US3617101A - Reference electrode for cathodic protection systems - Google Patents

Reference electrode for cathodic protection systems Download PDF

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Publication number
US3617101A
US3617101A US833097A US3617101DA US3617101A US 3617101 A US3617101 A US 3617101A US 833097 A US833097 A US 833097A US 3617101D A US3617101D A US 3617101DA US 3617101 A US3617101 A US 3617101A
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Prior art keywords
silver
cathodic protection
coated
electrode
reference electrode
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Expired - Lifetime
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US833097A
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English (en)
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Edward P Anderson
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Engelhard Minerals and Chemicals Corp
Electrocatalytic Inc
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Engelhard Minerals and Chemicals Corp
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Assigned to ENGELHARD CORPORATION reassignment ENGELHARD CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PHIBRO CORPORATION, A CORP. OF DE
Assigned to CHEMICAL BANK, A NEW YORK BANKING CORP. reassignment CHEMICAL BANK, A NEW YORK BANKING CORP. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ELECTROCATALYTIC, INC., A NJ. CORP.
Assigned to ELECTROCATALYTIC INC. reassignment ELECTROCATALYTIC INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ENGELHARD CORPORATION
Anticipated expiration legal-status Critical
Assigned to CHASE MANHATTAN BANK, THE reassignment CHASE MANHATTAN BANK, THE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ELECTROCATALYTIC LIMITED, ELECTROCATALYTIC, INC.
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions

Definitions

  • Kovalich ABSTRACT A reference electrode for cathodic protection systems on ships and boats comprising a metal base consisting of titanium, tantalum or niobium having a surface coated with silver, the silver-coated surface being a roughened surface in the form of ridges and depressions, e.g. an embossed surface, and the roughened surface being coated with silver chloride.
  • Cathodic protection consists basically of applying an electrical current to an anode, immersed in an electrolyte, and to the surface to be protected as the cathode, whereby the surface potential is maintained cathodic with respect to the electrolyte, thus preventing corrosion of the surface.
  • anodic protection consists basically of applying an electrical current to an anode, immersed in an electrolyte, and to the surface to be protected as the cathode, whereby the surface potential is maintained cathodic with respect to the electrolyte, thus preventing corrosion of the surface.
  • painted metallic surfaces such as ship hulls, however, when the impressed current density exceeds a certain amount the paint film will become damaged, whereas an insufficient current results in inadequate protection against corrosion.
  • cathodic protection systems in which the fluctuating potential on the metallic surface is continuously registered and the power output to the anodes controlled accordingly, either by manually or automatically adjusting the output.
  • reference electrodes immersed in the electrolyte are used, in conjunction with the cathodic protection system, and which perform in cooperation with the metallic surface as a voltaic cell to produce a current which functions to indicate the condition of the metallic surface and whose response is utilized in a system to automatically monitor and adjust the output of the cathodic protection system.
  • the reference electrodes usually employed for such purpose are the silver-silver chloride type electrodes. Some such electrodes are of the silver button-type coated with silver chloride. In any case, such electrodes are subject to deterioration either by lack of desirable physical strength of the silver button or a too rapid loss of the silver chloride, as by abrasion, to maintain the reference electrode potential stability for long periods.
  • a reference electrode preferably constructed to be positionable approximately flat to the surface to be protected, e.g., a ships hull, with insulation means therebetween and of sufficient strength to withstand prolonged usage while at the same time having a composition and construction such as will provide a copious supply of the chloride ion and which will maintain a stabilized electrical potential for extended periods.
  • the electrode can be in the form of a disc, washer, or a rivet having a rivet head as the functioning electrode, and composed of a metal base consisting of titanium, tantalum or niobium having its outer surface roughened, e.g., embossed, or otherwise provided with such a roughened surface which is characterized by ridges and depressions, e.g., a surface having intersecting grooves, with the roughened surface being coated with a silver layer and then with a silver chloride layer which fills the depressions and covers the ridges, the depressions functioning as a reservoir of silver chloride should the silver chloride covering the ridges become substantially depleted as by abrasion from the ridges or deterioration over extended periods.
  • a metal base consisting of titanium, tantalum or niobium having its outer surface roughened, e.g., embossed, or otherwise provided with such a roughened surface which is characterized by ridges and depressions, e.g., a surface having intersect
  • the use of the particular base metal composition is less expensive than the use of a solid silver base and is of critical significance because when exposed to the electrolyte, e.g., by abrasion, the metal has the ability to readily form upon itself a film of insulating oxide which will prevent the development of stray currents which would otherwise unbalance the original stabilized current output of the electrode.
  • FIG. I illustrates a partly elevational and partly cross-sectional side view of an electrode assembly according to the invention
  • FIG. 2 illustrates a top view of the electrode assembly along lines 2-2 of FIG. 1 with the base metal being so modified that the roughened surface thereof is in the form of an embossed surface,
  • FIG. 3 illustrates an enlarged fragmentary view along lines 3-3 of FIG. 2.
  • the electrode assembly comprises a reference electrode generally designated as Iin the form of a circular disc having a circumferential marginal portion 2 thereof extending downwardly and forming a flange which is embedded in an insulating platelike resin base 3 with the major portion of the electrode surface exposable to an electrolyte.
  • a tubular stem 4 is mounted on the insulating plate and extends outwardly of the undersurface 5.
  • the tubular stem comprises a flanged end portion 6 embedded in the resin plate.
  • An insulated electrical conductor means 7 containing electrically conducting wires 8 passes through the stem 4, which is threaded on its outer surface as at 9 for subsequent mounting through a ships hull by a mounting nut (not shown).
  • the end of the insulated conductor means passing through the stem and adjacent the undersurface of the electrode has its conductor wires 8 electrically connected to the bottom surface of the electrode,-for example by welding or soldering as at 10.
  • the electrode disc illustrated by FIG. 1 comprises a metal base 11 of titanium, tantalum or niobium having its outer surface 12 in a roughened condition characterized by ridges and depressions, e.g., a surface having intersecting grooves or otherwise being embossed as more particularly shown by FIGS. 2 and 3.
  • FIGS. 2 and 3 illustrate the invention showing the metal base 11 of titanium, tantalum or niobium having a roughened surface, e.g., an embossed surface as illustrated, is coated, as by electroplating, to provide an intermediate layer of silver 14 with the silver-coated layer being then coated with an outer layer 13 of silver chloride, as by dipping in molten silver chloride or by sprinkling silver chloride powder on the surface and heating sufficiently to melt the silver chloride into ad herence with the roughened surface.
  • a roughened surface e.g., an embossed surface as illustrated
  • the roughened or embossed surface of the base metal is characterized by ridges I5 and depressions 16 with the layer of silver 14 conforming with the roughened surface leaving the depressions 16 as reservoirs 17 of excess silver chloride should the coatings l3 and M become abraded from the elevated portions or ridges of the base metal and to still leave a sufficient amount of silver chloride on the electrode to maintain a copious supply of the chloride ion and with the metal composition of the base, as above described, being capable, when exposed to the electrolyte, of readily forming an insulating oxide film which will prevent the development of stray currents to unbalance the original stabilized current output of the electrode.
  • the platelike resin insulating base 3 is provided with an annular groove 18 inwardly adjacent to the marginal portions of the insulator plate to receive the downwardly extending flange- 2 of the electrode 1 and the top central portion 19 of the insulator base is slightly recessed to receive the electrode in conformity with the shape and thickness of the disc 1 in such manner that the surface of the electrode does not extend above the ridge 20 on the marginal portion of the insulator base.
  • an insulating resin e.g., an epoxy resin 21 so that the top surface of the electrode and the marginal portions of the platelike base are substantially in a common plane.
  • a reference electrode comprising a metal base consisting of titanium, tantalum or niobium, the metal base having a roughened surface characterized by ridges and depressions, a layer of silver on the roughened surface, and a layer of silver chloride coating the silver layer, said silver chloride layer filling the silver-coated depressions and covering the silver-coated ridges.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Prevention Of Electric Corrosion (AREA)
  • Electrolytic Production Of Metals (AREA)
US833097A 1969-06-13 1969-06-13 Reference electrode for cathodic protection systems Expired - Lifetime US3617101A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US83309769A 1969-06-13 1969-06-13

Publications (1)

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US3617101A true US3617101A (en) 1971-11-02

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US833097A Expired - Lifetime US3617101A (en) 1969-06-13 1969-06-13 Reference electrode for cathodic protection systems

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US (1) US3617101A (enExample)
JP (1) JPS5022973B1 (enExample)
FR (1) FR2051021A5 (enExample)
GB (1) GB1257437A (enExample)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940510A (en) * 1972-09-12 1976-02-24 Siemens Aktiengesellschaft Process for the manufacture of silver-coated tungsten carbide electrode material
US4187164A (en) * 1977-07-08 1980-02-05 Marston Excelsior Limited Anode
US4695362A (en) * 1985-12-24 1987-09-22 Eastman Kodak Company Acid or acid salt wash of a metal chloride layer of an ion selective electrode
US5825668A (en) * 1996-08-27 1998-10-20 Mitsubishi Denki Kabushiki Kaisha Monitoring method and apparatus of surface area of semiconductor wafer
US6270680B1 (en) 1997-11-07 2001-08-07 Bioquest Amperometric sensor probe for an automatic halogen control system
US20050127097A1 (en) * 2003-10-29 2005-06-16 Rheodyne, Llc Dosing engine and cartridge apparatus for liquid dispensing and method

