نتایج جستجو برای: diamond
تعداد نتایج: 20974 فیلتر نتایج به سال:
Recent studies of microdiamonds from orogenic belts related to continental collisions induced experimentalists to explore new crystallization media possible for diamond synthesis. This has led to considerable progress in diamond-synthesis experiments under high pressures and high temperatures. Diamond was found to grow in a wide variety of systems, which drastically differ from the metal-solven...
In the present work copper/diamond composites, such as (Cu-10 Vf % diamond uncoated, Cu-30 Vf % diamond uncoated, Cu-10 Vf % diamond coated NiCrB and Cu-30 Vf % coated NiCrB) as heat sink materials have been fabricated using powder metallurgy and electroless techniques. The copper powder used in this study has been fabricated using electroless technique and the diamond powder was electroless co...
Diamond is a material of interest due to its unique combination of properties, including its chemical inertness and biocompatibility. Polycrystalline diamond (poly-C) has been used in experimental biosensors that utilize electrochemical methods and antigen-antibody binding for the detection of biological molecules. Boron-doped poly-C electrodes have been found to be very advantageous for electr...
The chemistry of the intermediate layer that develops at the interface between diamond and a non-diamond substrate during diamond chemical vapor deposition is analyzed using a thermodynamic quasi-equilibrium model. Substrates of Si, Mo, W, Ti, Ta, Fe and Ni are examined, and the physical parameters such as substrate temperature, reactor pressure, and CH rH ratio in the gas phase required for 4 ...
Diamond possesses many extreme properties that make it an ideal material for fabricating nanofocusing x-ray optics. Refractive lenses made from diamond are able to focus x-ray radiation with high efficiency but without compromising the brilliance of the beam. Electron-beam lithography and deep reactive-ion etching of silicon substrates have been used in a transfer-molding technique to fabricate...
Two-dimensional laser induced fluorescence measurements are applied to the chemical vapor deposition of diamond by an oxyacetylene flame. The fluorescence distributions of C2, CH, and OH are measured for various deposition conditions. The influence of the temperature of the molybdenum substrate and the distance between the substrate and the flame front on the two-dimensional distributions and o...
The shock-induced transition from graphite to diamond has been of great scientific and technological interest since the discovery of microscopic diamonds in remnants of explosively driven graphite. Furthermore, shock synthesis of diamond and lonsdaleite, a speculative hexagonal carbon polymorph with unique hardness, is expected to happen during violent meteor impacts. Here, we show unprecedente...
Mineral inclusions in diamonds provide an important source of information about the composition of the continental lithosphere at depths exceeding 120-150 km, i.e., within the diamond stability field. Fossilized high pressures in coesite inclusions from a Venezuela diamond have been identified and measured by using laser Raman and synchrotron x-ray microanalytical techniques. Micro-Raman measur...
In this paper the design of a simple, space constrained chemical vapour deposition reactor for diamond growth is detailed. Based on the design by NIRIM, the reactor is composed of a quartz discharge tube placed within a 2.45 GHz waveguide to create the conditions required for metastable growth of diamond. Utilising largely off-the-shelf components and a modular design, the reactor allows for ea...
Theoretical predictions using a modified radical species ternary diagram for C–H–O system indicate that addition of sulfur expands the C–H–O gas phase compositional window for diamond deposition. Sulfur addition to no-growth domain increases the carbon super-saturation by binding the oxygen and the addition of sulfur to the non-diamond domain reduces the heavy carbon super-saturation by decreas...
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