Showing papers on "Diamond published in 2000"
TL;DR: An unusually high value, lambda approximately 6600 W/m K, is suggested for an isolated (10,10) nanotube at room temperature, comparable to the thermal conductivity of a hypothetical isolated graphene monolayer or diamond.
Abstract: Recently discovered carbon nanotubes have exhibited many unique material properties including very high thermal conductivity. Strong sp 2 bonding configurations in carbon network and nearly perfect self-supporting atomic structure in nanotubes give unusually high phonon-dominated thermal conductivity along the tube axis, possibly even surpassing that of other carbon-based materials such as diamond and graphite (in plane). In this chapter, we explore theoretical and experimental investigations for the thermal-transport properties of these materials.
3,011 citations
TL;DR: Experimental evidence is given that hydrogen is only a necessary requirement for SC; exposure to air is also essential and a mechanism in which a redox reaction in an adsorbed water layer provides the electron sink for the subsurface hole accumulation layer is proposed.
Abstract: Hydrogen-terminated diamond exhibits a high surface conductivity (SC) that is commonly attributed to the direct action of hydrogen-related acceptors. We give experimental evidence that hydrogen is only a necessary requirement for SC; exposure to air is also essential. We propose a mechanism in which a redox reaction in an adsorbed water layer provides the electron sink for the subsurface hole accumulation layer. The model explains the experimental findings including the fact that hydrogenated diamond is unique among all semiconductors in this respect.
823 citations
TL;DR: In this paper, the authors observed photon antibunching in the fluorescent light emitted from a single nitrogen-vacancy center in diamond at room temperature, and the possibility of generating triggerable single photons with such a solid-state system is discussed.
Abstract: We observed photon antibunching in the fluorescent light emitted from a single nitrogen-vacancy center in diamond at room temperature. The possibility of generating triggerable single photons with such a solid-state system is discussed.
616 citations
TL;DR: In this article, the basic science and technology underlying the chemical vapour deposition of diamond thin films, and how this is leading to the development of diamond as a 21st century engineering material are discussed.
Abstract: Diamond has some of the most extreme physical properties of any material, yet its practical use in science or engineering has been limited due its scarcity and expense. With the recent development of techniques for depositing thin films of diamond on a variety of substrate materials, we now have the ability to exploit these superlative properties in many new and exciting applications. In this paper, we shall explain the basic science and technology underlying the chemical vapour deposition of diamond thin films, and show how this is leading to the development of diamond as a 21st century engineering material.
608 citations
TL;DR: It is observed that photon antibunching in the fluorescent light emitted from a single nitrogen-vacancy center in diamond at room temperature is observed.
Abstract: We have observed photon antibunching in the fluorescence light emitted from a single N-V center in diamond at room temperature. The possibility of generating triggerable single photons with such a solide state system is discussed
496 citations
452 citations
13 Apr 2000
TL;DR: In this article, the authors present a structural and physicochemical analysis of ultrahard materials, including carbon and carbonitrides, based on the CO 2 -Laser Heating Technique in a diamond cell.
Abstract: Introduction: Novel Ultrahard Materials (A. Zerr & R. Riedel) STRUCTURES AND PROPERTIES Structural Chemistry of Hard Materials (W. Jeitschko, et al.) Phase Transitions and Material Synthesis using the CO 2 -Laser Heating Technique in a Diamond Cell (A. Zerr, et al.) Mechanical Properties and their Relation to Microstructure (D. Sherman & D. Brandon) Nanostructured Superhard Materials (S. Veprek) Corrosion of Hard Materials (K. Nickel & Y. Gogotsi) Interrelations Between the Influences of Indentation Size, Surface State, Grain Size, Grain-Boundary Deformation, and Temperature on the Hardness of Ceramics (A. Krell) Transition Metal Carbides, Nitrides, and Carbonitrides (W. Lengauer) New Superhard Materials: Carbon and Silicon Nitrides (J. Lowther) Effective Doping in Novel sp 2 Bonded Carbon Allotropes (G. Jungnickel, et al.) SYNTHESIS AND PROCESSING Directed Metal Oxidation (V. Jayaram & D. Brandon) Self-Propagating High-Temperature Synthesis of Hard Materials (Z. Munir & U. Anselmi-Tamburini) Hydrothermal Synthesis of Diamond (K. Nickel, et al.) Chemical Vapor Deposition of Diamond Films (C.-P. Klages) Vapor Phase Deposition of Cubic Boron Nitride Films (K. Bewilogua & F. Richter) Polymer to Ceramic Transformation: Processing of Ceramic Bodies and Thin Films (G. Soraru & P. Colombo) MATERIALS AND APPLICATIONS Diamond Materials and their Applications (R. Caveney) Applications of Diamond Synthesized by Chemical Vapor Deposition (R. Sussmann) Diamond-like Carbon Films (C.-P. Klages & K. Bewilogua) Ceramics Based on Alumina: Increasing the Hardness for Tool Applications (A. Krell) Silicon Carbide Based Hard Materials (K. Schwetz) Silicon Nitride Based Hard Materials (M. Herrmann, et al.) Boride-Based Hard Materials (R. Telle, et al.) The Hardness of Tungsten Carbide-Cobalt Hardmetal (S. Luyckx) Data Collection of Properties of Hard Materials (G. Berg, et al.) Index
401 citations
TL;DR: The cyclic voltammetric and kinetic data presented can serve as a benchmark for research groups evaluating the electrochemical properties of semimetallic (i.e., conductive), hydrogen-terminated, polycrystalline diamond.
Abstract: Standard electrochemical data for high-quality, boron-doped diamond thin-film electrodes are presented. Films from two different sources were compared (NRL and USU) and both were highly conductive, hydrogen-terminated, and polycrystalline. The films are acid washed and hydrogen plasma treated prior to use to remove nondiamond carbon impurity phases and to hydrogen terminate the surface. The boron-doping level of the NRL film was estimated to be in the mid 1019 B/cm3 range, and the boron-doping level of the USU films was ∼5 × 1020 B/cm-3 based on boron nuclear reaction analysis. The electrochemical response was evaluated using Fe(CN)63-/4-, Ru(NH3)63+/2+, IrCl62-/3-, methyl viologen, dopamine, ascorbic acid, Fe3+/2+, and chlorpromazine. Comparisons are made between the apparent heterogeneous electron-transfer rate constants, koapp, observed at these high-quality diamond films and the rate constants reported in the literature for freshly activated glassy carbon. Ru(NH3)63+/2+, IrCl62-/3-, methyl viologen, a...
386 citations
TL;DR: In this article, the melting point depression of iron at high pressure was investigated in the presence of light elements and the structure of the inner core of the Earth's inner core was shown to decrease with increasing pressure.
Abstract: The interpretation of seismic data and computer modeling requires increased accuracy in relevant material properties in order to improve our knowledge of the structure and dynamics of the Earth's deep interior. To obtain such properties, a complementary method to classic shock compression experiments and theoretical calculations is the use of laser-heated diamond cells, which are now producing accurate data on phase diagrams, equations of state, and melting. Data on one of the most important measurements, the melting temperatures of iron at very high pressure, are now converging. Two other issues linking core properties to those of iron are investigated in the diamond cell: One is the melting point depression of iron in the presence of light elements, and the other is the structure of iron at the conditions of the inner core. First measurements on eutectic systems indicate a significant decrease in the melting point depression with increasing pressure, which is in contrast to previous predictions. X-ray diffraction measurements at simultaneously high pressure and high temperature have improved significantly with the installation of high-pressure “beam lines” at synchrotron facilities, and structural measurements on iron are in progress. Considerable efforts have been made to develop new techniques to heat minerals at the conditions of the deep mantle in the diamond cell and to measure their phase relations reliably. Even measurements of the melting behavior of realistic rock compositions at high pressure, previously considered to be impossible in the diamond cell, have been reported. The extrapolated solidus of the lower mantle intersects the geotherm at the core-mantle boundary, which may explain the seismically observed ultra low velocity zone. The diamond cell has great potential for future development and broad application, as new measurements on high-pressure geochemistry at deep mantle and core conditions have opened a new field of research. There are, however, strict experimental requirements for obtaining reliable data, which are summarized in the present paper. Results from recent measurements of melting temperatures and phase diagrams of lower mantle and core materials at very high pressure are reviewed.
382 citations
TL;DR: A series of molecular-dynamics simulations using a many-body interatomic potential has been performed to investigate the behavior under load of several symmetrical tilt grain boundaries in diamond.
