Abstract: An improved non-thermal plasma treatment method and apparatus provide for the pretreatment of nitric oxide-bearing exhaust gas with ethanol, either by vapor absorption or direct vapor injection. Advantageously, the high vapor pressure of ethanol permits a significant portion of the ethanol to be absorbed. Moreover, the solubility of ethanol permits the ethanol to be readily scrubbed from the exhaust gas, along with the nitrogen dioxides converted from the nitric oxides. The non-thermal plasma apparatus comprises a non-thermal plasma reactor having a chamber which provides a plurality of electrodes. The apparatus further comprises an inlet and an outlet connected to the reaction chamber, permitting the exhaust gas to enter and leave the chamber. In one embodiment, the inlet is further connected to a diverter equipped with an injector, which diverts a portion of the gas stream through the ethanol bath before reinjecting the ethanol-bearing gas stream into the inlet.

Abstract: Providing triatomic nitrogen (N.sub.3) as a relaxation species to an exhaust gas that includes nitrogen oxide compounds (NO.sub.x) increases the rate of reducing NO.sub.x in a corona discharge apparatus.

Abstract: A process for reducing particulate, Hg, NOx, and SO.sub.2 emissions from the combustion of fossil fuel while providing the capability of producing an end product that is commercially useful comprising the steps of oxidizing Hg, NOx and SO.sub.2 using a barrier discharge reactor to produce the HgO and acids HNO.sub.3 and H.sub.2 SO.sub.4, collecting the HgO, acids and particulates in a wet ESP, and then draining them from the wet ESP to remove them from the flue gas stream.

Abstract: A reactor for corona destruction of volatile organic compounds (VOCs), a multi-surface catalyst for the reactor and a method of making the catalyst for the reactor. The reactor has a catalyst of a high dielectric material with an enhanced surface area. A catalyst layer stack is formed by depositing a high dielectric layer on a substrate and, then depositing a conductive layer on the dielectric layer. The catalyst layer stack is bombarded by low RF energy ions to form an enhanced surface area and to form a protective layer over the conductive layer. Catalyst layer stacks may be joined back to form double-sided catalyst layer stacks. The catalyst layer stack may be diced into small pieces that are used in the reactor or the whole catalyst layer stack may be used.

Abstract: In particular for exhaust-gas purification, different processes have been proposed. According to the invention, the polluted exhaust gas flows through a reactor volume to which non-thermal gas discharges are applied, while being brought into contact with a solid reducing agent at least once, and preferably several times. The reducing agent can, in particular, consist of carbon fibers. A suitable device for combining dielectric barrier discharges with the reduction has means for field enhancement substantially periodically spaced in the reactor.

Abstract: A process and apparatus for reducing particulate, nitrogen oxides ("NOx"), sulfur dioxide ("SO.sub.2 "), and mercury ("Hg") emissions from the combustion exhaust of fossil fuel fired plants while producing an end product that is commercially useful, comprising the steps of oxidizing Hg, NOx and SO.sub.2 using a barrier, pulse, corona, or electron beam electrical discharge apparatus (100) to produce HgO and the acids HNO.sub.3 and H.sub.2 SO.sub.4 collecting the HgO, acids and particulates in a wet ESP (120), and separating the particulates from the collected acid mixture, then separating and concentrating the acids for industrial use.

Abstract: An apparatus and a method for enhancing the rate of a chemical reaction in a gas stream. The apparatus includes at least one heterogeneous catalyst having an upstream end and a downstream end, and at least one surface having a plurality of catalytically active sites on the surface, where the catalyst is positioned so that at least a portion of the gas stream contacts at least a portion of the catalytically active sites on the surface. At least one device for producing radicals or other active species from at least one of water vapor or other gaseous species, such as a corona discharge device or a UV light source is used to produce radicals or other active species, which are introduced into the gas stream at a position upstream of the downstream end of the catalyst.

