Abstract: A process for forming a thermally stable low-dielectric constant material is provided. A gas mixture is prepared to form a fluorinated amorphous carbon (a-C:F) material. The gas mixture is mixed with a boron-containing gas.

Abstract: An electron-emitting device having an electroconductive film including an electron-emitting region arranged between a pair of device electrodes is manufactured. The electroconductive film is formed by applying a liquid containing the material of the film to a substrate by using an ink-jet method, then drying and heating the applied liquid. Defective conditions, if any, in the applied liquid or the precursor film formed by drying the liquid or the electroconductive film formed by heating the precursor film are detected and remedied by applying the same liquid again to the area detected for a defective condition. The detection and remedy of any defective condition may be conducted after the liquid-applying, drying or baking step.

Abstract: Disclosed are methods of safely producing a high quality negative electrode material composed of a mixture of a non-carbon material and a carbon material, a negative electrode using the negative electrode material, and a non-aqueous electrolyte battery using the negative electrode. The high quality negative electrode is produced by pulverizing and classifying each of the non-carbon material and the carbon material in an inert gas atmosphere, and further mixing them to each other in an inert gas atmosphere.

Abstract: A method of applying a conductive carbon coating to a nonconductive surface, conductive carbon compositions for that purpose, and a printed wiring board having through holes or other nonconductive surfaces treated with such carbon compositions are disclosed. A conditioning agent, made (for example) by condensing a polyamide and epichlorohydrin, is applied to the nonconductive surface to form a conditioned surface. A liquid dispersion of electrically conductive carbon (for example, graphite) having a mean particle size no greater than about 50 microns is coated on the conditioned surface to form an electrically conductive carbon coating. The conductive carbon coating is then optionally fixed on the (formerly) nonconductive surface. Fixing may be accomplished, for example, by applying a fixing liquid such as a dilute aqueous acid to the carbon-coated surface. The coating is then dried.

Abstract: The invention involves a method for locating the probe of a scanning tunneling micrograph a predetermined distance from its conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate. The Fullerene C60 molecule is approximately spherical, and a monolayer of fullerene has a thickness of one nanometer. By providing a monolayer of fullerene on the conducting surface and locating the probe on the surface of the monolayer, a distance of one nanometer can be established between the probe tip and the conducting surface.

Abstract: A method and apparatus for vacuum arc deposition of carbon on a substrate inhibits or eliminates emission of contaminating carbon particles in the ion plasma by maintaining an elevated local plasma pressure at the cathode or target surface, thereby minimizing the role of heat conduction in the creation of the particles and strongly increasing the electron emission cooling effects.

Abstract: A magnetic recording medium is provided with dual carbon-containing protective overcoats for high magnetic recording performance and high mechanical performance. Embodiments include a dual protective overcoat comprising an amorphous carbon layer on a magnetic layer and a nitrogenated carbon layer on the amorphous carbon layer.

Abstract: A solution for the pretreatment of electrically non-conductive surfaces and a method for coating surfaces with solid matter particles, for example carbon black, graphite, silicon dioxide, aluminum oxides, transition metal chalcogenides and titanium dioxide. Furthermore, the invention relates to a production method for the solution also. The solution contains a solvent, polyelectrolytic compound as a coagulation trigger, and a charged surfactant which has opposite polarity relative to the polyelectrolytic compound. After pretreatment of surfaces with the solution, the surfaces are then brought into contact with a dispersion containing the solid matter particles.

Abstract: A process for preparing sol-gel graphite composite electrodes is presented. This process preferably uses the surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) and eliminates the need for a cosolvent, an acidic catalyst, a cellulose binder and a thermal curing step from prior art processes. Fabrication of screen-printed electrodes by this process provides a simple approach for electroanalytical applications in aqueous and nonaqueous solvents. Examples of applications for such composite electrodes produced from this process include biochemical sensors such as disposable, single-use glucose sensors and ligand modified composite sensors for metal ion sensitive sensors.

Abstract: A method of applying a conductive carbon coating to a non-conductive surface, conductive carbon compositions for that purpose, and a printed wiring board having through holes or other nonconductive surfaces treated with such carbon compositions are disclosed. A liquid dispersion of electrically conductive carbon (for example, graphite) having a mean particle size no greater than about 50 microns is coated on the non-conductive surface to form an electrically conductive carbon coating. The conductive carbon coating is then fixed on the (formerly) nonconductive surface. Fixing may be accomplished in a variety of different ways. For example, the fixing step can be carried out by applying a fixing liquid to the carbon-coated surface. One example of a suitable fixing liquid is a dilute aqueous acid. Fixing may also be carried out by removing the excess carbon dispersion with an air knife or other source of compressed air.

Abstract: A process for the co-deposition of fluorinated carbon and diamond material with electroless metal in which the electroless plating bath is formulated to contain an aqueous dispersion of the fluorinated carbon, the finely divided diamond material and an electroless metal salt in aqueous suspension. the plating bath can be used to plate workpieces wherein the fluorinated carbon and diamond material are co-deposited in a plated electroless metal matrix. It has been found that the use of a finely divided diamond material having an average diameter less than 10 nm provides not only improved bath stability but also facilitates the codeposition of the diamond material and fluorinated carbon with the electroless metal.

Abstract: A magnetic recording medium is provided with dual protective overcoats for excellent tribological properties at very low glide heights and long term durability. Embodiments include magnetic recording media comprising a dual protective overcoat system containing a silicon nitride oxide layer on a magnetic layer and a carbon-containing layer, such as amorphous hydrogenated carbon, amorphous nitrogenated carbon, or amorphous hydrogen-nitrogenated carbon on the silicon nitride layer oxide.

Abstract: A method for forming a film by a plasma CVD process in which a high density plasma is generated in the presence of a magnetic field is described, characterized by that the electric power for generating the plasma has a pulsed waveform. The electric power typically is supplied by microwave, and the pulsed wave may be a complex wave having a two-step peak, or may be a complex wave obtained by complexing a pulsed wave with a stationary continuous wave of an electromagnetic wave having the same or different wavelength as that of the pulsed wave. The process enables deposition of a uniform film having an excellent adhesion to the substrate, at a reduced power consumption.

Abstract: This invention covers a cathodic element free from asbestos fibres that can be obtained by deposition after filtration through a porous medium of an aqueous suspension comprising electrically conductive fibres, at least one cationic polymer, at least one electocatalytic agent, at least one pore-forming agent and at least one binder selected from among the fluoropolymers. The invention also covers a method for preparing such a cathodic element.

Abstract: A new method for ion beam deposition of diamond-like carbon coatings onto a variety of substrates is described. A high power, radio frequency excited-inductively coupled ion gun directs a beam of carbon and hydrogen ions at a substrate inside an ultra vacuum deposition chamber. A four axis scanner is used for coating large and nonplaner substrates. A quadrupole mass spectrometer is mounted inside the deposition chamber for real time monitoring of ion composition. The disclosed method is particularly effective for coating zinc sulfide and zinc selenide infrared windows.

Abstract: An electron-emitting device having an electroconductive film including an electron-emitting region arranged between a pair of device electrodes is manufactured. The electroconductive film is formed by applying a liquid containing the material of the film to a substrate by using an ink-jet method, then drying and heating the applied liquid. Defective conditions, if any, in the applied liquid or the precursor film formed by drying the liquid or the electroconductive film formed by heating the precursor film are detected and remedied by applying the same liquid again to the area detected for a defective condition. The detection and remedy of any defective condition may be conducted after the liquid-applying, drying or baking step.

Abstract: A method of forming films over an insulating material is provided whereby an underlayer film having electric conductivity is formed on the surface of the insulating material constituting a base member, and a hard carbon film is formed over the underlayer film so that the surface electrical resistance value of the hard carbon film can be controlled so as not to cause the surface thereof to be charged with static electricity by varying an electrical resistance value of the underlayer film. In the case where the underlayer film is formed of a metal film composed of titanium, chromium, tungsten, or the like, the resistance value thereof can be changed by varying the thickness of the metal film. In the case where the underlayer film is formed of a semiconductor film composed of silicon, germanium, or the like, the resistance value thereof can be changed by varying the thickness of the semiconductor film, or the concentration of an impurity added thereto.

Abstract: A method of creating a diamond-like carbon film on a substrate, including the steps of exposing the substrate to a hydrocarbon gas environment and generating plasma in the environment of an electron density greater than approximately 5.times.10.sup.10 per cm.sup.3 and a sheath thickness less than about 2 mm under conditions of high ion flux and controlled, low energy ion bombardment.

Abstract: There is provided a diamond crystal in which the (111) oriented plane is of the diamond crystal synthesized on a substrate by a chemical vapor deposition method parallel to a substrate surface, and the area of the (111) oriented plane parallel to the substrate surface is 1/24or less an area of the crystal on the substrate. A source gas is activated on a substrate consisting of a material which is not reactive with carbon. The source gas contains at least carbon and hydrogen in such a manner that the ratio of the number of carbon atoms to the total number of molecules of the source gas is 0.5% or less. Subsequently, a diamond crystal in which the (111) orientation plane is parallel to the substrate surface, and the area of the (111) orientation plane parallel to the substrate surface is precipitated on the substrate. A copper plate is preferably contains used as the substrate.

Abstract: A flat substrate polishing and polishing pad conditioning head for a chemical-mechanical-planarization apparatus is provided which has been shown to double the useable life of a polishing pad used to planarize and/or polish both oxide and metal outer layers in the processing of semiconductor wafers and to provide for more uniform polishing during the life of the polishing pad. The polishing pad conditioning head comprises a suitable substrate (26), a diamond grit (28) that is evenly distributed over the surface of the substrate (26) and a CVD diamond (30) grown onto the diamond grit (28) and the substrate (26) so that the diamond grit (28) becomes encased in the CVD diamond (30) and bonded to the surface of the substrate (26). The method for evenly distributing a mono-layer of diamond grit in a highly uniform manner over the exposed surface of a substrate can be done either by using diamond grit applied over a photoresist pattern or a screen printed pattern, or using diamond grit from a liquid mixture.

Abstract: DLC film formed on at least one surface of a plastic film, and this DLC film has a composition comprising 75 to 55 mol% of carbon and 25 to 45 mol% of hydrogen. And this DLC film is formed by a plasma deposition process while the plastic film is loaded with a tensile force in a biaxial direction.

Abstract: A method for treating a non-conductive through hole surface of a printed wiring board is disclosed. A printed wiring board including through holes is cleaned, conditioned, and a conductive coating is applied to the initially-nonconductive through hole by contacting it with a series of baths. The conductive coating, for example a graphite dispersion coating, facilitates later electroplating of the conductive surface. While at least partially immersing the through hole in one or more of these baths, ultrasonic energy is introduced in the bath in the vicinity of the through hole. The ultrasonic energy can be introduced during the entire immersing step, before the immersing step, or both. The ultrasonic energy reduces the formation of blowholes during later processing (and especially soldering) of the printed wiring board.

Abstract: An electrode plate in which electrode active material powder and an electrode mixture layer mainly composed of a thermoplastic binder are held on a conductive substrate is crushed. Then, the crushed materials are mixed with organic solvent so that a coating material made of the crushed electrode is prepared. The coating material made of the crushed electrode is applied to the surface of the conductive substrate so that an electrode is manufactured. As an alternative to this, an electrode mixture coating material made of electrode active material powder, thermoplastic resin and organic solvent is dried so that a solid electrode is obtained. Crushed materials obtained by crushing the solid electrode are mixed with organic solvent so that a coating material made of the crushed electrode is prepared. The coating material made of the crushed electrode is applied to the conductive substrate so that an electrode is manufactured.

Abstract: A method for making particles coated with a diamond-like network, which can include additive components. The method comprises subjecting a multiplicity of particles to a carbon-based plasma in an evacuated radio frequency powered capacitively coupled reactor system in which ion sheaths are formed around the electrodes and wherein the particles are agitated in such a manner as to expose their surfaces to the reactive species in the plasma while keeping the particles substantially within an ion sheath.

Abstract: In a method of synthesizing diamond on a substrate from plasma containing a carbon component, filaments containing tungsten as a thermoelectron-emitting material are arranged above a substrate in a chamber. An electrode is provided at a position separated from and particularly above the filaments. The filaments are at least temporarily energized with a potential relatively higher than that of the substrate, while the electrode is at least temporarily supplied with a potential relatively higher than that of the filaments. Thus, plasma is generated between the filaments and the substrate, while electrons are moved from the filaments to the electrode for also generating plasma between the filaments and the electrode, thereby forming nuclei of diamond on the substrate. Thereafter, the respective potentials of the electron emitting filaments and the electrode are equalized with each other, for growing a film of diamond from the nuclei of diamond.

Abstract: A microporous carbon film for use as electrodes in energy strorage devices is disclosed, which is made by the process comprising the steps of: (1) heating a polymer film material consisting essentially of a copolymer of polyvinylidene chloride and polyvinyl chloride in an inert atmosphere to form a carbon film; and (2) activating said carbon film to form said microporous carbon film having a density between about 0.7 g/cm.sup.2 and 1 g/cm.sup.2 and a gravimetric capacitance of about between 120 F/g and 315 F/g.

Abstract: A nonaqueous secondary battery comprising a negative electrode, a positive electrode in which a chalcogenated substance containing lithium is used as a positive electrode active material and a nonaqueous ion conductor, said negative electrode containing a negative electrode active material which is a carbon material where an amorphous carbon is adhered on the surface of graphite particles which are subjected to an oxidizing treatment.

Abstract: A rf plasma enhanced chemical vapor deposition process is presented, wherein a precursor gas stream having a high helium content produces hard, wear resistant, hermetically sealing, high refractive index Diamond-Like-Carbon (DLC) coatings on numerous substrates at deposition rates of at least 0.4 .mu.m/hr. Internal pressures of 1 to 10 Torr and radio frequencies no higher than 100 kHz are employed. The process may be applied to both batch and linear production methods. Linear products such as optical fibers, capillary tubing, wires, and sheets can be coated in-line while minimizing the introduction of flaws on their surfaces and minimizing exacerbation of any pre-existing flaws. The effects of surface flaws can be minimized further by introducing a helium etch of the substrate surface prior to exposure to the DLC coating precursor gas mixture.

Abstract: The present invention relates to a method of forming a two-layer intermediate film over the inner surface of a cylindrical member, such as a bushing or a cylinder, with a DLC film being formed on the intermediate film with a uniform thickness by using an auxiliary electrode, greatly enhancing of abrasion resistance of the inner surface. The cylindrical member is placed in a vacuum vessel, an auxiliary electrode of a first intermediate film forming material is inserted in the bore of the cylindrical member, a sputtering gas is supplied into the vacuum vessel, keep the auxiliary electrode at ground potential or a negative DC voltage is applied to the auxiliary electrode to produce a plasma around the auxiliary electrode in order that a first intermediate film is formed over the inner surface of the cylindrical member.

Abstract: A carbon-based composite is made by the steps of(1) impregnating a fibrous material with a phthalonitrile thermoset polymer precursor,(2) curing the product of step (1) to form a fiber-reinforced thermoset polymer and(3) pyrolyzing the product of step (2) to form the carbon-based composite. The carbon-based composite may be made with only one cycle of the steps (1), (2), and (3).

Abstract: An amorphous fluorinated carbon film for use as a dielectric insulating layer in electrical devices is formed from a fluorinated cyclic hydrocarbon precursor. The precursor may be selected from the group consisting of hexafluorobenzene, 1,2-diethynyltetrafluorobenzene and 1,4-bis(trifluoromethyl) benzene. The film is deposited by a radiation or beam assisted deposition technique such as an ion beam assisted deposition method, a laser assisted deposition method, or a plasma assisted chemical vapor deposition method. The film is thermally stable in non-oxidizing environment at temperatures up to 400.degree. C. and has a low dielectric constant of less than 3.0. The film can be suitably used as an insulator for spacing apart conductors in an interconnect structure.

Abstract: An object of the invention is to provide a high quality synthetic diamond having a high bonding strength between a substrate surface and synthetic diamond or between synthetic diamond films. The object can be attained by a process for the synthesis of diamond comprising pre-heating mixed gases of a hydrocarbon and hydrogen by a heating body and feeding the heated mixed gases to a substrate surface heated to deposit diamond thereon, characterized by allowing the distance between the heating body and substrate surface to be apart from each other as far as possible in the carburizing step of the heating body and allowing the distance between the heating body and substrate surface to be nearer in the step of synthesizing diamond than in the former case.

Abstract: A novel field emitter device for cold cathode field emission applications, comprising a multi-layer resistive carbon film.The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced.

Abstract: A method of depositing a polycrystalline diamond layer on a nitride substrate is disclosed, which comprises chemically-etching the nitride substrate with a KOH or NaOH solution or melt and depositing the polycrystalline diamond layer on the nitride substrate from a vapor phase, wherein the etching temperature, time and concentration of the etchant are controlled so that at least 75% of the interface between the substrate and the diamond layer is covered by diamond crystals, each diamond crystal having a contact area with the substrate of .gtoreq.20 um.sup.2.

Abstract: A method for treating an organic polymer material, preferably a vinylidene chloride/vinyl chloride copolymer (Saran) to produce a flat sheet of carbon film material having a high surface area (.apprxeq.1000 m.sup.2 /g) suitable as an electrode material for super capacitor applications. The method comprises heating a vinylidene chloride/vinyl chloride copolymer film disposed between two spaced apart graphite or ceramic plates to a first temperature of about 160.degree. C. for about 14 hours to form a stabilized vinylidene chloride/vinyl chloride polymer film, thereafter heating the stabilized film to a second temperature of about 750.degree. C. in an inert atmosphere for about one hour to form a carbon film; and finally activating the carbon film to increase the surface area by heating the carbon film in an oxidizing atmosphere to a temperature of at least 750-850.degree. C. for between 1-6 hours.

Abstract: An auxiliary electrode which is to be connected to a ground potential or applied with a positive DC voltage is disposed in a center bore which forms an inner surface of a guide bush, and a ringlike dummy member made of a conductive material having an internal diameter equal to or larger than the diameter of the center bore of the guide bush with its both ends having a different diameter is placed on an end face of the guide bush opening the inner surface thereof so that one end having the smaller diameter contacts the end face of the guide bush with its center in alignment with the central axis of the center bore. A DLC film is formed over an inner surface of a guide bush which is in sliding contact with a workpiece held in the guide bush by disposing the guide bush in a vacuum vessel after evacuating the vessel and introducing a gas containing carbon, producing a plasma in a vacuum vessel by applying a DC voltage or a radio frequency power to the guide bush by the plasma CVD process.

Abstract: The invention concerns a method of manufacturing highly conducting composites, the method being characterized by the following steps: a) contacting a powder or fibers with an aqueous solution containing an appreciably water-soluble high-molecular substance, b) optionally washing with water, c) contacting with a dispersion containing finely particulate electrically conducting material, wetting agents (surfactants) and an ionogenic metal compound, d) optionally washing with water and e) molding to required shape.

Abstract: A method of forming a sufficiently thin, highly amorphous and homogeneous glass-like carbon film on the surface of a titanium metal with high efficiency. In this method, the surface of a titanium metal is polished by e.g. buffing with emery paper and alumina or chromium suspension as polishing agents to form a mirror surface. A dense and rigid titanium oxide film layer is formed on the mirror surface. The surface of the titanium oxide film is then subjected to plasma heating in an atmosphere containing a hydrocarbon gas under a gas pressure of 0.1-30 Torr at 400-1100.degree. C. to form a glass-like carbon film thereon.

Abstract: A process and apparatus for deposition of a carbon-rich coating onto a moving substrate is provided. The process and apparatus involve the creation of an electric field surrounding a rotatable electrode in a carbon-containing gaseous environment. This results in carbon-rich plasma formation, wherein the electrode is negatively biased with respect to the electrode which results in ion acceleration from the plasma toward the electrode. Ion bombardment continuously occurs on a substrate in contact with the electrode producing a continuous carbon-rich coating over the length of the substrate.

Abstract: graphite sheet or block anode material can be used for non-aqueous lithium secondary battery, which has the improved characteristics of battery charge-discharge, as well as a circuit substrate and a shield plate in which dopants should be intercalated. The graphite sheet or block can be made of graphitized polymer film or films and comprises: a) an electric conductive body having a surface, in which graphite crystals are oriented along the surface of the graphite sheet or block and b) interphase insertion potions uniformly distributed over the surface of the graphite sheet or block, in which graphite phases are built perpendicularly to the surface to permit dopant to be inserted into a gap between graphite phases.

Abstract: A carbon electrode for a nonaqueous secondary battery is provided, which comprises a metal collector serving to catalyze carbon graphitization, graphite particles, and a carbon material having a lower crystallinity than the graphite particles, the graphite particles and the carbon material being sintered together on the metal collector or in the presence of the metal collector.

Abstract: According to the present invention, a method and apparatus are provided for growing C.sub.60 thin film or films having a high degree of textured crystallinity using vacuum evaporation with a high deposition rate onto the substrate maintained at substantially high temperature. The method includes producing a thin film of C.sub.60 with high degree of textured crystallinity on the substrate using a vacuum evaporation system having the steps of using a metal substrate; operating the substrate at a high temperature of during the growth or deposition period; and ensuring that the deposition rate of C.sub.60 onto the substrate be high.

Abstract: A process of manufacturing a porous carbon material and a capacitor having the same is provided. The process is comprised of: forming an intermediate blank (in the shape of a desired electrode) made of a metal carbide material having a porosity in the range of substantially 30% to 50% by volume. The blank is then impregnated by exposure to a gaseous hydrocarbon mixture at a temperature exceeding the decomposition of the hydrocarbon until the mass of the blank increases by about 10% to 25%. Next the inner surface of the blank is activated by heating. The blank is then exposed to gaseous chlorine and heated to remove the metal and form the blank having transport channels. Further chlorination occurs which forms nano sized pores in the structure. Thus, a porous carbon material is made which contains transport channels and nano sized pores.

Abstract: A magnetic head/slider construction and a magnetic data recording disk, as well as a method for fabricating the magnetic head/slider construction and the magnetic data storage disk. To practice the method, there is formed over the air bearing surface of each of a magnetic head/slider construction and a magnetic data storage disk a wear resistant carbon layer. Over each of the wear resistant carbon layers is then formed a lubricating carbon layer. The lubricating carbon layers may be formed in-situ upon the wear resistant carbon layers. The wear resistant carbon layers may be formed from nitrogenated wear resistant carbon materials having a nitrogen content of from about 15 to about 30 atomic percent and hydrogenated wear resistant carbon materials having a hydrogen content of from about 15 to about 25 atomic percent. The lubricating carbon layer is preferably formed from a hydrogenated lubricating carbon material having a hydrogen content of from about 30 to about 40 atomic percent.

Abstract: This invention concerns a method for protecting surfaces of diamond, diamondlike carbon and of other forms of carbon, from the effects of oxidation which can occur at high temperatures in an oxidizing environment. The method involves exposing the surface of the diamond or other carbon material to energetic ions of, or containing, an element or elements which can be caused to react with the carbon to form a thin layer containing a carbide compound that is itself more oxidation resistant than the diamond or other carbon material and which is able to serve as a barrier to prevent or delay penetration of oxygen to the thereby protected diamond or other carbon material.

Abstract: The invention provides a composite structure for microelectronic components having a self-supporting metal plate, an electrically insulating layer adhering to the metal plate, and a functional layer adhering to the insulating layer for the application of at least one microelectronic component. An at least largely monocrystalline information layer which covers the metal plate at points is applied to the self-supporting metal plate. The regions of the surface of the metal plate which are free of the information layer are provided with the insulating layer. When the surface of the information layer is exposed at least in regions, the functional layer is deposited on the insulating layer and on the exposed information layer. The crystal information required for an epitaxial deposition of the functional layer is taken from the information layer.

Abstract: A method and apparatus for forming a multilayer insulating film on a substrate involves forming a number of carbon-based layers on the substrate, each interlaid with layers of organic material, such as parylene. Preferably, the carbon-based layers are formed using a high-density plasma chemical vapor deposition system, although other CVD systems may also be used. The result is a multilayer insulating film having a low overall dielectric constant, excellent gap-fill characteristics, and desirable thermal properties.

Abstract: A method for producing hollow diamond tubes by diamond growth using chemical vapor deposition (CVD) techniques. Suitable substrate material, such as tungsten, molybdenum, copper or silicon, typically in the form of wire, having diamond nucleation sites is formed into a helix. The helix is then placed, or moved through, a CVD chamber for deposition of diamond on the helix. Suitable pitch and diameter of helix results in deposition diamond on the helix until such time as the growth surfaces of the diamond fuse to form a hollow diamond tube.

Abstract: An active material for a positive electrode of a secondary cell comprises particles of a metal oxide and a conductive layer formed on the surfaces of individual particles of the metal oxide and made of a carbon powder which has a specific surface area of at least 150 m.sup.2 /g when measured prior to the formation of the conductive layer. The conductive layer covers at least 15% of an apparent surface of the individual particles of the metal oxide and has a thickness ranging from 0.01 .mu.m to 0.3 .mu.m. The active material has a specific surface area of 3.5 m.sup.2 /g to 100 m.sup.2 /g. A method for making the active material is also described along with a positive electrode comprising the active material and a non-aqueous electrolytic secondary cell comprising the positive electrode.

Abstract: The substrate (10) is placed in an enclosure (12) and is heated so as to establish a temperature gradient within the substrate such that the substrate has a temperature in its portions remote from its exposed surfaces that is greater than its temperature at said surfaces. A gas constituting a precursor of carbon and comprising at least one saturated or unsaturated hydrocarbon is admitted into the enclosure, with the formation of pyrolytic carbon be favored in the higher temperature portions of the substrate. The gas comprises a mixture containing at least one saturated or unsaturated hydrocarbon and hydrogen, and the substrate is heated in such a manner as to establish a temperature gradient within the substrate on either side of a temperature of 1500 K, with hydrogen having an inhibiting role at temperatures below 1500 K.