Abstract: A series of molecular-dynamics simulations using a many-body interatomic potential has been performed to investigate the behavior under load of several ^001& and ^011& symmetrical tilt grain boundaries ~GB’s! in diamond. Cohesive energies, the work for fracture, maximum stresses and strains, and toughness as a function of GB type are evaluated. Results indicate that special short-period GB’s possess higher strengths and greater resistance to crack propagation than GB’s in nearby misorientation angles. Based on dynamic simulations, it was found that the mechanism of interface failure for GB’s without preexisting flaws is not that implied by Orovan’s criterion, but rather GB strength is defined by GB type instead of cleavage energy. In simulations of crack propagation within GB’s on the other hand, it was found that critical stresses for crack propagation from atomistic simulation and from the Griffith criterion are consistent, indicating that GB cleavage energy is an important characteristic of GB toughness. Crack propagation in polycrystalline diamond samples under an applied load was also simulated and found to be predominantly transgranular rather than intergranular.
371 citations
TL;DR: In this article, the electron energy loss spectroscopy (EELS) and the Raman spectra were used to confirm the absence of sp2 bonded carbon and showed strong contributions from surface plasmons.
TL;DR: In this article, the role of quantum corrections to the classical thermal conduction was examined, and it was shown that these effects are small for fairly harmonic systems such as diamond, and that vacancies dramatically decrease the thermal conductivity, and can be described by a reciprocal relation with a scaling as n va, with a50.6960.
Abstract: Based on the Green‐Kubo relation from linear response theory, we calculated the thermal current autocorrelation functions from classical molecular dynamics ~MD! simulations. We examined the role of quantum corrections to the classical thermal conduction and concluded that these effects are small for fairly harmonic systems such as diamond. We then used the classical MD to extract thermal conductivities for bulk crystalline systems. We find that ~at 300 K! 12 C isotopically pure perfect diamond has a thermal conductivity 45% higher than natural ~1.1% 13 C! diamond. This agrees well with experiment, which shows a 40%‐50% increase. We find that vacancies dramatically decrease the thermal conductivity, and that it can be described by a reciprocal relation with a scaling as n va , with a50.6960.11 in agreement with phenomenological theory (a51/2 to 3/4!. Such calculations of thermal conductivity may become important for describing nanoscale devices. As a first step in studying such systems, we examined the mass effects on the thermal conductivity of compound systems, finding that the layered system has a lower conductivity than the uniform system. © 2000 American Institute of Physics.@S0021-9606~00!70140-1#
TL;DR: In this paper, thin boron-doped diamond films have been prepared by HF CVD (hot filament chemical vapour deposition technique) on conductive p-Si substrate (Si/Diamond), and the morphology of these Si/diamond electrodes has been investigated by SEM and Raman spectroscopy.
Abstract: Thin boron-doped diamond films have been prepared by HF CVD (hot filament chemical vapour deposition technique) on conductive p-Si substrate (Si/Diamond). The morphology of these Si/diamond electrodes has been investigated by SEM and Raman spectroscopy. The electrochemical behaviour of the Si/diamond electrodes in 1 M H2SO4 and in 1 M H2SO4 + carboxylic acids has been investigated by cyclic voltammetry. Finally, the electrochemical oxidation of some simple carboxylic acids (acetic, formic, oxalic) has been investigated by bulk electrolysis. These acids can be oxidized at Si/diamond anodes to CO2, in the potential region of water and/or the supporting electrolyte decomposition, with high current efficiency.
TL;DR: The theoretical strength of diamond has been calculated using a first principles approach and is found to be strongly dependent on crystallographic direction, which is believed to be the reason for the remarkable dominance of the 111 cleavage plane when diamond is fractured.
Abstract: The theoretical strength of diamond has been calculated for the $〈100〉$, $〈110〉$, and $〈111〉$ directions using a first principles approach and is found to be strongly dependent on crystallographic direction. This elastic anisotropy, found at large strains, and particularly the pronounced minimum in cohesion in the $〈111〉$ direction, is believed to be the reason for the remarkable dominance of the ${111}$ cleavage plane when diamond is fractured. The extra energy required to cleave a crystal on planes other than ${111}$ is discussed with reference to simple surface energy calculations and also the introduction of bond-bending terms.
TL;DR: The electrochemistry of histamine and serotonin in neutral aqueous media (pH 7.2) was investigated using polycrystalline, boron-doped diamond thin-film electrodes and cyclic voltammetry, hydrodynamic voltametry, and flow injection analysis (FIA) with amperometric detection were used to study the oxidation reactions.
