【摘要】 在压力5.3 GPa、温度1603 K的FeNiCo(wt%55∶29∶16)触媒中沿{111}面合成Ⅰb型及Ⅱa型宝石级金刚石过程中金刚石周围分别伴随有片状及粉末状石墨析出。这两种不同形态的石墨均会对金刚石生长产生不利影响。对这两种石墨进行XRD和SEM测试分析表明:生长Ⅰb型和Ⅱa型金刚石时所析出的石墨分别为再结晶石墨和微晶石墨。本文分析了这两种石墨析出原因的异同点。更多还原

【Abstract】 Large diamonds have been synthesized in FeNiCo-C system under HPHT conditions.Diamonds of type Ⅰb or Ⅱa grows upon(111) facet under 5.3 GPa and 1603 K,while flake or powder graphite respectively appears around the growing crystal.Graphite with different shape retards drastically the growth of large diamonds.The as-described flake or powder graphite from growth process of traditional type I b or Ⅱ a diamonds were distinguished by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The flake or powder graphite was testified to be re-grown graphite or micro-crystal graphite.The precipitation reasons of re-grown graphite and micro-crystal graphite were discussed.更多还原