Hughes Aircraft Company

Other

Technic, Inc.

Frank A Ludwig

Bruce M Eliash

Nguyet H Phan

Vilambi N Reddy

Carl W Townsend

John McHardy

Carlyle L Helber, Jr

Andrew Kindler

Lin R Higley

Kazimierz J Wikiel

Chilengi P Madhusudhan

Cheryl Manger

Robert A Osteryoung

A method for monitoring the constituents present in an electroless plating bath solution. The method involves measuring ac spectra using a working electrode which has a high hydrogen overvoltage. First, a selected dc potential is applied to a working electrode which has been subjected to pretreatment and which is present in the electroless bath being analyzed. The electrode must have a high hydrogen overvoltage and is preferably an alloy of a low hydrogen overvoltage noble metal and a high overvoltage metal. A constant ac signal is superimposed on the dc potential. The dc potential is then swept over a chosen range at a selected sweep rate. The various constituents in the bath are then monitored by measuring the ac current at one or more reference phase angles with respect to the constant ac signal between the working electrode and a reference electrode as the dc potential is varied. The resulting ac spectra provides a useful measurement of the make-up of the constituents in the electroless plating solution. Regulation of solution temperature to optimize the ac spectra is also disclosed.

Method of monitoring constituents in electroless plating baths

A method for monitoring the constituents present in conversion coating bath solutions. The method involves using specific ac and dc voltammetry and using platinum or other noble metal working electrodes. First, a selected dc potential is applied to a working electrode which has been subjected to pretreatment and which is present as an in-tank sensor in the bath being analyzed. A constant ac signal is superimposed on the dc potential. The dc potential is then swept over a chosen range at a selected sweep rate. The various constituents in the bath are then monitored by measuring dc current and the ac current at one or more reference phase angles with respect to the constant ac signal between the working electrode and a reference electrode as the dc potential is varied. The resulting dc and ac spectra provide a useful measurement of the make-up of the constituents in the bath solutions.

Method of monitoring constituents in conversion coating baths

A thermal electrochemical system in which an electrical current is generated between a cathode immersed in a concentrated aqueous solution of phosphoric acid and an anode immersed in a molten salt solution of ammonium phosphate and monohydric ammonium phosphate. Reactants consumed at the electrodes during the electrochemical reaction are thermochemically regenerated and recycled to the electrodes to provide continuous operation of the system.

Thermoelectrochemical system and method

A method of monitoring the concentration of certain plating bath major constituents such as acid is provided which is insensitive to the effects of hydrogen produced during plating. The method involves applying an ac signal superimposed on a dc potential to a sensing electrode in contact with the solution, producing an ac response current. The steady state value of the ac response current is then measured and provides an accurate indication of the acid concentration within the solution. The method can be performed using a single sensing electrode. Furthermore, the method complements and is easily integrated with known voltammetric techniques and equipment suitable for analysis of other plating bath constituents.

Method of monitoring acid concentration in plating baths

A method of monitoring major constituents within a plating bath. The method involves applying an electrical signal to a working electrode positioned within the plating bath solution, varying signal parameters, and measuring the resultant response signal. The characteristics of the response signal indicate major constituent concentration levels. The method complements and is easily integrated with known voltammetric techniques for analysis of trace constituents, thus forming an integral part of an efficient overall plating bath analysis system. By adjusting major constituent concentration levels in accordance with measurements made using the method of the present invention, a high quality plating bath can be easily and inexpensively maintained.

Method of monitoring major constituents in plating baths

A method of preconditioning an electrode for use in a plating bath monitoring process. The method involves applying at least one anodic signal to an electrode in contact with the plating bath solution in order to yield a reproducibly clean and stabilized electrode surface, and then applying a plating signal to deposit a layer of metal on the anodically treated electrode. The resultant preconditioned electrode improves the accuracy and precision of subsequent voltammetric monitoring measurements for a variety of different plating baths. The method is easily integrated with and thereby enhances the capabilities of known voltammetric plating bath monitoring processes.

Electrode preconditioning method for a plating bath monitoring process

A method and system for monitoring the quality of a phosphate coating on a metal surface having a large surface area. The method comprises applying a current or potential between the metal surface and one or more counter electrodes while they are in the phosphating solution and superimposing a constant ac signal thereon. An ac impedance spectra is obtained by measuring the ac potential between the metal substrate and one or more reference electrodes located between the counter electrode and the substrate. The ac impedance spectra provide an indication of defects in the phosphate coating even when the defects are located within a relatively small region of the total surface area of the metal surface.

