Synthesis Of Diamonds In Different Solvent System Under High Temperature And High Pressure

Diamond has been widely used in many fields such as industry, scientific research, national defence, medical treatment and etc.. Due to its remarkable properties.Especially large diamond, it is indispensable for high-tech developments. At abroad, the large-diamond synthetic techniques have reached commercial production levels. While at present, due to its great commercial value, the information concerning diamond's synthetic techniques has always been kept secret. It is significant for china that we have held independently the high-level technology of large diamonds.Synthesis of diamonds is the phase transition of carbon allotrope, as catalyst involved in making diamond synthesis pressure and synthesis temperature was much lower. Now the catalysts of synthesis of diamonds are metal alloys, however, Diamond special the performances may be given by different alloys . Different catalysts will affect the crystal of diamond and the internal distribution of impurities , so studying the different behaviors of the catalyst, especially for the synthesis of diamonds is necessary.In this paper,Ib diamond crystals have been synthesized by temperature gradient method (TGM) under high pressure and high temperature (HPHT) in China-made cubic anvil high-pressure apparatus. The growth cycle of Ib-type diamonds is longer, requiring in a stable environment for long-term. In this paper , we chosed theΦ10 cavity assembly to meet the growth of large single crystals required. Ib-type diamond contains hundreds ppm nitrogen impurity, which affects the optical properties of diamond and restricts its applications in some fields seriously .While the content of nitrogen impurities in the typeⅡa is less than 1 ppm, so the typeⅡa diamond crystals can make the maximum use of those outstanding properties. For the reason that, we preliminary studied the synthesis ofⅡa diamonds in the FeNi traditional sheet and suppression Fe70 powder catalyst system separately, synthesis of IIa type diamond growth characteristics were studied in the two catalyst systems and the related mechanisms were researched and discussed..