Abstract: The electrochemistry of histamine and serotonin in neutral aqueous media (pH 7.2) was investigated using polycrystalline, boron-doped diamond thin-film electrodes. Cyclic voltammetry, hydrodynamic voltammetry, and flow injection analysis (FIA) with amperometric detection were used to study the oxidation reactions. Comparison experiments were carried out using polished glassy carbon (GC) electrodes. At diamond electrodes, highly reproducible and well-defined cyclic voltammograms were obtained for histamine with a peak potential at 1.40 V vs SCE. The voltammetric signal-to-background ratios obtained at diamond were 1 order of magnitude higher than those obtained for GC electrodes at and above 100 μM analyte concentrations. A linear dynamic range of 3−4 orders of magnitude and a detection limit of 1 μM were observed in the voltammetric measurements. Well-defined sweep rate-dependent voltammograms were also obtained for 5-hydroxytryptamine (5-HT). The characteristics of the voltammogram indicated lack of adso...
TL;DR: A comparison of the response of different dosimeters in narrow photon beams of 6 and 18 MV bremsstrahlung has been performed and significant differences in the output factors were obtained with the different detectors.
Abstract: A comparison of the response of different dosimeters in narrow photon beams (phi > or = 4 mm) of 6 and 18 MV bremsstrahlung has been performed The detectors used were a natural diamond detector, a liquid ionization chamber, a plastic scintillator and two dedicated silicon diodes The diodes had a very small detection volume and one was a specially designed double diode using two parallel opposed active volumes with compensating interface perturbations The characteristics of the detectors were investigated both for dose distribution measurements, such as depth-dose curves and lateral beam profiles, and for output factors The dose rate and angular dependence of the diamond and the two diodes were also studied separately The depth-dose distributions for small fields agree well for the diamond, the scintillator and the single diode, while the measured dose maximum for the double diode is about 1% higher and for the liquid chamber about 1% lower than the mean of the others when normalized at a depth of 10 cm The plastic scintillator and the liquid ionization chamber detect a penumbra width that is slightly broadened due to the influence of their finite size, while the double diode may even underestimate the penumbra width due to its small size and high density When corrected for the extension of the detector volume a good agreement with Monte Carlo calculated beam profiles was obtained for the plastic scintillator and the liquid ionization chamber Profiles measured with the diamond show an asymmetry when positioned with the smallest dimension facing the beam, while the double diode, the scintillator and the liquid chamber measure symmetric profiles irrespective of positioning Significant differences in the output factors were obtained with the different detectors The natural diamond detector measures output factors close to those with an ionization chamber (less than 1% difference) for field sizes between 3 x 3 and 15 x 15 cm2, but overestimates the output factors for large fields and underestimates the output factors for the smallest field sizes The single and double diodes overestimated the output factor for large field sizes by up to 7 and 12% respectively due to the high content of low-energy photons The double diode, and to some extent the single diode, also showed a relative increase in response compared with the more water equivalent liquid chamber and plastic scintillator at the smallest fields where there is a lack of lateral electron equilibrium Both the plastic scintillator and the liquid chamber also show responses that deviate from the ionization chamber for larger field sizes The major deviations can be explained based on the characteristics of the sensitive materials and the construction of the detectors
TL;DR: In this article, the authors summarized the recent developments in the area of TiO2 photocatalysis and diamond electrochemistry, with emphasis on the findings at the University of Tokyo.
TL;DR: In this article, the authors measured the thermal conductivity in a bulk crystal of highly enriched (99.8588%) 28 Si for temperatures between 2 and 310 K. This is six times larger than in natural silicon and even exceeds the maximum in diamond with natural isotope abundance.
TL;DR: The gasketed diamond-anvil cell has become the standard tool for the generation of high pressures over the last three decades and has been applied in a wide range of experimental studies such as Brillouin scattering (Whitfield et al. 1976), Raman spectroscopy (Sharma 1977, Sherman 1984), NMR measurements (Lee et al., 1987) and, of course X-ray diffraction.
Abstract: The development of apparatus to maintain materials at high hydrostatic pressure has been an active area of research for many years. From the pioneering work of Bridgman, during the early part of this century (Bridgman 1971), until the late 1960s, massive hydraulicly driven Bridgman-anvil and piston-cylinder devices dominated high-pressure science. Although there were later improvements in design, such as multi-anvil devices, it was not until the advent of the gasketed diamond-anvil cell, in the mid 1960s, that high-pressure studies were possible in non-specialized laboratories. Diamond has remarkable properties; not only is it the hardest known material it is also highly transparent to many ranges of electromagnetic radiation. Indeed incorporating these attributes, the gasketed diamond-anvil cell has become the standard tool for the generation of high pressures over the last three decades and has been applied in a wide range of experimental studies such as Brillouin scattering (Whitfield et al. 1976), Raman spectroscopy (Sharma 1977, Sherman 1984), NMR measurements (Lee et al. 1987) and, of course X-ray diffraction. It is this utility across a large range of science through physics, earth science and lately the life sciences that makes the development of the diamond-anvil cell as significant a revolution for measurement under non-ambient conditions in the physical sciences as that of the invention of the transistor to the whole sphere of electronics and computation.
