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Abdelrahman Zkria Fouad Abdel-Wahab Yuki Katamune Tsuyoshi Yoshitake 《Current Applied Physics》2019,19(2):143-148
Ultrananocrystalline diamond/hydrogenated amorphous carbon composite films were deposited in the ambient of hydrogen by coaxial arc plasma deposition. The film compositions and chemical bonding structures were investigated by X-ray diffraction, X-ray photoemission and hydrogen forward scattering spectroscopies. The sp3/(sp2+sp3) ratio and hydrogen content in the film were estimated to be 64% and 35?at.%, respectively. The optical parameters and the optical dispersion profile were determined by using a variable angle spectroscopic ellipsometer at 55°, 65° and 75° angle of incidence in the photon energy range of 0.9–5?eV. Combinations of multiple Gaussian, and Tauc-Lorentz or Cody-Lorentz dispersion functions are used to reproduce the experimental data. Results of ellipsometry showed a refractive index of approximately 2.05 (at 2eV) and optical band gap of 1.63?eV. The imaginary part of dielectric function exhibited a peak at 3.8?eV, which has assigned to π-π* electron transitions. Furthermore, Electron spin resonance measurements implied the existence of dangling bonds, which might have a partial contribution to the optical absorption properties of the deposited films. A correlation between optical parameters and structural profile of the deposited films is discussed. 相似文献
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The incorporation of hydrogen within ultrananocrystalline diamond/amorphous carbon composite films has been investigated by nuclear reaction analysis (NRA) and Fourier transform infrared spectroscopy (FTIR). The film bulk contains ca. 7.5–8% H (for a deposition temperature of 600 °C), while the H concentration in the surface region is considerably higher. FTIR measurements show that the hydrogen‐rich surface is formed right at the beginning of the deposition process and grows outward as the film thickness increases. It can thus be concluded that surface hydrogen species play an active role in the formation of ultrananocrystalline diamond/amorphous carbon films. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Hydrogen-free amorphous carbon films with hardness up to 75 GPa have been deposited by special pulsed arc techniques. The influence of plasma and deposition conditions on the film properties is discussed and some applications are shown. PACS 52.77.Dq; 68.60.-p; 81.15.Aa; 81.15.Ef; 81.70.Ex 相似文献
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A. A. Airapetov L. B. Begrambekov O. I. Buzhinskiy A. V. Grunin A. A. Gordeev A. M. Zakharov A. M. Kalachev Ya. A. Sadovskiy P. A. Shigin 《Physics of Atomic Nuclei》2015,78(14):1640-1642
A device intended for boron carbide coating deposition and material testing under high heat loads is presented. A boron carbide coating 5 μm thick was deposited on the tungsten substrate. These samples were subjected to thermocycling loads in the temperature range of 400–1500°C. Tungsten layers deposited on tungsten substrates were tested in similar conditions. Results of the surface analysis are presented. 相似文献
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W. Sun X. Xiong B.Y. Huang G.D. Li H.B. Zhang P. Xiao Z.K. Chen X.L. Zheng 《Applied Surface Science》2009,255(16):7142-7146
To eliminate cracks caused by thermal expansion mismatch between ZrC coating and carbon-carbon composites, a kind of ZrC/C composite coating was designed as an interlayer. The atmospheric pressure chemical vapor deposition was used as a method to achieve co-deposition of ZrC and C from ZrCl4-C3H6-H2-Ar source. Zirconium tetrachloride (ZrCl4) powder carrier was especially made to control accurately the flow rate. The microstructure of ZrC/C composite coating was studied using analytical techniques. ZrC/C coating shows same morphology as pyrolytic carbon. Transmission electron microscopy (TEM) shows ZrC grains with size of 10-50 nm embed in turbostratic carbon. The formation mechanism is that the growth of ZrC crystals was inhibited by surrounding pyrolytic carbon and kept as nano-particles. Fracture morphologies imply good combination between coating and substrate. The ZrC crystals have stoichiometric proportion near 1, with good crystalline but no clear preferred orientation while pyrolytic carbon is amorphous. The heating-up oxidation of ZrC/C coating shows 11.58 wt.% loss. It can be calculated that the coating consists of 74.04 wt.% ZrC and 25.96 wt.% pyrolytic carbon. The average density of the composite coating is 5.892 g/cm3 by Archimedes’ principle. 相似文献
