Abstract: A power supply in a system utilizing as a source of fuel a generator for separating hydrogen and oxygen gasses from natural water and having the capabilities to control the production of gasses by varying the amplitude of the voltage and/or the pulse repetition rate of the voltage pulses applied to a pair of plate exciters in a vessel of natural water, comprising a sequence of circuitry operative to limit the current of a d.c. potential to a minimum value relative to the magnitude of the voltage applied to the plate exciters. The circuits each function up to a given magnitude of voltage to inhibit and curtail the flow of electrons from the plate exciter having the negative voltage potential applied thereto. The first circuit operative from a first magnitude of voltage comprises converting the voltage potential applied to the plate exciters to a unipolar pulse voltage d.c. of a repetitive frequency. The next circuit varies the duty cycle of the unipolar pulse voltage d.c.

Abstract: A process is provided for obtaining crack-free deposits of rhodium by a pulse electroplating process.

Abstract: A process is described whereby a workpiece is immersed in an electrode, any interlocking between the workpiece and electrode and/or damage to flanks of the workpiece is avoided, and the desired accuracy and surface condition are obtained, by turning negative flanks of a tooth through an angle .gamma. in relation to a center of the negative tooth space. A first, a second, a third and even a fourth movement may be combined with the aforementioned steps such that there is constant adaptation of the parameters of a machining generator depending on a remaining path to be covered.

Abstract: An apparatus and method for dewatering sludges and the like as part of landfill operations by electrokinetic techniques including placing anode and cathode electrode modules in contact with the sludge and applying electrical energy to the electrodes to establish an electric field in the sludge. Charged particles within the sludge, including macro-molecules, colloids, and suspended particles, electrophoretically migrate to the oppositely charged counter electrode and consolidate. A filtration media located at one of the electrodes permits the electro-osmotic removal of water from the sludge to encourage solids densification. The electrical energy applied to the electrodes is a chopped, time-varying, intermittent unidirectional current having a rapid rise edge which provides dewatering results comparable to prior methods that used direct current or full AC current but at substantially reduced energy consumption to provide more economical dewatering.

Abstract: An improved etching method for enhancing the operation rate of manufacturing equipment as well as manufacturing electrode foil with a high enlarging factor in a manufacturing method for electrode foil for aluminum electrolytic capacitors, which enables one to obtain an electrode foil with a high surface enlarging factor by performing electrolytic etching, using alternating current in an acidic hydrochloric acid solution, which does not produce white powder, under the conditions of the ratio of the negative to the positive cycle part of the electric charge impressed on the aluminum foil, being in a range between 0.2 and 2.0 and the duty ratio being 51-90%.

Abstract: A process for the surface treatment of carbon fiber tows each consisting of a multiplicity of filaments, comprises treating the tows by electrolytic oxidation, using each tow as a positive electrode and applying an electric current in the form of pulses. The pulse spacing is such that the electric supply and non-supply durations are 0.02-20 sec. each, preferably 0.1-5 seconds each. The pulse shape is rectangular, triangular, or sine waves. The applied voltage is 3-15 V and the current density 0.2-1000 A/m.sup.2, preferably 1-100 A/m.sup.2, more preferably 5-20 A/m.sup.2. The electrolyte is an aqueous solution of an oxidizing agent, strong acid or base, neutral salt, or weak acid or base.

Abstract: A method for electrolytically etching an aluminium foil for use as an electrode of an aluminium electrolytic capacitor is described. In the method, an aluminium foil is electrolytically etched an on the surfaces thereof in a 3 to 25% hydrochloric acid solution containing aluminium chloride by application of an AC current. The AC current has a waveform, each cycle of which consists of positive and negative half cycles and an OFF time interval between the respective half cycles at which the AC current becomes zero whereby the size of pits formed by the etching is suitably controlled.

Abstract: A method and apparatus for electroplating the surface of a conductive substrate using an electroplating solution having a low concentration of plating ions. Forward and reverse polarity current pulses are alternatively provided between the part to be plated and an anode in an electroplating bath. The process voltage, V.sub.p, between the part to be plated and the anode is sensed and the time ratio between the forward and reverse current pulses is varied to maintain the process voltage V.sub.p below a burn voltage V.sub.b.

