US2640024A - Electrophoretic borating of copper wire - Google Patents

Electrophoretic borating of copper wire Download PDF

Info

Publication number
US2640024A
US2640024A US57994A US5799448A US2640024A US 2640024 A US2640024 A US 2640024A US 57994 A US57994 A US 57994A US 5799448 A US5799448 A US 5799448A US 2640024 A US2640024 A US 2640024A
Authority
US
United States
Prior art keywords
wire
copper wire
coating
suspension
oxide
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
US57994A
Inventor
Russell E Palmateer
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.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products 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
Application filed by Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Priority to US57994A priority Critical patent/US2640024A/en
Application granted granted Critical
Publication of US2640024A publication Critical patent/US2640024A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00Electrophoretic coating characterised by the process
    • C25D13/02Electrophoretic coating characterised by the process with inorganic material

Definitions

  • This invention relates to a method of coating wire; more particularly it relates to a method of coating wire with a vitreous material by an electrophoretic process.
  • the vitreous forming material has normally been applied in a purely mechanical manner by dipping or brushing the material onto the surface of the wire.
  • the wire is first heated in an air furnace to remove contamination and more particularly to oxidize the copper surface since this oxide surface appears to be quite necessary if a satisfactory borate coating is to be applied.
  • the thickness of this oxide and its appearance is, therefore, quite critical.
  • the borate is applied in a thin coating by painting on or by dipping the wire into a water suspension or solution of the borate maintained at the proper consistency to deposit the most desirable amount of solid material, after which it is dried and heated at a critical temperature to fuse flow the coated material into a skin.
  • coating wire such as Dumet which is a copper clad nickel iron wire used for glass sealing in the electronic industry, a continuous process has been developed wherein the wire is moved successively through these stages and finally after suiiicient cooling is wound on spools. Such a process is diagrammatically illustrated in Patent No. 2,316,984.
  • Fig. 1 is a schematic drawing showing the preferred method and apparatus embodying features of this invention
  • Fig. 2 is a schematic drawing showing a. modified version of the method and apparatus shown in Fig. 1.
  • metal can be coated with a vitreous material in a manner requiring no preoxidation to obtain even uniform coatings having no bubbles in the finished surface if the material is coated electrophoretically from a bath containing a suspension of the vitrifiable frit material in intimate mixture with an oxide of the material to be covered.
  • Electrophoretic methods of coating metals with non-conductors are of course quite well known to the art.
  • wire which could only be borated electrophoretically at the slow rate of seven feet per minute could be borated at the rate of 16 feet per minute or more than twice as fast if copper oxide were present in the bOrating suspension.
  • the spool H] of the annealed wire as shown in Fig. 1 feeds the wire l2 over a guide pulley l4 electrically grounded by line [6.
  • the wire 12 passing downwardly into .a coating tbath around ta-guide pulley at the bottom of it, upwardly out of the bath past a cathode connected to a power line 20.
  • a, furnace .30 which .is operated at a temperature of about 900 degrees C. or above to fuse the borate coating.
  • the wire thereupon passes up to a winding ispoolrn which is located a sufiicient distanceiabove the furnace that the borate will solidify before it reaches the winding spool or pulley 32.
  • a dryer 40 may be placed between the coating bath and the furnace for the purpose of ievaporating the solvents before the wire reaches the furnace .30 if so desired.
  • .the coating bath - is;made -.up of a suspension of the vitrifiable material in finely divided form and powdered metallic oxide .ina suspension of the water free organic medium which is not hydrophi1ic.and.does7not have a tendency to absorb moisture.
  • .Agpreferred formula forthe boratingzof @Dumet wire 21S for example, one which-contains 1 grams :of sodium borate (anhydrous), .5 gram OfCUZQ,/20.0 CCS. of amyl acetate .and 100 cos. of lacquer :containing approximately .9 .gram of anhydrous 1000 second nitrocellulose per .100 .ccs.
  • .Gl .glass has the Jollowing approximate compositions .of: .2016% P1), 62.2% or SiOz, 6.84% .of .NazCea, 6.45% of .KzQ :and 1.05% of R203.
  • non-conductingsmaterials suchgas glass frit, aluminum oxide, silica, any-of .theanhydrous sillcatesor anyother yitrifiablemateria-l can be deposited electrophoretically.
  • Thenovel feature in the composition has vin the inclusion of a metallic .oxide which .permits -.the .omission of a preoxidation treatment .as welhas means -.to speed up the electrophoresis .while ,yet .obtaining satisfactorygood adherent coatings .of .the yitreous material.
  • the amount of .tungstic oxide which maybe added .without deleteriously affecting .the coating is as much .as 2% of the total solids. 'With .chromic oxide, themetal-oxide can be further increased to as much as .5% without deleteriously affecting .the adhesive properties of .the coating.
  • An electrophoretic bath .for oxidized copper wire with .a lborate coating preliminary to using it in making a seal .to glass consisting essentially of .a suspension of a mixture :of sodium "borate and powdered cuprous oxide in an anhydrous non-hydrophilic organic liquid-of 'low electrical conductivity.
  • cuprous oxide in a non-aqueous, alone-hydro philic organic medium, maintaining an electric potential between said metal and a cathode through said suspension and thereby causing the mixture of ,sodium borate and cuprous oxide to coat the copper wire, withdrawing the copper wire from the suspension and passing the coated copper wire through a heated area wherein the sodium borate is caused to flow evenly over the surface of the copper wire.

