多晶金刚石烧结中晶粒表面石墨化的实验研究

THE SURFACE GRAPHITIZATION OF DIAMOND GRAINS IN THE PROCESS OF SINTERING POLYCRYSTALLINE DIAMOND

利用X射线微区衍射,X射线光电子谱(XPS)及激光拉曼光谱等分析,对高温高压下以金刚石微粉为原料的多晶金刚石烧结过程中,金刚石晶粒表面石墨化现象进行了考察。结果表明,虽经历了烧结过程,但在没有掺杂剂作用的区域内,没有发现金刚石晶粒表面的石墨化。晶粒表面石墨化的高峰期,处于掺杂剂刚开始液化,但尚未饱合充填金刚石晶粒间空隙的烧结初期阶段,随着液相掺杂剂的饱和充填和作用,金刚石晶粒表面的石墨消失,并最终完成多晶金刚石的烧结。

The surface graphitization of diamond grains, which is induced in the process sintering polycrystalline diamond under high pressure, is studied. The results of analysis by micro-area X-ray diffraction, XPS and laser Raman spectrum etc. show that no graphitization is detected in the area where the doped agents have not been liquefied or permeated althrough the sintering process was undergone. The most active period of the surface graphitization is at the moment when the doped agents are just liquefied and permeated into the spaces among diamond grains. The surface graphite of diamond grains will be eliminated and the sintering of polycrystalline diamond will be completed with the spaces being filled fully and the doped agents reacting with the diamond grains.