Abstract: Method and apparatus for cyclic control of both potential and current in electrolysis, called Cyclic, Controlled-potential, controlled current Electrolysis. The method can be used with a two-electrode cell (W and C), or a three-electrode set-up using a reference electrode R to form two half cells. The method involves supplying a controlled current, preferably a constant current, to the W and C electrodes to operate the electrolysis within well-defined upper and lower potential limits. In a first embodiment (called the constant-current, preset-voltage mode), when a predetermined voltage is reached, the current is reversed until a second predetermined voltage is reached. The cycle is then repeated continuously. In a second embodiment (called the preset-voltage, preset-time mode) the current is maintained constant until the predetermined voltage is reached. Then the voltage is maintained constant by reducing the current until a predetermined time of operation has elapsed.

Abstract: In the electroerosive machining of workpieces with the aid of a tool electrode, a pulse-like d.c. voltage is applied between the workpiece and electrode, the applied voltage being in the form of pulse groups where the pulse groups are formed of individual pulses having current amplitudes of selected magnitudes. Preferably, the individual current pulses belonging to the pulse group have successively rising amplitudes. Several individually controllable power switching circuits are connected in parallel to the work gap. The primary side of a pulse transformer connected to each power switching circuit is driven by a control device for the time shaping of the pulse groups. At least one controlled switch belonging to each power switching circuit is connected to a second control device for shaping the current pulse amplitudes.

Abstract: The present invention relates to a method for the electrodeposition of an ordered alloy structured in alternate discrete layers said alloys possessing high elastic modulus and adjustable magnetic susceptibility. According to the invention, the electrodeposition of at least two metals, characterized by a redox potential gap of at least 0.1 V between said metals, is obtained by the pulse plating technique with a frequency in the range of 0.02 Hertz to 15 Hertz. The concentrations of the noblest metal in the electrodeposition solution should be in the range of 0.001M to 2.0M while that of the less noble metal is about its saturation at room temperature. The discrete layers obtained according to the method are less than 90 Angstroms thickness, being substantially pure. Examples of the metals to be electrodeposited according to the invention are copper-nickel; copper-palladium; nickel-gold; copper-nickel-iron and corresponding alloys with cobalt or iron replacing nickel.

Abstract: A device and process for inducing membrane fusion under an electric field. The process comprises the steps of (a) suspending said membranes in an aqueous buffered medium in a manner so that the membranes are without contact with each other; (b) altering said membranes to a fusogenic state by applying 2-30 pulses of direct current at a rate of 2 to 5 pulses per second in an electrical field strength of about 500-1000 volts/mm in the medium, said pulses having a rapid rise time not exceeding about 10 micro seconds and an exponential decay half time of about 0.2 milliseconds to about 1.2 milliseconds; and (c) thereafter bringing said fusogenic membranes in contact with each other. A long-lived metastable fusogenic state of membranes can be obtained by the device and process.

Abstract: An electrolytic apparatus for applying a voltage to a workpiece (1) and a counter electrode (5) both immersed in an electrolyte (3) contained in a vessel (4) thereby processing the workpiece (1) comprises a voltage source (15, 15') for applying voltage between the workpiece (1) and the counter electrode (5) in the form of pulses whose polarity is periodically changed, a beam generator (16) for irradiating a subsidiary energy beam (17) on a selected region of the workpiece (17) by generating the beam (17) in the form of periodic pulses and a timing control device (21) for synchronizing the periods of the voltage pulses and the beam pulses.

Abstract: A method and apparatus for electrolytic treatment employing graphite electrodes wherein an asymmetrical waveform alternating current is applied to the electrodes to subject a metal web to a continuous electrolytic treatment. A graphite electrode in a treatment section is arranged confronting the metal web. Two graphite electrodes in current supply sections are arranged respectively upstream and downstream of the graphite electrode in the treatment section relative to a direction of movement of the metal web. Two auxiliary anode electrodes in the current supply sections are arranged respectively upstream and downstream of the two graphite electrodes in current supply sections. A part of an asymmetrical alternating waveform current is supplied to the auxiliary anode electrodes so that a current causing a cathode reaction on the surfaces of the graphite electrodes is made larger than a current causing an anode reaction thereon.

