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1.
We study the technique of nanoindentation hardness measurement applied to extremely hard and elastic thin films. We do the
study with the aid of Hertz’s solutions for elastic contacts. The effect of different apical angles in ideally sharp conical
diamond indenters is analyzed. In addition, the blunt tip shape of practical diamond indenters is discussed. The area function
of the tip of real indenters is deduced from experimental nanoindentation measurements performed with these indenters on fused
quartz. Triangular-base pyramidal indenters with Berkovich and cube corner geometries are considered. Theoretical hardness
values applying Hertz’s and Oliver and Pharr’s methods of analysis are obtained and compared with the experimental data deduced
from nanoindentation measurements performed on very hard and elastic ta-C films. The theoretical analysis shows a necessary
dependence of the calculated hardness values with the apical angle of the indenter in totally elastic materials and to some
extent in elastoplastic materials. Moreover, when the indenter tip is blunt or when there are inaccuracies in the measured
area function of the indenter tip, hardness values decrease for very small penetration depths. Besides, in these films, because
of their very small thickness, measured hardness values also decrease for measurements with penetration depths larger than
a fraction of film thickness, due to the effects of the softer substrate.
Received: 13 June 2000 / Accepted: 21 June 2000 / Published online: 5 October 2000 相似文献
2.
S. Gloor V. Romano W. Lüthy H.P. Weber V.V. Kononenko S.M. Pimenov V.I. Konov A.V. Khomich 《Applied Physics A: Materials Science & Processing》2000,70(5):547-550
Two-dimensional antireflective periodical microstructures for the IR range are fabricated on the surface of CVD diamond films.
These structures are created using an ArF excimer laser (λ=193 nm) and a direct writing scheme consisting of a beam collimator
and a microscope objective to focus the beam onto the sample. Two different arrays are investigated. One has a spacing of
3 μm and is produced with single shots and the other one has a spacing of 4 μm and is produced with three shots per spot.
The hole depth and shape are measured with an atomic force microscope (AFM). The optical transmittance and the scattering
properties of the structure at 10.6 μm are reported for a CO2 laser beam. With a spectrometer further transmission measurements in the range of 5 to 20 μm are performed.
Received: 16 September 1999 / Accepted: 11 October 1999 / Published online: 24 March 2000 相似文献
3.
3 radical in the plume of an arcjet plasma during diamond film chemical vapor deposition. C3, identified using laser-induced fluorescence, is distributed in a shell surrounding the diamond-depositing core of the arcjet
plasma plume.
Received: 13 June 1996/Revised version: 5 September 1996 相似文献
4.
L.-W. Yin M.-S. Li J.-J. Cui Y.-J. Song F.-Z. Li Z.-Y. Hao 《Applied Physics A: Materials Science & Processing》2001,73(5):653-657
For understanding the mechanism of diamond growth at high temperature–high pressure (HTHP) from a metallic catalyst–graphite
system, it is of great interest to perform atomic force microscopy (AFM) experiments, which provide a unique technique different
from that of normal optical and electronic microscopy studies, to study the topography of HTHP as-grown diamond single crystals.
In the present paper, we report first AFM results on diamond single crystals grown from a Fe-Ni-C system at HTHP to reveal
the growth mechanism of diamond single crystals at HTHP. AFM images for as-grown diamond samples show dark etch pits on the
(111) surface, indicating dislocations. Some fine particles about 100–300 nm in dimension were directly observed on the (100)
diamond surface. These particles are believed to have been formed through transition of graphite to diamond under the effect
of the catalyst and to have been transported to the growing diamond surface through a metallic thin film by diffusion. The
roughness of the (100) diamond surface is found to be about several tens of nanometers through profile analysis. The diamond
growth at HTHP, in a sense, could be considered as a process of unification of these fine diamond particles or of carbon-atom-cluster
recombination on the growing diamond crystal surface. Successive growth interlayer steps on the (111) diamond surface were
systemically examined. The heights of the growth interlayer steps were measured by sectional analysis. It was shown that the
heights of the growth interlayer steps are quite different and range from about 10 to 25 nm. The source of the interlayer
steps might be dislocations. The diamond-growth mechanism at HTHP could be indicated by the AFM topography of the fine diamond
particles and the train-growth interlayer steps on the as-grown diamond surfaces.
