Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
  • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/923—Physical dimension
  • Y10S428/924—Composite
  • Y10S428/926—Thickness of individual layer specified
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/9335—Product by special process
  • Y10S428/934—Electrical process
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12431—Foil or filament smaller than 6 mils
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
  • Y10T428/12812—Diverse refractory group metal-base components: alternative to or next to each other
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
  • Y10T428/12819—Group VB metal-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12875—Platinum group metal-base component

Definitions

• thermoelectric bonding of said metal layers to the substrate being effected under sufficient thermoelectric heat and pressure to cause visible surface deformation of said substrate and intimate adherence of said intermediate and outer metal layer to the thus deformed surfaces of the substrate.
• a preferred general purpose electrode has a titanium substrate, an intermediate layer of columbium or tantalum and an outer layer of a platinum metal.
• the substrate can be columbium, the intermediate layer tantalum and the outer layer a platinum metal.
• Materials which are most advantageous in electrode construction both from the standpoint of chemical resistance and electric conductivity are the metals of the platinum group including in particular platinum, rhodium, iridium, ruthenium and alloys thereof. These metals are so expensive, however, as to prevent their use as electrodes for most electrolytic processes except as such metals are applied as thin layers or foils to less expensive supporting materials.
• the improved electrodes as disclosed in said copending application comprises a laminated body of platinum metal foil bonded to a compatible metal substrate which is highly resistant to electrolytic oxidation, the bonding being effected by applying along a line of contact between a small diameter cylindrical member of hard conductive metal, rotatable in a massive electric conductor, in engagement with said foil, and a second massive electric conductor in engagement with said substrate, a pressure of about 10 to 300 pounds per linear inch, and an electric current below 12 volts at an amperage to provide at least 3 kva. per linear inch of said line of contact, while advancing said small diameter cyindrical member in a direction perpendicular to said line of contact at a rate to provide a bonding heat suflicient to soften, without melting, the substrate surface.
• the platinum metal can be platinum, rhodium, iridium or ruthenium or alloys thereof; the substrate metal can be tantalum, titanium, niobium or alloys thereof; and the bonding is preferably effected at a pressure of 50 to 150 pounds per linear inch, using current of 0.1 to 5 volts at an amperage to provide 7 to kva. per linear inch.
• Preparing electrodes according to the method above described requires extreme precision in the pressure and rate of feed applied to the small diameter cylindrical member which forms the line of electrical contact with the workpieces. Insufiicient pressure or too rapid advance of the cylindrical member can result in incomplete or discontinuous bonding of the platinum metal foil to the substrate, and too slow or uneven advance of the cylindrical member can cause rupture or burn-through of the foil. The latter type of damage can usually be detected by visual inspection and remedied by spot patching with additional foil applied by the same method. The incomplete or discontinuous bonding of the foil to the substrate is a more serious problem since it is diflicult to detect by inspection.
• thermoelectrically bonded electrodes have been operated at unusually high voltages for extended periods of time; and the surprising and unexpected results of such high voltage operation have indicated that there is a real need for eliminating the problem of latent failure due to incomplete or discontinuous bonding.
• the key to the superior bonding attained with the three component system appears to be the use of an intermediate foil which has a substantially higher melting point than the platinum metal and the substrate. This provides a greater concentration of heat at a location to permit more effective surface softening of the substrate and assurance of intimate contacting of the superimposed metal surfaces throughout the length of the small cylindrical conductor as it is pressed against and rolled along the assemblage.
• This explanation of what is apparently taking place is based both on the intense orange glow which develops in the intermediate foil in alignment with the small cylindrical roller, and on the slight surface deformation of the bonded substrate and foils. In fact the path of the cylindrical roller on the assemblage tends to assume a slightly rippled contour, indicating that the localized heating is so instantaneous and sensitive that the softening of the substrate surface varies slightly in each cycle of the current supply.
• the middle foil should have a higher melting point than the outer foil and substrate it follows that if the substrate is titanium, the middle foil can be either columbium or tantalum; but if the substrate is columbium the middle foil will be tantalum. Also, if the middle foil is columbium, iridium and ruthenium should not be employed as the outer foil except as lower melting alloy for-ms.
• Titanium can withstand only about 7 to 10 volts before showing signs of breakdown.
• Columbium on the other hand, can withstand up to about 45 volts and tantalum about 130 volts.
• a middle foil of columbium over a titanium substrate provides reasonable protection for the substrate in the event of damage to the platinum metal exposing portions of the middle foil.
• such protection would best be provided by switching to a tantalum middle foil, and suitably also switching to columbium as the substrate.
• the equipment employed in assembling the new electrodes is the same as that described in said pending application.
• the substrate can rest on a large massive conductor suitably in the form of a heavy plate of copper or highly conductive harder copper alloys.
• the cylindrical roller can be of a length to traverse the full Width of the electrode substrate or it can have a portion of enlarged diameter (fitting within a recess in the upper massive conductor) which provides a line of contact substantially shorter than the width of the electrode, requiring a number of passes to fully bond the superimposed foils to the substrate.
• the fiat bed massive conductor can be replaced, as disclosed in said pending application, with a large diameter roller, driven in synchronism with the small diameter roller, and having a diameter of the order of 10 to 20 times the diameter of the small diameter roller.
• the operating conditions for assembling the three part electrode are somewaht more severe than those described in said pending application for laminating platinum metal foil directly to the substrate.