Abstract: A method of treating industrial gases to remove contaminants is disclosed. Ions are generated in stream of injectable gas. These ions are propelled through the contaminated gas as it flows through a collection unit. An electric field is applied to the contaminated gas. The field causes the ions to move through the contaminated gases, producing electrical charges on the contaminants. The electrically charged contaminants are then collected at one side of the electric field.The injectable gas is selected to produce ions which will produce reactions with particular contaminants. The process is thus capable of removing particular contaminants. The process does not depend on diffusion as a transport mechanism and is therefore suitable for removing contaminants which exist in very low concentrations.

Abstract: A solid-state power processor circuit and method is used to supply power to generate a discharge in a corona discharge pollutant destruction apparatus. The circuit uses field effect transistors (FETs) and integrated circuit devices based upon metal oxide semiconductor field effect transistor (MOSFET) technology to amplify low-voltage pulse signals to high voltage levels. A resonator in the power processor circuit generates sinusoidal oscillation from the high voltage pulses, and provides the high-voltage, high-frequency electrical power necessary for corona discharge.

Abstract: An apparatus and method for treating exhaust gases. In this apparatus, a plurality of stages of reactor chambers (R.sub.1, R.sub.2, . . . . and R.sub.n) are connected in series in the direction of an exhaust gas flow. Further, high-voltage power supplies (V.sub.1, V.sub.21 . . . and V.sub.n) are connected to the reactor chambers (R.sub.1, R.sub.2, . . . . and R.sub.n), respectively. Moreover, in each of these reactor chambers, a streamer discharger plasma is generated. Furthermore, the more downstream a reactor chamber of a stage is placed, the lower energy to be cast into the reactor chamber becomes. The density of electrons generated in a gas decomposition unit is high in a portion thereof on the upstream side of the exhaust gas flow and the electron density is low in a portion thereof on the downstream side. Additionally, the present invention further provides a pulse generator in which a high voltage, which is an output voltage of a D.C. charger (V.sub.

Abstract: The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes.

Abstract: A corona discharge pollutant destruction system has two or more corona discharge reactors in series, with each stage optimized for either oxidation of hydrocarbons (HC) and carbon monoxide (CO) or reduction of nitrogen oxides (NO.sub.x). The reactors may be arranged with initial oxidation stages followed by reduction stages. Alternatively, the oxidation and reduction reactors may be arranged in alternate stages, with each oxidation reactor followed by a reduction reactor. The treatment of different pollutants by different reactors is achieved by supplying the different reactors with different power levels.

Abstract: A pollutant destruction apparatus has a corona discharge reactor attached to conductive end plates at the ends of the reactor. The reactor has inner and outer electrodes deposited respectively on the inner and outer surfaces of a hollow dielectric cylinder, the interior of which defines the reactor chamber. The inner electrode is electrically connected to the end plates, which are grounded, while the outer electrode is connected to a high-voltage power supply to establish a corona discharge. The outer electrode is tapered near the ends of the reactor to reduce the possibility of arcing. A hole in each end plate is aligned with the reactor chamber to allow gas flow into and out of the reactor.

Abstract: A process and apparatus for reducing particulate, nitrogen oxides ("NOx"), sulfur dioxide ("SO.sub.2 "), and mercury ("Hg") emissions from the combustion exhaust of fossil fuel fired plants while producing an end product that is commercially useful, comprising the steps of oxidizing Hg, NOx and SO.sub.2 using a barrier, pulse, corona, or electron beam electrical discharge apparatus to produce HgO and the acids HNO.sub.3 and H.sub.2 SO.sub.4, collecting the HgO, acids and particulates in a wet ESP, and separating the particulates from the collected acid mixture, then separating and concentrated the acids for industrial use.

Abstract: A process for removing both sulfur dioxide and nitrogen oxides from a gaseous stream where the stream is contacted in a first wet scrubbing unit with an alkaline earth compound to remove sulfur dioxide and humidify the gaseous stream, passing of the humidified gaseous stream to a coronal discharge unit to convert NO.sub.x therein to nitric acid, and then contacting the gaseous stream to a second wet scrubbing unit and contacting the gaseous stream with an alkaline earth compound to remove the nitric acid as an alkaline earth nitrate prior to discharge of the gaseous stream to the atmosphere. The effluent from the first wet scrubbing unit is maintained separate from the effluent from the second wet scrubbing unit during the removal steps so as to provide pure recoverable by-products.