Description

May 26, 1953 R. E. PALMATEER 7 2,640,024
ELECTROPHORETIC BORATING OF COPPER WIRE Filed Nov. 2. 1948 EA. 6.92 V. 2 $92 1 ,INVENTOR. Russelfi. fizz/mates MKw-ZWAA Attorney Patented May 26, 1953 ELECTROPHORETIC BORATING OF COPPER WIRE Russell E. Palmateer, Emporium, Pa., assignor to .Sylvania Electric Products Inc., a corporation of Massachusetts Application November 2, 1948, Serial No. 57,994
2 Claims. 1
This invention relates to a method of coating wire; more particularly it relates to a method of coating wire with a vitreous material by an electrophoretic process.
In accordance with prior art practices for coating wire with a vitreous material such as borates or soft glass materials, the vitreous forming material has normally been applied in a purely mechanical manner by dipping or brushing the material onto the surface of the wire. For example, in the borating of copper or copper clad wire as has heretofore been the custom, the wire is first heated in an air furnace to remove contamination and more particularly to oxidize the copper surface since this oxide surface appears to be quite necessary if a satisfactory borate coating is to be applied. The thickness of this oxide and its appearance is, therefore, quite critical. Following this, the borate is applied in a thin coating by painting on or by dipping the wire into a water suspension or solution of the borate maintained at the proper consistency to deposit the most desirable amount of solid material, after which it is dried and heated at a critical temperature to fuse flow the coated material into a skin. In coating wire such as Dumet which is a copper clad nickel iron wire used for glass sealing in the electronic industry, a continuous process has been developed wherein the wire is moved successively through these stages and finally after suiiicient cooling is wound on spools. Such a process is diagrammatically illustrated in Patent No. 2,316,984.
Although this process has been used commercially for some considerable time, it is understandably not completely satisfactory since it is somewhat dependent upon pre-oxidation of the wire which step needs to be kept under careful control at all times if a satisfactory product is to be obtained. Furthermore, the presence of the water along with the borate also leads to the formation of bubbles in the surface. These are attributable to the hydrated salts that are used thus producing finished products whose coating can by no means be considered smooth and even. Furthermore it is at times difficult to control the coating thickness. Since this mechanical coating method dependsin large part upon the heating of the wire, before the dipping operation in order to form a suitable oxide finish, it was not considered the best manner of application on an annealed wire used for such purposes.
It is an object of this invention to provide an improved method of applying a vitreous coating to metals which is adapted to produce an even uniform coating having no bubbles in the finished surfacesuch as those normally encountered due to the use of hydrated salts.
It is a further object of this invention to provide a method of applying a vitreous coating which will require no previous oxidation of the metal. I
It is a still further object of this invention to provide a method of applying a vitreous coating in a manner which will not interfere with the annealed condition of the base metal to be coated.
In accordance with this invention these and other advantages which are incidental to its application, can be attained by electrophoretically coating the wire from a suspension ,of vitrifiable material and metal oxides.
In the accompanying drawing which illustrates the preferred method of this invention:
Fig. 1 is a schematic drawing showing the preferred method and apparatus embodying features of this invention;
Fig. 2 is a schematic drawing showing a. modified version of the method and apparatus shown in Fig. 1.
In accordance with this invention, it has been found that metal can be coated with a vitreous material in a manner requiring no preoxidation to obtain even uniform coatings having no bubbles in the finished surface if the material is coated electrophoretically from a bath containing a suspension of the vitrifiable frit material in intimate mixture with an oxide of the material to be covered.
