Synthesis and Study of S-doped Diamond under High Temperature and High Pressure
|School||Henan Polytechnic University|
|Course||Materials Physics and Chemistry|
|Keywords||High temperature and pressure Doped S Diamond Codoped Crystal growth Crystal defects|
Diamond is a superhard material representation of products, has many excellent physical and chemical properties, functional materials is a limit. It is widely used in industry, science and technology, national defense, health and other fields, plays an important role in the promotion of industrial development. China is not the natural diamond-rich country, independently acquire a high level of synthetic diamond technology is of strategic significance. Natural diamond produced in multi crust kimberlite and lamproite, nonmetallic element sulfur contained in the rock, and sulfide is a common natural diamond inclusions, therefore study the additive effects of sulfur on diamond growth help understand the causes of natural diamond. At the same time, this study is also conducive to the development of new catalytic synthesis of specialty diamond. Solvent theory 5.4GPa ,1250-1320 ℃ conditions, FeS (S) as an additive, B as synergistic additives with nickel manganese cobalt, iron and nickel as the catalyst, the use of synthetic gem diamond single temperature gradient method crystal investigated the the FeS diamond growth characteristics, including the growth rate of the crystal, the crystal color, morphology, and quality. The study found that, in the a single FeS doping system, when the FeS content of less than 1%, the color of the crystals from yellow to yellow-gray, while the crystal quality basic changes little; when the FeS content greater than 1%, the crystal changes the color of the gray and black, and greatly reduces the transparency of the crystal, while the crystal quality begins to accelerate deterioration, especially apparent in the (100) crystal plane; when the FeS content was 1.75%, the crystals present on the (100) crystal faces have suffered more serious damage to the (111) plane appears at the same time a large number of spontaneous nucleation of diamond small particles, the easy produce connected crystallization phenomenon when continue to improve the content of the growth system of FeS, the epitaxial growth of crystals, The crystal growth rate dropped to less than 1mg / h. While FeS inhibition of axial growth rate of (100) crystal face is greater than the axial growth rate of (111) plane, leading to the morphology of the diamond with the FeS content increases by octahedral transition to the octahedral. Co-doped crystal growth experiment, when the B / S (B, S atomic ratio) ≈ 0.4, the crystal quality is good, the crystal is golden yellow color; When the system B / S lt; 0.4, the color of the crystal by S doped heteroaryl diamond decision caused by lattice defects, the surface of the crystal defects are mainly present in the (100) crystal plane; When the system B / S GT; 0.4, the color of the crystal is mainly by B-doped diamond caused by the formation of mono-substituted B The lattice defects decided, the surface defects of the crystal is mainly present in the (111) crystal plane. Synthesis crystal spectroscopy analysis showed that the presence of small amounts of S element in the crystal surface, and the crystal; Raman spectrum shows, in addition to a strong diamond peak at 1332.3 cm-1 appears at 1540 cm-1 position a half width larger unknown peaks; infrared absorption spectrum shows the crystal 50-600ppm, mono-substituted nitrogen (C heart) impurities, and has a high intensity is not position of the peak at 1050 cm-1, formed by the peak bit reasons temporarily unclear.