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AbstractUltrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition (PECVD) and hydrogen-free amorphous carbon (a-C) films of similar thickness deposited by filtered cathodic vacuum arc (FCVA) were subjected to rapid thermal annealing (RTA). Cross-sectional transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) were used to study the structural stability of the films. While RTA increased the thickness of the intermixing layer and decreased the sp3 content of the a-C:H films, it did not affect the thickness or the sp3 content of the a-C films. The superior structural stability of the FCVA a-C films compared with PECVD a-C:H films, demonstrated by the TEM and EELS results of this study, illustrates the high potential of these films as protective overcoats in applications where rapid heating is critical to the device functionality and performance, such as heat-assisted magnetic recording. 相似文献
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C. Popov W. Kulisch S. Bliznakov B. Mednikarov G. Spasov J. Pirov M. Jelinek T. Kocourek J. Zemek 《Applied Physics A: Materials Science & Processing》2007,89(1):209-212
Thin nanocrystalline diamond/amorphous carbon (NCD/a-C) composite films and amorphous diamond-like carbon (DLC) films were
prepared by three methods: microwave plasma chemical vapour deposition (MWCVD) from methane/nitrogen mixtures (NCD/a-C), RF
magnetron sputtering of a pure graphite target in argon/methane ambients, and pulsed laser deposition (PLD) in vacuum or argon
atmosphere (DLC). The films prepared by the three techniques were comprehensively characterized with respect to their bonding
structure by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
PACS 81.05.Uw; 82.80.Pv 相似文献
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采用基于密度泛函理论的第一性原理平面波赝势方法, 研究了硬质合金刀具基底黏结相Co元素对金刚石涂层膜基界面结合强度的影响机理. 借助Materials Studio软件建立了WC/Diamond膜基界面模型和WC-Co/Diamond膜基界面模型, 采用CASTEP仿真软件计算了WC/Diamond膜基界面模型和WC-Co/Diamond膜基界面模型的最优稳定结构. 通过仿真计算, 获得了WC/Diamond膜基界面模型和WC-Co/Diamond膜基界面模型的界面结合能、电荷密度图及Mulliken重叠布居数. 经对比分析后发现, 硬质合金基底中磁性元素Co的存在能转移金刚石涂层膜基界面处W元素及C元素的电荷, 从而使膜基界面处的原子因失电荷而相斥, 这直接导致了金刚石涂层膜基界面间距变大, 使得金刚石涂层膜基界面结合能降低. 相似文献
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The interface of hydrogenated amorphous carbon films grown on single crystal silicon by plasma assisted chemical vapor deposition from methane was studied by angle-resolved X-ray photoelectron spectroscopy. The effect of varying RF power for films grown on a RF-powered electrode was investigated, as well as the effect of varying pulse height for films grown under high voltage pulsed biasing on a non-RF-powered electrode. The spectra of the films deposited at the powered electrode revealed the presence of an approximately stoichiometric silicon carbide layer at the interface. In contrast, the interfacial carbide for films formed at the pulsed biased electrode was found to be nonstoichiometric and silicon rich, which could be ascribed to the relatively much smaller high-energy ion flux to the substrate. The effective thickness of the interfacial layer, as determined from the angle-resolved spectra, however, correlated well with the kinetic energy of plasma ions impinging on the silicon substrate, regardless of the average stoichiometry. The thickness varied from ˜ 4 to 12 Å for kinetic energies ranging from ˜ 150 to 1100 eV. The results indicate that the thickness of the interfacial carbide is determined by the average penetration depth of plasma ions into the silicon substrate, as controlled by their kinetic energy. 相似文献
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Wenran Feng Chizi Liu Guangliang Chen Guling Zhang Weichao Gu Erwu Niu Si-Ze Yang 《Applied Surface Science》2007,253(11):4923-4927
