Study on the characteristics of Ib diamond crystals synthesized with Fe3O4 doped in an Fe–Ni–C system

CrystEngComm ◽  
2020 ◽  
Vol 22 (22) ◽  
pp. 3854-3862 ◽  
Author(s):  
Shuai Fang ◽  
Hongan Ma ◽  
Zheng hao Cai ◽  
Chun xiao Wang ◽  
Chao Fang ◽  
...  
Keyword(s):  
Natural Diamond ◽  
Diamond Crystals ◽  
System P

Fe3O4 is a common earth mineral, which often exists in the form of inclusions in natural diamond.

Effect of pressure on synthetic diamond crystals at high temperatures and pressures in Fe/Ni catalyst system

CrystEngComm ◽  
2021 ◽  
Author(s):  
Shuai Fang ◽  
Yongkui Wang ◽  
Liangchao Chen ◽  
Zhiyun Lu ◽  
Zhenghao Cai ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Growth Mechanism ◽  
Synthetic Diamond ◽  
Natural Diamond ◽  
Catalyst System ◽  
Necessary Condition ◽  
Ni Catalyst ◽  
Effect Of Pressure ◽  
Diamond Crystals ◽  
System P

Pressure is a necessary condition for the growth of natural diamond. Studying the effect of pressure on the nitrogen content of diamond is important for exploring the growth mechanism of...

Contact electrization of natural diamond crystals

2010 ◽  
Vol 36 (2) ◽  
pp. 162-165 ◽  
Author(s):  
E. V. Ryabov ◽  
Yu. S. Mukhachev
Keyword(s):  
Natural Diamond ◽  
Diamond Crystals

scholarly journals Surface Porosity of Natural Diamond Crystals after the Catalytic Hydrogenation

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1341
Author(s):  
Aleksei Chepurov ◽  
Valeri Sonin ◽  
Dmitry Shcheglov ◽  
Egor Zhimulev ◽  
Sergey Sitnikov ◽  
...  
Keyword(s):  
Catalytic Hydrogenation ◽  
Materials Science ◽  
Crystal Surface ◽  
Natural Diamond ◽  
Substrate Material ◽  
Diamond Surfaces ◽  
Diamond Crystals ◽  
Type Ia ◽  
Strong Resemblance ◽  
Natural Type

The study of diamond surfaces is traditionally undertaken in geology and materials science. As a sample material, two natural diamond crystals of type Ia were selected, and their luminescence and nitrogen state was characterized. In order to etch the surface catalytic hydrogenation was performed using Fe particles as an etchant. Micromorphology of the surface was investigated by scanning electron and laser confocal microscopy. It was demonstrated that etching occurred perpendicular to the crystal surface, with no signs of tangential etching. The average depth of caverns did not exceed 20–25 μm with a maximal depth of 40 μm. It is concluded that catalytic hydrogenation of natural type Ia diamonds is effective to produce a porous surface that can be used in composites or as a substrate material. Additionally, the comparison of results with porous microsculptures observed on natural impact diamond crystals from the Popigai astrobleme revealed a strong resemblance.

scholarly journals A quantitative study of diffracted X-ray intensities from natural diamond crystals by using multicrystal X-ray diffractometers and comparison with silicon crystals

1987 ◽  
Vol 43 (a1) ◽  
pp. C212-C212
Author(s):  
K. Lal ◽  
S. Niranjana ◽  
N. Goswami ◽  
V. Kumar ◽  
S. K. Halder ◽  
...  
Keyword(s):  
Quantitative Study ◽  
Natural Diamond ◽  
X Ray ◽  
Silicon Crystals ◽  
Diamond Crystals

Study on growth characteristics of Ib-type diamond in an Fe–Ni–C–S system

CrystEngComm ◽  
2019 ◽  
Vol 21 (40) ◽  
pp. 6010-6017 ◽  
Author(s):  
Shuai Fang ◽  
Hongan Ma ◽  
Zhanke Wang ◽  
Zhiqiang Yang ◽  
Zheng-hao Cai ◽  
...  
Keyword(s):  
Natural Diamond ◽  
Growth Characteristics ◽  
System P ◽  
Sulfur Containing ◽  
Diamond Inclusions

FeS is the main sulfur-containing compound in natural diamond inclusions.

