Synthesis of coarse-grain diamond crystals is studied in a China-type SPD6× 1670T cubic high-pressure apparatus with high exact control system. To synthesize high quality coarse-grain diamond crystals, advanced i...Synthesis of coarse-grain diamond crystals is studied in a China-type SPD6× 1670T cubic high-pressure apparatus with high exact control system. To synthesize high quality coarse-grain diamond crystals, advanced indirect heat assembly, powder catalyst technology and optimized synthesis craft are used. At last, three kinds of coarse- grain diamond （about 0.85 mm） single crystals with hexahedron, hex-octahedron and octahedron are synthesized successfully under HPHT （about 5.4 GPa, 1300-1450℃）. The growth characters of different shape crystals are discussed. The results and techniques might be useful for the production of coarse-grain diamonds.展开更多
The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive ...The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR).The results show that the growth region of the {111} face becomes wide,whereas the growth region of the {100} face becomes narrow and nearly disappears as increasing additive boron in the sample.The crystal will be opaque and imperfect,and the concentration of nitrogen will be decreased when the boron atoms are incorporated into gem diamond lattice.These techniques are very important and will be widely applied.展开更多
The growth of coarse grains of diamond was observed with graphite as carbon source and Fe80Ni20 alloy powder as catalyst at HPHT in a China-type SPD 6×1670T cubic high-pressure apparatus with highly exact control...The growth of coarse grains of diamond was observed with graphite as carbon source and Fe80Ni20 alloy powder as catalyst at HPHT in a China-type SPD 6×1670T cubic high-pressure apparatus with highly exact control system. To synthesize coarse grains of diamond crystal with high quality,ad-vanced indirect heat assembly,powder catalyst technology and catalyst with optimal granularity were used. Especially the nucleation of diamond and the growth rate were strictly controlled by the opti-mized synthesis craft. At last,diamond crystals (about 0.85 mm) in the perfect hex-octahedron shape were successfully synthesized at ～5.4 GPa and ～1360℃ in 60 min. The characteristic of crystal growth with powder catalyst technology under HPHT was discussed. The results and techniques might be useful for production of coarse grains of diamond.展开更多
基金Supported by the National Natural Science Foundation of China （Grant No. 50572032）.
文摘Synthesis of coarse-grain diamond crystals is studied in a China-type SPD6× 1670T cubic high-pressure apparatus with high exact control system. To synthesize high quality coarse-grain diamond crystals, advanced indirect heat assembly, powder catalyst technology and optimized synthesis craft are used. At last, three kinds of coarse- grain diamond （about 0.85 mm） single crystals with hexahedron, hex-octahedron and octahedron are synthesized successfully under HPHT （about 5.4 GPa, 1300-1450℃）. The growth characters of different shape crystals are discussed. The results and techniques might be useful for the production of coarse-grain diamonds.
基金supported by the National Natural Science Foundation of China (Grant No.50572032)
文摘The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR).The results show that the growth region of the {111} face becomes wide,whereas the growth region of the {100} face becomes narrow and nearly disappears as increasing additive boron in the sample.The crystal will be opaque and imperfect,and the concentration of nitrogen will be decreased when the boron atoms are incorporated into gem diamond lattice.These techniques are very important and will be widely applied.
基金Supported by the National Natural Science Foundation of China (Grant No.50572032)
文摘The growth of coarse grains of diamond was observed with graphite as carbon source and Fe80Ni20 alloy powder as catalyst at HPHT in a China-type SPD 6×1670T cubic high-pressure apparatus with highly exact control system. To synthesize coarse grains of diamond crystal with high quality,ad-vanced indirect heat assembly,powder catalyst technology and catalyst with optimal granularity were used. Especially the nucleation of diamond and the growth rate were strictly controlled by the opti-mized synthesis craft. At last,diamond crystals (about 0.85 mm) in the perfect hex-octahedron shape were successfully synthesized at ～5.4 GPa and ～1360℃ in 60 min. The characteristic of crystal growth with powder catalyst technology under HPHT was discussed. The results and techniques might be useful for production of coarse grains of diamond.