Received: 29 March 2001 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
5.
G.A. Shafeev E.D. Obraztsova S.M. Pimenov 《Applied Physics A: Materials Science & Processing》1997,65(1):29-32
2 O, (CH3)2SO). Diamond samples are virtually transparent at this wavelength, and the coupling of laser radiation to diamond is via the
formation of a thin graphitized layer at the diamond surface. The etching rate in liquid media is slightly higher than in
air at otherwise equal conditions and is as high as 50 μm/s for etching with a scanning laser beam. Raman spectra measurements
carried out on diamond samples etched in air show the presence of glassy carbon on the surface, whereas for samples etched
in a liquid the diamond peak at 1332 cm-1 dominates with significantly lower intensity of the glassy carbon peak. Electroless copper deposition on the laser-etched
features is studied to compare the catalytic activity of the diamond surface etched in air with that etched in liquids. Possible
mechanisms responsible for the observed difference both in the structure of the etched area and in the electroless Cu deposition
onto the surface etched in various media (air or liquids) are discussed.
Received: 2 August 1996/Accepted: 7 January 1997 相似文献
6.
Design of a Class of New sp2-sp3 Carbons Constructed by Graphite and Diamond Building Blocks
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The sp2–sp3-hybridized carbon allotropes with the advantage of two hybrid structures possess rich and fascinating electronic and mechanical properties and they have received long-standing attention.We design a class of versatile sp2–sp3carbons composed of graphite and diamond structural units with variable sizes.This class of sp2–sp3carbons is energetically more favorable than graphite under high pressure,and their mechanical and dynamical stabilities are further confirmed at ambient pressure.The calculations of band structure and mechanical properties indicate that this class of sp2–sp3carbons not only exhibits peculiar electronic characteristics adjusted from semiconducting to metallic nature but also presents excellent mechanical characteristics,such as superhigh hardness and high ductility.These sp2–sp3carbons have desirable properties across a broad range of potential applications. 相似文献
7.
研究了金刚石光学特性与氮杂质及其含量的关系,从传统的金刚石氮含量标定方法出发,修正了金刚石氮含量的计算方法,并且用添加叠氮化钠的原料在六面顶压机上进行了高氮含量金刚石的制备研究.随着体系中叠氮化钠的添加,金刚石红外吸收谱在800—1400 cm-1范围的吸收强度相对于基线不断升高,这表明金刚石中存在的氮含量在随着叠氮化钠添加而升高,金刚石在单声子区域吸收强度大大增强.用含叠氮化钠的原料制备的金刚石呈现绿色、墨绿色甚至黑色,颜色的深浅依赖于叠氮化钠添加的多少.傅里叶红外光谱测试结果表明
关键词:
金刚石
光学材料
杂质
红外 相似文献
8.
Due to different oriented diamond films having different properties, in this paper optical and electrical properties of different oriented diamond films have been investigated. The measured results indicate diamond films are of high quality and the properties of the (0 0 1)-oriented diamond film are better than those of the (1 1 1)-oriented one. Refractive index and extinction coefficient of (0 0 1)-oriented diamond film in the wavelength range of 2.5-12.5 μm is 2.391 and in the order of 10−5, respectively. And for the (1 1 1)-oriented one it is 2.375 and in the order of 10−4. The dark current of the (0 0 1)-oriented diamond film is 33.7 nA under an applied electric field of 100 kV/cm. The resistivity of the (0 0 1)-oriented diamond film obtained is about 2.33 × 1010 Ω cm. The current of (0 0 1)-oriented diamond film is almost no change with the time testing. 相似文献
9.
The outstanding properties of diamond, such as radiation hardness, high carrier mobility, high band gap and breakdown field, distinguish it as a good candidate for radiation detectors. The detector's performance is strongly limited by the concentration of defects (grain boundaries and/or impurities) in chemical vapor deposition (CVD) diamond. We report the response of free-standing CVD diamond with a thickness of 300 μm and area of 2×2 cm2, synthesized by a hot filament chemical vapor deposition (HFCVD) technique, to 5.9 keV X-ray radiation from a 55Fe source. The linear I-V characteristics indicate that CVD diamond has good ohmic contacts. This detector also shows good results such as dark-current of 10−8 A, photocurrent of 10−6 A, energy resolution <0.4%, and a high ratio of signal to noise. 相似文献
10.
