Diamond micropowder synthesis via graphite etching in a microwave hydrogen plasma

Yao, Kaili; Dai, Bing; Zhu, Jiaqi; Ralchenko, V.G.; Shu, Guoyang; Zhao, Junhong; Wang, Peng; Liu, Benjian; Gao, Ge; Sun, Min; Liu, Kang; Lv, Zhijun; Yang, Lei; Han, Jiecai

doi:10.1016/j.powtec.2017.09.021

Cited by 16 publications

(9 citation statements)

References 27 publications

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“…For comparison, the as‐grown aggregated diamond powders were separated into individual particles by mechanical grinding for 30 min in a stainless‐steel mortar. [ 5 ] SEM images of the deaggregated diamond particles are shown in Figure a. The particles were attached to a glass slide as described earlier and the WCA measured.…”

Section: Resultsmentioning

confidence: 99%

“…For comparison, our as‐grown aggregated diamond powders were separated into individual particles by mechanical grinding for 30 min in a stainless‐steel mortar. [ 5 ] In addition, we purchased 20 μm commercial diamond powders from Zhengzhou Sino‐Crystal Diamond Company. These two types of powders were tested for WCA and compared with our aggregated samples.…”

Section: Methodsmentioning

confidence: 99%

“…Diamond exhibits a series of extraordinary properties, such as extreme mechanical hardness, high chemical stability, and high resistance to acids and alkalis. [ 5–7 ] The rapid advances in high‐pressure high‐temperature (HPHT) and chemical vapor deposition (CVD) of diamond over the last decade [ 8,9 ] now mean that diamond in various forms (single‐crystal gemstones, thin layers, or powders) can be purchased from a wide range of commercial suppliers at inexpensive prices. As such, diamond is becoming a promising material for a range of engineering applications, including those which require a controlled hydrophobic or hydrophilic surface, especially in extreme environments.…”

Section: Introductionmentioning

confidence: 99%

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Hydrophobicity and Adhesion of Aggregated Diamond Particles

Yao

Dai

May

et al. 2020

Physica Status Solidi (a)

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Diamond powders with high hydrophobicity are prepared by etching graphite plates using a hydrogen/argon (H2/Ar) plasma. The morphology and size of the diamond powders are found to vary with the proportion of Ar in H2 from 0% to 50%. Wettability is measured using water contact angle (WCA) measurements giving values between 129.7° and 146.9°. The high hydrophobicity can be ascribed to the aggregated structure of the as‐grown diamond powders. To check this assumption, the aggregated diamond powders are separated into individual particles by mechanical grinding; then, the WCAs of separated as‐grown diamond powders and commercial dispersed diamond powders are compared. The separated diamond surfaces show the lower WCAs of 99.68° and 96.96°. The surface of the aggregated diamond powders also exhibits high adhesion to water. The diamond surface grown in 2% Ar suspends 40 μL of water under a tilt angle of 180°. Such aggregated diamond powders are promising for no‐loss liquid transportation.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrophobicity and Adhesion of Aggregated Diamond Particles

Yao

Dai

May

et al. 2020

Physica Status Solidi (a)

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“…The size of the diamond grain with the agglomerates also increase with process time. The specific diamond grain size distributions after de-aggregation [20] were characterized by laser granular analyzer and the result is presented in Figure 3a, b.…”

Section: Resultsmentioning

confidence: 99%

“…Those diamond particles were typically agglomerates of smaller diamond grains, formed due to an incessant re-nucleation [19]. Therefore to separate the aggregated particles to individual grains they were ground for 30 min in a stainless steel mortar, followed by ultrasonically cleaning with acetone and alcohol [20]. Only the diamond particles grown after 3h, 8h and 13h were collected and treated, whereas the fine powder grown after 1h graphite etching was difficult to collect.…”

Section: Methodsmentioning

confidence: 99%

Diamond Deposition on Graphite in Hydrogen Microwave Plasma

Zhu

Yao

Dai

et al. 2018

J. Coat. Sci. Technol.

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Hydrogen plasma etching of graphite generates radicals that can be used for diamond synthesis by chemical vapor deposition (CVD). We studied the etching of polycrystalline graphite by a hydrogen microwave plasma, growth of diamond particles of the non-seeded graphite substrates, and characterized the diamond morphology, grain size distribution, growth rate, and phase purity. The graphite substrates served simultaneously as a carbon source, this being the specific feature of the process. A disorder of the graphite surface structure reduces as the result of the etching as revealed with Raman spectroscopy. The diamond growth rate of 3-5 µm/h was achieved, the quality of the produced diamond grains improving with growth time due to inherently nonstationary graphite etching process.

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The Etching Mechanisms of Diamond, Graphite, and Amorphous Carbon by Hydrogen Plasma: A Reactive Molecular Dynamics Study

Zhang

et al. 2023

Advcd Theory and Sims

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Understanding how hydrogen plasma etches various potential products during the diamond growth process can contribute to improving the knowledge of diamond growth. However, due to the absence of an in situ characterization technique during the etching process, the complex chemical reactions involved in the process obscure the atomic‐scale etching mechanisms. In this paper, the etching mechanisms of diamond (001), graphite (0001), and amorphous carbon substrates irradiated by hydrogen plasmas are investigated and compared using molecular dynamics simulations based on ReaxFF. When the incident energy of H atoms is 1 eV, the rate of carbon loss from graphite and amorphous carbon are far higher than that from diamond. As the incident energy of H atoms increases, the etching rate of diamond shows a slow increase, while the etching rates of amorphous carbon and graphite exhibit more significant increases. It can be concluded that the etching rate of diamond is significantly lower than that of graphite and amorphous carbon under H plasma. In the Chemical Vapor Deposition (CVD) process of diamond growth, the generated graphite and amorphous carbon are rapidly etched, leaving only diamond. This offers a plausible explanation for the growth mechanism of diamond through CVD.

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Diamond micropowder synthesis via graphite etching in a microwave hydrogen plasma

Cited by 16 publications

References 27 publications

Hydrophobicity and Adhesion of Aggregated Diamond Particles

Hydrophobicity and Adhesion of Aggregated Diamond Particles

Diamond Deposition on Graphite in Hydrogen Microwave Plasma

The Etching Mechanisms of Diamond, Graphite, and Amorphous Carbon by Hydrogen Plasma: A Reactive Molecular Dynamics Study

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