Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
  • H01M4/46—Alloys based on magnesium or aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/003—Alloys based on aluminium containing at least 2.6% of one or more of the elements: tin, lead, antimony, bismuth, cadmium, and titanium
• • 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
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This invention relates to sacrificial galvanic anodes and more particularly is concerned with a novel aluminum based alloy exhibiting a high oxidation potential and a useful high electrical output per unit mass of metal; i.e. a high electrochemical equivalent, which is suitable for use in such galvanic anodes.
• aluminum should be expected to perform satisfactorliy as a galvanic anode because the element aluminum fulfills the two primary requirements for anodes: (l) a high theoretical oxidation potential (1.80 volts versus calomel reference) and (2) a high theoretical electrical output per unit mass of metal consumed (2.98 amp-hours per gram).
• aluminum has not proved to be satisfactory for use in such applications since it does not exhibit these favorable theoretical properties when used as a sacrificial galvanic anode.
• the presence of the normally passive oxide surface film on the aluminum apparently presents a barrier to the oxidation of the aluminum metal thereby reducing the effective oxidation potential to about 0.7 volt (as measured in closed circuit at either 250 to 1000 milliamperes/ square foot in a synthetic sea water electrolyte with a standard saturated KCl calomel cell as reference).
• the effective oxidation potential to about 0.7 volt (as measured in closed circuit at either 250 to 1000 milliamperes/ square foot in a synthetic sea water electrolyte with a standard saturated KCl calomel cell as reference).
• the anode exhibits no useful electrical output.
• the actual working potential of magnesium is about 1.5 volt and of zinc is about 1 volt.
• the present invention comprises. a novel aluminum based alloy composition containing small amounts of gallium, indium, bismuth and lead.
• the present composition comprises aluminum and from about 0.005 to about 0.2 weight percent gallium, from about 0.015 to about 0.5 weight percent indium, from about 0.02 to about 3 weight percent bismuth and about 0.02 to about 3 weight percent lead. If desired, larger amounts of lead and/ or bismuth can be employed without detrimentally affecting the properties of the alloy composition.
• the alloy comprises aluminum having alloyed therewith from about 0.01 to about 0.03 weight percent gallium, from about 0.02 to about 0.3 weight percent indium, from about 0.1 to about 1 weight percent bismuth and from about 0.1 to about 1 weight percent lead. All weight percents are based on the total composition weight.
• the present novel alloy composition when employed as sacrificial galvanic anodes exhibits a satisfactory corrosion pattern, a high operating oxidation potential and a high electrical output per unit mass of metal consumed.
• Galvanic anodes can be prepared from the novel composition by use of alloying and casting or fabricating techniques ordinarily employed in the aluminum art. No special metal handling or fabricating operations are required.
• Aluminum for use in preparing the present novel alloy composition can be commercial grade (99.5 to 99.9% Al) metal having normal production introduced impurities associated therewith wherein the silicon impurity level can be as high as about 0.1 weight percent and the iron can be as high as about 0.22 weight percent. If desired, higher purity aluminum (e.g. 99.99% purity) can be employed, but this is not necessary to achieve high potentials and anode efficiencies (i.e. high electrical output per unit mass of metal).
• the alloying metals also can be of high purity or of commercial grade.
• the resulting alloy product is not detrimentally degraded by storage in normal atmospheres through air oxidation.
• Example.A number of anodes of the present invention were prepared by melting commercial 99.9% purity aluminum ingot in a graphite crucible positioned within a electric furnace. Requisite amounts of gallium, indium, bismuth and lead alloying ingredients were introduced into the molten aluminum and the resulting mixture stirred to effect dispersion of the alloying ingredients throughout the melt. The resulting alloy was cast in a graphite mold into cylindrical specimens about 5 /2 inches long and about inch in diameter. The cooling and solidification rate of the castings were controlled such that these simulated cooling rate experienced in production of commercial, field-sized cast anodes.
• the performance of the alloys was evaluated by positioning each cast cylindrical specimen (as anode) in a schedule 40 steel can 3 inches in diameter and 6 inches tall (as cathode). Synthetic sea water was used as an electrolyte with about 4 inches of each specimen being immersed. The cells were completed with respect to electrical circuitry, a rectifier being employed to maintain a constant current through a group of cells connected in series.
• anodes D-shaped in cross section, having dimensions of about 3 /2 inches diameter and 12 inches long were prepared from the present novel alloy composition consisting essentially of 0.02 weight percent gallium, 0.03 weight percent indium, 0.5 weight percent bismuth, 0.5 weight percent lead, and balance aluminum. Upon being subjected to actual field tests in flowing sea water for about 9 weeks these anodes performed in a satisfactory manner as sacrificial galvanic anodes in that they exhibited a potential of about 1.45 volts and current efificiencies of about 60 percent.
• novel alloys all exhibit a high oxidation potential and electrical output and therefore are suitable for use as sacrificial anodes for applications such as galvanic pigments in paint films, galvanic anode materials for primary batteries, sacrificial galvanic coatings for sheet steel and other metals cathodic to aluminum and sacrificial anodes for cathodic protection. Additionally these compositions find utility as an active ingredient in flares, for use in chemical reductions and in the preparation of aluminum alkyls.
• An aluminum alloy having a high oxidation potential and a high electrical equivalent consisting essentially of:
• An aluminum based sacrificial galvanic anode having a high useful oxidation potential which comprises:
• An aluminum based sacrificial galvanic anode having a high useful oxidation potential which comprises:

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Prevention Of Electric Corrosion (AREA)

Priority Applications (8)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23518696

Family Applications (1)

Country Status (7)

Cited By (3)

Citations (2)

• 1964
  • 1964-07-23 US US384773A patent/US3337332A/en not_active Expired - Lifetime
• 1965
  • 1965-07-08 SE SE9019/65A patent/SE306620B/xx unknown
  • 1965-07-21 DE DED47785A patent/DE1258606B/de not_active Withdrawn
  • 1965-07-22 GB GB31228/65A patent/GB1066724A/en not_active Expired
  • 1965-07-23 DK DK380565AA patent/DK106948C/da active
  • 1965-07-23 BE BE667340A patent/BE667340A/xx unknown
  • 1965-07-23 NL NL656509581A patent/NL144441B/xx unknown

Patent Citations (2)

Also Published As

Similar Documents