Figure 1.
Assembly of the gasketed diamond-anvil cell: principle of pressure generation.
As with all successful designs, the principles upon which the gasketed diamond-anvil cell (Van Valkenburg 1964) operates are elegantly simple (Fig. 1). The sample is placed in a pressure chamber created between the flat parallel faces (culets) of two opposed diamond anvils and the hole penetrating a hardened metal foil (= the gasket). A pressure calibrant is placed beside the sample and the free volume within …
TL;DR: The semiconducting properties of phosphorus-doped diamond thin films grown using a metal-chamber-type microwave plasma-assisted chemical vapor deposition system have been investigated by Hall measurements over a wide temperature range.
TL;DR: The practical analytical utility of the differential pulse voltammetry and chronoamperometry method is demonstrated by the measurement of UA in human urine and serum without any preliminary treatment.
Abstract: Electrochemically anodized diamond film electrodes were used for selective detection of uric acid (UA) in the presence of high concentrations of ascorbic acid (AA) by differential pulse voltammetry and chronoamperometry. Because the oxidation peak potential for AA is ∼450 mV more positive than that for UA at anodized diamond electrodes, UA can be determined with very good selectivity. By use of chronoamperometry, linear calibration curves were obtained for UA over the concentration range up to 1 × 10-6 M in 0.1 M HClO4 solution, with the lowest experimental value measured being 5 × 10-8 M. This is consistent with the fact that a statistical analysis of the calibration curve yielded a detection limit of 1.5 × 10-8 M (S/N = 3). AA in less than 20-fold excess does not interfere. The practical analytical utility of the method is demonstrated by the measurement of UA in human urine and serum without any preliminary treatment.
TL;DR: The exceptional combination of mechanical, thermal, chemical and optical properties of diamond make this material an ideal choice for numerous applications in which materials are required to operate in adverse environments exposed to abrasion or chemical attack, or in situations requiring the dissipation of extreme levels of power such as windows for high power lasers as mentioned in this paper.
TL;DR: In this paper, a linear relationship exists between the full width at half maximum and frequency shift, which shows that these are Kramers-Kronig related, and the annealing behavior of the sharp Raman feature at 1490 cm-1 suggests that this peak is associated with vacancies with an activation energy of 4.06 eV.
Abstract: Raman microscopy has been employed to investigate the nature of damage created when natural type-IIa diamond is irradiated with MeV alpha particles. Three features appear in the Raman spectrum due to damage, viz., (i) the first-order diamond Raman line is broadened and downshifted, (ii) broad features appear which are a measure of the vibrational density of states of ion-beam-amorphized diamond, and (iii) the damage causes the appearance of sharp defect-induced Raman peaks at 1490 and 1630 cm-1. For damage below an amorphization threshold, a linear relationship exists between the full width at half maximum and frequency shift, which shows that these are Kramers-Kronig related. The annealing behavior of the sharp Raman feature at 1490 cm-1 suggests that this peak is associated with vacancies with an activation energy for annealing of 4.06 eV, while the 1630-cm-1 peak is due to an interstitial related defect with an activation energy of 1.2 eV. For sub-MeV ion irradiation, damage beyond the critical amorphization level usually leads to relaxation of the diamond structure to graphite upon thermal annealing. However, for MeV ion irradiation, it was found that annealing, even when the ion induced damage level is well above the amorphization threshold, could restore the original diamond structure. We attribute this result to the high internal pressure the damaged layer is subjected to which does not allow relaxation to graphitically bonded structures.
TL;DR: In this article, the energy and resonance width of quasilocal vibrations in crystals caused by heavy isotopic impurity atoms are analyzed in terms of interaction with local vibrations connected with impurity and with the short-wavelength lattice phonons.