Abstract: In a gaseous pollutant destruction apparatus employing a corona discharge reactor for reducing nitrogen oxide compounds (NO.sub.x), a fuel injection system provides a precisely controlled small quantity of hydrocarbon fuel to the corona discharge reactor to facilitate the destruction of NO.sub.x.

Abstract: A corona discharge pollutant destruction reactor employs two or more electrodes to enhance the effective corona discharge treatment volume by distributing a varying electric field pattern over the reactor's interior chamber. Appropriate delay circuitry allows the inner electrodes to be driven out of phase with each other by a sinusoidal voltage waveform, or corona producing voltage pulses to be cyclically supplied to the inner electrodes in sequence, preferably without overlapping the pulses.

Abstract: A pollutant destruction system connects a capacitive corona discharge chamber in a self-resonant circuit with an inductive element. Intermittent energizing signals are furnished from a power supply to induce corona discharges within the chamber, with the resonant circuit responding to the energizing signals by initiating additional corona discharges between energizing signals in a highly energy efficient operation. One or more discharge chambers can be provided in the resonant circuit, with each discharge chamber comprising a dielectric enclosure with a distributed electrode outside and an elongate electrode inside the enclosure. The inner electrode can extend either along the chamber axis, or along the inner chamber wall for better support and heat dissipation.

Abstract: A process for the production of substantially crystalline silicon nitride comprising heating a mixture of ammonia and a silicon halide by means of an electric plasma formed in a stream of a non-oxidizing gas is described. Energy is transferred to the stream of gas at a rate of at least 30 kilowatts per mole of silicon halide per minute and at least 25 kilowatts. In a preferred embodiment gaseous material is caused to recirculate within the reactor so that there is a recirculation ratio (RR) greater than 2.5 where RR is defined by ##EQU1## wherein M.sub.n =mass flow of gas stream through the inlet nozzle, R=internal radius of the reactor into which said gas stream flows, M=mass flow of gases in the reactor at a distance 4R downstream from the inlet nozzle, R.sub.n =radius of inlet nozzle, D.sub.n =density of gas stream passing through the inlet nozzle, D=density of gases in reactor at a distance 4R downstream from the inlet nozzle.

Abstract: This invention presents an NO.sub.x environment effective reduction apparatus comprising a sulfur tolerant, high water vapor (about 3% to about 18%) tolerant, packing-free coronal-catalyst. In one embodiment the invention comprises an NO.sub.x reduction apparatus of high water vapor tolerant coronal-catalyst adapted and configured for hypercritical presentation of an electrical field to an NO.sub.x bearing gas stream, where the electrical field has a minimum field power density of at least about 75 watts/cubic meter, and optionally, accompanying downstream scrubbers. In a particular embodiment, downstream wet or dry absorption arrest particular NO.sub.x reduction products NO.sub.2 and HNO.sub.3, optionally upon exposure to an arresting agent, including basic, caustic, or alkali materials such as CaO or NH.sub.3.

Abstract: A method and apparatus for glow discharge at pressures of atmospheric and above stabilized between two electrodes spaced apart greater than 3 mm by a swirling gas path. The passage of a reactant gas in the swirling gas stream may be utilized for highly efficient chemical reactions and heating of the gas stream. The simple and compact apparatus for atmospheric pressure glow discharge is suitable for chemical conversion of hydrocarbon gases into higher molecular weight products of greater value, for pretreating combustible hydrocarbon gases for enhanced combustion and for production of intense white light.

Abstract: A method is disclosed for producing Ag/Ni composite ion selective electrode on polymer substrates. By utilizing a nitrogen glow discharge pretreatment of the polymer substrate, silver may be deposited directly thereon. Further, because of the glow discharge pretreatment, aging of the silver layer prior to nickel deposition and bleaching operation is not necessary.