Hard films prepared by pulsed high energy density plasma (PHEDP) are characterized by high film/substrate adhesive strength, and high wear resistance. Titanium carbonitride (TiCN) films were deposited onto YG11C (ISO G20) cemented carbide cutting tool substrates by PHEDP at room temperature. XRD, XPS, SEM, AES, etc. were adopted to analyze the phases (elements) composition, microstructure and the interface of the films, respectively. The results show that, the uniform dense films are composed of grains ranging from 70 to 90 nm. According to the AES result, there is a broad transition layer between the film and the substrate, due to the ion implantation effect of the PHEDP. The transition layer is favorable for the film/substrate adhesion. 相似文献
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Xinchun ChenZhijian Peng Xiang YuZhiqiang Fu Wen YueChengbiao Wang 《Applied Surface Science》2011,257(8):3180-3186
In order to smooth the rough surface and further improve the wear-resistance of coarse chemical vapor deposition diamond films, diamond/tetrahedral amorphous carbon composite films were synthesized by a two-step preparation technique including hot-filament chemical vapor deposition for polycrystalline diamond (PCD) and subsequent filtered cathodic vacuum arc growth for tetrahedral amorphous carbon (ta-C). The microstructure and tribological performance of the composite films were investigated by means of various characterization techniques. The results indicated that the composite films consisted of a thick well-grained diamond base layer with a thickness up to 150 μm and a thin covering ta-C layer with a thickness of about 0.3 μm, and sp3-C fraction up to 73.93%. Deposition of a smooth ta-C film on coarse polycrystalline diamond films was proved to be an effective tool to lower the surface roughness of the polycrystalline diamond film. The wear-resistance of the diamond film was also enhanced by the self-lubricating effect of the covering ta-C film due to graphitic phase transformation. Under dry pin-on-disk wear test against Si3N4 ball, the friction coefficients of the composite films were much lower than that of the single PCD film. An extremely low friction coefficient (∼0.05) was achieved for the PCD/ta-C composite film. Moreover, the addition of Ti interlayer between the ta-C and the PCD layers can further reduce the surface roughness of the composite film. The main wear mechanism of the composite films was abrasive wear. 相似文献
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Diamond-like carbon (DLC) is an attractive biomedical material due to its high inertness and excellent mechanical properties. In this study, DLC films were fabricated on Ti6Al4V and Si(1 0 0) substrates at room temperature by pulsed vacuum arc plasma deposition. By changing the argon flow from 0 to 13 sccm during deposition, the effects of argon flow on the characteristics of the DLC films were systematically examined to correlate to the blood compatibility. The microstructure and mechanical properties of the films were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) surface analysis, a nano-indenter and pin-on-disk tribometer. The blood compatibility of the films was evaluated using in vitro platelet adhesion investigation, and the quantity and morphology of the adherent platelets was investigated employing optical microscopy and scanning electron microscopy.The Raman spectroscopy results showed a decreasing sp3 fraction (an increasing trend in ID/IG ratio) with increasing argon flow from 0 to 13 sccm. The sp3:sp2 ratio of the films was evaluated from the deconvoluted XPS spectra. We found that the sp3 fraction decreased as the argon flow was increased from 0 to 13 sccm, which is consistent with the results of the Raman spectra. The mechanical properties results confirmed the decreasing sp3 content with increasing argon flow. The Raman D-band to G-band intensity ratio increased and the platelet adhesion behavior became better with higher flow. This implies that the blood compatibility of the DLC films is influenced by the sp3:sp2 ratio. DLC films deposited on titanium alloys have high wear resistance, low friction and good adhesion. 相似文献
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Tribological properties of diamond-like carbon films deposited by pulsed laser arc deposition 总被引:1,自引:0,他引:1
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A novel method, pulsed laser arc deposition combining the advantages
of pulsed laser deposition and cathode vacuum arc techniques, was
used to deposit the diamond-like carbon (DLC) nanofilms with
different thicknesses. Spectroscopic ellipsometer, Auger electron