Abstract: A method of enhancing naturally developed color of an anodic oxidation coat on Al or Al alloy wherein the coat is formed by an electrolysis employing a warmed electrolyte containing at least sulfuric acid and an electric current of which the polarity is periodically reversed to be negative for a period less than 50% of each cycle while being applied to Al or Al alloy dipped in the electrolyte as anode for 20 to 40 minutes and the thus coated Al or Al alloy is subjected to a heat treatment in a boiling sealing liquid or a boiling metallic salt solution for 20 minutes. Preferably, the electrolysis is carried out for most of the electrolysis time with the current reversed for a small period of about 5% each cycle and during the terminating stage with the current reversed for a larger period of 30 to 35% each cycle. A sulfur compound is accumulated in the coat during such electrolysis and is combined with an added alloy element of the Al alloy during the heat treatment to further develop the color of the coat.

Abstract: A method of plating a ductile Ni-Sb alloy on a substrate from a solution containing a Ni salt and a mixed alkali metal-antimony salt comprises pulse plating wherein the off-time is much longer than the on-time.

Abstract: A method for producing a support for a lithographic printing plate is described, which comprises mechanically graining the surface of an aluminum sheet, and then electrolytically graining the surface of the aluminum sheet in a solution containing hydrochloric acid, nitric acid, or a mixture thereof by applying thereto an alternating current in such manner that the ratio the quantity of electricity during the cathodic period to the quantity of electricity anodic period is in the range of from 1.0/1 to 2.5/1.

Abstract: An electrochemical process is provided for the production of a zerovalent metal/organo-phosphorus ligand complex by passing a current through an electrolyte bath which includes a transition metal salt and a trivalent organic phosphorous compound, the improvement comprising the current being a pulsed direct current.

Abstract: A method is provided for electrolytically graining an aluminum lithographic plate to produce a grained surface with a honeycomb topography, non-directional grain structure, and a substantially reduced production of smut. The reduction of smut is achieved by utilizing an alternating current of higher frequencies, generally in the range of approximately 140 to 400 Hz.

Abstract: The invention features an electrolytic process for producing lithographic plates. The plates are immersed in a bath and fed a shaped alternating wave having a multiplicity of zero voltage intermissions. The grain topography of the plate can be varied by changing the frequency and duration of the intermissions in the wave.

Abstract: A process is described for electrolytically producing nickel electrodes by subjecting a porous nickel structure (generally a nickel plaque) to alternating anodic and cathodic pulses in an aqueous halide (generally chloride) solution. The alternating pulses first anodically dissolve the nickel from the porous nickel plaque and then cathodically precipitate the nickel in the form of the hydroxide. Particularly attractive is the use of a stable, simple solution, room temperature operation and the broad variation in operating conditions (pH, etc.) that still produce optimum results.

Abstract: A method for continuously electrolytically processing a metal web in which the consumption rate of graphite electrodes is remarkably reduced. Auxiliary anodes made of a nonreactive material are provided separately from the graphite electrodes. One half of a symmetrical waveform is applied directly between the graphite electrodes, while for the other half of the waveform, a portion of the current is distributed through the auxiliary anodes. In this manner, the magnitude of the current contributing to a cathode reaction on the surfaces of the graphite electrodes is made larger than the magnitude of the current contributing to an anode reaction on the surfaces of the graphite electrodes, thereby reducing the consumption rate of the graphite electrodes.

Abstract: Pretreatment of aluminum strip or foil for lacquering, adhesive coating or laminating processes involves heavy metal compounds which are considered undesirable for many packaging purposes, in particular for foodstuff packaging. These disadvantages are avoided if the strip or foil is pretreated in an electrolyte by subjecting it to a three phase alternating current of which one phase is rectified and the side of the strip or foil to be treated is made to pass in sequence three electrodes of which at least one is connected to the rectified phase while the others are connected to the other phase of the alternating current. Such a pretreatment has the advantage over an alternating current treatment that the oxide layers offer high strength of adhesion and the treatment can be performed faster.

