US3383297A - Zinc-rare earth alloy anode for cathodic protection - Google Patents

Zinc-rare earth alloy anode for cathodic protection Download PDF

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Publication number
US3383297A
US3383297A US437474A US43747465A US3383297A US 3383297 A US3383297 A US 3383297A US 437474 A US437474 A US 437474A US 43747465 A US43747465 A US 43747465A US 3383297 A US3383297 A US 3383297A
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zinc
weight
anode
component
rare
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US437474A
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Eberius Ernst
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C18/00—Alloys based on zinc
    • 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
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/12—Electrodes characterised by the material
    • C23F13/14—Material for sacrificial anodes

Definitions

  • the present invention relates to cathodic protection against corrosion, and more particularly to the provision of cathodic protection for minimizing corrosion of metals such as steel and like ferrous materials.
  • One of the methods used to prevent such corrosion is to provide means affording cathodic protection whereby the metal to be protected is made the cathode in the corrosive electrolyte with which it is in contact and an active anode is provided.
  • active anodes are generally made of magnesium, aluminum or zinc and are in electrical contact with the metal to be protected. These may be anodes buried in the ground for protec tion of underground pipelines or applied as attachments to surfaces of equipment such as condenser water boxes or on ships hulls.
  • the anti-corrosion electrical current required is generated by electrochemical attack upon the anode material.
  • These anodes taking into consideration the common surface areas, are placed in short-circuit contact with the iron or other ferrous structures to be protected.
  • the present invention involves the use, as an anode to provide cathodic protection of metals subject to corrosion, of a zinc-alloy anode consisting essentially of metallic zinc and a rareearth alloying component which constitutes at least about 0.02% by weight of the body.
  • the alloying component 3,383,297 Patented May 14, 1968 should consist of at least 35% by weight lanthanum and can be selected from the group consisting of lanthanum a combination of lanthanum with up to 50% of cerium and mischmetal.
  • the alloying of zinc with lanthanum alone, lanthanum and cerium combinations or with mischmetal which is an alloy of lanthanum with cerium and other rare earths such as neodyium and praseodymium (e.g. 35% by weight lanthanum, 15% by weight of a mixture of neodymium and praseodymium and 50% by weight cerium) affords considerable activation of the anode, as compared to the use of zinc and conventional zinc alloys.
  • the use of anodes made of such materials provide a significant reduction in the usual polarization inhibition of corrosion as well as in the covering effect, and simultaneously provide a high activity constant for the anode surface.
  • the capacity and potential remain constant according to the present invention because the surfaces of the anodes of the invention do not become coated with solid, cementlike layers, but instead there is formed on the anodes a thin, brittle film which falls off itself, or a leafy film which is easily washed oft with water, so that the cf.- ficiency-determining interfacial contact between the clear anode metal and the surrounding electrolyte always remains constant.
  • a metal structural element 10 made, for example, of steel which is embedded in the ground 11.
  • the earth includes salt-containing water 13 which serves as an electrolyte.
  • an anode 12 which is made of pure zinc alloyed with 0.5% by weight of mischmetal consisting of 35% lanthanum, 10% neodymium, 5% praseodymium and 50% cerium.
  • the body 12 serves as an anode while the body 10 serves as the cathode, the liquid 13 in the ground 11 acting as electrolyte; the corrosion on the meal body 10 is thus minimized.
  • Example I An anode for the cathodic protection of a steel pipe embedded in the ground was prepared by adding to 98.5% purity zinc in a molten state about 0.02% lanthanum. The body, after casting, was applied to the pipe and in surface contact therewith. It was found that the anode gave the cathodic protection of a conventional zinc anode but was substantially free from encrustation and scaling and functioned etlectively for a considerably longer period than did the ordinary zinc anode.
  • Example II The test of Example I was carried out on the steel hull of a ship with cerium substituted for half of the lanthanum of Example I. Again no cement-like scale was found.
