US2347039A - Method of anodically polishing copper - Google Patents

Method of anodically polishing copper Download PDF

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Publication number
US2347039A
US2347039A US302951A US30295139A US2347039A US 2347039 A US2347039 A US 2347039A US 302951 A US302951 A US 302951A US 30295139 A US30295139 A US 30295139A US 2347039 A US2347039 A US 2347039A
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United States
Prior art keywords
copper
water
phosphoric acid
composition
bath
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US302951A
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English (en)
Inventor
Charles L Faust
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Battelle Memorial Institute Inc
Original Assignee
Battelle Memorial Institute Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE478068D priority Critical patent/BE478068A/xx
Priority to LU28805D priority patent/LU28805A1/xx
Priority to NL71372D priority patent/NL71372C/xx
Priority to US302952A priority patent/US2407543A/en
Priority to US302950A priority patent/US2366712A/en
Priority to US302954A priority patent/US2373466A/en
Priority to US302953A priority patent/US2366713A/en
Application filed by Battelle Memorial Institute Inc filed Critical Battelle Memorial Institute Inc
Priority to US302951A priority patent/US2347039A/en
Priority to US304450A priority patent/US2347040A/en
Application granted granted Critical
Publication of US2347039A publication Critical patent/US2347039A/en
Priority to CH272841D priority patent/CH272841A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/16—Polishing
    • C25F3/22—Polishing of heavy metals

Definitions

  • This invention relates to a method of and electrolyte for anodically polishing copper. More particularly, the invention relates to an aqueous electrolyte comprising phosphoric acid, chromic acid and water and to the use of such electrolyte in the anodic polishing of copper.
  • compositions of electrolyte have heretofore been proposed for use in the anodic treatment of copper.
  • an aqueous electrolyte comprising phosphoric acid, chromic acid and Water, as the essential ingredients, constitutes a very satisfactory electrolyte for use in the anodic polishing of copper. If the relative proportions of these ingredients of the bath be kept within certain limits, which I have determined, very satisfactory polishes can be produced on copper, while at the same time producing surface finishes having relatively superior characteristics to those obtainable by mechanical polishing or bulllng operations.
  • the gure represents a triaxial diagram showing the relative proportions of phosphoric acid, chromic acid and water for compositions of the electrolytes coming within the scope of this invention.
  • the respective sides of the triangle indicate the percentages of phosphoric acid (H3PO4) of water (H2O), and of chromic acid (CrOa) from to 100%.
  • H3PO4 phosphoric acid
  • H2O water
  • CrOa chromic acid
  • I have determined the relative proportions of phosphoric acid, chromic acid and water that give compositions of electrolyte that are operative for the anodic polishing of copper
  • the arca representing operative compositions of electrolyte is dened on the accompanying triaxial diagram by the solid lines AB, BC, CD and DA. Within the area so defined, any composition selected will be found to be operative in the method hereinafter described for the anodic polishing of copper.
  • the point indicated by the reference letter C a composition comprising 10% of phosphoric acid, say 0.1% of chromic acid and the balance, or somewhat less than 90% of Water
  • the point represented by the letter D a composition comprising about 0.1% of phosphoric acid, 10% of chromic acid and the balance, or about 90% water
  • the point represented by the reference letter E a composition comprising 50% of phosphoric acid, 26% of chromic acid and 24% of water
  • the maximum phosphoric acid content is about and the minimum about 0.1%; the maxlmum chromic acid content 65% and the minimum about O.l%; and the maximum water content and the minimum about 13%.
  • the preferred composition limits are from 20 to 85% phosphoric acid, from 0.1 to 39% CrOa, and from 13 to 80% water. It should be understood, however, that the relative percentages of these three ingredients are all inter-dependent, so that a point should be selected within the above described areas in order to insure that the composition of electrolyte be a satisfactory one.
  • suitable baths of these three ingredients may also include other ingredients, such as other acids and/or salts. From the diagram, however, the relative proportions that phosphoric acid, chromic acid and water should bear to each other may be determined for operative and preferred ranges of composition, regardless of what other non-essential ingredients may be present in the bath.
  • the point X on the triaxial diagram as being a bath of preferred composition.
  • the composition represented by the point X would be 60% of phosphoric acid, of chromic acid and 30% of water.
  • the bath composition would necessarily change, owing to the anodic dissolution into the bath of copper from the copper undergoing polishing.
  • chromic acid equivalent is therefore intended to include chromic acid itself (CrOz) and stoichiometrically equivalent weights of soluble chromates and bichromates.
  • phosphoric acid in place of orthophosphoric acid, other phosphoric acids, such as metaand pyrophosphoric acids, may be used and are to be considered as included within the term phosphoric acid.
  • the copper, or an article having a surface of copper is made the anode in a bath of the selected composition and an electric current is passed therethrough of suiiicient density and for a sufficient length of time to produce the desired high degree of luster, or polish, on the metal surface.
  • an electrolyte having a composition within the preferred area dened on the accompanying triaxial diagram a highly lustrous, mirror-like surface can be readily obtained.
  • the highly lustrous surface obtainable by my method, using an electrolyte of preferred composition is an important feature of my invention and one that sharply distinguishes it from the prior art finishes produced in the electrolytic cleaning of copper.
  • relatively high current densties such as those of the order of magnitude of from to 1000 amperes per sq. ft. It will be understood, however, that lower current densities, even as low as 50 amperes per sq. ft., may be employed with consequent prolongation of the time of treatment. Higher current densities, up to as high as 2000 or 3000 amperes per sq. ft., may also be employed, but such' high current densities imply, in general, larger currents which require more expensive equipment.
  • the length of time to effect the desired resuits depends upon the magnitude of the current densities employed and to some extent upon the particular characteristics of the copper to be polished, and also upon the character of the surface of the copper initially. Rough surfaces, of course, require a longer time to polish than relatively smooth ones.
  • compositions of electrolyte lying within the preferred area defined by the lines EB, BF and FE, on the accompanying triaxial diagram, excellent polishes are obtained on copper, when the metal is made the anode therein at current densities of 500 amperes per sq. ft. and the treatment carried out for a period of 1% to 12 minutes, employing a bath temperature lying within the range of 60 to 170 F. In general, the temperature may be maintained at any point between room temperature and the boiling point of water, but temperatures of around 100 F. are found very satisfactory.
  • the method of anodically polishing copper which comprises making the copper the anode in a solution comprising essentially from 0.1 to 85% of phosphoric acid, from 0.1 to 65% of CrOa, and from 13 to 90% of water, all of said percentages being by Weight of said solution and the relative percentages of said three solution ingredients lying within the area dened in the accompanying diagram by the line AB, the straight line BC, the straight line CD, and the straight line DA, and passing an electric current therethrough of sufiicient density and for a suiiicient period of time to effect the polishing of said copper.
  • the method of anodically polishing copper which comprises making copper the anode in a solution comprising essentially from 20 to 85% of phosphoric acid, from 0.1 to 39% of CrOa, and from 13 to 80% of water, all of said percentages being by weight of said solution and the relative percentages of said three solution ingredients lying Within the area dened in the accompanying diagram by the line EB, the straight line BF, and the line FE, and passing an electric current therethrough of sufficient density and for a suicient period of time to effect the polishing of said copper.
  • the method oi anodically polishing copper, which comprises making copper the anode in a solution comprising essentially from 20 to 85% of phosphoric acid, from 0.1 to 39% of CrOs, and from 13 to 80% of water, all of said percentages being by weight of said solution and the relative percentages of said three solution ingredients lying within the area dened in the accompanying diagram by the line EB, the straight line BF, and the line FE, and passing an electric current therethrough of between 100 and 1,000 amperes per square foot at a hath temperature between 60 and 170 F. for a sufficient period of time to effect the polishing of said copper.

