Li Yantao1, Li Ying1, Jia Xiaopeng2, Ma hongan2, Zhou lin2
(1. Henan University of Technology, 450007
2. State Key Laboratory for Superhard Materials, Jilin University, 130012)
Abstract The diamond, which was synthesized by the powdered catalyst made of Ni70Mn25Co5 and sulfur in the high pressure and high temperature conditions (HPHT), was measuring by Scanning Electron Microscopy (SEM), Electron Probe and Wave Dispersive X Radial Fluorescence (WDXRF). Finally, diamond strength is checked. The results show that the colure of diamond gradually becomes dark and the surface of diamond appears cavities with sulfur increasing in the raw materials. When the quantity of sulfur is little in Ni-Mn-Co powder, there are lots of cavities on the (100) surface, whereas when the quantity of sulfur increase, there will appear so many cavities on both (100) and (111) surface that crystal becomes more misshapen. The distribution of impurities on the surface is inhomogeneous, and Ni, Co, S impurities, especially Mn have a tendency to (100) surface. The content of sulfur in the diamond tends approximately to augment with additive sulfur increased. Under the same condition, the concentration of Mn tends to increase, but there are not obvious disciplinarians for Ni impurity. The Toughness Index (TI) and the Thermal Toughness Index (TTI) of the diamond incline to be depressed with additive sulfur increased.
Keywords sulfur; diamond; Ni-Mn-Co powdered catalyst; impurity distribution; impurity content