Method and system for monitoring quality of phosphate coating

A method of monitoring a plating bath which combines ac and dc voltammetry to accurately measure major and trace constituent concentrations. The method involves applying both ac and dc voltammetric signals to a pretreated electrode in contact with the plating bath solution, measuring the ac and dc response current spectra, and comparing the resultant spectra to determine which provides maximum spectral detail for monitoring particular constituents with minimum interference from other constituents. Then, the ac and dc response current spectra are each used to monitor the particular constituents for which each provides the best accuracy. The method complements and is easily integrated with known voltammetric techniques and equipment.

Method of monitoring constituents in plating baths

An electrochemical synapse adapted for use in a neural network which includes an input terminal and an output terminal located at a distance of less than 100 microns from the input terminal. A permanent interconnect having controllable conductivity is located between the two inputs. The conductivity of the permanent interconnect is controlled by either growing or eliminating metallic whiskers between the inputs. The growth and elimination of whiskers provides a rapid and controllable electrochemical synapse. Partial neural network systems are disclosed utilizing the electrochemical synapse.

Electrochemical synapses for artificial neural networks

An electric power system particularly adapted for use in powering the electric motor or motors used in the drive train of an electric vehicle. The power system includes a power cell which is a continuous flow concentration cell which utilizes the electrochemical reaction between an acid electrolyte and a base electrolyte to produce electrical energy. Both the acid and base electrolyte utilized in the power cell are kept in external reservoirs. The use of external reservoirs for the electrolytes provides for increases in the energy of the system which is only limited by the size of the reservoirs. Recharging of the system is quickly and conveniently accomplished by recharging the reservoirs with fresh electrolyte, or by electrically recharging the system.

Acid-base concentration cell for electric power generation

A method for monitoring the status of a plating bath purification treatment cycle. The method involves applying a swept dc measurement signal to a pretreated electrode which is in contact with the plating solution, and monitoring the resultant response current signal. The electrode potential corresponding to the peak current density in the cathodic sweep of the response current signal provides an accurate indication of the status of the purification treatment cycle. The method tracks the progress of the purification process thereby ensuring the optimal termination points for the treatment process. The method can be used in conjunction with voltammetric plating bath analysis methods and equipment, as part of an overall plating bath monitoring and control system.

Method for monitoring purification treatment in plating baths

A method of monitoring the concentration of metal ions comprising a major constituent in a plating bath which is insensitive to the effects of other codepositing constituents within the bath. The method involves applying a brief plating signal to a pretreated electrode positioned within the plating bath solution, applying a stripping signal to the plated electrode, and monitoring the resultant stripping signal response current. Certain characteristics of the stripping signal response current accurately indicate major constituent concentration levels and are unaffected by the codepositing constituents. The method complements and is easily integrated with known voltammetric techniques for analysis of trace constituents, thus forming an integral part of an efficient overall plating bath analysis system. By adjusting major constituent concentration levels in accordance with measurements made using the method of the present invention, a high quality plating bath can be easily and inexpensively maintained.

Method of monitoring major constituents in plating baths containing

A method of monitoring in-tank and on-line metal ion content within a plating bath. The method involves the steps of applying a pretreatment signal to a sensing electrode positioned within the plating bath, applying a sweep signal to the pretreated sensing electrode, and measuring the voltammetric peak current of the resultant response signal. The voltammetric peak current is proportional to the metal ion content of the plating bath. The method complements and is easily integrated with known voltammetric techniques for analysis of trace and major constituents, and is thus an integral part of an efficient overall plating bath analysis system.

Method of monitoring metal ion content in plating baths

An electrochemical sensor adapted for use in the electrochemical analysis of liquids. The sensor includes a cell assembly having a liquid flow control chamber, sensing chamber and liquid exit chamber. Liquids to be measured are pumped into the liquid flow control chamber where any turbulence in the liquid is dampened. The non-turbulent liquid is passed from the liquid flow control chamber to the sensing chamber. The sensing chamber includes a working electrode and a counter-electrode. The non-turbulent liquid is passed from the sensing chamber to the liquid exit chamber where it is contacted with a reference electrode. The liquid then exits the sensor. The sensor is well-suited for use in the electrochemical analysis of plating bath solutions where sub-milliampere type AC and DC voltammetric measurements are required in order to generate electrochemical spectra which are indicative of constituents present in the solution.

In-tank electrochemical sensor

A method of forming a reference electrode having a continuously stable reference voltage and particularly well-suited for use in an in-tank electrochemical sensor. The method utilizes an inert substrate and a counter electrode, both immersed in electroplating fluid. Current is passed between the inert substrate and the counter electrode to strip and subsequently replate the inert substrate, which then serves as the reference electrode. The steps of stripping and replating the reference electrode are periodically repeated to maintain the stability of the reference electrode voltage.

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Rancho Palos Verdes, CA, United States of America

Frank A Ludwig