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Showing papers on "Diamond published in 1973"


Journal ArticleDOI
Glen A. Slack1
TL;DR: The diamond has the highest known thermal conductivity at 300k K at room temperature as discussed by the authors, and is the only non-metallic crystal with thermal conductivities of > 1 W/cmK at 300K.

1,523 citations



Journal ArticleDOI
R. M. Chrenko1
TL;DR: In this paper, the acceptor center of laboratory-grown semiconducting diamonds has been investigated and it has been shown that boron is the dominant acceptor in laboratory-generated semiconductor diamond, and not aluminum as has been assumed previously.
Abstract: A study has been made to determine the nature of the acceptor center in laboratory-grown semiconducting diamonds. Analyses for nitrogen, aluminum, boron, and uncompensated-acceptor content of aluminum and boron-doped crystals have shown that (i) the aluminum content of inclusion-free crystals is very low, (ii) there is not enough aluminum to account for the acceptor content, (iii) the nitrogen content is very low and only a small degree of compensation by deep-lying nitrogen donors could exist for many semiconducting diamonds, and (iv) there is a good correlation between boron content and acceptor content. These results indicate that boron is the dominant acceptor in laboratory-grown semiconducting diamond, and not aluminum as has been assumed previously by a number of authors. These results, when combined with other data on resistivity and activation energy for conduction, indicate that the dominant semiconducting properties of both natural and laboratory-grown diamond are due to one acceptor, boron, at different concentrations. Previous papers on laboratory-grown semiconducting diamonds which based arguments on the large aluminum content and the assumed high nitrogen content are critically reexamined.

137 citations


Journal ArticleDOI
TL;DR: In this paper, a boron-doped diamond was grown by vapor deposition from a 0.83% diborane in methane gas mixture at 1050°C and 0.2 Torr on 0 to 1μ nominal size natural type-I diamond powder.
Abstract: p‐type semiconducting diamond was grown by vapor deposition from a 0.83% diborane in methane gas mixture at 1050°C and 0.2 Torr on 0 to 1‐μ nominal size natural type‐I diamond powder. Total mass increases of about 9% were achieved which correspond to average linear growth rates of less than 10−3 μ/day. Evidence showing the growth was boron‐doped diamond included chemical etching, x‐ray and electron diffraction, density measurements, Seebeck and resistivity measurements, chemical analysis, optical measurements, induced electron emission spectroscopy, and scanning electron microscopy. The crystalline quality of the new diamond has not been established; it may be highly defective. A distinct change in color of the diamond seed crystals from an off‐white or gray for virgin crystals to light blue after growth was observed. The results are further confirmation that diamond may be grown at low pressures where it is thermodynamically metastable with respect to graphite. It is also further evidence that boron is t...

101 citations


Patent
14 Aug 1973
TL;DR: An improved diamond abrasive tool and method of manufacture characterized by a direct brazing technique of diamond crystals to a substrate surface which requires no pre-conditioning of the surface of the diamond in order to obtain the necessary wetting thereof is presented in this paper.
Abstract: An improved diamond abrasive tool and method of manufacture characterized by a direct brazing technique of diamond crystals to a substrate surface which requires no pre-conditioning of the surface of the diamond in order to obtain the necessary wetting thereof. The method employed utilizes readily available, very hard and durable brazing alloys which have been discovered to readily wet the diamond surface to obtain a final product wherein the minimum depth of the alloy bond tends to occur intermediate adjacent diamond crystals with outstanding retention of the crystals and greatly extended tool life.

100 citations


Journal ArticleDOI
TL;DR: In this article, two zero phonon lines at 1.665 and 1.673 eV have been associated with the defect, and an energy level scheme is proposed to explain the thermal behaviour of the lines.
Abstract: The GR 1 radiation damage centre in diamond has been studied by means of optical absorption and uniaxial stress. Two zero phonon lines at 1.665 and 1.673 eV have been associated with the defect, and an energy level scheme is proposed to explain the thermal behaviour of the lines. The energy level diagram facilitates the interpretation of the uniaxial stress data, and it is concluded that the defect possesses tetrahedral symmetry. Comparison of the energy level scheme derived experimentally with theoretical treatments of intrinsic defects in diamonds suggests that the GR 1 centre is probably the neutral vacancy.