Abstract: This invention presents an NO.sub.x environment effective reduction apparatus comprising a sulfur tolerant coronal-catalyst such as high dielectric coronal-catalysts like glass wool, ceramic-glass wool or zirconium glass wool and method of use. In one embodiment the invention comprises an NO.sub.x reduction apparatus of sulfur tolerant coronal-catalyst adapted and configured for hypercritical presentation to an NO.sub.x bearing gas stream at a minimum of at least about 75 watts/cubic meter.

Abstract: This invention presents an NO.sub.x environment effective reduction apparatus comprising a sulfur tolerant coronal-catalyst such as high dielectric coronal-catalysts like glass wool, ceramic-glass wool or zirconium glass wool and method of use. In one embodiment the invention comprises an NO.sub.x reduction apparatus of sulfur tolerant coronal-catalyst adapted and configured for hypercritical presentation to an NO.sub.x bearing gas stream at a minimum of at least about 75 watts/cubic meter.

Abstract: A method for the production of a nitride of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium, gallium, indium or thallium either alone or as mixtures is claimed. Ammonia and a halide of at least one of these elements are heated by means of a direct electric current plasma in a non-oxidizing gas in a reactor in which recirculation is induced such that the defined recirculation ratio is greater than 2.5 and preferably greater than 4.0. Any titanium halide present shall be less then 40% by weight of mixed halides.

Abstract: A method which comprises the manufacture of black titanium nitride which comprises heating ammonia and titanium halide by means of an electric plasma formed in a stream of non-oxidizing gas generated by the discharge of direct current electricty between a pair of electrodes. The heated gases are introduced through an inlet nozzle into a reactor so constructed and operated as to induce circulation of the gases with a specifically defined recirculation ratio.

Abstract: An electromagnetic converter directs the exhaust stream of a fossil fuel combustion process, for example the exhaust from an internal combustion engine, through a series of electrostatic fields to convert a substantial portion of the pollutants into non-harmful base elements. In an exemplary embodiment, the exhaust stream is directed through an anti-turbulator chamber, which conditions the flow. The chamber includes an electron transfer grid in the path of the flow. The grid has a negative dc charge of sufficient strength to achieve the first ionization level of the HC, CO, and CO.sub.2 molecules present. The ionized exhaust is thereafter directed to an ion generator chamber, which includes coils carrying a very high positive dc charge, e.g. 20,000-50,000 volts dc, sufficient to achieve ionization potential of the molecules to induce molecular breakdown into the base components of carbon, hydrogen, and oxygen.

Abstract: A process for ion nitriding aluminum material which comprises the steps of placing an object of aluminum or aluminum alloy for treatment in a closed vessel; evacuating residual oxygen gas from said closed vessel; charging said closed vessel with a heating gas and inducing discharges in said closed vessel, thereby heating the surface of the object for treatment to a prescribed nitriding temperature; charging said closed vessel with a surface-roughening gas composed of a rare gas and 5-2000 ppm of a gas containing at least one element of oxygen, nitrogen, and carbon, and roughening the surface of the object for treatment by means of glow discharges or ion beams in the atmosphere of said surface roughening gas; and charging said closed vessel with a nitriding gas and simultaneously inducing glow discharges in said closed vessel, thereby forming a nitride layer on the surface of the object for treatment.

Abstract: A method for synthesizing ultrafine powder materials, for example, ceramic and metal powders, comprises admitting gaseous reactants from which the powder material is to be formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400.degree. K. (127.degree.C.). The gaseous reactants are directed through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material.

