Study On Diamond Synthesis From Organic Carbon Source Under High Static Pressures

China is a big diamond industry country.However,the diamond synthesis technology of China has not yet reached the world advanced level.The diamond industry in China needs upgrading urgently.At present,diamond synthesis in China mainly relies on high static pressure methods with using metal catalysts.The presence of metal catalysts would inevitably bring about some adverse influences on the performance and quality of diamonds.Organic carbon sources can be used as precursors to synthesize diamonds in response to above problems.This work focuses on diamond synthesis from polycyclic organics:1.The temperature-pressure(P-T)conditions for diamond synthesis from naphthalene were investigated.The lower limit of pressure required for diamond synthesis is around 211 bar(8 GPa).The naphthalene sample can be completely transformed into diamond at pressure of 268 bar(10 GPa)?2.The P-T conditions for diamond synthesis from anthracene were investigated.The sample can be completely transformed into diamond at a condition of ? 268 bar(11 GPa)and 1700 ? .3.The P-T conditions for diamond synthesis from acridine were investigated.The thermal conversion process of acridine under pressure was discussed.Diamond can be synthesized from acridine under pressures lower than 268 bar(10 GPa).The sample can be completely converted into diamond under the condition of ? 268 bar(11 GPa)and 1700 ? .4.The P-T conditions for diamond synthesis from phenanthroline were explored.At ? 268 bar(11 GPa)and 1700 ? ,the sample can be partially converted into diamond.The pressure required for complete conversion should be higher than ?268 bar(11 GPa).5.The influences of pressure and temperature gradient on the yield of diamond were studied.Under P-T conditions lower than those required for sample completely transforming into diamond,the temperature or pressure gradients can significantly affect diamond yields.6.The influence of nitrogen content in the molecular structure of organic carbon source on pressure conditions required for diamond synthesis was discussed.The higher the nitrogen content in precursor,the higher the pressure conditions required for diamond synthesis.