US3189532A - Process for making conductive-core magnetic device - Google Patents

Process for making conductive-core magnetic device Download PDF

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Publication number
US3189532A
US3189532A US30362A US3036260A US3189532A US 3189532 A US3189532 A US 3189532A US 30362 A US30362 A US 30362A US 3036260 A US3036260 A US 3036260A US 3189532 A US3189532 A US 3189532A
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United States
Prior art keywords
wire
magnetic
iron
nickel
rod
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Expired - Lifetime
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US30362A
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English (en)
Inventor
Eric T K Chow
Harry L Watkins
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NCR Voyix Corp
National Cash Register Co
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NCR Corp
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Publication date
Priority to NL265014D priority Critical patent/NL265014A/xx
Application filed by NCR Corp filed Critical NCR Corp
Priority to US30362A priority patent/US3189532A/en
Priority to CH584961A priority patent/CH394299A/fr
Priority to GB17723/61A priority patent/GB905476A/en
Priority to BE603829A priority patent/BE603829A/fr
Priority to FR862181A priority patent/FR1302439A/fr
Application granted granted Critical
Publication of US3189532A publication Critical patent/US3189532A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/45—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of non-linear magnetic or dielectric devices
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/34—Pretreatment of metallic surfaces to be electroplated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/041—Printed circuit coils
    • H01F41/046—Printed circuit coils structurally combined with ferromagnetic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/24—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates from liquids
    • H01F41/26—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates from liquids using electric currents, e.g. electroplating
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/80—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using non-linear magnetic devices; using non-linear dielectric devices
    • H03K17/84—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using non-linear magnetic devices; using non-linear dielectric devices the devices being thin-film devices
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/4902—Electromagnet, transformer or inductor
    • Y10T29/49069—Data storage inductor or core