Abstract: A process utilizing a microwave discharge technique for performing direct nitridation of silicon at a relatively low growth temperature of no more than about 500.degree. C. in a nitrogen plasma ambient without the presence of hydrogen or a fluorine-containing species. Nitrogen is introduced through a quartz tube. A silicon rod connected to a voltage source is placed in the quartz tube and functions as an anodization electrode. The silicon wafer to be treated is connected to a second voltage source and functions as the second electrode of the anodizing circuit. A small DC voltage is applied to the silicon wafer to make the plasma current at the wafer and the silicon rod equal and minimize contamination of the film.

Abstract: A process for removing pollutants including sulfur dioxide and/or nitrogen oxides from effluent gas which relies on the use of corona discharge to enhance the efficiency of the process. In one embodiment, corona discharge is utilized in a conventional spray dryer. In another it is combined with an ammonia injection technique. In yet another embodiment corona discharge treatment is followed by exposing the acidic mist byproduct leaving the discharge treatment chamber to a neutralizing reagent directed into the path of the effluent. The reagent may be provided with an electrical charge opposite to that on the acidic mist byproduct emerging from the corona reaction chamber to enhance neutralization.

Abstract: A new high energy chemical complex is provided formed from metastable hel fixed on ammonia (HE.sub.m NH.sub.3), so that the metastable helium electron is captured so as to be held in the "L" layer of the metastable helium atom.The process for producing the He.sub.m NH.sub.3 complex comprises the following steps: excitation of helium to create metastable helium; deposition of metastable helium on NH.sub.3 to form the complex; and accumulation or condensation of the product.The invention finds a particular application as a propellant in the aerospace field.

Abstract: A process for ion nitriding aluminum or an aluminum alloy as an article to be treated, in which: the article is disposed in a sealed vessel; the oxygen gas in the vessel is removed; the surface of the article is heated to a prescribed nitriding temperature; the surface of the article is activated to facilitate the formation of an aluminum nitride layer by the subsequent nitriding treatment; and thereafter the article is subjected to ion nitriding, thereby forming an aluminum nitride layer having excellent wear resistance and high hardness. This ion nitriding treatment for aluminum material can be carried out even at temperatures lower than a solution treatment temperature of aluminum material.

Abstract: A device designed to use exhaust gas discharged out of an engine combustion chamber by dissociating chemical substances contained in the exhaust gas such as CO, CO.sub.2, NOx, HC, etc., in an exhaust gas molecule dissociating tube and drawing components of the exhaust gas, oxygen in particular, again into the engine combustion chamber. The device is so constructed as to collect dust including the carbon component of the exhaust gas in a cyclone drum for removal from the exhaust gas, which allows all of the engine exhaust to be recycled without releasing it in the atmosphere. The device is utilizable with various engines, e.g., gasoline engines, diesel engines and so on, and well-suited to mass production on account of its simple, compact and lightweight construction.

Abstract: A process for ion nitriding of aluminum or an aluminum alloy and an apparatus therefor, wherein aluminum or an aluminum alloy as an article to be treated is disposed on a substrate holder provided in a sealed container. A predetermined metal having an intensive affinity for oxygen is also disposed in the vicinity of the article to be treated, and a glow discharge is operated between an electrode provided in the sealed container as an anode and the substrate holder as a cathode. The electrode may be directly provided at the sealed container itself or it may be independently provided therein. According to the process and apparatus of the present invention, it is possible to form on the surface of aluminum or an aluminum alloy an aluminum nitride layer having an intensive adhesion to a substrate thereof, high hardness and excellent wear resistance.

Abstract: A method for applying electrical energy within a reactant chamber to enhance a process being carried out in said chamber. The chamber is filled solely or in part with an electrical energy-producing material which will produce electrical energy when excited. In one embodiment the electrical energy-producing material is a piezoelectric material, e.g. Rochelle salt, which is excited by a stress exerted by a piston within the chamber. In another embodiment, the electrical energy-producing material is a ferroelectric material, e.g. barium titanate, which is excited by an external electrical field applied through an electrode within the chamber. In certain processes, e.g. adsorption, catalysis, etc., the electrical energy-producing material may be mixed with an appropriate process material, e.g. adsorbent, catalyst, etc., to form the bed of material in the chamber.