• the pressure applied should be about 600 to 3000 pounds and preferably about 840 to 1440 pounds per linear inch of contact between the small diameter cylinder (or enlarged portion thereof) and the superimposed foils and subtsrate; and the roller is rotated to advance the line of contact about 12 to 36 inches per minute.
• the applied voltage should be less than 10 volts, and suitably in the 0.5 to 5 volt range, with the applied current providing at least 30 and suitably 40 to kva. per linear inch of contact by the small diameter roller (or enlarged portion thereof) -when using relatively thin substrate and foils. As the thicknesses of substrate and foils, and particularly the intermediate foil, are increased, the kva. can be increased to as much as about 500 kva. per linear inch.
• the substrate metal can be of any desired thickness to provide the desired rigidity in the electrode.
• a thickness of about .03 to .25 inch is generally suitable.
• the middle foil is about .0003 to .01 inch and preferably about .001 to .0015 inch thick; and the outer platinum metal foil is about .0003 to .005 inch and preferably about .0003 to .0006 inch thick.
• Electrodes are prepared by bonding to flat sheets of titanium measuring 2 inches by 6 inches by .06 inch thick an intermediate foil 0.0015" thick of tantalum and an outer foil 0.0005" thick of platinum.
• the titanium plate is placed on a large copper alloy bed providing one terminal of an electrical circuit.
• a hand held copper electrode forming the outer side of said current has a transverse groove in the lower end thereof which receives a rotatable tungsten carbide cylinder about 0.5 inch in diameter having a central enlargement about 0.75 inch in diameter, and having an axial length about 0.25 inch, with a slightly rounded surface contour.
• the end of the cylinder is provided with an offset crank to facilitate controlled rotation along the foils as the same slidably rotates in the hand held electrode.
• Overhanging edges of the foils are cut off slightly beyond the edges of the titanium plates, folded around the titanium plate, and bonded to the reverse side thereof by inverting the assemblage on the conductor base and repeating the bonding procedure along the folded over portions of the foils.
• Terminal posts are then welded to the reverse side of the titanium plate, and the reverse side and edges of the assemblage are encased in a resistant resin, suitably a polyacrylic resin such as methyl 'methacrylate polymer toinsulate and protect portions of the assemblage not covered by the superimposed foils.
• a resistant resin suitably a polyacrylic resin such as methyl 'methacrylate polymer toinsulate and protect portions of the assemblage not covered by the superimposed foils.
• Electrodes prepared as above described are extremely durable in chlorinating operations at 10 to 40 volts, and current densities ranging from a trace to amps/ sq. in. of electrode surface, and such electrodes have an estimated useful life, based on to 12 hours per day of operation, in excess of five years.
• the electrodes have operated successfully for long extended periods at current densities as high as 30 amps/sq. in. of electrode surface. Furthermore the electrodes have shown remarkable stability at potentials as high as 220 volts and current density of the order of 1 amp/sq. in. of electrode surface.
• tantalum and platinum metal foils can be bonded to the reverse side of the electrode, if desired, by repeating the procedural steps described with the previously bonded surface bearing against the copper alloy bed.
• such coating of the reverse side of the electrode is unnecessary and would be uneconomical in view of the cost of the foil materials.
• the procedure as described in the foregoing example can readily be adopted to the bonding of substrate and foils of different thickness or different composition.
• the applied pressure and the kva. of current per linear inch should be increased as the thicknesses of the substrate and foils are increased, and decreased as these thicknesses are decreased.
• the amount of heat generated along the line of contact of the pressure roller with the assemblage can be increased or decreased by respectively slowing or increasing the rate of advance of the line of contact, while holding the applied current constant.
• tantalum intermediate foil in the foregoing example is replaced by the same thickness foil of the lower melting columbium the same operating conditions will nevertheless apply.
• the titanium substrate is replaced by the higher melting columbium somewhat higher current or slower advance of the line of contact of the pressure roller is required to provide the same degree of softening of the substrate surface.
• a three component electrode having enhanced resistance to voltage damage comprising a heavy substrate selected from the group consisting of titanium and columbium having thermoelectrically bonded thereto an intermediate layer about .0003 to .01 inch thick of a metal selected from the group consisting of tantalum and columbium and higher melting than the metal of said substrate, and an outer layer about .0003 to .005 inch thick of a platinum metal selected from the group consisting of platinum, rhodium, iridium, ruthenium and alloys thereof, and having a melting point lower than the metal of said intermediate layer, the thermoelectric bonding of said metal layers to the substrate being effected under sufiicient thermoelectric heat and pressure to cause visible surface deformation of said substrate and intimate adherence of said intermediate and outer layers to the thus deformed surface of the substrate.
• a massive electrode supporting said substrate and a conductive roller electrode engaging said outer layer by aplying a voltage below 10 volts at an amperage to provide at least 30 kva. per linear inch of conductive roller contact with the superimposed layers while applying a pressure of 600 to 3000 pounds per linear inch and advancing said line of contact at the rate of about 12 to 36 inches per minute.
• thermoelectric bonding is effected between a massive electrode supporting said substrate and a conductive roller electrode engaging said outer layer by applying a voltage in the 0.5 to 5 volt range at an amperage to provide 40 to 100 kva. per linear inch of conductive roller contact with the superimposed layers while applying a pressure of about 840 to 1440 pounds per linear inch and advancing said line of contact at the rate of about 12 to 36 inches per minute.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Laminated Bodies (AREA)

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Cited By (10)

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Citations (4)

• 1968
  • 1968-05-28 US US732510A patent/US3547600A/en not_active Expired - Lifetime
• 1969
  • 1969-05-13 GB GB24419/69A patent/GB1274242A/en not_active Expired
  • 1969-05-27 CH CH802269A patent/CH522438A/de not_active IP Right Cessation
  • 1969-05-28 DE DE19691927059 patent/DE1927059A1/de active Pending
  • 1969-05-28 FR FR6917344A patent/FR2009499A1/fr active Pending

Patent Citations (4)

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