spectroscopy, x-ray photoelectron spectroscopy, Raman spectroscopy,
atomic force microscopy, scanning electron microscopy and
multi-functional friction and wear tester were employed to
investigate the physical and tribological properties of the deposited
films. The results show that the deposited films are amorphous and
the sp$^{2}$, sp$^{3}$ and C--O bonds at the top surface of the films
are identified. The Raman peak intensity and surface roughness
increase with increasing film thickness. Friction coefficients are
about 0.1, 0.15, 0.18, when the film thicknesses are in the range of
17--21~nm, 30--57~nm, 67--123~nm, respectively. This is attributed to
the united effects of substrate and surface roughness. The wear
mechanism of DLC films is mainly abrasive wear when film thickness
is in the range of 17--41~nm, while it transforms to abrasive
and adhesive wear, when the film thickness lies between 72 and 123~nm. 相似文献
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采用脉冲激光气相沉积(PLD)法,研究了氢气压强对非晶CH薄膜性能的影响。原子力显微镜图和白光干涉图显示,薄膜表面平整致密,随着氢气压强增大,粗糙度变大。拉曼光谱分析表明,氢气压强增加,G峰和D峰位置都在向高波数方向移动。傅里叶变换红外光谱分析显示,薄膜中存在sp3—CH2和sp2—CH等基团。最后,采用PLD漂浮法在最优参数氢气压强为0.3 Pa下,成功制备了不同厚度(100~300 nm)、满足一定力学强度、无明显宏观缺陷的自支撑CH薄膜。 相似文献
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Pure hydrogenated amorphous carbon (α-C:H) and nitrogen doped hydrogenated amorphous carbon (α-C:H:N) thin films were prepared using end-Hall (EH) ion beam deposition with a beam energy ranging from 24 eV to 48 eV. The composition, microstructure and mechanical properties of the films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning probe microscopy (SPM), and nano-scratch tests. The films are uniform and smooth with root mean square roughness values of 0.5-0.8 nm for α-C:H and 0.35 nm for α-C:H:N films. When the ion energy was increased from 24 eV to 48 eV, the fraction of sp3 bonding in the α-C:H films increased from 36% to 55%, the hardness increased from 8 GPa to 12.5 GPa, and the Young's modulus increased from 100 GPa to 130 GPa. In the α-C:H:N films, N/C atomic ratio, the hardness and Young's modulus of the α-C:H:N films are, 0.087, 15 and 145 GPa, respectively. The results indicate that both higher ion energy and a small amount of N doping improve the mechanical properties of the films. The results have demonstrated that smooth and uniform α-C:H and α-C:H:N films with large area and reasonably high hardness and Young's modulus can be synthesized by EH ion source. 相似文献
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M. Therasse 《Solid State Communications》2004,129(2):139-142
Amorphous carbon nitride films (a-CNx) were deposited on Si(100) under different rf power and at different substrate temperature TS using rf magnetron sputtering of a high-purity graphite target in pure nitrogen. IR absorption, Raman spectra, and residual stress measurements are used to characterise the films in the as deposited state. The differences in the microstructure of the a-CNx films is related to differences in the deposition mechanism. The TS contribution can operate to increase the connectivity of the C-C network. The stress evolution is the result of the densification, i.e. a structural transformation within of the films that accompanies the nitrogen evolution, due to the C-N and C-C evolution when TS is increased. 相似文献
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OES study of the gas phase during diamond films deposition in high power DC arc plasma jet CVD system
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This paper used optical emission spectroscopy (OES) to study the gas
phase in high
power DC arc plasma jet chemical vapour deposition (CVD) during diamond films growth processes. The
results show that all the deposition parameters (methane concentration,
substrate temperature, gas flow rate and ratio of H2/Ar) could strongly
influence the gas phase. C2 is found to be the most sensitive radical
to deposition parameters among the radicals in gas phase. Spatially resolved
OES implies that a relative high concentration of atomic H exists near the
substrate surface, which is beneficial for diamond film growth. The
relatively high concentrations of C2 and CH are correlated with high
deposition rate of diamond. In our high deposition rate system, C2 is
presumed to be the main growth radical, and CH is also believed to
contribute the diamond deposition. 相似文献