Definitions

  • the present invention is in the field of magnetic devices used, for example, as logical elements and/or informationstore devices in information-processing systems such as digital computers. More particularly, the invention relates to an improved process of producing slender rod-like bistable magnetic devices having as a core a small gauge stiti resilient non-magnetic electric conductor with an bistable. magnetic devices having as a core a small-gauge herent thin electroplated layer of iron-nickel composition, and the improved product produced by the process.
  • a first type of device of this nature comprises a resilient base of an electrically non-conductive material such as glass, with an oriented thin film of adherent bistable'magnetic materiaL'
  • a second type of such device comprises a resilient base formed of electrically conductive material such as a copper alloy wire and an electrolytically applied layer or film of bistable magnetic material which in the finished devices has been so applied or so disposed that there is an easy direction of magnetization which is oriented at an angle to the longitudinal axis of the device.
  • Orientation of the direction of easiest magnetization may be attained either by deposition of the magnetic material under the influence of a properly oriented magnetic field (as in Fisher et al., supra), or, in some cases, by mechanical operations such as by mechanically twisting the base wire before or after applicat on of the magnetic material, or by scratching or grooving the wire to provide spirally oriented deformations or alterations of the surface of the wire (as in Tsu, supra), and
  • a stiff resilient wire or fine-gauge rod of copper-beryllium alloy is thoroughly cleaned and rinsed in or with distilled water in accord with a special procedure, and is immediately electroplated in a special electrolytic bath to produce a thin film of bistable magnetic material comprising a high percentage' of iron and a minor proportion of nickel on the peripheral surface of the wire or fine-gauge rod, along the length thereof.
  • the preferred composition of magnetic material is about 97% to 98% iron and 3% to 2% nickel, by weight, although acceptable devices may be produced with the composition ranging from about 93% to 99% iron and the remainder nickel.
  • the switching time (time for reversal of stable state) of the material is shortened as the percentage of nickel in the composition is decreased.
  • the magnetic material may be and preferably is electroplated onto the wire while the latter I is disposed in a magnetic field so directed relative to the wire that the magnetic material is oriented along the Wire similar tovv that disclosed in copending application for US.
  • bistable magnetic rod-like devices of the general type forming the subject of the present invention met with indifferent and extremely variable results.
  • the magnetic characteristics of the material such as the coercivity and rectangularity" of the magnetization or hysteresis characteristic curve, varied considerably along the length of the wire or rod-like device. Since the devicesare intended to be used as long lengths and in large numbers in magnetic data-store matrices, rather than as very short individual portions, it
  • the magnetic characteristics be as uniform as possible throughout'the entire length of each rod-like device and from device to device among a large number of the devices.
  • Prior to the present invention no reasonable or acceptable degree of uniformity of the magnetic characteristics could be attained when electrically conductive wires or rod-like cores were used.
  • the previously acceptable rod-like bistable magnetic devices of the general character of those provided by the present invention were ofa type using a slender glass (non-conductor) filament as a base structure for supporting the magnetic material.
  • the devices using glass filament as a base are, however, relatively expensive because of the high cost of uniform filaments and due to the relatively complicated procedurere quired to produce acceptable and uniform magnetic devices.
  • the stiff resilient copper-beryllium wire base usedaccording to the present invention is relatively inexpensive and, when prepared and electroplated according to the invention, provides long lengths, of. magnetic 'rod-likex bistable' dc.-
  • a principal object of the invention is to provide an improved bistable magnetic rodlike device having a resilient rod-like electrically conductive base supporting a magnetic film or plate of excellent magnetic characteristics and improved uniformity, the magnetic material having either no easiest direction of magnetization (unoriented), or oriented to have an easiest direction of magnetization longitudinally of the conductive base.
  • Another object is to provide a simpler and less expensive process for production of slender rodlike devices having a thin film or layer of bistable magnetic material supported by a stiff resilient electrically conductive rod-like (wire) base.
  • Another object is to provide a stiff, resilient, very slender rod-like magnetic device having a surface layer of bistable magnetic material of uniform characteristics and which device is not brittle.
  • Another object of the present invention is to provide improvements in slender rod-like magnetic devices suit able for use as core-stock or cores for magnetic information-store or magnetic switch devices.
  • FIG. 1 is a view, greatly magnified, of a magnetic device comprising a stiff resilient conductive core and a thin adherent layer of magnetic material possessing a substantially rectangular magnetic hysteresis characteristic as plotted on Cartesian coordinates, the proportions being distorted to facilitate illustration and an intermediate portion of the device having been broken away;
  • FIG. 2 is a partly diagrammatic and grossly enlarged view depicting a length of a magnetic device such as is illustrated in FIG. 1, with exemplary windings units comprising plural-turns coils, encircling respective assigned portions of the device, with one of the windings units shown in the section and with an intermediate portion of the device broken out to facilitate illustration;
  • FIG. 3 is a procedure table outlining the major procedural steps of the process of producing the device depicted in FIG. 1.
  • the stiffresilient rod-like magnetic device is denoted generally by the ordinal 10, and comprises essentially a stiff resilient or spring-like filament or wire 20 of an alloy of copper and beryllium, and a very thin adherent film or coating 30 of magnetic material.
  • the rod-like alloy filament or wire. 20 may be of the type which has been heat-treated to give it stiffness and resilience.
  • the magnetic material which is electrolytically deposited on the wire in accord with a procedure and by means hereinafter described, i com posed essentially of a large major proportion of iron and a small minor proportion of nickel, and is such asv to possess a substantially rectangular magnetization hysteresis characteristic curve.
  • the preferred proportions of iron to nickel are of the order of 97 parts iron to 3 parts nickel, by weight; however, usable devices are producible with the percentage of iron in the range from 93 to 99 and the percentage of nickel in the range from 7 to 1, all by weight.
  • the relative percentages of iron and nickel may be varied by variation of the proportion of iron and nickel salts in the electrolyte bath in which the magnetic material is electro-plated onto the rod-like base.
  • the copper-beryllium rod or wire base is of fine gauge, that is, of the order of from five to fifty mils in maximum 4 cross-sectional dimension (diameter, in the case of a wire circular cross-section); and a preferred examplary form is a very springy straight wire of twelve mils diameter.
