through the FTIR spectra it can be seen that the concentration of former crystal is lower,but the latter is higher.