Electrophoretic methods of coating metals with non-conductors are of course quite well known to the art.
However, it has not heretofore been considered possible to apply a vitreous coating to such metals without previously oxidizing the metal if a good adherent coating was desired.
In accordance with the method of this invention however, it becomes unnecessary to oxidize the surface of the wire to produce good adherent coatings. Furthermore it has been found that the presence of the oxide of the base metal in the frit suspension tends to increase the rate at which the vitrifiable material can be applied to the base metal by electrophoresis.
In the case of copper wire, for example, it was found that wire which could only be borated electrophoretically at the slow rate of seven feet per minute could be borated at the rate of 16 feet per minute or more than twice as fast if copper oxide were present in the bOrating suspension.
In accordance with preferred embodiments of this invention in which clean copper wire is borated without first applying an oxide film to the wire, the spool H] of the annealed wire as shown in Fig. 1 feeds the wire l2 over a guide pulley l4 electrically grounded by line [6. The wire 12 passing downwardly into .a coating tbath around ta-guide pulley at the bottom of it, upwardly out of the bath past a cathode connected to a power line 20. As the wire leaves the coating bath it passes through a, furnace .30 which .is operated at a temperature of about 900 degrees C. or above to fuse the borate coating. The wire thereupon passes up to a winding ispoolrn which is located a sufiicient distanceiabove the furnace that the borate will solidify before it reaches the winding spool or pulley 32. .-.shown.in.l .ig..2, a dryer 40 may be placed between the coating bath and the furnace for the purpose of ievaporating the solvents before the wire reaches the furnace .30 if so desired. FI-his dryer :norm'ally operates at 150-.20.0'degrees- C..in preferred-cases.
In accordance with preferred embodiments of this invention, .the coating bath -is;made -.up of a suspension of the vitrifiable material in finely divided form and powdered metallic oxide .ina suspension of the water free organic medium which is not hydrophi1ic.and.does7not have a tendency to absorb moisture. .Agpreferred formula forthe boratingzof @Dumet wire 21S, for example, one which-contains 1 grams :of sodium borate (anhydrous), .5 gram OfCUZQ,/20.0 CCS. of amyl acetate .and 100 cos. of lacquer :containing approximately .9 .gram of anhydrous 1000 second nitrocellulose per .100 .ccs. of .-hi gh purity amyl acetate. This solution .to give -.the-best.results:is ball-milled vlover night, that is, .for a period :of about 12 .hours after which .the suspension :gives best results after having been diluted with .two litres ofamyl acetate. Whensoperating with'this solution, it has been found that-.the;heat +required for boratingtotakeplace is 1900degrees C. The rate of coating .isabout .16 -feet per minute. This permits the wire to be heated at 900 degreesCtfor 4- .seconds and allows .it :to :be cooled in air :for 320 seconds. The process requires the [use of :voltages of less than 100 volts .during which the borate moves and adheres to ithe wire :at low electrical potential. For .the eoatingrof .0162.:Dumet=wire, the voltage required .at the beginning iiszabout r60 volts which is gradually increased to :90 volts when 10,000 feet of wire have ;.passed through the suspension.
method has been found .to 'be. successful and satisfactory .for ,.pr.oduction 'of even coatings with other vitreous materials besides :borates namely with glass Hit of types G12, '61 -borax glass. The composition for -G12 glass .-is approximately .as follows: 5.6.7 iof .SiQz, 3.32% :of Na2CO3, 7.9% of mo, 06% of Ca, 28.4% :EOf PbO, 1.3% of R203. .Gl .glass has the Jollowing approximate compositions .of: .2016% P1), 62.2% or SiOz, 6.84% .of .NazCea, 6.45% of .KzQ :and 1.05% of R203. There is, of.course,--nothing.novel in thefact that non-conductingsmaterials:suchgas glass frit, aluminum oxide, silica, any-of .theanhydrous sillcatesor anyother yitrifiablemateria-l can be deposited electrophoretically. Thenovel feature in the composition has vin the inclusion of a metallic .oxide which .permits -.the .omission of a preoxidation treatment .as welhas means -.to speed up the electrophoresis .while ,yet .obtaining satisfactorygood adherent coatings .of .the yitreous material.