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4259164A (en) * 1979-08-13 1981-03-31 Eastman Kodak Company Silver/silver halide electrodes comprising chromium or nickel
GB2169410B (en) * 1984-11-16 1988-09-01 Taylor Woodrow Const Ltd Half cell assembly for use as reference half cell in a cathodic protection system for steel in reinforced concrete

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2719797A (en) * 1950-05-23 1955-10-04 Baker & Co Inc Platinizing tantalum
US3022243A (en) * 1959-04-28 1962-02-20 Engelhard Ind Inc Anode assembly for cathodic protection systems
US3081252A (en) * 1959-09-30 1963-03-12 Chemionics Engineering Lab Inc Pipe plug anode
US3129161A (en) * 1958-10-10 1964-04-14 Engelhard Ind Inc Reference electrode assembly
US3133873A (en) * 1961-06-23 1964-05-19 Walter L Miller Electrolytic anode and connection
US3488274A (en) * 1967-05-31 1970-01-06 Us Navy Electrolytic composite anode and connector

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2719797A (en) * 1950-05-23 1955-10-04 Baker & Co Inc Platinizing tantalum
US3129161A (en) * 1958-10-10 1964-04-14 Engelhard Ind Inc Reference electrode assembly
US3022243A (en) * 1959-04-28 1962-02-20 Engelhard Ind Inc Anode assembly for cathodic protection systems
US3081252A (en) * 1959-09-30 1963-03-12 Chemionics Engineering Lab Inc Pipe plug anode
US3133873A (en) * 1961-06-23 1964-05-19 Walter L Miller Electrolytic anode and connection
US3488274A (en) * 1967-05-31 1970-01-06 Us Navy Electrolytic composite anode and connector

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940510A (en) * 1972-09-12 1976-02-24 Siemens Aktiengesellschaft Process for the manufacture of silver-coated tungsten carbide electrode material
US4187164A (en) * 1977-07-08 1980-02-05 Marston Excelsior Limited Anode
US4695362A (en) * 1985-12-24 1987-09-22 Eastman Kodak Company Acid or acid salt wash of a metal chloride layer of an ion selective electrode
US5825668A (en) * 1996-08-27 1998-10-20 Mitsubishi Denki Kabushiki Kaisha Monitoring method and apparatus of surface area of semiconductor wafer
US6270680B1 (en) 1997-11-07 2001-08-07 Bioquest Amperometric sensor probe for an automatic halogen control system
US20050127097A1 (en) * 2003-10-29 2005-06-16 Rheodyne, Llc Dosing engine and cartridge apparatus for liquid dispensing and method
US7544289B2 (en) 2003-10-29 2009-06-09 Idex Health & Science Llc Dosing engine and cartridge apparatus for liquid dispensing and method
US20090266751A1 (en) * 2003-10-29 2009-10-29 Idex Health & Science Llc Dosing engine and cartridge apparatus for liquid dispensing and method
US8431020B2 (en) 2003-10-29 2013-04-30 Idex Health & Science Llc Dosing engine and cartridge apparatus for liquid dispensing and method

Also Published As

Publication number Publication date
JPS5022973B1 (enExample) 1975-08-04
DE2029085A1 (de) 1970-12-23
DE2029085B2 (de) 1972-08-17
GB1257437A (enExample) 1971-12-15
FR2051021A5 (enExample) 1971-04-02

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AS Assignment

Owner name: ENGELHARD CORPORATION 70 WOOD AVENUE SOUTH, METRO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PHIBRO CORPORATION, A CORP. OF DE;REEL/FRAME:003968/0801

Effective date: 19810518

AS Assignment

Owner name: CHEMICAL BANK, 277 PARK AVENUE, NEW YORK, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNOR:ELECTROCATALYTIC, INC., A NJ. CORP.;REEL/FRAME:004574/0053

Effective date: 19860611

AS Assignment

Owner name: ELECTROCATALYTIC INC., A NEW JERSEY CORP.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ENGELHARD CORPORATION;REEL/FRAME:004621/0589

Effective date: 19860611

AS Assignment

Owner name: CHASE MANHATTAN BANK, THE, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNORS:ELECTROCATALYTIC, INC.;ELECTROCATALYTIC LIMITED;REEL/FRAME:006357/0328

Effective date: 19921120