89 citations


Patent
18 Sep 1973
TL;DR: A diamond particle of the MD or the SD type has a composite coating comprising a thin continuous layer of titanium adjacent the diamond surface and a metal layer on the titanium layer, the metal of the metal layer being capable of forming an alloy with titanium under the influence of heat and the titanium/diamond interface being essentially free of chemical bond formation.
Abstract: A diamond particle of the MD or the SD type having a composite coating comprising a thin continuous layer of titanium adjacent the diamond surface and a metal layer on the titanium layer, the metal of the metal layer being capable of forming an alloy with titanium under the influence of heat and the titanium/diamond interface being essentially free of chemical bond formation. The invention further provides a method of making a metal bonded abrasive device which includes the steps mixing the above described particles with a suitable metal matrix, heating the mixture to a temperature exceeding 500*C, maintaining the mixture at the elevated temperature for a period of from 10 to 30 minutes, and allowing the mixture to return to ambient conditions.

61 citations


Journal ArticleDOI
TL;DR: The wear of diamond when rubbing against materials softer than itself is investigated in this paper, and it is shown that the rate of wear depends primarily on the hardness of the second member, varying as hardness to the power 3.5 for hardnesses above 200 V.n.p.
Abstract: The wear of diamond when rubbing against materials softer than itself is investigated. It is shown that the rate of wear depends primarily on the hardness of the second member, varying as hardness to the power 3.5 for hardnesses above 200 V.p.n. When the hardness of the second member is high enough, the tensile stresses acting on the diamond reach the fracture stress, and the wear quickly becomes visible. Below this point, the rate of wear is small and there is an appreciable delay before its onset can be detected. For metals, such as copper, silver and gold, which are well below the critical hardness, the scale of the wear process becomes extremely small and the relation between wear rate and hardness changes. It is thought that in these conditions the rate of wear becomes affected by residual effects arising from the stressing of the surface during the initial processes of polishing.

58 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the direction in which the cube surface has been polished affects both the magnitude and the symmetry of the friction, which implies that the friction arises from a ratchet-type mechanism.
Abstract: The friction has been measured as a function of the applied load, the direction of sliding and the degree of lubrication of the surface. It is found that the direction in which the cube surface has been polished affects both the magnitude and the symmetry of the friction. Our results imply, in contrast to earlier work, that the friction arises from a ratchet-type mechanism, and that polished diamond surfaces have unusual properties.

58 citations


Patent
26 Mar 1973
TL;DR: Composite wire drawing die construction is described in this paper in which a centrally-located mass of diamond, cubic boron nitride or a polycrystalline mixture thereof defines at least the throat of the wire drawing hole, the mass being flanked or girded by at least one mass of metal bonded carbide that is directly bonded thereto.
Abstract: Composite wire drawing die construction is described in which a centrally-located mass of diamond, cubic boron nitride or a polycrystalline mixture thereof defines at least the throat of the wire drawing hole, the mass being flanked or girded by at least one mass of metal bonded carbide that is directly bonded thereto. The composite is readily ground into the form of a solid of revolution. In the preferred construction (for dies for drawing 0.008 inches diameter wire and larger) a composite assembly includes at least one high strength metal ring that is press fitted around a composite body or sub-assembly comprising a polycrystalline mass of diamond girded by a metal-bonded carbide jacket.

57 citations


Journal ArticleDOI
TL;DR: In this paper, a diamond anvil high pressure cell suitable for use in infrared and Raman spectroscopy is described and its performance is demonstrated with particular reference to the pressure dependence of the infrared spectrum of K2PtCl6 and the Raman spectrum of W(CO)6.
Abstract: A new design of diamond anvil high pressure cell suitable for use in infrared and Raman spectroscopy is described. Its performance is demonstrated with particular reference to the pressure dependence of the infrared spectrum of K2PtCl6 and the Raman spectrum of W(CO)6. In contrast to earlier reports, in which forward scattering geometry was used, this design of cell is shown to be very suitable for Raman use in the 180° excitation mode. However, severe limitations are imposed by the fluorescence emission of diamond and of sapphire. Conditions under which the cell can be used for Raman work are summarized. New fluorescence and Raman features are reported for diamond. In particular, a band at 1730 cm−1 is characteristic of type I stones and may be due to C to N bond stretching at defect centers.

Journal ArticleDOI
J. Wilks1
01 May 1973-Nature
TL;DR: In this article, a diamond surface has unusual properties because polishing of the brittle material generally proceeds by mechanical chipping, and the diamond surfaces have unusual properties due to their brittle nature.
Abstract: Polished diamond surfaces have unusual properties because polishing of the brittle material generally proceeds by mechanical chipping.