Although copper oxide 'isperhaps the mostuse- 4 ful of the metallic addition agents to the suspension in view of the large use of copper clad wire in making glass to metal seals, other metallic oxides can also be used to advantage particularly when the base material is to be coated a metal other than copper. Examples of *suchoxides are chromic oxide'ICriOa,;tungstic ox- -ide W Oa cobaltieoxide,iron oxide and-aluminum oxide.
Other examples of preferred bath formulations in whichsuch oxides are used are, for ex- ;ample, as follows:
I. 25 gms. of #775 Pyrex glass (powdered) '25znl.:amyljacetate 5 ml. .of .lacquer containing approximately 3133 g. of anhydrous 60-80 second nitrocelzlulose per ml. of high purity amyl acetate .5 gm.tungstic oxide -.(WO3) 1 gm. sodium borate H. 200 gmsmpulverized G-l glass 250 m1. amyl acetate 50ml. of lacquer (same as in I) 10 gins. green anhydrous chromicoxideyCmO:
The :amount of oxide activator added .to the electrophoretic bath -may, -.of course, .vary over wide limits. Increasin the amountof the oxide in the .bathain relation .to .the .total solid material tends .to increasethespeed at'which the'electrophoretic deposition willtake place. However, if toorgreatainountsaroused, there willbea tendencyfointhe deposit to become'non-adherent and flaky. For this reason, itehasbeenfoundpreferable when depositin from baths -.containing "cuprous oxide, for example, .to limit the cuprous oxide to..04% vto.08% of the .total solid-material. On the other hand, the amount of .tungstic oxide which maybe added .without deleteriously affecting .the coating is as much .as 2% of the total solids. 'With .chromic oxide, themetal-oxide can be further increased to as much as .5% without deleteriously affecting .the adhesive properties of .the coating.
It is, .of .course, understood that while :the process of .this invention .makes vit possible to coat either single or composite :metals without previously oxidizing the metal surface to be coated, the fact that such metal surface may have controlled oxidation is not detrimentaland will not have a deleterious .effect on the finished product.
"While the above description and drawings submitted herewith disclose preferred :and practical embodiments .of .the coating method of this invention, .it .will vbe understood by those skilledin the .art that the specific -.details shown and describedare .by way of.il1ustration and .are not to be construed aslimiting .the scope of the invention.
What is claimed is:
'1. An electrophoretic bath .for oxidized copper wire with .a lborate coating preliminary to using it in making a seal .to glass consisting essentially of .a suspension of a mixture :of sodium "borate and powdered cuprous oxide in an anhydrous non-hydrophilic organic liquid-of 'low electrical conductivity.
.2. In the .eleotrophoretic method of coating unoxidized copper wire with :a borate coating preliminary to using .it .in making a seal :to glass, the steps .comprising passing the copper wire through a suspension -.of a mixture :con sisting essentially of sodium'borate .and powdered coating .un-
cuprous oxide .in a non-aqueous, alone-hydro philic organic medium, maintaining an electric potential between said metal and a cathode through said suspension and thereby causing the mixture of ,sodium borate and cuprous oxide to coat the copper wire, withdrawing the copper wire from the suspension and passing the coated copper wire through a heated area wherein the sodium borate is caused to flow evenly over the surface of the copper wire.
RUSSELL E. PALMA'I'EER.
References Cited in the file 0! this patent UNITED STATES PATENTS Number Name Date Steenbeck et al Aug. 15, 1933 Ruben Sept. 10, 1940 Verwey et a1 June 8, 1943 Robinson et a1 June 3, 1947

