US3669866A - Apparatus for obtaining wires for magnetic memories - Google Patents

Apparatus for obtaining wires for magnetic memories Download PDF

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Publication number
US3669866A
US3669866A US24635A US3669866DA US3669866A US 3669866 A US3669866 A US 3669866A US 24635 A US24635 A US 24635A US 3669866D A US3669866D A US 3669866DA US 3669866 A US3669866 A US 3669866A
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United States
Prior art keywords
core
wire
deposition
driving
sag
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Expired - Lifetime
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US24635A
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English (en)
Inventor
Rene Fernand Victor Girard
Jacques Le Guillerm
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Bull SA
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Societe Industrielle Honeywell Bull
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/06—Thin magnetic films, e.g. of one-domain structure characterised by the coupling or physical contact with connecting or interacting conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/143—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of wires
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S205/00—Electrolysis: processes, compositions used therein, and methods of preparing the compositions
    • Y10S205/922—Electrolytic coating of magnetic storage medium, other than selected area coating

Definitions

  • the conductive core is unwound from a drum and, under the action of driving means, traverses first a fabrication apparatus consisting of treatment means for preparing the core for receiving a magnetic deposit and of means for effecting such deposit and treating the deposit, and then traverses apparatus for measuring the physical properties of the completed wire.
  • the treatment and deposition means consist generally of electrolysis tanks.
  • the core is pushed through the core preparation means, the deposition and deposit treatment means, and the device for measuring the properties of the fabricated wire.
  • the wire is pulled through the fabrication apparatus and the measuring device by imposing a mechanical tension of some 10s to about 100 grams.
  • This method does not have all the disadvantages of the preceding, but it presents others.
  • These depositions can be effected under internal stresses of the same sense and of the same magnitude, so that the wire emerging from the output of the fabrication apparatus has been compensated for, but this is difficult to provide.
  • the present invention remedies these disadvantages.
  • the process for continuous fabrication of a wire having a conductive core covered with a thin magnetic film, wherein the conductive core is prepared for receiving a magnetic layer, the layer is deposited and then treated for conferring on it the desired properties, after which the physical properties of the completed wire are measured, is characterized in that the core is pulled with substantially zero tension during the preparation of the wire, the deposition and the treatment of the magnetic layer, and then pushed during the measure of its physical properties.
  • an arrangement for the continuous fabrication of such a wire starts with a core which is wound on a drum.
  • the core traverses, under the action of driving means, apparatus comprising in succession, preparation means for such core, means for deposition of the layer, means for treatment of the magnetic layer on the core, and a device for measuring the magnetic properties of the fabricated wire.
  • the driving means comprises, first, a motor driving the drum to unwind the core to provide a zero-tension sag in the core between drum and fabrication apparatus, a device for sensing the dimensional extent of said sag, and means controlled by the sag sensing device for providing regulation of the speed of the motor to a value greater or lesser in accordance with the tendency of the size of the sag to decrease or to increase, and, second, a driving device disposed between the fabrication apparatus and the measuring device.
  • the core is pulled under very low mechanical tension through the means of deposition and of treatment, such that the two steps can be carried out under the best conditions.
  • the wire is pushed through the measuring device so that its properties can be measured without stresses, which is important because it will be employed without stresses.
  • the measuring device effects a magnetostriction test of the magnetic deposit, which necessitates a mechanical torsion or a tension of the wire, the conditions of deposition (which are sensitive to external stresses), are not disturbed because the driving device is formed, for example, of two rollers turning in opposite sense between which passes the wire, thereby isolating the means of deposition and of treatment from the measuring device.
  • the sole figure illustrates schematically the process and the arrangement of the invention providing for obtaining continuously a wire, especially adapted for magnetic memories, having a conductive core covered with a thin magnetic sheath.
  • a conductive metallic core 1 for example a wire of an alloy of copper and of beryllium having a diameter of some 10s of microns, is unwound from a drum 2 by the action of a roller 3 keyed on a shaft 4 of an electric motor 5.
  • This conductive core 1 is then introduced into a fabrication apparatus 6 which provides for obtaining at its output a wire 7 having a core covered with a thin magnetic sheath.
  • Wire 7 is pulled in the direction of the arrow F through apparatus 6 by a device 8, which comprises the non-slipping driving rollers 9 and 10 between which passes wire 7.
  • wire 7 is pushed through a device 11 for measuring the wire s physical properties and then a cutting device 12. The latter can be controlled by device 1 1 for cutting wire in which a defect is detected.