  • Example III The test was repeated with substantially 0.02% by weight of mischmetal serving as the rare-earth alloying component. Again scaling was found to be of the thinlayer type readily sloughed off by the anode.
  • the mischmetal consisted of 35% by weight lanthanum, 10% by weight neodymium, 5% by weight praseodymium and 50% by weight cerium.
  • Example IV The rare-earth components of Example I through III were alloyed with high-grade zinc (purity of 99.999% purity) in three separate tests with buried iron pipe. In each case, efiec ive cathodic protection was observed without the development of hard and inpenetrable scales upon the anode surface.
  • Example V The alloys of Examples I through IV were formed into anodes applied to the steel hull of a ship as a cathodic protection against corrosion in seawater. In each case the effective protection was obtained with a noticeable decrease in polarization phenomena and in the absence of significant scaling of the anode.
  • Example VI The tests of Examples 1 through V were carried out except that the rare-earth component in each alloy constituted 5% by weight thereof. Similar results were obtained. With alloys containing more than 5% by weight of the rare-earth component, no further increase in the antipolarization and antiscaling phenomena were observed.
  • a zinc alloy consisting essentially of metallic zinc and from 0.02% to substantially 5% by weight of a rareearth component consisting of at least one rare-earth element.
  • a zinc alloy consisting essentially of metallic zinc and from 0.02% to substantially 5% by weight of a rareearth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • a zinc alloy consisting essentially of metallic zinc and from 0.02% to substantially 5% by weight of a rareearth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element selected from the group consisting of neodymium, praseodymium and cerium.
  • a zinc alloy consisting essentially of metallic zinc of at least 98.5% purity and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • a zinc alloy consisting essentially of metallic zinc of at least 98.5% purity and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element selected from the group consisting of neodymium, praseodymium and cerium.
  • An anode body for cathodic inhibition of corrosion composed of a Zinc alloy consisting es entially of metallic zinc and from 0.02% to substantially 5% by Weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • An anode body for cathodic inhibition of corrosion composed of a zinc alloy consisting essentially of metallic Zinc of at least 98.5% purity and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rareearth element selected from the group consisting of neodymium, praseodymium and cerium.
  • a corrosion-resistant assembly comprising a metal cathode in contact with an electrolyte and corrodable thereby; and an anode electrically connected wi h said cathode and in contact with said electrolyte, said anode being composed of a zinc alloy consisting essentially of metallic zinc and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constiiuted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • a corrosion-resistant assembly comprising a ferrous-metal cathode in contact with an e'ectrolyte and corrodable thereby; and an anode electrically connected with said cathode and in contact with said electrolyte, said anode being composed of a zinc alloy consisting essentially of metallic zinc and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • a corrosion-resistant assembly comprising a ferrous-metal cathode in contact with an electrolyte and corrodable thereby; and an anode electrically connected with said cathode and in contact with said electrolyte, said anode being composed of a zinc alloy consis'ing essentially of metallic zinc of at least 98.5% purity and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element selected from the group consisting of neodymium, praseodymium and cerium.
  • the improvement which comprises the step of disposing a zinc-alloy body in electrically conductive relationship with said ferrous-metal body and in contact with said electrolyte, said body being composed of a zinc alloy consisting essentially of metallic Zinc and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element.
  • the improvement which comprises the step of disposing a zinc-alloy body in electrically conductive relationship with said ferrous-metal body and in contact with said electrolyte, said body being composed of a zinc alloy consisting essentially of metallic Zinc of at least 98.5% purity and from 0.02% to substantially 5% by weight of a rare-earth component, said component being constituted by at least 35% by weight of lanthanum and at least one additional rare-earth element selected from the group consisting of neodymium, praseodymium and cerium.

