Hybrid carbon-hydrocarbon structure

2021 ◽  
Vol 9 ◽  
pp. 79-84
Author(s):  
S. A. Eremin ◽  
◽  
N. O. Kudryashova ◽  
I. A. Leontiev ◽  
Y. M. Yashnov ◽  
...  
Keyword(s):  
Synthetic Diamond ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Average Diameter ◽  
Diamond Powder ◽  
Gas Mixture ◽  
Nanocrystalline Graphite ◽  
Diamond Powders ◽  
Synthetic Diamond Powder ◽  
Hybrid Carbon

A new hybrid carbon-hydrocarbon structure was discovered after pumping a gas mixture of methane and hydrogen through 314 – 400 µm synthetic diamond powder. The experiment was carried out on the microwave plasmachemical installation designed for deposition of polycrystalline diamond films. The main parameters during the experiment were the following: the power of the microwave generator 3,5 kW, the flow rate of hydrogen 400 ml/min, methane 20 ml/min, the pressure in the reactor chamber 63 torr. The gas mixture was pumped at pressure drop of 13 torr. The diamond powders were placed in molybdenum cups inserted into a copper pedestal. In the gaps between the diamond particles of the surface layer unidirectional thread-like structures (length 100 – 500 μm, diameter 2 μm) were found, some of which ended in spherical formations (average diameter 18 μm). Such a composition of thread-like structures and spherical formations was called “dandelion” one. Raman spectroscopy was performed to examine the nature of these formations. The thread-like structure was determined as monocrystalline graphite. The surface of the spherical formation was represented by spindle-shaped structures of nanocrystalline graphite (length 2 μm, thickness 200 nm) and nanodiamond grains with trans-polyacetylene chains [C2H2]n.

Nanostructuring of diamond films using self-assembled nanoparticles

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Oleg Babchenko ◽  
Alexander Kromka ◽  
Karel Hruska ◽  
Miroslav Michalka ◽  
Jiri Potmesil ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Self Assembly ◽  
Diamond Films ◽  
Diamond Powder ◽  
Gas Mixture ◽  
Assembly Strategy ◽  
Nano Structures ◽  
Mask Type ◽  
Different Types ◽  
Nano Rods

AbstractWe report the use of gold, nickel and diamond nanoparticles as a masking material for realization of diamond nano-structures by applying the dry plasma etching process. Applying low power plasma (100 W) in a gas mixture of CF4/O2 for 5 minutes results in a formation of three different types of diamond nanostructures, depending on the mask type material and particle size. Using of the Ni mask results in realization of diamond nano-rods, applying of the Au mask brings cauliflower-like structures, and using the diamond powder allows the production of irregular nano-structures. The main advance of the presented etching procedure is use of a self-assembly strategy where no lithographic steps are implemented.

A Method for an Improvement in the Quality of Diamond Composite Thermostable Material

2010 ◽  
Vol 660-661 ◽  
pp. 844-847 ◽  
Author(s):  
Ana Lúcia Diegues Skury ◽  
Sérgio Neves Monteiro ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
Marcia G. de Azevedo
Keyword(s):  
Polycrystalline Diamond ◽  
Diamond Powder ◽  
Polycrystalline Materials ◽  
Sintering Process ◽  
Compact Structure ◽  
Powder Consolidation ◽  
Fine Diamond ◽  
Sintered Diamond ◽  
Diamond Powders

It is still in focus the problem of obtaining high quality polycrystalline materials by means of sintering fine diamond powders. The most important task of this problem is the consolidation or improvement of the processed polycrystalline diamond. It is worldwide recognized that the plastic deformation of the diamond particles performs the most important role on the diamond powder consolidation. In some cases, the contact and shear tensions reconstruct the compact structure. In this work the sintering process used a mixture of micro and nanodiamonds. The sintering process was carried out in a toroidal high-pressure device. The effects of nanodiamond addition and sintering conditions on the microstructure and mechanical properties sintered diamond bodies were studied. The sintering parameters were pressure of 6.8 GPa and a temperature of 1850 K, and these conditions were maintained for 1 minute. Homogeneous sintered bodies were obtained, which have a Vickers' hardness over 40 GPa, and fracture toughness around 7.1 – 7.9 MPa.m1/2.

scholarly journals FINISH MACHINING OF THE CUTTING INSERTS FROM CUBIC BORINE NITRIDE BL GROUP COMPOSITE

2021 ◽  
pp. 102-114
Author(s):  
Anatolii Chumak ◽  
Sergey Klimenko ◽  
Sergei Klimenko ◽  
Andriy Manokhin ◽  
Artem Naydenko ◽  
...  
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Synthetic Diamond ◽  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
Diamond Powder ◽  
Abrasive Machining ◽  
Abrasive Particles ◽  
Cutting Inserts ◽  
Synthetic Diamond Powder

Finishing methods of machining of superhard composite’s working elements based on cubic boron nitride BL group are considered. The results of the microgeometry formation research of the cutting inserts’ surfaces during machining by free powders of synthetic diamond, grinding wheels and a method of vibro-magnetic-abrasive machining (VMAM) are presented. It is shown that during VMAM the friction between the inserts’ surfaces and the abrasive particles result in microremoval of the material, which reduces the roughness of the cutting inserts’ surfaces. It is established that additional fine grinding with 14/10 mkm synthetic diamond powder provides the absence of microgeometry defects of the cutting inserts’ surfaces left by pre-machining. The result of high-quality rounding of cutting edges and the formation of surfaces of cutting inserts with less roughness is an increase in strength and wear resistance of metal-cutting tools in high-speed machining under conditions of significant loads.