Abstract: A method of electrolytic treatment on the surface of metal web, such as may be employed to fabricate offset printing plates supports, in which the rate of consumption of graphite electrodes used with the process is remarkably reduced. A current having asymmetric positive and negative half cycles is applied between graphite electrodes disposed in a main cell. A portion of the current of the half cycle having the larger average value is applied to an auxiliary anode electrodes provided in an independent auxiliary cell separated from the graphite electrodes. The auxiliary electrode is made of an insoluble material. By making the current density for anode reaction on the surfaces of the graphite electrodes smaller than the current density for cathode reaction on the surfaces of the graphite electrodes, the consumption rate of the graphite electrodes is greatly reduced.

Abstract: Disclosed is a method and apparatus for electrolytic processing of a metal surface which, in a preferred embodiment, is anodization of an aluminum or aluminum alloy surface. An apparatus and method is provided which automatically senses the process voltage applied to the surface to be anodized and adjusts the duration of anodizing current pulses accordingly. Direct current anodizing pulses are interrupted by non-anodizing pulses which may be either zero current or reverse current pulses. The ratio of anodizing to non-anodizing pulse power is varied during anodizing such that the anodizing to non-anodizing time power ratio is reduced. In a preferred embodiment, a microprocessor follows the process voltage necessary to maintain a constant current flow to the metal surface and reduces the anodizing to non-anodizing time power ratio in a predetermined manner.

Abstract: A process and apparatus for treating a metal foil to enhance its ability to be bonded to a substrate comprise immersing the metal foil in an electrolytic cell having an electrolyte bath solution containing copper and applying a current having regularly recurring pulses and preferably flowing in only one direction to the cell. The current causes a dendritic layer of copper to be deposited on at least one surface of the metal foil at a first current density and bonded thereto at a second current density. The process and apparatus are particularly suited for treating copper foil.

Abstract: An improved process for electroplating bonding pads, such as of gold, onto semiconductor devices is disclosed. Upon electrically connecting a masked semiconductor body and a suitable anode to the negative and positive terminals respectively of a power supply and submerging the wafer and anode into a suitable electrolyte, a modulated, rather than direct, current is applied to the electrolyte. A low stress, fine grain bonding pad layer is provided and, unexpectedly, non-planarities in the semiconductor body surface having a depth of about 1-3 microns can be substantially planarized when the thickness of the layer deposited is about 6-8 microns or more.

Abstract: Electrodeposition is carried out using an electric current which is applied in the form of pulses between a workpiece and an electrode in an electrolyte from which metal is to be deposited upon the workpiece. The pulses have a pulse duration not greater than 100 microseconds and the pulse duration is preferably between 1-50 microseconds while the off time or interval between adjacent pulses is more than twice as long as the on time of the pulses.

Abstract: A substrate such as carbon, graphite, or various semiconductors is coated with a "two-dimensional" thin film form of flat isolated crystallites of platinum, palladium or silver to form a catalyst useful in a fuel cell. The method of formation of the catalyst is to place the substrate in an electrolyte such as H.sub.2 PtCl.sub.6 about 1% and one molar sulfuric acid. The potentiostatic pulse plating method is employed. A high potential pulse of very short duration is followed by a low potential of substantial duration. The very high potential nucleates crystals at various randomly distributed nucleation sites such as imperfections in the surface of the substrate. The resulting catalyst has a large surface area of hexagonal crystals about 20 to 40 Angstroms in diameter.

Abstract: Disclosed is a process for electrochemically roughening aluminum or alloys thereof, in an aqueous electrolyte, under the action of an alternating current having a frequency in the range from 0.3 to 15 Hz. The materials roughened in this way are used as supports for radiation-sensitive reproduction coatings in the field of manufacturing offset-printing plates. Also disclosed are roughened aluminum supports and printing plates produced by the above process.

Abstract: Disclosed is a method and apparatus for electrolytic processing of a metal surface which, in a preferred embodiment, is anodization of an aluminum or aluminum alloy surface. An apparatus and method is provided which automatically senses the process voltage applied to the surface to be anodized and adjusts the duration of anodizing current pulses accordingly. Direct current anodizing pulses are interrupted by non-anodizing pulses which may be either zero current or reverse current pulses. The ratio of anodizing to non-anodizing pulse power is varied during anodizing such that the anodizing to non-anodizing time power ratio is reduced. In a preferred embodiment, a microprocessor follows the process voltage necessary to maintain a constant current flow to the metal surface and reduces the anodizing to non-anodizing time power ratio in a predetermined manner.