Composition and structure of the diamond/low carbon steel transition zone obtained by contact heating in vacuum at Fe–C eutectic temperature

2021 ◽  
pp. 47-59
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. N. Makharova ◽  
S. P. Yakovleva ◽  
V. I. Popov
Keyword(s):  
Carbon Steel ◽  
Heating Temperature ◽  
Natural Diamond ◽  
Low Carbon Steel ◽  
Gradual Transition ◽  
Vacuum Furnace ◽  
Low Carbon ◽  
Cooling Mode ◽  
Metal Base ◽  
Diamond Crystals

The study covers the structure, elemental and phase composition of products formed in the contact interaction between diamond and low-carbon steel in vacuum at the Fe–C eutectic melting temperature. Cylindrical tablets made of low carbon steel with a maximum carbon content of 0.1 wt.% and natural diamond crystals in the form of a pyramid (or truncated pyramid) were used as contact pairs. The flat bases of diamond crystals were mounted on the horizontal surface of steel tablets with the load applied to the top of diamond crystals. Contact samples were sintered in a vacuum furnace at a maximum heating temperature of ~1165 °C. After holding at this temperature for 5 minutes, the furnace was turned off and the temperature in its chamber decreased in free cooling mode. Sintered diamond/steel tablet samples were studied by optical and scanning electron microscopy, X-ray diffraction analysis and Raman spectroscopy. It was found that the Fe–C eutectic melt forms in the diamond/steel tablet contact zone, a thin layer of which, when solidified, welds a diamond crystal to the steel tablet under the temperature-time heating mode specified in the experiment. Their bonding strength is such that welded samples without separation can withstand intense cyclic loads during grinding and polishing when making longitudinal sections of samples necessary for metallographic studies. It was shown that the Fe–C eutectic alloy is a gray cast iron with a ferrite-perlite metal base and lamellar graphite inclusions. The microhardness of the solidified Fe–C eutectic was ~1714 MPa. The initial steel tablet with a ferrite-perlite structure was subjected to cementation during sintering in contact with diamond. The most intensive cementation occurred in the ~110 μm thick unmelted upper layer of the steel tablet, which adjoined the Fe–C eutectic during sintering. The microhardness of this layer was ~4945 MPa. As it deepens into the steel tablet there is a gradual transition of the perlite-cementite structure to a perlite one and further to the initial ferrite-perlite microstructure inwards the steel tablet. At the same time, the microhardness changes from ~ 4945 to 1570 MPa.

On the real combinations of cubes and octahedra

2020 ◽  
Vol 76 (2) ◽  
pp. 206-210
Author(s):  
Yury L. Voytekhovsky ◽  
Dmitry G. Stepenshchikov
Keyword(s):  
Automorphism Group ◽  
Natural Diamond ◽  
Symmetry Point ◽  
The Real ◽  
Diamond Crystals ◽  
Point Groups

All the real combinations of cubes and octahedra (77657 in total) are enumerated and characterized by facet symbols and symmetry point groups. The most symmetrical polyhedra (with automorphism group orders not less than 6, 163 in total) are shown. It is assumed that they represent the most probable forms of natural diamond crystals. The results are discussed with respect to the Curie dissymmetry principle.

Evidence of deformation twinning in natural diamond crystals

1970 ◽  
Vol 31 (4) ◽  
pp. 890-891 ◽  
Author(s):  
C.K.R. Varma
Keyword(s):  
Natural Diamond ◽  
Deformation Twinning ◽  
Diamond Crystals

Impurity distribution in natural diamond crystals

1982 ◽  
Vol 17 (11) ◽  
pp. 1389-1392
Author(s):  
L. N. Aleksandrov ◽  
D. S. Gafitullina ◽  
A. A. Khaidarov
Keyword(s):  
Natural Diamond ◽  
Impurity Distribution ◽  
Diamond Crystals

scholarly journals STRUCTURE OF POLYCRYSTALLINE DIAMOND COATINGS DEPOSITED BY СVD METHOD IN THE PLASMA OF GLOW DISCHARGE WITH THE USE OF PULSE POWER SUPPLY

2021 ◽  
pp. 113-118
Author(s):  
K.I. Koshevoy ◽  
Yu.Ya. Volkov ◽  
V.E. Strel’nitskij ◽  
E.N. Reshetnyak
Keyword(s):  
Glow Discharge ◽  
Power Supply ◽  
Natural Diamond ◽  
Polycrystalline Diamond ◽  
Lattice Parameter ◽  
Pulse Mode ◽  
Crystal Lattice Parameter ◽  
Diamond Coatings ◽  
Deposition Parameters ◽  
Diamond Crystals

The structure of CVD carbon coatings synthesized in a hydrogen-methane mixture in the plasma of a glow discharge stabilized by a magnetic field using a pulsed power supply was studied by X-ray diffraction analysis and optical microscopy. The range of deposition parameters is determined, which ensure formation of polycrystalline diamond coatings. The coatings consist of diamond crystals with a clearly defined cut and the crystal lattice parameter close to the tabular value for natural diamond. The influence of the methane partial pressure in the gas mixture and the substrate temperature on the size and predominant orientation of diamond crystals in the coatings was determined. It is established that the use of the pulse mode and grounding of the substrate holder helps to improve the quality of diamond coatings.

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