Abstract: A system and a method of nitrogen fixation is disclosed in which nitrogen and other gases such as oxygen are electrically activated and reacted on a catalyst-like material to provide a fixed nitrogen product in such a way that the reactant gases are first placed into an excited state by a single electrode electric discharge acting on a gas stream and then by means of the stream the reactants are contacted on the catalyst-like material on which they are then combined and the product compounds which are thereby formed are shielded by the same catalytic material from ultra violet radiation generated by the electric excitation, said shielding being to prevent subsequent disassociation of the product compounds, and the gas stream emerging on the downstream side of the catalyst carries the products to an absorption bed on which they are absorbed and concentrated and then reacted with a periodic flow of hydrogen to provide ammonia.

Abstract: A method for the chemical vapor deposition of amorphous, glass-like, phosphorous-nitrogen based films on the surface of a substrate is disclosed. The process entails exposing the substrate to a reactant gas stream comprising phosphorous, nitrogen and hydrogen. This method is particularly suited for passivating Group III-V semiconductor materials.

Abstract: There is disclosed a method for forming a decorative metallic nitride coating on the surface of a substrate comprising the steps of disposing said substrate to be coated as a cathode in a material gas atmosphere at a pressure of 0.1 to 10 Torr, with said substrate maintained at a temperature of 200.degree. to 1000.degree. C., and applying a voltage of 200 to 8000 V to said substrate to prepare a direct current glow discharge space in the vicinity of said substrate, the improvement which comprises using as said material gas a mixed gas of a halide of titanium, zirconium or hafnium; hydrogen; and nitrogen, and controlling the current density of the electric current flowing through said substrate to be within the range of 0.01 to 1 mA/cm.sup.2.The method according to the present invention provides a uniform and beautiful metallic nitride coating which has a metallic luster stable with time, is excellent in mar resistance, and is suitable for decoration.

Abstract: A glow discharge surface treatment process wherein only the selected portions of a workpiece adjacent to or surrounded by the associated secondary electrodes are surface-treated so as to provide different treatments on the workpiece according to the position of the secondary electrodes. The each secondary electrode is provided close to at least a portion of the workpiece, and the workpiece and the associated secondary electrode are both connected to the cathode. When a voltage is applied between the cathode and the wall of the container in the treatment apparatus which forms the anode, mutual interference effect (which is referred to as a hollow cathode effect) of negative glow discharges is established between the workpiece and the associated secondary electrode so as to accelerate the heat treatment for the selected portion of the workpiece surrounded by the secondary electrode. The gas pressure in the container is varied to control the hollow cathode effect.

Abstract: A process for the chromization by gas of steels containing more than 0.2% of carbon, consisting of three successive treatments, the chromization treatment proper employing a cement having a ferrochrome base containing between 1% and 3% of carbon, and preferably 2%. The process is particularly useful in the chromization of structural and tool steels.

Abstract: A method of controlling color hues of coatings particularly gold color coatings on substrate using a housing capable of being evacuated, and having an evacuated chamber, a hot cathode chamber in communication with the evacuated chamber and a support structure for the substrate to be coated and a crucible for the material to be evaporated acting as an anode and with a hot cathode in the hot cathode chamber, comprises evaporating the material in the evaporation chamber while maintaining a residual gas atmosphere containing nitrogen therein, producing an electric gas arc discharge between the cathode and the anode of a low voltage, and mixing a carbon containing gaseous compound to the residual gas while applying a negative biasing voltage relative to the housing to the substrate to be coated.

Abstract: Material surfaces are provided which maintain their characteristic properties over long periods and which resist degradation by the environment in which they are utilized. The surfaces are formed by exposing a surface of atomically clean material to a gas or liquid which interacts with the clean surface to form a composition having the properties desired and which is stable against degradation in the environment of use. The process is useful, for example, to render metals or metal alloys, such as iron or iron alloys, stable against oxidation by air by exposing the atomically clean surface to an ultrapure nitrogen environment, prior to exposure to a degrading environment, such as air. A new oxidation-resistant iron surface composition also is provided which comprises body-centered iron structures including nitrogen atoms interstitially.

