粉末触媒粒度与金刚石粒度之间的对应关系

Relationship about the diamond size and the solvent-catalyst size

选用普遍采用的混合粒度Fe70Ni30触媒粉,经筛分后得到140/170目、170/200目、200/230目、230/270目2、70/325目及325/400目6种不同粒度的触媒样品,在国产JHY-Ⅲ型六面顶压机上,合成出不同粒度的优质金刚石单晶,合成压力为5.3 GPa,温度为1 350℃。首先通过Nanoscope IIIa型扫描电子探针和OXFORD MS-500型投射式穆斯堡尔谱仪对选用的触媒的粒度、微观形貌以及被氧化程度等进行了分析。结果表明,触媒粉在实验过程中并无氧化现象。其次,通过不同粒度的触媒合成出的金刚石单晶峰值的比较,总结出了触媒粒度与合成的金刚石晶体粒度大小之间的一般规律。铁基触媒的粒度与合成的金刚石单晶的粒度密切相关:230/270目触媒最适生长粗颗粒的金刚石单晶,越远离这个粒度(越粗或越细)的触媒合成的金刚石单晶粒度越细。利用镍锰钴触媒同样验证了这一规律。

Fe70Ni30 powder was used as solvent-catalyst after sieved to 140/170、170/200、200/230、230/270、270/325 and 325/400 mesh.Using the above catalysts,high quality diamond were synthesized at about 5.3 GPa and 1 350 ℃ in JHY-Ⅲ cubic apparatus.Firstly,we observed the size and the micro-topography of solvent-catalyst powder by Nanoscope IIIa type atomic force microscope（AFM） and OXFORD MS-500 type Mossbauer spectroscope,and it was confirmed that solvent-catalyst powder we used was not oxidized though the size of particles were finer than 400 mesh.Secondly,the relationship between the diamond size and the solvent-catalyst size was concluded by comparing diamond′s peak value granularity synthesized with different sized Fe70Ni30 powder.The result showed that 230/270 mesh solvent-catalyst was suitable for coarse diamond synthesis,and the more different from this granularity,the finer the diamond synthesized.In the end,we confirmed this regulation again through synthesis test using Ni70Mn25Co5 powder.