Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD

Wiora, Matthias; Brühne, Kai; Flöter, A.; Gluche, P.; Willey, Trevor M.; Kucheyev, S. O.; Buuren, T. van; Hamza, A. V.; Biener, J.; Fecht, Hans-Joerg

doi:10.1016/j.diamond.2008.11.026

Cited by 93 publications

(32 citation statements)

References 18 publications

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“…The (MCD/NCD) bilayer films have a minor K than MCD single-layer film as a result of higher hardness of MCD in comparison to NCD. Because the presence of amorphous carbon or graphite at grain boundaries and lower sp 3 /sp 2 ratios would result in the decrease of hardness, elastic modulus of NCD films compared with MCD films [43]. And the variation trend of K for (MCD/NCD) bilayer film is also consistent with that of roughness in figure 3(a).…”

Section: Tribological Behaviorssupporting

confidence: 71%

Effect of bottom micro-crystalline diamond (MCD) layer and top nano-crystalline diamond (NCD) layer onto the tribological behavior of (MCD/NCD) bilayer film

Luo

et al. 2020

Mater. Res. Express

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In this study, a comparative study of a series of (MCD/NCD) bilayer films with different MCD grain sizes and NCD layer thickness deposited on cemented tungsten carbide (WC-Co) flat substrates was conducted by changing the deposition time. Tribological behaviors of these diamond films were evaluated by using a reciprocal tribometer without lubrication. In friction test against Si 3 N 4 balls, the (3hMCD/6hNCD) bilayer film showed the lowest coefficient of friction (0.059) and wear rates of counterpart balls (1.75×10 −6 mm 3 N −1 m −1 ) because of its lowest surface roughness and higher sp 2 content. This work provides a guide to choose suitable (MCD/NCD) bilayer basic structure in multilayer diamond film for getting a fine diamond film with low roughness and great tribological performance for different applications.

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Section: Tribological Behaviorssupporting

confidence: 71%

Effect of bottom micro-crystalline diamond (MCD) layer and top nano-crystalline diamond (NCD) layer onto the tribological behavior of (MCD/NCD) bilayer film

Luo

et al. 2020

Mater. Res. Express

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“…A simple estimate indicates that the fraction of atoms connected with grain boundaries may increase to about 10% for crystal sizes of a few nanometers. 57 RUS and laser-Doppler interferometry have been used to determine sets of elastic coefficients, assuming cubic symmetry. 58 It turned out that the diagonal stiffness coefficients C 11 and C 44 decreased as the grain size decreased, while, simultaneously, the off-diagonal coefficient C 12 increased significantly in comparison with microcrystalline diamond.…”

Section: E Nanocrystalline Diamondmentioning

confidence: 99%

The mechanical properties of various chemical vapor deposition diamond structures compared to the ideal single crystal

Hess

2012

Journal of Applied Physics

114

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Bias-enhanced nucleation and growth processes for improving the electron field emission properties of diamond films J. Appl. Phys. 111, 053701 (2012) Direct visualization and characterization of chemical bonding and phase composition of grain boundaries in polycrystalline diamond films by transmission electron microscopy and high resolution electron energy loss spectroscopy Appl. Phys. Lett. 99, 201907 (2011) Impurity impact ionization avalanche in p-type diamond Appl. Phys. Lett. 99, 202105 (2011) Ultrathin ultrananocrystalline diamond film synthesis by direct current plasma-assisted chemical vapor deposition J. Appl. Phys. 110, 084305 (2011) Diamond nanoparticles with more surface functional groups obtained using carbon nanotubes as sourcesThe structural and electronic properties of the diamond lattice, leading to its outstanding mechanical properties, are discussed. These include the highest elastic moduli and fracture strength of any known material. Its extreme hardness is strongly connected with the extreme shear modulus, which even exceeds the large bulk modulus, revealing that diamond is more resistant to shear deformation than to volume changes. These unique features protect the ideal diamond lattice also against mechanical failure and fracture. Besides fast heat conduction, the fast vibrational movement of carbon atoms results in an extreme speed of sound and propagation of crack tips with comparable velocity. The ideal mechanical properties are compared with those of real diamond films, plates, and crystals, such as ultrananocrystalline (UNC), nanocrystalline, microcrystalline, and homo-and heteroepitaxial single-crystal chemical vapor deposition (CVD) diamond, produced by metastable synthesis using CVD. Ultrasonic methods have played and continue to play a dominant role in the determination of the linear elastic properties, such as elastic moduli of crystals or the Young's modulus of thin films with substantially varying impurity levels and morphologies. A surprising result of these extensive measurements is that even UNC diamond may approach the extreme Young's modulus of singlecrystal diamond under optimized deposition conditions. The physical reasons for why the stiffness often deviates by no more than a factor of two from the ideal value are discussed, keeping in mind the large variety of diamond materials grown by various deposition conditions. Diamond is also known for its extreme hardness and fracture strength, despite its brittle nature. However, even for the best natural and synthetic diamond crystals, the measured critical fracture stress is one to two orders of magnitude smaller than the ideal value obtained by ab initio calculations for the ideal cubic lattice. Currently, fracture is studied mainly by indentation or mechanical breaking of freestanding films, e.g., by bending or bursting. It is very difficult to study the fracture mechanism, discriminating between tensile, shear, and tearing stress components (mode I-III fracture) with these partly semiquantitative methods. A nov...

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“…In contrast, nanocrystalline diamond films grown by HFCVD usually possess high electrical resistivity. HRTEM investigation 10 have shown that these films have almost pure diamond content and thin grain boundaries of 0.6 nm, which is the main factor, leading to the almost insulating properties. We present here, for the first time, the growth of highly conductive ultra-nanocrystalline diamond films by HFCVD without additional nitrogen in the gas phase.…”

Section: Introductionmentioning

confidence: 99%

Structural properties of highly conductive ultra-nanocrystalline diamond films grown by hot-filament CVD

et al. 2017

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In this work we show the correlation of the electrical conductivity of ultra-nanocrystalline (UNCD) diamond films grown by hot filament chemical vapor deposition (HFCVD) with their structural properties. The substrate temperature, the methane to hydrogen ratio and the pressure are the main factor influencing the growth of conductive UNCD films, which extends from electrical resistive diamond films (<10-4 S/cm) to highly conductive diamond films with a specific conductivity of 300 S/cm. High-resolution-transmission-electron-microscopy (HRTEM) and electron-energy-loss-spectroscopy (EELS) have been done on the highly conductive diamond films, to show the origin of the high electrical conductivity. The HRTEM results show random oriented diamond grains and a large amount of nano-graphite between the diamond crystals. EELS investigations are confirming these results. Raman measurements are correlated with the specific conductivity, which shows structural changes of sp2 carbons bonds as function of conductivity. Hall experiments complete the results, which lead to a model of an electron mobility based conductivity, which is influenced by the structural properties of the grain boundary regions in the ultra-nanocrystalline diamond films.

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Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD

Cited by 93 publications

References 18 publications

Effect of bottom micro-crystalline diamond (MCD) layer and top nano-crystalline diamond (NCD) layer onto the tribological behavior of (MCD/NCD) bilayer film

Effect of bottom micro-crystalline diamond (MCD) layer and top nano-crystalline diamond (NCD) layer onto the tribological behavior of (MCD/NCD) bilayer film

The mechanical properties of various chemical vapor deposition diamond structures compared to the ideal single crystal

Structural properties of highly conductive ultra-nanocrystalline diamond films grown by hot-filament CVD

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