Claims (1)

  1. 2. IN THE ELECTROPHORETIC METHOD OF COATING UNOXIDIZED COPPER WIRE WITH A BORATE COATING PRELIMINARY TO USING IT IN MAKING A SEAL TO GLASS, THE STEPS COMPRISING PASSING THE COPPER WIRE THROUGH A SUSPENSION OF A MIXTURE CONSISTING ESSENTIALLY OF SODIUM BORATE AND POWDERED CUPROUS OXIDE IN A NON-AQUEOUS, NON-HYDROPHILIC ORGANIC MEDIUM, MAINTAINING AN ELECTRIC POTENTIAL BETWEEN SAID METAL AND A CATHODE THROUGH SAID SUSPENSION AND THEREBY CAUSING THE MIXTURE OF SODIUM BORATE AND CUPROUS OXIDE TO COAT THE COPPER WIRE, WITHDRAWING THE COPPER WIRE FROM THE SUSPENSION AND PASSING THE COATED COPPER WIRE THROUGH A HEATED AREA WHEREIN THE SODIUM BORATE IS CAUSED TO FLOW EVENLY OVER THE SURFACE OF THE COPPER WIRE.
US57994A 1948-11-02 1948-11-02 Electrophoretic borating of copper wire Expired - Lifetime US2640024A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US57994A US2640024A (en) 1948-11-02 1948-11-02 Electrophoretic borating of copper wire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US57994A US2640024A (en) 1948-11-02 1948-11-02 Electrophoretic borating of copper wire

Publications (1)

Publication Number Publication Date
US2640024A true US2640024A (en) 1953-05-26

Family

ID=22013996

Family Applications (1)

Application Number Title Priority Date Filing Date
US57994A Expired - Lifetime US2640024A (en) 1948-11-02 1948-11-02 Electrophoretic borating of copper wire

Country Status (1)

Country Link
US (1) US2640024A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2826541A (en) * 1954-06-15 1958-03-11 Vitro Corp Of America Method of making ceramic-clad metal structures
US2828254A (en) * 1954-01-05 1958-03-25 Vitro Corp Of America Method of forming a high friction element
US2830017A (en) * 1954-01-18 1958-04-08 Vitro Corp Of America Method of forming a sacrificial lubricating layer
US2848391A (en) * 1953-10-19 1958-08-19 Vitro Corp Of America Method of making a multiple lamination construction
US2861935A (en) * 1954-05-20 1958-11-25 Vitro Corp Of America Electrophoretic method of applying a lubricant coating
US3024184A (en) * 1958-09-29 1962-03-06 Sylvania Electric Prod Electrophoretic article coating machine
GB2548266B (en) * 2015-11-04 2018-06-27 Payton Planar Magnetics Ltd Planar transformer components comprising electrophoretically deposited coating

