US3032485A - Electrolytic bath for use in electrodeposition of ferromagnetic compositions - Google Patents

Electrolytic bath for use in electrodeposition of ferromagnetic compositions Download PDF

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US3032485A
US3032485A US764522A US76452258A US3032485A US 3032485 A US3032485 A US 3032485A US 764522 A US764522 A US 764522A US 76452258 A US76452258 A US 76452258A US 3032485 A US3032485 A US 3032485A
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concentration
bath
per liter
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ions
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US764522A
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Tsu Ignatius
Robert D Fisher
Harsukh J Modi
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NCR Voyix Corp
National Cash Register Co
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NCR Corp
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Priority to US764522A priority patent/US3032485A/en
Priority to US827412A priority patent/US2945217A/en
Priority to US773843A priority patent/US3032486A/en
Priority to US803585A priority patent/US3031386A/en
Priority to DEN17319A priority patent/DE1216647B/en
Priority to FR806358A priority patent/FR1241315A/en
Priority to GB33301/59A priority patent/GB896263A/en
Priority to CH7910659A priority patent/CH393026A/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
    • 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
    • H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
    • H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
    • H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
    • H01F10/14—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing iron or nickel
    • 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
    • H01F41/20—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 by evaporation
    • 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
    • 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

  • This invention relates generally to the manufacture of ferromagnetic memory elements such as wires, bobbin and torroidal shaped cores, and the like, for use in present day electronic computers and data processors, and more specifically relates to new and improved electrolytic baths for use in the manufacturing of such elements which possess greatly improved magnetic characteristics than heretofore possible.
  • the magnetic memory elements be relatively small in size, require negligible expenditure of time and effort in order to be electrically connected in circuit, be physically sturdy and economical to manufacture utilizing mass production techniques, possess relatively high magnetic remanence and relatively low magnetic coercivity properties, be readily adaptable to fast switching operations measured in fractions of microseconds, and additionally, possess substantially rectangular hysteresis characteristics resulting in substantially high signal-to-noise ratios.
  • the primary object of the present invention is to devise a new and improved aqueous electrolytic bath for utilization in the process of electrodeposition of a ferromagnetic coating onto an electrically conductive carrier whereby magnetic memory elements are produced which possess all of the above-mentioned characteristics.
  • such a bath includes as essential constituents iron ions in a concentration in the range of .7 to 16 grams per liter, nickel ions in a concentration in the range of 3 to grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent.
  • the plating bath preferably contains simple salts of iron, nickel, and molybdenum in complexed form wherein iron is initially added as either a ferrous salt such as ferrous chloride (FeCl -4H O) or as a ferric salt such as ferric chloride (FeCl -6H O).
  • a ferrous salt such as ferrous chloride (FeCl -4H O)
  • a ferric salt such as ferric chloride (FeCl -6H O).
  • the chlorides of iron are preferred, however, any salt of iron may be used provided the anion does not cause precipitation in the overall system.
  • Nickel is preferably added to the plating bath as a simple nickel chloride salt (NiCl -6H O). However, following the addition, several nickel species may appear as free nickel ions, nickel amine complexes, nickel chelates, nickel addition agent complexes, and nickel complexes with other added metal salts. Nickel may be added in the form of other salts, as an illustrative example nickel sulfate (NiSO -6H O) provided precipitation does not occur. The form in which nickel exists in a given system depends upon many factors such as the nickel concentration, pH, ammonium ion concentration, chelating agent concentration, iron concentration, addition agent concentration, complexing agent concentration, temperature, and concentration of other metal salts.
  • the nickel species in the bulk of the solution are not necessarily the same as the nickel species occurring in the so-called double layer at the cathode. It is the latter species from which deposition actually occurs and which is of major importance in determining the magnetic properties of the deposit.
  • Molybdenum ing bath and it is preferably added to the bath in the form of sodium molybdate (Na MoO -2H O).
  • molybdenum may be added in the form of other compounds provided they cause no precipitation in the overall system.
  • molybdenum may be added in the form of molybdic acid (H2MOO4), phosphomolybdic acid (P O 24MoO -XH O), potassium molybdate ammonium molybdate [(NH MoO -2H O], ammonium heptamolybdate [(NH4)6M0I1O24'4H2O], molybdenum trioxide (M00 etc.
  • the concentration of molybdenum (V1) is critical and the optimum concentration depends upon the overall conditionof the system.
  • the molybdate concentration is excessive, for example an ionic concentration thereof in excess of approximately 2 grams per litter, little or no deposit results.
  • Molybdate in such bath has been found to effect the plating bath similarly to addition agents in that, for example, molybdate lowers the discharge potential of the plating process and is believed to lcjo$plex with the iron and/ or nickel constituents in the Due to the fact that even the hydroxides of iron begin to precipitate even in acid solutions, it is desirable to utilize a complexing agent to maintain the plating bath in solution.
  • the preferred complexing agent for this purpose is ammonium citrate [(NH HC H O
  • any material which forms a complex with the iron ions of sufiicient solubility and stability is a suitable complexing agent.
  • complexing agents which may be used with equal success are sodium citrate and potassium citrate (K C H5Oq2H2O).
  • Various acids such as citric acid (H3C6H507'XH2O), glycolic acid (C H O -XH O), aspartic acid (C H O N-XH O), and the sodium salt of ethylenediaminetetraacetic acid etc. may be used, provided there is no breakdown of the complex for example anodic oxidation during the plating process which might form oxidation. products at the anode thus modifying the plating bath and, consequently, modifying the magnetic properties of the cathode deposit.
  • the essential function of the complexing agent is to provide a (VI) has an appreciable effect in the platsoluble reservoir of iron, nickel, and/or molybdenum (VI) ions from which are formed, through dynamic equilibria, the species from which the deposition actually occurs.
  • the complexing agent must be of a concentration in the bath to supply the iron, nickel and molybdenum (VI) species rapidly enough through equilibria to provide a suitable concentration of species for deposition, and yet, not rapidly enough to form an appreciable amount of other species whose solubility limits are exceeded to cause precipitation in the bath.
  • the complexing agent partially determines the concentration of the reactive species present in the plating bath, the choice of the particular complexing agent has an effect on the composition and structure, and consequently the magnetic properties of the cathode deposit, which influence may be modified by the other constituents of the plating system.
  • Ammonia is preferably added to the plating bath in the form of ammonium hydroxide (NH OH) to control the pH thereof. Even though it is possible to utilize the plating baths, in accordance with the present invention, to prepare cathode deposits having magnetic properties without the addition of ammonia, it is desirable that the baths have a pH within the range of 7.5 to 9.5, preferably 8.5. