Abstract: An apparatus and method for selectively electrochemically etching a surface is described. The use of the apparatus and the related method allows the establishment of etched planar surface which may be inclined with respect to the original surface.The apparatus has a cathode and multiple connectors which attach to the workpiece whose surface is to be etched. When the apparatus is operated the potential of the connectors are set so that the cathode is at least as negative as the lowest potential of the connectors.

Abstract: A method of etching aluminum by applying an alternating electric current to aluminum which is in contact with an electrolyte containing hydrochloric acid, in which the alternating current has a symmetrical waveform wherein the current rises rapidly from zero to a maximum, then subsequently decreases rapidly in a first stage to an intermediate value which is about one-third to about one-half of the maximum, and thereafter decreases more slowly to zero in a second stage. Thereafter the current rises and falls in the opposite direction with the same waveform. The ratio of time of the second stage to time of the first stage of the waveform is in the range from 1 to 6. By this procedure higher capacitance values of the etched aluminum are obtained in comparison to prior procedures.

Abstract: A method for preparing a support for a planographic printing plate using an electrolytic surface treatment of an aluminum plate is disclosed, wherein an alternating charge voltage is applied to the aluminum plate in an acidic electrolyzing bath, and the wave form representing the voltage includes an intermission of zero voltage in at least one of the anode or the cathode phases, and is such that the electric quantity for the anode phase is larger than the electric quantity for the cathode phase.

Abstract: Anodic deburring or brightening of steel articles is carried out in an alkaline solution containing, per liter of the solution, at least 200 grams of water, at least 300 grams of polyhydric alcohol and at least 200 grams of alkali sulphamate.

Abstract: A method of electrochemical processing comprises the steps as follows: maintaining a variable gap between a processing electrode and a work-piece, having a value equal to a minimum permissible gap corresponding to processing conditions; with the gap value reaching a critical value, moving the processing electrode to obtain a gap approximately equal to or less than the critical value; applying a train of voltage pulses; and changing the length of each pulse and/or the space interval between pulses. When the space interval becomes equal to a value commensurate with the time of withdrawal of the processing electorode, a single voltage pulse is applied.

Abstract: The invention is applicable to the griding with current-conducting abrasive tools of works of current-conducting churlish materials, such as hard, magnetic and refractory alloys, and to cutter sharpening.The method according to the invention consists in applying voltage pulses to a tool and a work placed in a liquid medium with a conductance of 10.sup.-4 to 2.multidot.10.sup.-2 ohm.sup.-1 .multidot.cm.sup.-1.The process of grinding the work and electric-erosion cleaning the tool is carried out at a pulse duration of 0.5 to 10 msec, pulse repetition frequency of 10 to 500 Hz, and amplitudie of pulses ranging from a minimum of 3 V to a maximum which is below a level required for a breakdown of the liquid medium between the tool and the work.Alternatively, simultaneously with machining the work the electric-erosion truing of the tool is performed with the use of a tool truing electrode.The tool truing electrode and the work are connected to the same pole of a power source.

Abstract: A continuous length of aluminum is anodized during passage through an anodizing electrolyte and then colored during passage through an inorganic coloring electrolyte, in which a counterelectrode is immersed. In the electrolytic coloring stage alternating current with a superimposed D.C. compound is preferably passed between the anodized aluminum and the counterelectrode when the electrolyte is appropriate for such treatment. The alternating current circuit for the electrolytic coloring stage is preferably completed via an electrode immersed in the anodizing electrolyte at a position facing substantially unanodized aluminum so as to effect a liquid contact.

Abstract: A method of plating an iron-cobalt alloy on a substrate is disclosed. The iron-cobalt alloy having a composition of 7.5-55% of iron and 92.5-45% of cobalt is plated by using a plating bath containing any one of fluoride, borofluoride, silicofluoride and acidic fluoride or further adding at least one of chloride, sulfate and sulfamate thereto.

Abstract: Pulses of a pulse duration not greater than 100 microseconds are applied by an electronic switch between a tool electrode having abrasive particles distributed over its surface and a workpiece across a polishing gap supplied with an electrolyte.

Abstract: The operation of an electrolytic machine tool is monitored over equal periods of time, so as to detect the number of short circuits, if any, which occur. Where a given number of short circuits are detected in any one time period, a signal is derived from the last of that number and utilised to switch off the electrode traverse motor through power and electrolyte flow are maintained to enable sludge clearance and observation of the resultant reduction in short circuits.

Abstract: A pulsating current comprising only positive half-waves separated by zero-current intervals is fed into an electrolyte between two electrodes in which the cathode is constituted by a tool and the anode is constituted by a part to be machined in accordance with the profile of the cathode. The electrolyte is of the passivating type which preferably contains between 30 and 50 grams per liter of sodium nitrate.

Abstract: Method for producing colored anodic oxide films on aluminum-based alloy materials comprising steps of subjecting the material having an oxide film thereon to a coloring electrolytic treatment in a bath of electrolyte containing water soluble nickel salt and boric acid. The material is applied with alternating voltage pulses having negative pulse duration which is the same as or greater than duration of positive voltage pulse.

Abstract: A method is provided for removing arsenic from arsenic and copper containing electrolytes by electrolysis while minimizing or substantially reducing the formation of arsine gas, through the application of a periodically reversed or interrupted current during such electrolysis. The method is particularly suitable for the purification of copper refinery electrolyte.

Abstract: A method for electrodeposition of polycrystalline silicon from a molten fluoride bath onto a metal cathode which is essentially non-alloying with silicon (e.g., silver, tungsten, niobium). The silicon is deposited as a continuous coherent, firmly-retained, non-spongy layer of large columnar grains on the substrate.

Abstract: A porous aluminum anode element having an increased effective surface area is prepared by an electrolytic etching process using an etchant solution containing CrO.sub.4 .sup.-- in a higher concentration and a lower current density than those heretofore proposed. Currents of a digital signal type, such as a pulse current, or those of triangular, sawtooth, trapezoidal or staircase waveform, are preferred.

Abstract: A process for the electrolytic refining of metals, especially copper, in which the copper is deposited from an electrolyte on the cathode of an electrolytic cell which comprises periodically reversing the current with a forward pulse time of 2 to 9 seconds and a reverse pulse time of 0.1 to 0.45 seconds.

Abstract: A method of electrochemically polishing a metal body which comprises juxtaposing the surface to be polished with a tool electrode in the presence of an abrasive and an electrolyte, and applying pulses having a duration not exceeding 100 microseconds between the electrode and the workpiece with the electrode being poled negatively.

Abstract: A process for electrowinning of copper from leach solutions containing a high concentration of iron in the range of about 5 to 40 gpl, is disclosed. The process consists in applying direct current through the solution and periodically reversing the polarity of such current to obtain a solution having a low ferric ion concentration, thereby increasing the operating current efficiency and consequently decreasing the power consumption.

Abstract: A method for electroplating in a single electroplating bath comprising varying the electric current density so that a non-magnetic plated film and a ferromagnetic plated film are selectively deposited. To achieve this effect the electroplating bath must contain at least about 1 g/l NaH.sub.2 PO.sub.2.H.sub.2 O.

Abstract: System for electric extraction of non-ferrous metals from their solutions. The system includes means for applying a reversing electric current of different duration for the current for the electric extraction and the dissolution. The system has means for conducting the process simultaneously in two groups of electrolytic baths, the electric current for dissolution for each group of electrolytic baths being provided by the electric current for electric extraction in the other group of electrolytic baths.

Abstract: A method of electroplating a crack-free hard chromium deposit comprises having present in the electroplating bath a complex halogen-containing compound which disassociates in an aqueous solution while maintaining the bond of a halogen in the complex. A plating voltage is used which periodically superimposes high voltage pulses on the base voltage.

Abstract: A method is provided for removing arsenic from arsenic and copper containing electrolytes by electrolysis while minimizing the formation of arsine gas, through the application of a periodic reverse current during such electrolysis. The method is particularly suitable for the purification of copper refinery electrolyte.

Abstract: A method for the electrodeposition of a relatively thick (20 to 45 microinches) layer of ruthenium includes the step of pulse current plating an intermediate layer of gold over the substrate to be plated. The ruthenium layer so obtained is characterized by low internal stress and an absence of surface cracks.

Abstract: A method for etching fine grooves in surfaces by the combination of pulsed currents in a modified E.C.M. (Electro Chemical Machining) method in combination with a flow guiding template.The method is very suitable for the etching of grooves in a surface used in a bearing.

Abstract: An electrode and an article plated, or to be plated, immersed in an electrolytic chromium-plating bath can be maintained in a normal condition even while electricity for plating is not supplied, by applying a low DC voltage of 1.27 to 2.2 volts between the electrode and the article while keeping them in the plating bath.

