RELIABLE HIGH PRESSURE TECHNIQUES AND SYNTHESIS OF DIAMOND

1.中国高压试验技术与日本高压试验技术的比较双斜面顶砧与单斜面顶砧相比，在顶面尺寸相同的情况下，可以约束一个更大的立方加压空间。在密闭立方尺寸的基础上，双斜面型的压力生成效率约为单斜面型的90%。然而，前者对“井喷”事故具有更好的机械稳定性。积累了有效使用两者的知识。在金属溶剂中分解碳化物生成金刚石的新反应(1)对SiC生成金刚石条件的详细考察表明，溶剂中Si浓度过高会阻碍SiC进一步溶解到溶剂中。Si可以作为杂质溶解到金刚石中。(3) B4C也可在熔融金属溶剂中分解，使金刚石结晶。该金刚石具有高浓度含B的特征。(4) 3d、4d和5d金属碳化物更难分解生成金刚石。对从TiC到Fe3C的三维碳化物进行了系统的实验。2 . VC和Cr3C2给出了少量的金刚石，Fe3C给出了少量的金刚石。金刚石中金属元素作为杂质的分析，已经发现了Si、Ni、Co和Mn的掺入。在本研究中，使用同步辐射作为激发源的x射线荧光方法显示，Fe的掺入浓度在1ppm左右，Cr的掺入浓度要低得多。首先用LAM-ICP质谱法测定了金刚石中Zr的浓度约为0.1ppm。鉴于本课题大力支持和推动的交流活动，1996年由中国政府颁发的外国人最高荣誉“友谊奖”授予首席研究员。

1.Comparison of high pressure experimental techniques in China with those in JapanAnvils with double-beveled flank surfaces can confine a cubic pressurized space which is larger than that confined by single-beveled anvils, if the top faces of the both types are the same in size. On the basis of the confined cube size, the pressure generation efficiency of the double-beveled type was about 90% of that of the single-beveled type. However, the former has an improved mechanical stability against the "blow-out" accident. Knowledge to use the both efficiently was accumulated.2.New reactions to form diamond from carbides decomposed in metallic solvents(1) Detailed examination of conditions to form diamond from SiC revealed that too high a concentration of Si in the solvent works against further dissolution of SiC into the solvent. (2) Si can be dissolve into diamond as an impurity. (3) B4C can also be decomposed in a molten metallic solvent to crystallize diamond. And such diamond was characterized containing B at high concentration. (4) 3d, 4d and 5d metal carbides are much more difficult to be decomposed to give diamond. Systematic experiments were performed on 3d carbides from TiC to Fe3C.VC and Cr3C2 gave diamond and Fe3C gave a trace amount of diamond, while others did not.3. Analyzes of metal elements in diamond as impuritiesIncorporation of Si, Ni, Co and Mn was already revealed. In the present study, x-ray fluorescence method using synchrotron radiation as the excitation source revealed Fe to be incorporated at a concentration around 1 ppm and Cr, at a much lower level. Concentration of Zr in diamond was first dectermined by the LAM-ICP mass spectroscopy as to be about 0.1ppm.4.An international award given by Chines governmentFriendship Award in 1996, which is the highest honor for a foreigner, was given to the head researcher based on the exchange activities supported and promoted much by the present subject.