Abstract: In a method for forming an insulating film on a semiconductor substrate surface, the silicon nitride of the insulating film has been formed by a plasma CVD or a direct nitridation. In the present invention, a gas plasma of a nitrogen-containing gas is generated in a direct nitridation reaction chamber, and the semiconductor silicon body is heated to a temperature of from approximately 800 to approximately 1300.degree. C. within the gas plasma atmosphere, thereby forming the silicon nitride film. The resulting silicon nitride film has a dense structure and a low oxygen concentration and a thick silicon nitride film is formed in a short period by direct nitridation of silicon.

Abstract: A process for the direct thermal nitridation of silicon semiconductor devices in which the semiconductor body is placed in an atmosphere of N.sub.2, at a temperature of less than 1000.degree. C. The N.sub.2 is activated by an RF electrical field which ionizes the nitrogen, which then combines with the silicon surface.

Abstract: A method of producing gold-color coatings on substrates by evaporating a coating material comprising a metallic titanium or zirconium in a housing which has walls which define an evaporation space, comprises, maintaining a vacuum atmosphere containing N.sub.2 and argon in the space. The method is carried out using an anode connected to a power source to produce a low voltage arc discharge in the vicinity of the coating material which is arranged within the evaporation space and also maintaining a low voltage arc between the anode and the substrates. A potential difference between the anode and the substrates of a range of between 5 v and 100 v are maintained during the process and, in addition, the electrical potential of the substrates is maintained between 0 and 150 volts lower than the potential of the housing walls which define the evaporation space. The substrate to be coated is coated at a rate of from between 1 to 15 nanometers per second. The N.sub.

Abstract: The object of the present invention is an improvement in chromizing methods, constituted by a method of chromizing steels to a depth e greater than 30 microns, usable for steels with a carbon content of at least 0.2%, especially for steels for construction work and steels for tools, characterized by the combination of three successive treatments, the first of these three treatments consisting of an ionic nitriding of a surface layer between 100 and 350 microns thick, this ionic nitriding being realized in an atmosphere constituted by a mixture of nitrogen and hydrogen, at a temperature of between 450.degree. C. and 650.degree. C., for between 5 and 40 hours, so as to obtain between 1.5% and 2.5% nitrogen in the nitrided layer, the second of these treatments consisting of a chromizing by gaseous method forming chromium carbides, lasting between 5 and 30 hours, and realized at temperatures of between 850.degree. C. and 1,100.degree. C.

Abstract: An ion-nitriding process in which workpieces are subjected to a two-step glow discharge in a nitrogen and hydrogen atmosphere, there being a larger nitrogen to hydrogen ratio in the second step.

Abstract: A multicathode thermochemical processing oven for the treatment of articles or metals such as steel or steel alloys by subjection thereof to ionic bombardment. The oven structure includes at least one anode and a plurality of cathodes which form individual anode-cathode couples positioned within an air-tight enclosure containing a processing gas for supplying ions. Each of the cathodes is adapted to carry an individual article and subject the article to a particular type of processing depending upon which cathode carries the part. Each of the anode-cathode couples are connected across a power supply, and each of the cathodes are connected through their own individual switching and coupling device for independently couplng to the power source and independent control to supply different types of energy to its respective cathode as well as control the conduction thereof.

Abstract: Thermochemical Treatment System and Process for the treatment of steel or steel alloys by ionic bombardment. Two successive stages of operation are involved in which during the first stage, a DC voltage is applied across the electrodes of a furnace so that the furnace operates at a point far enough away from the arc formation zone to prevent formation of an arc and lies in the zone of abnormal discharge. During the second stage, a succession of pulses of voltage pulses of high voltage but of limited energy is applied to the furnace electrodes, and the operating point of the furnace moves along the voltage-intensity curve to a limit point far enough away from the arc formation zone, so that no arc formation takes place.