  • a preferred exemplary magnetic film or layer is one of 97 parts iron and 3 parts nickel by weight, of the order of 3000 angstroms thick (as computed by indirect meth- ,ods), and is possessed of a very rectangular hysteresis characteristic curve as plotted in Cartesian coordinates, and is preferably unoriented. While the rod-like base member may be as small as five mils or as large as fifty mils in diameter in special cases, and the magnetic coating as thick as 10000 angstroms or as thin as 500 angstroms for certain special applications, the above given preferred dimensions have been found to provide devices having sufficient strength and rigidity to permit handling without necessity for exercise of unusual care, and having excellent magnetic characteristics for use in data-store arrays and matrices.
  • a suitably long length of the coated rod-like device is used in conjunction with a series of spaced-apart coil units, such ascoil units 40 illustrated in FIG. 2 of the drawings.
  • the coil units 40 are there shown disposed on a magnetic device 10 which comprises a stiff resilient copperberyllium wire base 20' and an adherent thin layer or film of bistable magnetic material.
  • Each coil unit comprises a plurality of plural-turns single-layer solenoidcoils arranged in generally concentric relationship and encircling a respective small length or portion of the magnetic thin film 30.
  • An exemplary coil unit as shown comprises three superposed coils such as 40a, 40b, and 400, each of ten turns of conductor, and each having a respective pair of coil leads such as 40a'-40a, 40b- 40b", and 406-400".
  • the conductors are insulated, and
  • the coil units are in use spaced along the magnetic rod-like device 10 sufficiently far apart to obviate undesirable mutual magnetic interactions; and this spacing may alternatively be effected by winding the coil units on the rod-like magnetic device or, and preferably, by the coil units being disposed in arrays or matrices in coaxial relationship along bores in an embedment (not shown).
  • coil units are relatively fixed in coaxial disposition with respect to each other by the embedding compound and they and bores coaxial with the coil units and extending through the embedding material are of internal diameter suitable for easy insetrion of the magnetic rodlike devices into the bores and thrugh the coil units.
  • many coil units as may be desired are arranged or disposed in spaced-apart relationship along a magnetic rod-like device, in either of the described modes; and for example, the number of coil units arranged for cooperation with respective portions of a magnetic rod-like device may be forty, or more, or less. Each coil unit thus cooperates with its own respective portion of the long magnetic film.
  • Examplary ten-turn coils may be of the order of one sixteenth of an inch in length.
  • bistable magnetic film The general nature of the bistable magnetic film, the coils of the units, and the interactions therebetween are like or similar to those described and explained in copending application of Donal A. Meier, Serial No. 728,739, filed April 15, 1958, now abandoned, to which reference may be had forfurther details in respect to these matters.
  • the present invention provides and presents improvements over the'procedures and devices disclosed in the aid application Serial No.'728,739.
  • the preferred electrolyte plating bath and procedure for producing the improved device will next be disclosed and explained.
  • the copper-beryllium alloy wire Prior to being subjected to electroplating action in the electrolytic bath, the copper-beryllium alloy wire is subjected to a thorough cleaning in a suitable alkaline cleaning bath (step 1).
  • a suitable alkaline cleaning bath As an example, a solution of the commercially available product named Shipleys Alkaline Cleaner I (step 2).
  • the copper-beryllium base rod or wire is thoroughly rinsed with distilled water thinsurface layer of the, copper-beryllium alloy (step 3);
  • a tion made up from 290 grams of FcCl -4H O, 12 grams of NiCI -6H O and 238 grams of CaCl per liter of solution, with addition of dilute l-lCl. if necessary, to bring the pH to a value of 1001005.
  • Enough iron powder or iron wool to make certain that the solution is ferrous rather than ferric may be added to the electrolyte bath.
  • An acceptable procedure for effecting the electroplating is to progressively pass or draw the wire or rod" downwardly through a three-inch long zone of contact with the electrolyte at a speed of about five inches per minute, using a plating current of from 12 to 25 milliamperes, at room temperature.
  • the wire is connected to the current source as the cathode of the system.
  • the exposure time and current density may be varied somewhat, depending upon the thickness of plating desired, and the size of wire.
  • the preceding data relate to plating of an exemplary copper-beryllium wire of ten mils diameter. Analysis of the plating deposited on the exemplary wire indicates a content of approximately 97% iron and 3% nickel by weight, with permissible variation of +-3% in the iron content.
  • the switching time may be lowered by using a somewhat lower concentration of NiCl -tSH O in the electrolyte; for example, 8 to 10 grams per liter of solution. Using concentrations of the order of that just noted, switching times faster than 25 millimicroseconds are attainable.
  • the plated wire is thoroughly rinsed with water (step 6) and immediately dried as by means of an acetone bath or spray (step 7); and the dried device is then immediately given a protective coating to avoid oxidation or other degradation of the iron-nickel magnetic film or coat.
  • the protective coating may be applied by dipping the dried device in a suitable moisture proof self-curing resin; and satisfactory protection has been secured using a commercially available resin. As soon as the resin or other protective coating has cured or dried, the magnetic device is ready for association with coil units as a data-store unit element.
  • the rod-like devices are of the order of from about ten mils to as much as fifty mils in diameter (preferably about fifteen mils forthe usual informationstore or memory applications) it is seen that they also possess equally with the better-known glass-filament rod-' like magnetic devices the distinct and meritorious advan-' tages over toroidal and slotted tubular magnetic devices of much simpler winding, much greater packin'g'density (bits per unit of space in a memory device), much smaller driving energy and much faster operation.
  • the relatively higher cost and complicated and painstaking process of producing the similar glass-rod type of device is considered, the considerable advantages of the process and device of the present invention become apparent.
  • a process of producing a slender 'od-like bistable magnetic device'having a thin iron-nickel film-like coatingexhibiting a uniform substantially rectangular magnetic hysteresis characteristic throughout a long length of the device consisting essentially of: providing a long length of a stiff resilient copper-beryllium wire having a diameter of the order of 5 to mils to serve as the core of said magnetic device, cleaning said copper-beryllium wire in an alkaline cleaning solution, immediately rinsing the cleaned wire with distilled water,
  • each portion of the wire in the plating bath being chosen so as to produce on the wire an adherent uniform bistable magnetic layer having a thickness ranging from 500 to 10,000 angstroms and composed of from about 93% to about 99% iron and from about 7% to about 1% nickel over the surface of a long length of the wire.
  • a process according to claim 1 including thestep of providing a longitudinally oriented magnetic field in which the electroplating is accomplished, whereby to produce a corresponding orientation of an easy direction of magnetization of the magnetic plated onto the wire core. 3. A process according to claim 1, including the steps of providing a longitudinally oriented magnetic field in the region in whichthe electroplating is effected whereby to produce a longitudinally oriented magnetic layer, washing anddrying the resulting product, and applying an oxylayer,

