Abstract: A method for electrochemically plating tin or tin alloy onto a workpiece to provide a tin or tin alloy deposit on said workpiece having a stress differential and workpieces characterized by a tin or tin alloy deposit having a stress differential.

Abstract: A layer of chromium metal is electroplated from trivalent chromium onto an electrically conducting substrate by immersing the substrate and a counter electrode in a electroplating bath and passing a modulated electric current between the electrodes. In one embodiment, the current contains pulses that are cathodic with respect to said substrate and in another embodiment the current contains pulses that are cathodic and pulses that are anodic with respect to said substrate. The cathodic pulses have a duty cycle greater than about 80%.

Abstract: An apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: A method and apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: An electrolytic filtration method and apparatus for the concentration and collection of suspended particulates from aqueous solutions is disclosed. The electrolytic cell contains at least an anode and a cathode, and in one embodiment contains a plurality of anodes and cathodes. The electrolytic cell also contains a filter, and in one embodiment the filter is a moving belt filter. While not bound by theory, the electrolytic filtration method and apparatus is based on the electrophoretic movement of algae particles suspended in an aqueous solution away from the filter under the influence of an electric field. In one embodiment the electric field is a pulsed waveform with unidirectional voltage or current pulses. In another embodiment, the electric field is a pulsed waveform with bidirectional voltage or current pulses.

Abstract: An electrolytic method and apparatus for the concentration and collection of suspended particulates from solutions is disclosed. In one embodiment, the solution is an aqueous solution and the suspended particles are algae particles. The electrolytic cell contains at least an anode and a cathode, and in one embodiment contains a plurality of anodes and cathodes. While not bound by theory, the electrolytic method and apparatus is based on the electrophoretic movement of algae particles suspended in an aqueous solution under the influence of an electric field. In one embodiment the electric field is a pulsed wavefrom with unidirectional voltage or current pulses. In another embodiment, the electric field is a pulsed waveform with bidirectional voltage or current pulses.

Abstract: A method and apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: A method for electrochemically etching a metal layer through an etch-resist layer pattern using a non-active electrolyte solution is described. The method is particularly useful in fabrication of advanced fuel delivery systems for land-based power generation turbines and aerospace turbine engines; of components for advanced thermal management in aerospace electronic devices and in cooling channels; of stents used in medicine; and of microchannels for sensors, chemical reactors, and dialysis and the like. In one embodiment of the invention the metal layer is copper and the non-active electrolyte solution is a mixture of sodium nitrate and sodium chloride and a pulse electric current is employed to accomplish the electrochemical etching.

Abstract: An apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: A method and apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: A method and apparatus for establishing more uniform deposition across one or more faces of a workpiece in an electroplating process. The apparatus employs eductors in conjunction with a flow dampener member and other measures to provide a more uniform current distribution and a more uniform metal deposit distribution as reflected in a coefficient of variability that is lower than conventional processes.

Abstract: A method for electrochemically plating tin or tin alloy onto a workpiece to provide a tin or tin alloy deposit on said workpiece having a stress differential and workpieces characterized by a tin or tin alloy deposit having a stress differential.

Abstract: A gas diffusion electrode for a proton exchange membrane fuel cell is prepared by electrodeposition of a catalytic metal in nanocrystalline form on a substrate by contacting an electrically conductive substrate and a counterelectrode with a plating bath containing ions of a metal to be deposited on the substrate and passing a pulsed electric current between the substrate and counterelectrode having pulses that are cathodic with respect to the substrate and have a short on-time and/or a short duty cycle with a frequency from about 10 hertz to about 5000 hertz. In a preferred embodiment the electric current is a modulated reversing electric current having pulses that are cathodic with respect to the substrate and pulses that are anodic with respect to the substrate, the cathodic pulses having a short on-time and/or short duty cycle, the charge transfer ratio of the cathodic pulses to the anodic pulses being greater than one, and the frequency of the pulses ranging from about 10 hertz to about 5 kilohertz.

Abstract: A sealing ring containing an electrode for sensing electrochemical conditions within a fluid handling system, in particular, the occurrence of crevice corrosion, has a body formed of a continuous loop of an electrically insulating fluid-impervious material having a surface which can form a fluid-tight seal with elements of a fluid handling apparatus, an electrode embedded within the body and electrically insulated from electronic conductive contact with those portions of the surface of the body that contact the fluid handling apparatus, and channels extending between the electrode and the surface of the body of the sealing ring to permit electrochemical contact between the electrode and the fluid within the system. The sealing ring also includes electronically conductive wires to connect the embedded electrode to external electrical devices, e.g., electronic measuring equipment.

Abstract: Metal salts are removed from solution in an electrolyte by subjecting the solution to electrolysis in a cell having an anode that has an anion exchange membrane closely associated therewith which sequesters the anion of the salt. The cathode may also be provided with a closely associated cation exchange membrane that sequesters, at least partially, the cation of the salt. A metal salt solution can be regenerated by reversing the polarity of the electrodes and conducting an electrolysis using fresh electrolyte.

Abstract: A waste solution containing electroactive species, e.g., metal ions, can be remediated to very low levels of contaminant by an electrolysis method including the steps of introducing an electrolyte containing an electroactive species into an electrolytic cell having a cathode and an anode, producing a flow of the electrolyte past at least one of the electrodes at an electrolyte flow rate, and passing an electric current through the solution between the anode and the cathode whereby the electroactive species undergoes an electrochemical reaction at one of the electrodes at an electrochemical reaction rate, using an electric current pulsed at a frequency of 0.5 to 1000 Hertz and a duty cycle of not greater than 50%, and adjusting the electrolyte flow rate for the pulsed current electrolysis such that the electrochemical reaction rate for pulsed current electrolysis is greater than the electrochemical reaction rate for direct current electrolysis.