Effect of stress state on graphitization behavior of diamond under high pressure and high temperature

Li, Qian; Zhang, Jiawei; Liu, Jin; Tian, Yi; Liang, Wenjia; Zheng, Linpeng; Zhou, Li; He, Duanwei

doi:10.1016/j.diamond.2022.109241

Cited by 9 publications

(4 citation statements)

References 33 publications

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“…Compared with the stress curve, it is found that the fluctuation of the sp 2 hybridization ratio curve during the early stage of the indentation process is similar to the fluctuation amplitude of the stress curve at the corresponding depth, and it is most obvious at a depth of 10 Å. Therefore, it can be explained that stress may be the dominant factor affecting the early phase transformation of diamond, which is consistent with previous research [68,69]. Further verification of this result will be conducted below.…”

Section: Indentation Depth and Its Effectssupporting

confidence: 89%

Exploring the evolution mechanisms of indentation and scratching on diamond structural transformation based on molecular dynamics

Tong,

Yang,

Liu

et al. 2024

Modelling Simul. Mater. Sci. Eng.

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Diamond, possessing high hardness and chemical stability, finds wide-ranging applications across various industries. However, during the friction process, a graphitization phenomenon may occur, which changes the mechanical properties of the diamond. In this study, molecular dynamics simulation was performed using SiC ball to investigate the influence of indentation depth and temperature on the graphitization transition of the diamond surface. The results showed that the dominant factor affecting the sp2 hybridization ratio during the indentation process was stress, while the temperature was the dominant factor during sliding. The results of this study can be used to understand the friction and wear behavior of diamonds and SiC ball and provide theoretical references for the industrial application of diamonds.

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Section: Indentation Depth and Its Effectssupporting

confidence: 89%

Exploring the evolution mechanisms of indentation and scratching on diamond structural transformation based on molecular dynamics

Tong,

Yang,

Liu

et al. 2024

Modelling Simul. Mater. Sci. Eng.

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“…As the sintering temperature increases, the carbon atoms in the Y zones with relatively low stress are not in the stable region of the diamond phase, leading to the partial graphitization of the sample 28 . Given the specific pressure and temperature conditions employed in this study to sinter the diamond micropowders, the occurrence of local graphitization in the resulting samples is an inevitable outcome, but graphite constitutes only a minute fraction of the overall sample composition (by calculation, the maximum volume percentage is determined to be 2.8% 29 ). As such, the prepared samples can still be regarded as nearly‐pure‐phase PCD sintered bodies, predominantly composed of diamond micropowder.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the relationship between hardness and wear resistance of polycrystalline diamond and cubic boron nitride

Zhou,

Zhang,

Tian

et al. 2024

J Am Ceram Soc.

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Hardness is an important indicator of the wear resistance of tool materials. The study of the effect of hardness on the wear resistance of tool materials has significant practical applications. In this experimental work, a series of polycrystalline cubic boron nitride (PcBN) and diamond (PCD) compacts with different hardness are sintered under high temperature and pressure, and these samples were fashioned into turning tools, used for edge wear testing in the granite turning process. Based on the measurements above, the relationship between hardness and wear resistance in two materials with identical grain sizes (1–2 µm) was examined, and the results reveal a significant positive correlation between the hardness and wear resistance of the two materials. Remarkably, the relationship between hardness and wear resistance in two materials complies with the same type of fitting function. But incredibly, the wear resistance of the two materials exhibits inconsistency as the hardness increases. Specifically, below 40 GPa Vickers hardness, both materials exhibit comparable wear resistance. However, above 40 GPa, the difference in wear resistance between the two materials becomes more pronounced with increasing hardness. At the Vickers hardness of 70 GPa, the abrasion ratio of the PCD is approximately 3.5 times that of the PcBN, and it is anticipated that the disparity between them will continue to expand within the broader range of hardness. Further analysis reveals that the intrinsic hardness of the crystal grains significantly impacts the wear resistance of polycrystalline materials.

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“…As the heating power increases, the G peak area gradually increases. The graphite content is represented by the ratio of the diamond peak area to the graphite G peak area (A C /A G ) [38][39][40][41], as shown in Figure 7. From Figure 7, it can be seen that under the same heating power and pressure conditions, as the diamond particle size increases, the A C /A G gradually increases, which indicates a lower degree of graphitization.…”

Section: Raman Spectramentioning

confidence: 99%

Densification and Surface Carbon Transformation of Diamond Powders under High Pressure and High Temperature

Mao,

Cui,

Hao

et al. 2024

Materials

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A new type of poly-diamond plate without a catalyst was produced via the high-pressure high-temperature (HPHT) compression of diamond powders. The densification of diamond powders and sp3 to sp2 carbon on the surface under HPHT compression was investigated through the characterization of the microstructure, Raman spectroscopy analysis and electrical resistance measurement. The densification and sp3-sp2 transformation on the surface are mainly affected by the pressure, temperature and particle size. The quantitative analysis of the diamond sp3 and sp2 carbon amount was performed through the peak fitting of Raman spectra. It was found that finer diamond particles under a higher temperature and a lower pressure tend to produce more sp2 carbon; otherwise, they produce less. In addition, it is interesting to note that the local residual stresses measured using Raman spectra increase with the diamond particle size. The suspected reason is that the increased particle size reduces the number of contact points, resulting in a higher localized pressure at each contact point. The hypothesis was supported by finite element calculation. This study provides detailed and quantitative data about the densification of diamond powders and sp3 to sp2 transformation on the surface under HPHT treatment, which is valuable for the sintering of polycrystalline diamonds (PCDs) and the HPHT treatment of diamonds.

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Effect of stress state on graphitization behavior of diamond under high pressure and high temperature

Cited by 9 publications

References 33 publications

Exploring the evolution mechanisms of indentation and scratching on diamond structural transformation based on molecular dynamics

Exploring the evolution mechanisms of indentation and scratching on diamond structural transformation based on molecular dynamics

Comparison of the relationship between hardness and wear resistance of polycrystalline diamond and cubic boron nitride

Densification and Surface Carbon Transformation of Diamond Powders under High Pressure and High Temperature

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