  • Conductive core 1 is disposed in a manner to have a sag of predetermined size between drum 2 and device 6.
  • This sag is maintained as constant as possible by means of a servomechanism which enables regulation of the speed of motor 5 to a greater or lesser value according to the tendency of the sag to decrease or to increase.
  • This sag provides a supply of the core of substantially zero tension for the subsequent fabrication.
  • This servomechanism consists of a sag sensing device comprising two contact members 16 and 17 disposed on opposite sides of conductive core 1 and connected to two inputs 36 and 37 of an electrical device 35.
  • the output terminals 38 of device 35 are connected to the supply terminals of motor by connecting leads 15.
  • the servomechanism is arranged so as to deliver on output terminals 38 a supply voltage V or a supply voltage U, according to whether input 36 or input 37 is placed at the potential of conductive core 1.
  • These supply voltages U and V are such that conductive core 1 is unwound from drum 2 with a speed which is less or greater than its velocity of transit through device 8, according to whether the motor is supplied by the voltage U or the voltage V.
  • conductive core 1 makes contact with contact member 16
  • input 36 of electrical device 35 is placed at the potential of conductive core 1, and device 35 furnishes to motor 5 the supply voltage V.
  • the conductive core is then unwound from drum 2 at a greater speed than its velocity of transit through device 8 and the sag tends to increase.
  • conductive core 1 makes contact with contact member 17, input 37 of electrical device 35 is placed at the potential of conductive core 1, and device 35 furnishes to motor 5 the supply voltage U.
  • the conductive core is then unwound from drum 2 at a lesser speed than its velocity of transit through device 8 and the sag tends to decrease.
  • an unwinding device for unwinding the core from its roll and feeding it to the input of fabrication apparatus 6 with substantially zero tension on the wire at the input point of the fabrication apparatus. Therefore, the wire can be drawn through the fabrication apparatus with the exertion of only minumum tension in the pulling device, i.e., the tension required only to overcome the residual friction imposed on the wire as it passes through the fluid-lubricated opening in each wall of the electrolysis and rinsing tanks.
  • a wire processed according to the instant invention is coated with a magnetic film under substantially zero imposed stresses. This is very important for a high quality of finished wire.
  • Fabrication apparatus 6 comprises a plurality of tanks 18-28 and an oven 29 traversed by the wire. These tanks and the oven, as well as driving device 8, measuring device 11, and cutting device 12 are mounted slidably, but in a manner to be' able to be removable or fixed on a rail 30 parallel to the wire.
  • the wire passes through each of devices 18-29, 8, 11, and 12.
  • the surface of core 1 is first subjected to preparation in treatment means 31, comprising the electrolysis tanks 18, 20, 22, and 23.
  • core 1 serves as the cathode or the anode and is surrounded by a helicoidal or annular anode or cathode, according to the particular circumstances.
  • the electrolyte in tanks 18, 20, 22, and 23 is preferably circulated. Rinsing tanks 19, 21, and 24 for the circulation of water are similarly provided in treatment means 31.
  • the length of electrolysis tanks 18, 20, 22, and 23 are chosen in order that each portion of the core remains about 1 minute in such tanks.
  • Core 1 is introduced into electrolysis tank 18, which contains a degreasing bath formed of a mixture of sodium bicarbonate and of sodium carbonate at 60 C.
  • the current density is about 20 amperes per square decimeter.
  • core 1 After having traversed rinsing tank 19, core 1 enters into electrolysis tank 20, which contains a deoxidation bath formed, for example, of a hydrochloric acid bath of one-tenth normality at ambient temperature. Core 1 is again rinsed by passage through tank 21 and then is subjected to a polishing. To effect this, it traverses an electrolysis tank 22 containing an 85 percent orthophosphoric acid bath. This bath is at the temperature of 17 C. and the current density is selected to be approximately 300 milliamperes per square centimeter.
  • electrolysis tank 20 contains a deoxidation bath formed, for example, of a hydrochloric acid bath of one-tenth normality at ambient temperature.
  • Core 1 is again rinsed by passage through tank 21 and then is subjected to a polishing. To effect this, it traverses an electrolysis tank 22 containing an 85 percent orthophosphoric acid bath. This bath is at the temperature of 17 C. and the current density is selected to be approximately 300 milliamperes per square centimeter
  • the core is activated at the time of its passage through electrolysis tank 23, and then it is rinsed in tank 24.
  • the activation bath of tank 23 is formed, preferably, of 30 percent sulfuric acid maintained at 50 C.
  • the action of the sulfuric acid may be augmented by passing core 1 later into a hath (not shown) containing 30 percent nitric acid held at 1 7 C.
  • the core emerging from treatment means 31 is at that time prepared for receiving a conductive deposit of copper, which is provided by means 32 containing, for example, two electrolysis tanks 25 and 26. in these two tanks, as well as in that hearing reference numeral 28, which will be described hereinafter, the electrolyte is circulated so as to cause only a very weak agitation.
  • Tanks 25 and 26 contain a copper-plating bath of 250 grams per liter of cuprous sulfate mixed with sulfuric acid. This bath is employed at a temperature below 40 C. with a current density of some tens of milliamperes per square centimeter. it is thus possible to cover core 1 with a copper layer of some thousands of angstroms of thickness.