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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)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • ing And Chemical Polishing (AREA)
US302951A 1939-11-06 1939-11-15 Method of anodically polishing copper Expired - Lifetime US2347039A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
NL71372D NL71372C (xx) 1939-11-15
BE478068D BE478068A (xx) 1939-11-15
LU28805D LU28805A1 (xx) 1939-11-15
US302950A US2366712A (en) 1939-11-06 1939-11-06 Method of anodically polishing stainless steel
US302952A US2407543A (en) 1939-11-06 1939-11-06 Method of anodically polishing brass
US302954A US2373466A (en) 1939-11-06 1939-11-06 Method of anodically polishing zinc
US302953A US2366713A (en) 1939-11-06 1939-11-06 Method of anodically polishing nickel
US302951A US2347039A (en) 1939-11-15 1939-11-15 Method of anodically polishing copper
US304450A US2347040A (en) 1939-11-15 1939-11-15 Method of anodically polishing steel
CH272841D CH272841A (fr) 1939-11-15 1947-08-08 Procédé pour le polissage des métaux.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US302951A US2347039A (en) 1939-11-15 1939-11-15 Method of anodically polishing copper
US304450A US2347040A (en) 1939-11-15 1939-11-15 Method of anodically polishing steel

Publications (1)

Publication Number Publication Date
US2347039A true US2347039A (en) 1944-04-18

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ID=26973181

Family Applications (2)

Application Number Title Priority Date Filing Date
US304450A Expired - Lifetime US2347040A (en) 1939-11-06 1939-11-15 Method of anodically polishing steel
US302951A Expired - Lifetime US2347039A (en) 1939-11-06 1939-11-15 Method of anodically polishing copper

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US304450A Expired - Lifetime US2347040A (en) 1939-11-06 1939-11-15 Method of anodically polishing steel

Country Status (5)

Country Link
US (2) US2347040A (xx)
BE (1) BE478068A (xx)
CH (1) CH272841A (xx)
LU (1) LU28805A1 (xx)
NL (1) NL71372C (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE974072C (de) * 1947-10-17 1960-10-06 Jacquet Hispano Suiza Soc Verfahren zur Ermittlung guenstiger Polierelektrolyte zwecks Erzeugung einer homogenen Oberflaeche von unregelmaessig gestalteten Metallteilen

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2475586A (en) * 1943-04-09 1949-07-12 Thompson Prod Inc Method of electropolishing the internal surface of a hollow valve
US3223602A (en) * 1961-05-17 1965-12-14 Gen Electric Iron-silicon alloys and treatment thereof
US3450610A (en) * 1964-11-30 1969-06-17 Uddeholms Ab Process for removing an oxide layer from the surface of hardened strip steel by an electrolytical method
US5087342A (en) * 1988-04-07 1992-02-11 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing
US4935112A (en) * 1988-04-07 1990-06-19 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE974072C (de) * 1947-10-17 1960-10-06 Jacquet Hispano Suiza Soc Verfahren zur Ermittlung guenstiger Polierelektrolyte zwecks Erzeugung einer homogenen Oberflaeche von unregelmaessig gestalteten Metallteilen

Also Published As

Publication number Publication date
CH272841A (fr) 1951-01-15
NL71372C (xx)
US2347040A (en) 1944-04-18
BE478068A (xx)
LU28805A1 (xx)

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