Abstract: A process and apparatus for treating a metal foil to enhance its ability to be bonded to a substrate comprise immersing the metal foil in an electrolytic cell having an electrolyte bath solution containing copper and applying a current having regularly recurring pulses and preferably flowing in only one direction to the cell. The current causes a dendritic layer of copper to be deposited on at least one surface of the metal foil at a first current density and bonded thereto at a second current density. The process and apparatus are particularly suited for treating copper foil.

Abstract: Disclosed is a process for electrochemically roughening aluminum or alloys thereof, in an aqueous electrolyte, under the action of an alternating current which is generated by superimposing at least two types of alternating current of different frequencies. The materials roughened in this manner are used as supports for radiation-sensitive reproduction coatings in the field of manufacturing offset-printing plates. Also disclosed are roughened aluminum supports and printing plates produced by the above process.

Abstract: An article, such as a semiconductor wafer (31), is selectively electrolytically plated to form metal deposits, such as contacts (26), adjacent to anodes of diode regions within such wafer by mounting the wafer in a plating chamber (36) opposite first and second electrodes (61 and 62), filling the chamber (36) with a metal plating electrolyte (49) and applying alternatingly plating pulses between the wafer (31) and the first electrode (61) and deplating pulses between the wafer (31) and the second electrode (62). The plating pulses are current controlled yielding a predetermined total plating current. The deplating pulses are voltage controlled yielding a deplating current which tends to subside in the course of the plating operation. The electrolyte in the chamber is agitated by streams of electrolyte pumped at a comparatively high rate toward the wafer (31) to break down surface layers of electrolyte adjacent to the wafer.

Abstract: A bath for electrodepositing gold utilizes, as the essential ingredients of its electrolyte, salts providing the tartrate radical and the carbonate radical. The bath will have a pH value ranging from approximately neutral to highly alkaline, and adjustments to lower the pH will most advantageously be made utilizing tartaric acid. The bath operates with relatively low gold concentrations, and is capable of producing highly pure deposits and highly desirable alloy deposits; it is especially well suited for semi-conductor industry applications.

Abstract: A process for the electrodeposition of a nickel chromium alloy on a catho substrate comprises:contacting the substrate with an aqueous electrolyte containing: about 50-125 g/l of CrCl.sub.3.6H.sub.2 O; about 10-125 g/l of NiCl.sub.2.6H.sub.2 O; about 10-115 g/l of formic acid; about 25-50 g/l of boric acid; and about 50-100 g/l of sodium citrate dihydrate;adjusting the pH of the bath to about 1-5 and the temperature to about 20.degree.-60.degree. C.; andpassing a sufficient current through the solution and to the substrate to effect deposition thereon of a nickel-chromium alloy.

Abstract: Etching aluminum foil by (both) a high frequency current of at least 1 KHz and subsequently by an alternating current of less than 1 KHz remarkably increases the effective surface area for use in an electrolytic capacitor.

Abstract: The electrolytic/electric discharge machining of a workpiece of a non-conductive hard material, for example, ceramic material is carried out by preparing a grinding wheel having conductive regions and non-conductive abrasive regions circumferentially alternately arranged on the circumferential edge of the wheel, and bringing the rotating grinding wheel in contact with the workpiece while applying AC or DC voltage across the grinding wheel and the non-conductive workpiece.

Abstract: A screen skeleton as a cathode is subjected to a pulsed current for depositing metal from an electrolytic bath onto the metal regions of the screen skeleton, said electrolytic bath containing a brightener of the second class. This process involves growth of metal substantially perpendicular to the screen skeleton surfaces thus maintaining the size of the openings of the screen skeleton.Small pulse current durations are advantageous. Preferably a pulsed current is used comprising pulse current and non-pulse current durations; more preferably the pulse current durations are subdivided into small pulse current and non-current pulse periods.

Abstract: A method and apparatus for effecting periodic current reversal in metal electro-deposition processes are disclosed. By using a circuit in which the current always flows in the same direction through a filter reactor, regardless of the current flow through the electro-deposition cell, faster reversal switching times are obtained. The overshoot and AC ripple encountered on current reversal are also decreased.