Synthetic diamond electrodes: Photoelectrochemical behavior of vacuum-annealed undoped polycrystalline diamond films

2005 ◽  
Vol 41 (3) ◽  
pp. 304-309 ◽  
Author(s):  
Yu. V. Pleskov ◽  
M. D. Krotova ◽  
V. G. Ralchenko ◽  
A. V. Khomich ◽  
R. A. Khmelnitskii
Keyword(s):  
Synthetic Diamond ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Diamond Electrodes

scholarly journals Electrical properties and Mott parameters of polycrystalline diamond films synthesized by HF CVD method from hydrogen/methanol gas mixture

2018 ◽  
Vol 35 (4) ◽  
pp. 830-837 ◽  
Author(s):  
Agnieszka Banaszak-Piechowska ◽  
Kazimierz Fabisiak ◽  
Elżbieta Staryga ◽  
Kazimierz Paprocki
Keyword(s):  
Charge Transport ◽  
Synthetic Diamond ◽  
Electronic Conductivity ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Temperature Dependent ◽  
Cvd Method ◽  
Crystallite Sizes ◽  
Hot Filament

Abstract The influence of diamond crystallinity and preferred orientation on electronic conductivity of synthetic diamond films grown by hot filament chemical vapor deposition (HFCVD) was investigated. The CVD diamond films of different morphologies and crystallite sizes varying from 36 nm to 67 nm, measured in h2 2 0i direction were considered. The charge transport mechanism in the diamond samples was studied using temperature dependent DC conductivity measurements. The obtained results showed that in the temperature range of 90 K to 300 K charge transport is realized via Variable Range Hopping (VRH, m = 1/4) mechanism. Using VRH model, the Mott parameters were evaluated i.e. density of states at Fermi level N(EF) (0.22 × 1015 eV-1·cm-3 to 1.7 × 1015 eV-1·cm-3), hopping energy W (43.5 meV to 142.3 meV) and average hopping distance R (1.49 × 10-5cm to 2.56 × 10-5cm). It was shown that above mentioned parameters strongly depend on diamond film preferential orientation.

Oxidation of diamond films synthesized by hot filament assisted chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2483-2489 ◽  
Author(s):  
K. Tankala ◽  
T. DebRoy ◽  
M. Alam
Keyword(s):  
Microwave Plasma ◽  
Synthetic Diamond ◽  
Natural Diamond ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Low Oxygen ◽  
Before And After ◽  
Lower Temperature ◽  
Hot Filament

Oxidation of polycrystalline diamond films on (111) Si wafers in air at temperatures up to 1073 K was investigated by thermogravimetry. The diamond films before and after partial oxidation were characterized by optical and scanning electron microscopy, x-ray, infrared, and Raman spectroscopy. The oxidation of synthetic diamond films started at a lower temperature than that for natural diamond. The rates of oxidation of the diamond films synthesized by the hot filament and the microwave plasma methods were intermediate between the rates of oxidation of the 111 and 100 planes of natural diamond crystals. The apparent activation energy for the oxidation of the synthetic diamond films agreed well with that for the oxidation of natural diamond via diamond to graphite transition at low oxygen pressures.

Application of the Rietveld method to quantitative analysis of impurities in synthetic diamond powder

2004 ◽  
Vol 19 (2) ◽  
pp. 141-144 ◽  
Author(s):  
Rashmi ◽  
Nahar Singh ◽  
A. K. Sarkar
Keyword(s):  
Phase Composition ◽  
Quantitative Analysis ◽  
Synthetic Diamond ◽  
Rietveld Method ◽  
Diamond Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Content ◽  
A Minor ◽  
Synthetic Diamond Powder

Synthetic diamonds are an important class of industrial material. During synthesis impurities may get introduced into diamond. Identification and quantification of impurities is important as they affect the properties and suitability of the diamonds for their application. Impurities in an industrial synthetic diamond powder sample were analyzed by X-ray diffraction (XRD) and also by chemical methods. X-ray diffraction pattern showed diamond as the major phase and α-iron as a minor phase. Quantitative analysis of crystalline phases was done by performing Rietveld refinement of the XRD profile. Chemical analysis showed the presence of several other impurities as well, though in small amounts. It was considered that the impurities other than iron were in amorphous form and an estimate of the amorphous content was made on this basis. Relative phase composition of diamond and iron as estimated by XRD were corrected for the amorphous content to obtain absolute phase composition.

Sign in / Sign up

Export Citation Format

Share Document