Influence of carbon convection field on high quality large single crystal diamonds morphology under high pressure and high temperature

Li, Yadong; Jia, Xiaopeng; Bi, Yan; Chen, Ning; Fang, Chao; Li, Yong; Sun, Shishuai; Ma, Hongan

doi:10.1039/c6ra01480a

Cited by 7 publications

(2 citation statements)

References 22 publications

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“…The three models used the same voltage and thermal boundary conditions in the simulation process, and the nite element model, material parameters and boundary conditions were obtained from our previous reports. 23,24 Experiments on the diamond synthesis were carried out in a china type cubic high pressure apparatus (CHPA) with a synthesis cavity of 42 Â 42 Â 42 mm 3 at a pressure of 5.7 GPa and temperature of 1300 C in all runs. High purity graphite powder (99.9% purity) and Fe 64 Ni 36 alloy were used as the carbon source and the catalyst, respectively.…”

Section: Simulation and Experimental Detailsmentioning

confidence: 99%

An effective method to improve the growth rate of large single crystal diamonds under HPHT processes: optimized design of the catalyst geometric construction

Wang

Chen

et al. 2019

RSC Adv.

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Section: Simulation and Experimental Detailsmentioning

confidence: 99%

An effective method to improve the growth rate of large single crystal diamonds under HPHT processes: optimized design of the catalyst geometric construction

Wang

Chen

et al. 2019

RSC Adv.

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“…Filiform defects were observed throughout the diamond obtained by traditional rapid cooling synthesis. Because of an uneven temperature distribution in the synthesis assembly, thermoelastic stresses were generated in synthetic diamonds. Thus, thermoelastic stress analysis is important for predicting the quality of synthetic materials.…”

Section: Introductionmentioning

confidence: 99%

Defect and Stress Reduction in High-Pressure and High-Temperature Synthetic Diamonds Using Gradient Cooling Technology

Chen

Zhang

et al. 2020

Crystal Growth & Design

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In order to eliminate filiform defects in high-pressure and high-temperature synthetic diamonds, we have developed a gradient cooling technology and applied it during the synthesis assembly cooling process used during the later stage of diamond synthesis. Finite element simulations showed that the von Mises stress at the end of the synthesis process varied greatly inside the diamond. The rapid thermoelastic stress relief and higher thermoelastic stress generated inside the diamond during rapid cooling of synthesis assembly were the root causes of filiform defects, which were completely eliminated from the diamond interior at a gradient cooling time of 300 min. Raman measurements indicated that the crystalline quality was higher and the compressive stress was lower in the diamond obtained using gradient cooling technology than in the diamond obtained using the traditional rapid cooling technology. This work improves the understanding of the origin of filiform defects in diamond and also provides an effective method for obtaining high-quality diamonds.

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Investigation of the ‘double cross’ splitting mechanism of single-crystal diamond under nanoindentation via molecular dynamics simulation

Wang

et al. 2017

J Mol Model

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Elucidating the mechanical response of diamond is a difficult task due to its ultrahard nature. Here, we applied a molecular dynamics (MD) method to investigate the mechanical response of single-crystal diamond under nanoindentation. There was no obvious "pop in" phenomenon on the load-depth curve, and the elastic modulus deduced from the curve was 1128 GPa, which was similar to the value obtained from experimental measurements. Results from computed tomography (CT) and the coordination number showed that the distribution of the mismatched C atoms around the deformation zone took the form of a 'double cross.' The atoms around the indenter tip could be divided into two zones, a translation zone and a lattice distortion zone, based on their movements. Subsequent first-principles calculations revealed that the C-atom displacement barrier varied significantly with direction, which resulted in shear stress between the two zones and the formation of the double-cross splitting. Graphical Abstract The displacement of the atoms around the indenter tip.

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Influence of carbon convection field on high quality large single crystal diamonds morphology under high pressure and high temperature

Abstract: The temperature and convection fields of a catalyst with three different heights were simulated in a temperature gradient growth (TGG) system under high pressure and high temperature (HPHT) conditions.

Cited by 7 publications

References 22 publications

An effective method to improve the growth rate of large single crystal diamonds under HPHT processes: optimized design of the catalyst geometric construction

An effective method to improve the growth rate of large single crystal diamonds under HPHT processes: optimized design of the catalyst geometric construction

Defect and Stress Reduction in High-Pressure and High-Temperature Synthetic Diamonds Using Gradient Cooling Technology

Investigation of the ‘double cross’ splitting mechanism of single-crystal diamond under nanoindentation via molecular dynamics simulation

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