Synthesis of high grade octahedron diamond through epitaxial growth

The work was based on the relationship between the crystal structure and parameters of diamonds in the synthetic process, in which Ni-Mn-C powder catalyst was used. At first, the diamond crystals nucleated in a cubic-octahedron morphology through controlling such synthetic parameters as temperature and pressure in a parameter region where cubic-octahedron ctystals can be obtained. Then the diamond nuclei grew epitaxially into crystals with a perfect octahedron morphology through increasing the synthesis temperature and decreasing the synthesis pressure in a parameter region where octahedron crystals can be obtained.