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)
US30362A 1960-05-19 1960-05-19 Process for making conductive-core magnetic device Expired - Lifetime US3189532A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL265014D NL265014A (en, 2012) 1960-05-19
US30362A US3189532A (en) 1960-05-19 1960-05-19 Process for making conductive-core magnetic device
CH584961A CH394299A (fr) 1960-05-19 1961-05-15 Procédé d'obtention d'un dispositif magnétique
GB17723/61A GB905476A (en) 1960-05-19 1961-05-16 Process for making a magnetic device
BE603829A BE603829A (fr) 1960-05-19 1961-05-16 Procédé d'obtention d'un dispositif magnétique
FR862181A FR1302439A (fr) 1960-05-19 1961-05-18 Procédé d'obtention d'un dispositif magnétique

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BE (1) BE603829A (en, 2012)
CH (1) CH394299A (en, 2012)
GB (1) GB905476A (en, 2012)
NL (1) NL265014A (en, 2012)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3328270A (en) * 1963-07-20 1967-06-27 Toko Inc Method of manufacturing conductors having coatings of magnetic material partially deposited thereon
US3330631A (en) * 1961-12-12 1967-07-11 Ncr Co Magnetic data storage devices
US3441494A (en) * 1963-05-25 1969-04-29 Kokusai Denshin Denwa Co Ltd Apparatus to deposit a ferromagnetic film on a conductive wire
US3468765A (en) * 1966-08-04 1969-09-23 Nasa Method of plating copper on aluminum
US3489660A (en) * 1966-01-03 1970-01-13 Honeywell Inc Electroplating bath and method
US3639217A (en) * 1969-06-11 1972-02-01 Western Electric Co Method of producing in seriatim separate coatings on a conductor
US3642602A (en) * 1969-04-11 1972-02-15 Licentia Gmbh Electroplating apparatus
US3645857A (en) * 1969-05-28 1972-02-29 Ferroxcube Corp Method of making plated wire memory element
US3669866A (en) * 1969-04-03 1972-06-13 Honeywell Bull Soc Ind Apparatus for obtaining wires for magnetic memories
US3920409A (en) * 1968-06-19 1975-11-18 Hitachi Ltd Plated ferromagnetic wire for wire memory
US3972786A (en) * 1974-06-28 1976-08-03 Ampex Corporation Mechanically enhanced magnetic memory
US4028064A (en) * 1976-02-17 1977-06-07 Texas Instruments Incorporated Beryllium copper plating process
US4048042A (en) * 1976-01-05 1977-09-13 Hooker Chemicals & Plastics Corporation Apparatus for electroplating plastic insulating cable sheaths
US4069110A (en) * 1976-02-17 1978-01-17 Texas Instruments Incorporated Treatment of beryllium copper surface prior to electroplating