Abstract: An electrolytic coloring process for aluminum or aluminum alloy is disclosed in which the aluminum is subjected to electrolytic treatment, in the absence of metal salts, in a low disolution electrolyte having a chemical activity equivalent to less than an H.sub.2 SO.sub.4 concentration of 4gm/liter, by applying an alternating current having a peak voltage of between 55 and 85 volts and a current density of less than 0.3 amp/dm.sup.2 and then treating the aluminum in an acid electrolyte containing a metal salt, again using alternating current of the same peak voltage range.

Abstract: The invention comprises an improved method for producing anodized aluminum articles colored by means of optical interference effects. The method comprises the steps of subjecting an aluminum article that has been anodized by conventional process to a treatment for modifying the pore structure of the anodic film, thereafter subjecting it while connected as anode to an electrolytic treatment for modifying the barrier layer between the oxide and the metal substrate and finally coloring the article while connected as cathode in an electrolyic bath containing one or more dissolved metal salts using DC current on which is superimposed a train of positive current pulses.

Abstract: A large number of electrically conductive solid, dense feed-through paths for the high-speed low-loss transfer of electrical signals between integrated circuits of a single silicon-on-sapphire body, or between integrated circuits of several silicon-on-sapphire bodies, are provided by an electroforming method utilizing periodic reverse-current pulsing.

Abstract: Aluminum electroplating installations containing aprotic electrolyte bath systems typically require an electrolyte operating temperature of over 80.degree. C. in order to achieve useable aluminum precipitations. The warming-up and heating of such aluminum electrolyte baths has heretofore been accomplished with indirect heating methods, such as surrounding the baths with a heating jacket or by conducting electrolyte out of the bath through a heat exchanger and then returning the heated electrolyte. The present invention concerns a more efficient heating method whereby Joule's heat is used to heat an aprotic electrolyte bath. Accordingly, at least two electrodes are immersed into the electrolyte and charged with alternating pulses by a square wave pulse generator such that a heating current flows through the electrolyte. The anodes and cathodes of the aluminization electrolyte bath are preferably used as the heating electrodes.

Abstract: A process is described for etching p-type semiconductors using a photoelectrochemical etching process. This etching process is highly advantageous because the etching site is highly defined by the incident light and the etching rate can be controlled in a number of ways including light intensity and electrode potential.

Abstract: Biofouling and scale control in conductive aqueous systems is effected on metal, preferably valve metal such as titanium, surfaces on which such fouling normally occurs by applying thereto a stable electrocatalytic coating, anodically polarizing said valve metal coating such that essentially only oxygen is evolved at the surface thereof, preferably at a rate of at least about 4.66 millimoles per square meter per hour without evolution of any chlorine. Periodic current reversal is effected to forestall biofouling upon any cathode utilized in implementing the instant invention.

Abstract: A system for generating and autocontrolling the voltage or current wave form in a process for the electrolytic coloring of anodized aluminium includes feeding power from a source of symmetrical direct current, with a neutral connection directly coupled to a load, while the positive and negative voltages supplied by the source pass through a power control stage which is controlled by a bipolar operational amplifier. The bipolar operational amplifier has two signal inputs, a positive or non-inverting input which is connected to a signal generator, and a negative or inverting input having a signal which corresponds to the signal which actually exists on the electrodes of the electrolytic bath. This signal is processed in a half-wave outer controller which is controlled by a programming system.

Abstract: Disclosed is a method of operating a solid polymer electrolyte chlor-alkali cell by imposing a pulsative current, e.g., pulsed direct current, half wave alternating current, or rectified alternating current, across the cell.Also disclosed is the chemical deposition of porous catalysts on a permionic membrane whereby to obtain a solid polymer electrolyte.

Abstract: Disclosed is a method of coloring an anodized and anodically reinforced aluminum or aluminum alloy article by cathodic treatment in a coloring solution wherein the cathodic electrolytic current is a negative voltage direct current having a duration substantially less than the interval therebetween and being repeated at a frequency sufficient to produce the required coloration.

Abstract: A process for electrolytically treating aluminum or its alloys in the form of a strip, wire or foil material in a continuous manner which comprises continuously passing the material through an anodic oxidation treatment cell through which a direct current, alternating current or AC-superimposed direct current is caused to flow and an electrolytic coloring cell through which an alternating current or AC-superimposed direct current is caused to flow and carrying out electrolysis in both said cells to anodize and color the material in a continuous manner.