Abstract: Electron-vibrational spectra of impurity-related optical centers of diamond are analyzed in terms of interaction with quasilocal and local vibrations connected with impurity atoms as well as with the short-wavelength lattice phonons. It is shown that the theoretical expressions for the energy and resonance width of quasilocal vibrations in crystals caused by heavy isotopic impurity atoms [Brout and Visscher, Phys. Rev. Lett. 9, 54 (1962)] can be satisfactorily applied for description of the acousticlike quasilocal vibrations in the diamond lattice caused by chemically different impurities. The model of quasilocal vibrations can also be successively applied for impurities (e.g., nitrogen) with masses comparable with the mass of the host carbon atom, provided these impurities form rigid clusters with host atoms vibrating as heavy units. The model is used for analysis of the optical centers in diamond containing Ti, Cr, Zn, Ag, Tl, W, Ni, Co, Ta, Si, and N impurities. Based on the results of this analysis, atomic models of the 3.188 eV N-related, 1.249 eV Ti-related, and 2.56 eV Ni-related centers are proposed.
TL;DR: In this article, the machining of a SiC-reinforced aluminum metal-matrix composite (MMC) with diamond inserts is presented, and two types of commercially available diamond tools are examined: brazed polycrystalline diamond (PCD) tools; and chemical vapor deposition (CVD) diamond coated tools.
TL;DR: In this paper, the bulk density of graphitized ultradisperse diamond (UDD) was measured by a gamma-ray attenuation method at 1370-1870 K. The reaction rate was modeled as a migration rate of the interface between the developing graphite-like carbon and the remaining diamond phase.
Abstract: The bulk density of graphitized ultradisperse diamond (UDD) was measured by a gamma-ray attenuation method at 1370–1870 K. These data combined with small angle x-ray scattering and true density measurements of the samples heated at various fixed temperatures were used to study the graphitization kinetics of the UDD. The reaction rate was modeled as a migration rate of the interface between the developing graphite-like carbon and the remaining diamond phase. A “reducing sphere” model was used to obtain the rates from the changes in densities. The estimated kinetic parameters in an Arrhenius expression, namely the activation energy, E=45±4 kcal/mol, and the pre-exponential factor, A=74±5 nm/s, allow quantitative calculations of the diamond graphitization rates in and around the indicated temperature range. The calculated graphitization rates agree well with the graphitization rates of diamonds with different dispersity estimated from high-resolution transmission electron microscopy data. The large differenc...
TL;DR: In this paper, a diamond peak at 1333 cm −1 was enhanced, while the D and G peak of graphite as well as photoluminescence was suppressed, compared with that measured by visible (514.5 nm) Raman.
TL;DR: In this article, the surface composition of diamond electrodes is linked to the electrochemical performance of diamond film electrodes and the extent to which changes in surface composition and electrode performance can be controlled and reversed by suitable plasma treatments is explored.
TL;DR: Owing to the unique combination of physical properties of coesite and diamond, this "coesite-in-diamond" geobarometer is virtually independent of temperature, allowing an estimation of the initial pressure of Venezuela diamond formation of 5.5 (+/-0.5) GPa.
Abstract: Mineral inclusions in diamonds provide an important source of information about the composition of the continental lithosphere at depths exceeding 120–150 km, i.e., within the diamond stability field. Fossilized high pressures in coesite inclusions from a Venezuela diamond have been identified and measured by using laser Raman and synchrotron x-ray microanalytical techniques. Micro-Raman measurements on an intact inclusion of remnant vibrational band shifts give a high confining pressure of 3.62 (±0.18) GPa. Synchrotron single-crystal diffraction measurements of the volume compression are in accord with the Raman results and also revealed direct structural information on the state of the inclusion. In contrast to olivine and garnet inclusions, the thermoelasticity of coesite favors accurate identification of pressure preservation. Owing to the unique combination of physical properties of coesite and diamond, this “coesite-in-diamond” geobarometer is virtually independent of temperature, allowing an estimation of the initial pressure of Venezuela diamond formation of 5.5 (±0.5) GPa.
TL;DR: In this article, a model-based simulation system is presented for the analysis of surface roughness generation in ultra-precision diamond turning, which takes into account the effect of tool geometry, process parameters and relative tool-work vibration.
Abstract: In this paper, a model-based simulation system is presented for the analysis of surface roughness generation in ultra-precision diamond turning. The system is based on a surface roughness model which takes into account the effect of tool geometry, process parameters and relative tool-work vibration. It is evaluated through a series of cutting experiments. The results indicate that the system can predict well the surface roughness profile and the roughness parameters of a diamond turned surface under various cutting conditions. With the use of the spectrum analysis techniques, the system can also help to analyze the effect of vibration on the surface quality of workpiece and to diagnose the machine faults. The potential application of the system in process optimization is also discussed in the text.