受激拉曼散射是一种重要的非线性光学频率变换技术,在拓展激光波段方面有十分广泛的应用前景。因此,寻找具有优良光学性质的拉曼介质,提高拉曼激光器性能,具有重要的研究价值。相比于传统的固体拉曼晶体,人造金刚石晶体具有拉曼增益系数大、拉曼频移大、导热率高和透过性好等显著优点,基于人造金刚石晶体的拉曼激光器能够获得更高的输出功率和转换效率。本文简要介绍了化学气相沉积法(CVD)制备的金刚石晶体的光学性质和热学特性,总结了基于人造金刚石晶体的拉曼激光器在紫外波段、可见光波段及红外波段的研究现状,并对其发展进行了展望。 相似文献
11.
B.N. Masina A. Forbes O.M. Ndwandwe B.W. Mwakikunga G. Katumba 《Physica B: Condensed Matter》2009,404(22):4485-4488
In this study we make use of laser heating of HTHP industrial diamond, to study temperature induced changes to the diamond structure, both chemically and mechanically, in the absence of mechanical forces. This has relevance to the efficacy of diamond as a hard material in such applications as rock drilling and material processing. We report on the induced defects when the diamond is irradiated with high power CO2 and Nd:YAG lasers respectively, and show that the thermal induced stresses in the diamond are sufficient to radically alter its physical properties, resulting in critical fracture. Raman spectroscopy, X-ray diffraction and scanning electron microscopy indicate that the heating does not result in graphitisation of the diamond, but rather diffusion from the non-diamond base results in cobalt and tungsten oxides forming on the diamond surface. This has a deleterious effect on the diamond performance. 相似文献
12.
The intrinsic character of the correlation between hardness and thermodynamic properties of solids has been established. The proposed thermodynamic model of hardness allows one to easily estimate hardness and bulk moduli of known or even hypothetical solids from the data on Gibbs energy of atomization of the elements or on the enthalpy at the melting point. The correctness of this approach is illustrated by an example of the recently synthesized superhard diamond-like BC5 and orthorhombic modification of boron, γ-B28. The pressure and/or temperature dependences of hardness were calculated for a number of hard and superhard phases, i.e. diamond, cBN, B6O, B4C, SiC, Al2O3, β-B2O3 and β-rh boron. Excellent agreement between experimental and calculated values is observed for temperature dependences of Vickers and Knoop hardness. In addition, the model predicts that some materials can become harder than diamond at pressures in the megabar range. 相似文献
13.
Diamonds attract enormous interest as gemstones. This rather frivolous “application” is based on their optical properties and contributes about 95 percent of the turnover in the diamond industry. Another area of application, which may now be seen as a crude application, is a diamond-tipped tool for the abrasive and cutting industries. These applications exploit the hardness and wear resistance of diamond, and dominate the demand for synthetic diamond production. These applications do not place the most stringent requirements on the quality of diamond. As has become clear at this workshop, a crucial new role for diamond in an ultra-high technology area is emerging. Diamond devices at synchrotrons require near– theoretical values of perfection of the diamond lattice. This material is vital to the continued increase in beam performance as well as the expansion of the suite of measurement techniques of modern synchrotrons. An international workshop on “diamond single crystals for 3rd and 4th generation X-ray sources” was held in Grenoble, France, on May 24–25, 2004. 相似文献
14.
We report results of steel substrates coated with hard amorphous carbon and with diamond films. In order to enhance the adherence to the substrate, steel substrates were pretreated by means of a silicon ion beam. Raman spectroscopy was used to analyze the structure of silicon interface while the elastic recoil detection analysis method was applied to determine their composition and thickness. The a-C adherence to the substrate and hardness were also tested. The diamond films were observed by SEM. 相似文献
15.
Growth and Characteristics of Freestanding Hemispherical Diamond Films by Microwave Plasma Chemical Vapor Deposition
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Freestanding hemispherical diamond films have been fabricated by microwave plasma chemical vapor deposition using graphite and molybdenum (Mo) as substrates. Characterized by Raman spectroscopy and scanning electron microscopy, the crystalline quality of the films deposited on Mo is higher than that on graphite, which is attributed to the difference in intrinsic properties of the two substrates. By decreasing the methane concentration, the diamond films grown on the Mo substrate vary from black to white, and the optical transparency is enhanced. After polishing the growth side, the diamond films show an infrared transmittance of 35-60% in the range 400-4000 cm^- 1. 相似文献
16.
