高温高压下石墨-Ni_(70)Mn_(25)Co_5体系中金刚石单晶合成工艺参数对金属包膜的影响

Effect of Procedure Parameters for Diamond Single Crystal on Metallic Films in a Graphite-Ni_(70)Mn_(25)Co_5 System under High Temperature and High Pressure

利用扫描电子显微镜和能谱仪,研究了高温高压下金刚石单晶合成工艺参数对石墨-Ni70Mn25Co5体系中金属包膜组织形貌和成分的影响。结果发现:合成压力和合成温度都合适时,金属包膜中基本无条状石墨,而且包膜中间都存在网状物,包膜中存在着明显的碳、镍和锰的成分起伏;此时合成时间对包膜的形貌影响不明显;而合成压力为5.1GPa的包膜中存在大量条状石墨,包膜中间无网状物。分析认为,网状物为溶入了锰、钴的镍基γ固溶体,该固溶体是高温高压合成过程中促使金刚石转变的催化相。

Scanning electron microscope（SEM） and Energy Dispersive Spectroscope（EDS） were used to investigate the effects of procedure parameters on the structures and composition of the metallic film covering on diamond single crystal from a graphite-Ni70Mn25Co5 system under high temperature and high pressure（HTHP）.The results show that there is hardly stripe graphite in the film,but there exist an obvious fluctuation in carbon,nickel and manganese distributions in the film and some reticulations in the middle region of the film when synthesizing pressure and temperature are fit for diamond growth.The effect of synthesizing time on the morphologies of the film is not obvious.However,when the synthesizing pressure is 5.1GPa,a large amount of stripe graphite appears in the whole film,and there is no reticulations in the middle region.The analysis suggests that the reticulations should be Ni-Mn-Co-C solid solutions（γ-phase）,which is a catalytic phase for diamond transformation in the film under HTHP.