  • deposition means 32 includes a gilding device (not shown) permitting the deposit of copper to be covered with a layer of gold of some thousands of angstroms.
  • the wire emerging from deposition means 32 passes through an electrolytic tank 27 containing an acid solution.
  • the wire traverses an electrolysis tank 28 containing a bath capable of depositing on such wire a layer of magnetic material.
  • This bath may be that which is described in French Pat. No. 1,438,564 and which provides for the deposition on a copper wire of an alloy of iron and nickel comprising about 18 percent of iron.
  • This ironnickel electrolyte permits obtaining suitable speeds of deposition without agitation and controlling almost perfectly the thickness of the deposit. Moreover, it has the advantage of giving to the deposit zero magnetostriction (at 18 percent of iron) and very low internal stresses. Nevertheless, this electrolyte does not tolerate large variations of potential along the wire without creating variations in the composition of the magnetic deposit along tank 28 and a composition gradient in the thickness. This disadvantage may be avoided by adapting the procedure described in French Pat. No. 1,533 ,398.
  • One such alloy of iron and nickel which is known comprises voids, that is to say crystalline gaps, which through their subsequent displacement in time modify the magnetic properties of the sheath.
  • the wire covered by its magnetic layer is introduced into an oven 29 which subjects the wire to annealing at a temperature of the order of 300 C., in certain circumstances in the presence of a magnetic field.
  • wire 7 consisting of core 1 covered with a magnetic layer passes between driving rollers 9 and 10 of device 8, which pushes the wire into device 11 for measuring its properties, then into cutting device 12.
  • the latter may be controlled by device 11 for cutting the wire when a defect is detected.
  • the core-supplying servomechanism supplies all of the force and energy required to maintain the core at a constant mid-sag level, to the device 8 pulling the core through the fabrication apparatus, the core virtually commences at the mid-bottom of the sag, and the only pull required of device 8 ahead of the fabrication apparatus is that required to lift the small length of core between the mid-bottom of the sag and the input of the fabrication apparatus.
  • the sag becomes a zero-tension reservoir of core for the processing apparatus.
  • Device 8 has only to overcome the residual friction imposed on the wire as it passes through the fluid-lubricated openings in the wall of the tanks.
  • the wire is pulled through fabrication apparatus 6 and pushed through measuring device 11.
  • This mode of fabrication in accordance with the invention is, as has been explained above, particularly important.
  • the position of driving device 8 is between device 11 and oven 29 which stabilizes by annealing.
  • Core 1 traverses the various tanks, which are sealed by means of plugs of synthetic material covering the openings provided in the opposed walls of these tanks.
  • plugs comprise two parts fitted opposite each other along surfaces at least partially plane, one of the two opposed plane parts being provided with a channel in which is engaged the wire.
  • the mechanical tension exercised on the wire by each of these plugs is only of the order of 30-60 milligrams. Therefore, the total tension required to pull the wire through the entire fabrication apparatus is between 0.7 and 1.4 grams.
  • said driving device comprises rollers between which passes the wire emerging from the fabrication apparatus.
  • Apparatus for continuously fabricating a wire having a core with a layer thereon, said core being initially provided as a roll comprising: a deposition device for continuously electrolyticly depositing said layer on said core as said core passes therethrough, first driving means for unwinding said core from said roll and inserting it into one end of said deposition device, wherein said first driving means maintains a sag in said core between said roll and said deposition device, said sag being maintained between predetermined maximum limits, and second driving means for pulling the coated core emerging from said deposition device with a very low tension.
  • the apparatus of claim 4 further including a testing device for testing the condition of said layer on the core of said completed wire, wherein the second driving means pushes the completed core through a testing device.
  • Apparatus for continuously fabricating a wire having a conductive core covered with a thin magnetic layer comprising, in combination: deposition means for receiving said core and for electrolyticly depositing said layer on said core as said core moves therethrough, supply means disposed at one end of said deposition means for supplying said core to said deposition means with substantially zero tension in said core, and driving means disposed at the other end of said deposition means for pulling the coated core emerging from said deposition means.
  • the apparatus of claim 7 further including a testing device for testing the condition of the layer on said core, and wherein said driving means pushes the coated core pulled from said deposition means through said testing device.
  • said supply means comprises a servomechanism for maintaining substantially zero tension in the core supplied to said deposition means.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Electroplating Methods And Accessories (AREA)
US24635A 1969-04-03 1970-04-01 Apparatus for obtaining wires for magnetic memories Expired - Lifetime US3669866A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6910210A FR2039555A5 (ru) 1969-04-03 1969-04-03

Publications (1)

Publication Number Publication Date
US3669866A true US3669866A (en) 1972-06-13

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ID=9031865

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Application Number Title Priority Date Filing Date
US24635A Expired - Lifetime US3669866A (en) 1969-04-03 1970-04-01 Apparatus for obtaining wires for magnetic memories

Country Status (6)

Country Link
US (1) US3669866A (ru)
BE (1) BE748285A (ru)
DE (1) DE2015219A1 (ru)
FR (1) FR2039555A5 (ru)
GB (1) GB1308678A (ru)
NL (1) NL165875C (ru)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947343A (en) * 1973-04-05 1976-03-30 International Standard Electric Corporation Electrotinning wire
US4038169A (en) * 1975-02-18 1977-07-26 National Plastics & Plating Supply Indexing system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2580801A (en) * 1946-04-10 1952-01-01 American Steel & Wire Co Method of making lustrous steel music wire
US3189532A (en) * 1960-05-19 1965-06-15 Ncr Co Process for making conductive-core magnetic device
US3287238A (en) * 1963-06-07 1966-11-22 Westinghouse Electric Corp Method of electropolishing tungsten wire
US3468783A (en) * 1965-03-08 1969-09-23 Republic Steel Corp Electroplating apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2580801A (en) * 1946-04-10 1952-01-01 American Steel & Wire Co Method of making lustrous steel music wire
US3189532A (en) * 1960-05-19 1965-06-15 Ncr Co Process for making conductive-core magnetic device
US3287238A (en) * 1963-06-07 1966-11-22 Westinghouse Electric Corp Method of electropolishing tungsten wire
US3468783A (en) * 1965-03-08 1969-09-23 Republic Steel Corp Electroplating apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947343A (en) * 1973-04-05 1976-03-30 International Standard Electric Corporation Electrotinning wire
US4038169A (en) * 1975-02-18 1977-07-26 National Plastics & Plating Supply Indexing system

Also Published As

Publication number Publication date
NL165875C (nl) 1981-05-15
BE748285A (fr) 1970-09-16
NL7003512A (ru) 1970-10-06
DE2015219A1 (de) 1970-10-15
NL165875B (nl) 1980-12-15
GB1308678A (en) 1973-02-21
FR2039555A5 (ru) 1971-01-15

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