17.
It is possible for Beryllium oxide (BeO) to have a cubic diamond structure although it normally has a hexagonal structure under ambient conditions. As the solution of cubic BN and diamond, the solid solution of cubic BeO- diamond or BeO-cBN-diamond can potentially be a kind of super-hard materials with designable hardness; and this solution has also been confirmed based on our preliminary first principles calculations. In addition, the nonstoichiometry of BeO could create a mobile carrier in the cubic BeO-C or BeO BN-C system and it might lead to a new type of semiconductor Be-diamond. 相似文献
18.
Micromachining and surface processing of the super-hard nano-polycrystalline diamond by three types of pulsed lasers 总被引:1,自引:0,他引:1
Takuo Okuchi Hiroaki Ohfuji Shoko Odake Hiroyuki Kagi Syohei Nagatomo Mitsuru Sugata Hitoshi Sumiya 《Applied Physics A: Materials Science & Processing》2009,96(4):833-842
Laser beam micromachining was applied to super-hard nano-polycrystalline diamond (NPD) synthesized by the direct conversion
of graphite at high pressure and high temperature. Three types of pulsed lasers were tested: nanosecond near-infrared, nanosecond
near-ultraviolet, and femtosecond near-infrared lasers. The latter two were also applied for synthetic single crystal of diamond
to compare the results with those of the NPD. It was demonstrated that the nanosecond near-infrared laser was the most efficient
device for rough shaping of the NPD, while the ultraviolet and femtosecond lasers give satisfactory results for precise surface
finishing of it. The properties of the laser-processed surfaces were analyzed by scanning and transmission electron microscopy,
laser scanning microscopy, and micro Raman spectroscopy. These analyses demonstrated that the three types of lasers play different
and complementary roles, and that their combination is the best suitable solution for micromachining of the hardest diamond
into any desired shapes. 相似文献
19.
The deformation mechanisms of GaN thin films obtained by metal-organic chemical vapor deposition (MOCVD) method were studied using nanoindentation with a Berkovich diamond indenter, micro-Raman spectroscopy and the cross-sectional transmission electron microscopy (XTEM) techniques. Due to the sharpness of the tip of Berkovich indenter, the nanoindentation-induced deformation behaviors can be investigated at relatively lower load and, hence, may cover wider range of deformation-related phenomena over the same loading range. The load-displacement curves show the multiple “pop-ins” during nanoindentation loading. No evidence of nanoindentation-induced phase transformation and cracking patterns were found up to the maximum load of 300 mN, as revealed from the micro-Raman spectra and the scanning electron microscopy (SEM) observations within the mechanically deformed regions. In addition, XTEM observation performed near the cross-section of the indented area revealed that the primary deformation mechanism in GaN thin film is via propagation of dislocations on both basal and pyramidal planes. The continuous stiffness measurement (CSM) technique was used to determine the hardness and Young's modulus of GaN thin films. In addition, analysis of the load-displacement data reveals that the values of hardness and Young's modulus of GaN thin films are 19 ± 1 and 286 ± 25 GPa, respectively. 相似文献
20.
G.A. Shafeev 《Applied Physics A: Materials Science & Processing》1998,67(3):303-311
2 O3, SiC, diamond, ZrO2, etc. are presented. The activation of the dielectric surface can be achieved in a wide range of laser wavelengths and is
stable in time. This activation allows selective deposition of various metals (Cu, Ni, Pt, Pd, etc.) with lateral dimensions
of several μm. The model of the activation process is discussed. This deals with the modification of the band gap of the dielectric,
which involves the appearance of a non-zero density of electronic states in the vicinity of the potential of electroless metal
reduction. These electronic states can arise either from the formation of point defects in the ablated surface (for example,
F centers in Al2O3, CeO2, or ZrO2) or from the band bending of the dielectric caused by residual mechanical stresses left in the material after laser ablation
(SiC or diamond). The data on the activation of dielectrics by mechanical indentation are qualitatively consistent with the
model.
Received: 5 January 1998/Accepted: 7 January 1998 相似文献