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1791642A (en) * 1926-05-29 1931-02-10 Schulte Louis Process of plating aluminum
US1965399A (en) * 1929-06-25 1934-07-03 Western Electric Co Method of and apparatus for electro-chemically producing articles
US2507400A (en) * 1943-08-02 1950-05-09 Sk Wellman Co Method of electroplating with iron and cobalt
US2619454A (en) * 1945-08-30 1952-11-25 Brush Dev Co Method of manufacturing a magnetic recording medium by electrodeposition
US2671950A (en) * 1950-03-09 1954-03-16 Sukacev Lev Method of constructing thermopiles
US2729601A (en) * 1953-04-24 1956-01-03 John G Beach Electroplating on beryllium
US2877540A (en) * 1956-03-22 1959-03-17 Ncr Co Method of making magnetic data storage devices
US2943956A (en) * 1952-12-18 1960-07-05 Automated Circuits Inc Printed electrical circuits and method of making the same
US2945217A (en) * 1958-10-01 1960-07-12 Ncr Co Magnetic data storage devices
US3039891A (en) * 1957-11-14 1962-06-19 Sperry Rand Corp Method of treating ni-fe thin metal film of body of magnetic material by subjecting to heat treatment in a magnetic field oriented transversely to the preferred axis of magnetization
US3047423A (en) * 1958-12-17 1962-07-31 Ibm Isotropic thin magnetic film

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1791642A (en) * 1926-05-29 1931-02-10 Schulte Louis Process of plating aluminum
US1965399A (en) * 1929-06-25 1934-07-03 Western Electric Co Method of and apparatus for electro-chemically producing articles
US2507400A (en) * 1943-08-02 1950-05-09 Sk Wellman Co Method of electroplating with iron and cobalt
US2619454A (en) * 1945-08-30 1952-11-25 Brush Dev Co Method of manufacturing a magnetic recording medium by electrodeposition
US2671950A (en) * 1950-03-09 1954-03-16 Sukacev Lev Method of constructing thermopiles
US2943956A (en) * 1952-12-18 1960-07-05 Automated Circuits Inc Printed electrical circuits and method of making the same
US2729601A (en) * 1953-04-24 1956-01-03 John G Beach Electroplating on beryllium
US2877540A (en) * 1956-03-22 1959-03-17 Ncr Co Method of making magnetic data storage devices
US2878463A (en) * 1956-03-22 1959-03-17 Ncr Co Magnetic data storage devices
US3039891A (en) * 1957-11-14 1962-06-19 Sperry Rand Corp Method of treating ni-fe thin metal film of body of magnetic material by subjecting to heat treatment in a magnetic field oriented transversely to the preferred axis of magnetization
US2945217A (en) * 1958-10-01 1960-07-12 Ncr Co Magnetic data storage devices
US3047423A (en) * 1958-12-17 1962-07-31 Ibm Isotropic thin magnetic film

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3330631A (en) * 1961-12-12 1967-07-11 Ncr Co Magnetic data storage devices
US3441494A (en) * 1963-05-25 1969-04-29 Kokusai Denshin Denwa Co Ltd Apparatus to deposit a ferromagnetic film on a conductive wire
US3328270A (en) * 1963-07-20 1967-06-27 Toko Inc Method of manufacturing conductors having coatings of magnetic material partially deposited thereon
US3489660A (en) * 1966-01-03 1970-01-13 Honeywell Inc Electroplating bath and method
US3468765A (en) * 1966-08-04 1969-09-23 Nasa Method of plating copper on aluminum
US3920409A (en) * 1968-06-19 1975-11-18 Hitachi Ltd Plated ferromagnetic wire for wire memory
US3669866A (en) * 1969-04-03 1972-06-13 Honeywell Bull Soc Ind Apparatus for obtaining wires for magnetic memories
US3642602A (en) * 1969-04-11 1972-02-15 Licentia Gmbh Electroplating apparatus
US3645857A (en) * 1969-05-28 1972-02-29 Ferroxcube Corp Method of making plated wire memory element
US3639217A (en) * 1969-06-11 1972-02-01 Western Electric Co Method of producing in seriatim separate coatings on a conductor
US3972786A (en) * 1974-06-28 1976-08-03 Ampex Corporation Mechanically enhanced magnetic memory
US4048042A (en) * 1976-01-05 1977-09-13 Hooker Chemicals & Plastics Corporation Apparatus for electroplating plastic insulating cable sheaths
US4028064A (en) * 1976-02-17 1977-06-07 Texas Instruments Incorporated Beryllium copper plating process
US4069110A (en) * 1976-02-17 1978-01-17 Texas Instruments Incorporated Treatment of beryllium copper surface prior to electroplating

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CH394299A (fr) 1965-06-30
BE603829A (fr) 1961-11-01
GB905476A (en) 1962-09-12
NL265014A (en, 2012)

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