Abstract: An electrodeposition method of electrodepositing a material with a flat and smooth surface, in which an electrolytic condition such as a speed of movement of a cathode relative to an electrolyte, an electrolytic current density, a duty ratio of an interrupted electrolytic current or an interruption frequency of an electrolytic current is changed periodically from a normal value to another value and back again.

Abstract: An electrochemically generated field desorption emitter for use in mass spectrometry, and a process for forming such an emitter by immersing a metal support, as a first electrode, and a second electrode in an electrolytic liquid mixture having appropriate concentration of a metal compound, and applying a plurality of short duration, electrical pulses between the electrodes. The emitter so formed comprises an elongated metal support having a plurality of metal dendrites extending in a generally radially outwardly direction therefrom.

Abstract: Apparatus for electrolytically coloring anodized aluminum comprises a power transformer whose secondary winding has one phase connected directly to the charge and its other phase connected to the charge through two anti-parallel thyristors. One of the thyristors is triggered in accordance with a predetermined program, and the other thyristor is triggered in dependence upon unbalance in the average values of the voltages applied to the charge in consecutive half cycles of the alternating current applied to the charge, in such a manner as to tend to eliminate the unbalance.

Abstract: A pulse plating system wherein the duty cycle is controlled by skipping pulses in producing the output signal. The circuitry for controlling the skipping of the pulses can either be analog or digital type circuitry.

Abstract: Electrolytic methods for making high density copper powder starting with copper powder of lower apparent density are disclosed. Copper powder of lower apparent density is used as a cathode for the formation of copper powder having a desired relatively high apparent density. According to one embodiment, an integral two-phase process is provided in which copper powder of relatively lower apparent density is formed by electrodeposition, and the powder so-formed is then used in a second phase electrodeposition process as a cathode on which copper powder of the desired relatively high apparent density is formed.

Abstract: A forward-reverse pulse cycling anodizing and electroplating process power supply wherein the forward-reverse cycle time, the ratio of positive to negative pulses during the cycle time, the width of the individual pulses and the voltages of the pulses are controlled. During the cycle time a series of discrete positive pulses are supplied during the first portion of the cycle, followed by a series of discrete negative pulses during the remainder of the cycle. The cycle is then repeated for as long as the power supply is energized. The discrete pulses supplied are portions of sinusoidal current waves. Triggerable unidirectional current conducting devices, disposed between the alternating current power supply and the electroplating load, are triggered into conduction at a selected point by a firing angle control circuit. Using the disclosed electroplating process power supply it is possible to hard anodize copper bearing aluminum alloys without etching.

Abstract: An a-c source of power is utilized to provide periodic d-c pulses of predrmined amplitude, duration, and frequency by synchronizing the delay sweep of a cathode ray oscilloscope with the sine wave of the a-c voltage input, timing the delay sweep to provide an output signal at the desired frequency and at the particular point on the sine wave which will impart the desired voltage peak thereto, and utilizing each output signal to trigger a first silicon controlled rectifier for initiating a current pulse while simultaneously providing a corresponding signal with a given delay for firing a second silicon controlled rectifier to terminate the current pulse and establish the duration desired thereof.

Abstract: A novel electrolytic cell performs an electrolysis process at improved efficiencies by supplying a pulsed DC current to the electrodes thereof. In preferred embodiment a generally cylindrical anode with a fluted outer surface is surrounded by a segmented cathode having an active area equal to the active area of the anode. An electrolyte, which may be a 25 percent solution of potassium hydroxide is introduced into the cell for production of hydrogen and oxygen at the cathode and anode respectively. The current for carrying on the electrolysis process is provided by a transformer which is preferably located within an oil filled chamber inside the anode. Heat from this transformer and a magnetic field also created thereby both have a beneficial effect upon the reaction rates. The pulsing of the electrode current may in one embodiment be carried out at a rate of between 5,000 and 40,000 pulses per minute, with a rate of about 10,000 pulses per minute being preferred.

Abstract: An electrolytic plating solution and method for depositing ferromagnetic recording films therefrom is described. The plating solution has cobaltous ion in the range of from about 3 to 15 grams per liter, nickelous ion in the range of from about 30 to 50 grams per liter, and orthophosphite ion in the range of from about 3 to 12 grams per liter. It is important that the ratio of nickelous ions to cobaltous ions be in the range of from about 3:1 to about 15:1. The plating solution is substantially free of hypophosphite ion, phosphate ion, copper and iron so that phosphite ion is the sole source of phosphorus. Optionally the solution may contain up to about 30 grams per liter of boric acid and up to about 25 grams per liter of formate ion. The pH of the solution is maintained in the range of from about 3.5 to 4.7.