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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)
  • Conductive Materials (AREA)
US437474A 1964-03-06 1965-03-05 Zinc-rare earth alloy anode for cathodic protection Expired - Lifetime US3383297A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEA45417A DE1231906B (de) 1964-03-06 1964-03-06 Verwendung von lanthan- und gegebenenfalls cerhaltigen Zinklegierungen als Aktivanoden fuer den kathodischen Korrosionsschutz

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US3383297A true US3383297A (en) 1968-05-14

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US (1) US3383297A (en)van)
BE (1) BE660683A (en)van)
DE (1) DE1231906B (en)van)
DK (1) DK109799C (en)van)
GB (1) GB1095832A (en)van)
NL (1) NL6502767A (en)van)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0048270A4 (en) * 1980-03-25 1982-07-12 Internat Lead Zinc Res Organis ZINC-ALUMINUM COATINGS.
WO1983000885A1 (fr) * 1981-09-07 1983-03-17 Radtke, Schrade, F. Perfectionnements aux procedes de galvanisation des toles ou bandes en acier
US4448748A (en) * 1980-03-25 1984-05-15 International Lead Zinc Research Organization, Inc. Zinc-aluminum alloys and coatings
US4626329A (en) * 1985-01-22 1986-12-02 Union Oil Company Of California Corrosion protection with sacrificial anodes
US4626330A (en) * 1984-01-25 1986-12-02 Dixie Electrical Manufacturing Company Torsionally installed anode and earth anchor/penetrator
EP0360067A1 (fr) * 1988-09-23 1990-03-28 n.v. UNION MINIERE s.a. Alliage de zinc pour godets de piles électrochimiques
CN111058044A (zh) * 2019-12-20 2020-04-24 山东南山铝业股份有限公司 一种高使用寿命的铸造铝合金牺牲阳极
CN111334688A (zh) * 2020-02-17 2020-06-26 北京大学 一种Zn-RE系锌合金及其制备方法与应用

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019102596A1 (de) * 2019-02-01 2020-08-06 Thyssenkrupp Steel Europe Ag Verfahren zum Herstellen eines geformten Stahlbauteils aus einem warmumformbaren, mit einer metallischen, vor Korrosion schützenden Beschichtung versehenen Stahlflachprodukt, ein Stahlflachprodukt sowie ein durch das Verfahren herstellbares Stahlbauteil

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829973A (en) * 1953-04-09 1958-04-08 Magnesium Elektron Ltd Magnesium base alloys
US2982705A (en) * 1958-07-15 1961-05-02 Mitsubishi Kenzoku Kogyo Kabus Corrosion preventive galvanic anode zinc alloy
US3254993A (en) * 1963-03-18 1966-06-07 Ball Brothers Co Inc Zinc alloy and method of making same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB837523A (en) * 1957-07-26 1960-06-15 Mitsubishi Metal Mining Co Ltd Corrosion preventive galvanic anode zinc alloy
GB883193A (en) * 1959-04-06 1961-11-29 Nat Smelting Co Ltd Improvements in or relating to zinc alloys

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829973A (en) * 1953-04-09 1958-04-08 Magnesium Elektron Ltd Magnesium base alloys
US2982705A (en) * 1958-07-15 1961-05-02 Mitsubishi Kenzoku Kogyo Kabus Corrosion preventive galvanic anode zinc alloy
US3254993A (en) * 1963-03-18 1966-06-07 Ball Brothers Co Inc Zinc alloy and method of making same

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0048270A4 (en) * 1980-03-25 1982-07-12 Internat Lead Zinc Res Organis ZINC-ALUMINUM COATINGS.
US4448748A (en) * 1980-03-25 1984-05-15 International Lead Zinc Research Organization, Inc. Zinc-aluminum alloys and coatings
WO1983000885A1 (fr) * 1981-09-07 1983-03-17 Radtke, Schrade, F. Perfectionnements aux procedes de galvanisation des toles ou bandes en acier
US4626330A (en) * 1984-01-25 1986-12-02 Dixie Electrical Manufacturing Company Torsionally installed anode and earth anchor/penetrator
US4626329A (en) * 1985-01-22 1986-12-02 Union Oil Company Of California Corrosion protection with sacrificial anodes
EP0360067A1 (fr) * 1988-09-23 1990-03-28 n.v. UNION MINIERE s.a. Alliage de zinc pour godets de piles électrochimiques
BE1002507A3 (nl) * 1988-09-23 1991-03-05 Acec Union Miniere Zinklegeringen voor hulzen van elektrochemische batterijen.
CN111058044A (zh) * 2019-12-20 2020-04-24 山东南山铝业股份有限公司 一种高使用寿命的铸造铝合金牺牲阳极
CN111334688A (zh) * 2020-02-17 2020-06-26 北京大学 一种Zn-RE系锌合金及其制备方法与应用

Also Published As

Publication number Publication date
BE660683A (en)van) 1965-09-06
NL6502767A (en)van) 1965-09-07
GB1095832A (en) 1967-12-20
DE1231906B (de) 1967-01-05
DK109799C (da) 1968-07-01

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