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1922221A (en) * 1929-07-20 1933-08-15 Westinghouse Electric & Mfg Co Resistance material
US2213969A (en) * 1937-02-23 1940-09-10 Ruben Samuel Electrical resistance element
US2321439A (en) * 1936-09-26 1943-06-08 Hartford Nat Bank & Trust Co Method of making vitreous coated bodies
US2421652A (en) * 1943-08-02 1947-06-03 Sprague Electric Co Electrical conductor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1922221A (en) * 1929-07-20 1933-08-15 Westinghouse Electric & Mfg Co Resistance material
US2321439A (en) * 1936-09-26 1943-06-08 Hartford Nat Bank & Trust Co Method of making vitreous coated bodies
US2213969A (en) * 1937-02-23 1940-09-10 Ruben Samuel Electrical resistance element
US2421652A (en) * 1943-08-02 1947-06-03 Sprague Electric Co Electrical conductor

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2848391A (en) * 1953-10-19 1958-08-19 Vitro Corp Of America Method of making a multiple lamination construction
US2828254A (en) * 1954-01-05 1958-03-25 Vitro Corp Of America Method of forming a high friction element
US2830017A (en) * 1954-01-18 1958-04-08 Vitro Corp Of America Method of forming a sacrificial lubricating layer
US2861935A (en) * 1954-05-20 1958-11-25 Vitro Corp Of America Electrophoretic method of applying a lubricant coating
US2826541A (en) * 1954-06-15 1958-03-11 Vitro Corp Of America Method of making ceramic-clad metal structures
US3024184A (en) * 1958-09-29 1962-03-06 Sylvania Electric Prod Electrophoretic article coating machine
GB2548266B (en) * 2015-11-04 2018-06-27 Payton Planar Magnetics Ltd Planar transformer components comprising electrophoretically deposited coating
US10192680B2 (en) 2015-11-04 2019-01-29 Payton Planar Magnetics Ltd. Planar transformer components comprising electrophoretically deposited coating

Similar Documents

Publication Publication Date Title
US2640024A (en) Electrophoretic borating of copper wire
US2321439A (en) Method of making vitreous coated bodies
GB1181033A (en) A Method of Applying a Coating comprising Tin Oxide upon Substrates
GB1042572A (en) Method of depositing coatings on a non-conducting surface
ES400128A1 (en) Process for the production of luster color coatings on ceramic, glass of similar bodies
US3249467A (en) Method of forming metallic films on glass
US2384542A (en) Inorganic insulation for electrical conductors
US2824020A (en) Fluxing and coating metal strip
US2217284A (en) Electric cable
US1879701A (en) Protective coating and method of applying same to nickel, nickel alloys, and chromium-iron alloys
US3653946A (en) Method of depositing an adherent gold film on the surfaces of a suitable substrate
US1779273A (en) Art of making enamel ware
US2416864A (en) Method of coating wire-wound electrical resistors
ATE18896T1 (en) PROCESS FOR MAKING PATTERNED LUESTER COATINGS ON SURFACES OF BODY.
US2121412A (en) Method for treating zinc and product formed thereby
GB980727A (en) Method of applying metallic coatings
DE1015298B (en) Process for the surface treatment of metals by applying layers of silicate
DE2166034C3 (en) Procedure for adjusting the coefficient of thermal expansion of a conductor
US3338737A (en) Quartz tube coating
JPS6129895B2 (en)
JPH0222148B2 (en)
US2783419A (en) Rectifier
GB605889A (en) Strongly adherent metal coated articles and means for producing the same
GB626357A (en) Improvements in or relating to methods of forming metal coatings on bases of ceramic, refractory or high melting point vitreous material
US1990070A (en) Bimetallic article