Patent
17 Sep 1973
TL;DR: High power laser systems with optical elements of diamond having a thermal conductivity of at least 10 watts/cm* K at 300*K were considered in this paper. But the performance of these systems was limited by the fact that the optical element of diamond has no optical absorption at the laser beam wavelength of no more than 20%.
Abstract: High power laser systems with optical elements of diamond having a thermal conductivity of at least 10 watts/cm.* K at 300*K. and an optical absorption at the laser beam wavelength of no more than 10-20%.

Journal ArticleDOI
TL;DR: In this paper, the low-temperature luminescence spectrum of an intrinsic defect in ion-implanted cubic SiC reveals a number of high-energy localized modes with an energy of 164·7 meV, equivalent to the highest lattice frequency in diamond, and far above the 120·5 meV lattice limit of SiC.

Patent
02 Nov 1973
TL;DR: Combinations of "dopant", "getter" and "compensator" materials are employed to produce gem stones of unusual color patterns, or zoned coloration, using specific reaction vessel configurations.
Abstract: Diamond crystals of controlled impurity content and/or impurity distribution and reaction vessel configurations for the production thereof are described. Combinations of "dopant", "getter" and "compensator" materials are employed to produce gem stones of unusual color patterns, or zoned coloration, using specific reaction vessel configurations.

Journal ArticleDOI
TL;DR: The ESR spectrum of an electron irradiated, type IIa diamond has been studied after it had been annealed at various temperatures up to 1400°C Six sets of lines were identified following anneals as mentioned in this paper.
Abstract: The ESR spectrum of an electron irradiated, type IIa diamond has been studied after it had been annealed at various temperatures up to 1400°C Six sets of lines were identified following anneals

Patent
02 Nov 1973
TL;DR: In this paper, the diamond seed material is separated from the plug of the catalyst-solvent plug by means for isolating the seed material from the catalytic material until after the latter has become saturated with carbon from the source of carbon.
Abstract: Improvements are provided in reaction vessel construction used in the growth of diamond by the process disclosed in U.S. Pat. No. 3,297,407 -- Wentorf, Jr. In assembly of the reaction vessel of this invention, the plug of catalyst-solvent material is disposed between the source of carbon and the diamond seed material as in the Wentorf, Jr. patent and, in addition, the diamond seed material is separated from the catalyst-solvent plug by means for isolating the diamond seed material from the catalyst-solvent material until after the latter has become saturated with carbon from the source of carbon. In addition, preferably the under surface of the plug of catalyst-solvent metal is covered with means for suppressing diamond nucleation. The nucleation suppressing means is usually in the form of a disc and may completely cover the underside of the catalyst-solvent plug or may have a hole therethrough in juxtaposition to the diamond seed/isolating means combination(s). When both the isolating means and the nucleation suppressing means are employed, capability is provided for simultaneously preventing dissolution of the diamond seed and suppressing spurious diamond nucleation.

Patent
10 Sep 1973
TL;DR: In this article, a graphite-free diamond particle having a continuous coating of titanium or molybdenum held in a matrix into which the titanium and moly bdenum can diffuse is described.
Abstract: A compact comprising substantially graphite-free diamond particles having a continuous coating of titanium or molybdenum held in a matrix into which the titanium or molybdenum can diffuse. The matrix may for example, be an alloy selected from the group of Fe/Ni, Ni/Co/Cr/Fe, Fe/Si and Ti/Si alloys. The invention also provides a method of making such a compact by mixing the desired metal powders in suitable proportions with the coated diamond particles and compacting the mixture under pressure and temperature conditions in the diamond stable zone.

Patent
26 Oct 1973
TL;DR: In this paper, a process for producing diamond-metallic materials comprising subjecting a system consisting of diamond powder and a metallic binder, to a pressure of 10 to 50 kbar is described.
Abstract: A process for producing diamond-metallic materials comprising subjecting a system consisting of diamond powder and a metallic binder, to a pressure of 10 to 50 kbar. The metallic binder is not mixed with the diamond powder initially, but rather is contained as a separate entity in any portion of the diamond powder. After packing, the diamond powder and metallic binder are heated, still under pressure, to a temperature sufficient to melt the metallic binder. The molten metallic binder is caused by the pressure to fill the inter-grain pores of the packed diamond powder.

Journal ArticleDOI
TL;DR: In this article, the relationship between radiation temperature and radiation power using films of several metals (copper, nickel, gold, and lead) as phonon radiators on diamond was investigated.
Abstract: Thermal phonon radiators allow short pulses of incoherent thermal phonon beams to generate in a simple manner and the center frequency of the broad frequency distribution of the emitted phonons to vary up to the acoustic cutoff frequencies. This paper reports experimental investigations of the connection between radiation temperature and radiation power using films of several metals (copper, nickel, gold, and lead) as phonon radiators on diamond. The measured dependencies of the radiation temperature on the radiation power show that the radiation process is by far better described by assuming acoustic mismatch between radiator and transmission medium than using the model of perfect match. Some metals on diamond give a phonon radiation power of several kilowatts per square millimeter radiator area. With a diamond substrate held at liquid‐helium temperature, a radiation temperature of a few hundred degrees Kelvin was achieved. If the phonon radiator deposited on diamond is immersed in liquid helium, the tra...

Book ChapterDOI
01 Jan 1973
TL;DR: In this paper, the 3-to-l chemical compounds of the group III elements B, Al, Ga, and In with the group V elements N, P, As, and Sb have been studied.
Abstract: Of the various compound semiconductors, the III–V compounds have properties most similar to the group IV elemental semiconductors. Like Si and Ge, the III–V compounds may readily be doped as n- orp-type to form p-n junctions, the most useful and widespread application of semiconductors. They are 1-to-l chemical compounds of the group III elements B, Al, Ga, and In with the group V elements N, P, As, and Sb. The III–V compounds are tetrahedrally coordinated, and the majority crystallize in the zinc-blende structure illustrated in figure 6.1 for GaAs. The zinc-blende structure is the diamond lattice of Si or Ge, but with group III and V atoms occupying adjacent lattice sites. Although the diamond and zinc-blende structures are similar, the differences in lattice constant, the presence or absence of d-shell electrons, and the ionicity of the III–V compounds result in significant differences in the band structure [1]. The varied band structures and large range of energy gaps possible with the III–V compounds have led to many potential applications. The crystal structure, lattice constant, type of energy gap, and the room temperature energy gap are summarized in Table 6.1 for the elemental semiconductors Si and Ge and the III–V compound semiconductors.

Patent
22 Mar 1973
TL;DR: In this paper, a method of producing metal coated diamond particles in which the coatings are strongly bonded to the diamond particles characterised in that a layer of an alloy consisting of a major proportion of a metal such as copper, nickel or iron and a minor proportion of an carbide-forming metal, such as titanium, chromium or vanadium, is applied to the uncoated particles and then the coated particles are heat treated to a temperature of between 500*C and a temperature just below the melting point of the alloy for a time sufficient to enable a bonding carbide
Abstract: A method of producing metal coated diamond particles in which the coatings are strongly bonded to the diamond particles characterised in that a layer of an alloy consisting of a major proportion of a metal such as copper, nickel or iron and a minor proportion of a carbide-forming metal such as titanium, chromium or vanadium is applied to the uncoated particles and then the coated particles are heat treated to a temperature of between 500*C and a temperature just below the melting point of the alloy for a time sufficient to enable a bonding carbide layer to form at the alloy/diamond interface, the steps being carried out in a non-oxidising atmosphere. The invention further provides diamond particles having bonded thereto an alloy comprising a major proportion of nickel and a minor proportion of a carbide-forming metal such as titanium, chromium or vanadium, the bonding being achieved by means of a carbide layer, which is preferably continuous, at the alloy/diamond interface.

Journal ArticleDOI
16 Nov 1973-Nature
TL;DR: In this article, it was shown that cavitation can occur when flowing magma in a pipe encounters a constriction, and that in the ensuing collapse of a bubble very substantial transient dynamic pressures, of magnitude sufficient to be of thermodynamic importance for diamond synthesis, can be produced.
Abstract: LET us grant, in accordance with Galimov's proposals1, that cavitation can occur when flowing magma in a pipe encounters a constriction, and that in the ensuing collapse of a bubble very substantial transient dynamic pressures, of magnitude sufficient to be of thermodynamic importance for diamond synthesis, can be produced. In granting this, we overlook some quantitative details in his calculation, such as the apparent implication that the bubbles would contain gas at 10 or 20 kbar, and yet that their compression (by a factor of 64,000 in volume) can be calculated by ideal gas theory. He ignores the fundamental difference in rate control between martensitic conversion of crystals from one modification to another, which makes a product of the same chemical composition as the starting material, and other processes of crystal growth requiring a composition change. In the former class, to which production of diamond by the action of shock waves on graphite belongs, the limit on growth velocity is essentially the shock wave velocity. Thus, so far as that is concerned, quite a large diamond might be made within a few microseconds. Further characteristics of martensitic processes are, however, that the product takes the form of thin lenses, whereby the constraint by the matrix on shape change in the converting region is minimised and, second, that as a rule there is a multiplicity of orientations of the martensitic product in the parent crystal, so that a microcrystalline product results.

Patent
02 Apr 1973
TL;DR: In this article, a method of making unitary polycrystalline diamond composite by sintering a body of diamond particles at a temperature between about 1100*-3900*K and at a pressure ranging up to about 170 kilobars depending on the temperature.
Abstract: A method of making unitary polycrystalline diamond composite by sintering a body of diamond particles at a temperature between about 1100*-3900*K and at a pressure ranging up to about 170 kilobars depending on the temperature.

Journal ArticleDOI
TL;DR: The Hartree-Fock bulk modulus is calculated to be 4.27 × 1012 dyn/cm2, compared to the experimental value of 4.42 × 1037 dyn/ cm2 as discussed by the authors.
Abstract: The equilibrium lattice constant of diamond is calculated in the Hartree-Fock approximation to be 3.547 ± 0.0019 A. This value is slightly smaller than the experimental value of 3.567 A, as it should be. The Hartree-Fock bulk modulus is calculated to be 4.64 ± 0.27 × 1012 dyn/cm2, compared to the experimental value of 4.42 × 1012 dyn/cm2.

Journal ArticleDOI
01 Aug 1973-Carbon
TL;DR: In this article, the synthesis of diamond in its metastable region from carbonaceous gases, in particular methane, was discussed and the diamond synthesis on seed crystals is made possible owing to the orientation effect of surface forces on the formation of a new phase.

Journal ArticleDOI
TL;DR: In this article, the diffuse X-ray scattering from coal tar pitch has been investigated by using Fourier transformation for the 002 band and diamond's least-squares method for the 11 band.
Abstract: The diffuse X-ray scattering from coal tar pitch has been investigated by using Fourier transformation for the 002 band and Diamond’s least-squares method for the 11 band From the results of this investigation, the layers were found to be stacked parallel to each other, partly in groups of 8–9 layers, the average number of the layers being 246 The distribution of the layer size showed a peak at the diameter of 84–10 A, the average layer size was 89 A, which corresponded to 25 atoms per layer

Patent
Curtis N Potter1
13 Sep 1973
TL;DR: A planar preformed element which becomes a permanent part of the diode structure is used to transfer the forces which form the bond between the diamond heat conducting member and the heat sink as mentioned in this paper.
Abstract: High frequency diodes are manufactured by methods forming an efficient heat path from the active diode junction through a diamond heat conducting member to a heat sink. A planar preformed element which becomes a permanent part of the diode structure is used to transfer the forces which form the bond between the diamond heat conducting member and the heat sink; simultaneously, the preformed element is bonded to an opposite side of the diamond, becoming a permanent part of the high frequency circuit of the diode.

Journal ArticleDOI
TL;DR: In this article, it was concluded that the microstructure of framesite is the result of plastic deformation of diamond grains probably under conditions such that brittle fracture was inhibited, and that the narrow zones represented by these surface striations are harder than any orientation of the matrix (as revealed by abrasion resistance).

Journal ArticleDOI
17 Dec 1973-Nature
TL;DR: In this article, the authors have recently completed some preliminary experiments on this aspect of deformation in the indentation and scratch hardness processes and the results indicate that the cumulative effects, due to repeated loading, may well play an important part in subsequent macro-deformation.
Abstract: WHEN a scratch or indentation hardness measurement is made one is generally more concerned with gross changes in shape, due to macro-deformation or fracture, than in any aspects of small scale or micro-deformation which might also form a part of the permanent deformation process. Consequently, certain guide lines have been established1. The possibility of micro-deformation in a relatively hard crystal due to point contact through a significantly softer indenter or slider may have been assumed but there seems to be little published information on its nature and extent. We have recently completed some preliminary experiments on this aspect of deformation in the indentation and scratch hardness processes and the results indicate that the cumulative effects, due to repeated loading, may well play an important part in subsequent macro-deformation. Most of the experiments were carried out on magnesium oxide because the resultant distribution of dislocations could be readily observed, using the etchant perfected by Gilman and Johnston2, on a (001) plane prepared by cleavage and then chemically polished. Lead, copper and diamond cones, having apical angles of 136°, were used as indenters and sliders. The relevant diamond cone indentation hardness values for the magnesium oxide, copper and lead were 6,000 MN m−2, 980 MN m−2 and 50 MN m−2 respectively and can be assumed to be between 69,000 to 96,000 MN m−2 for diamond3.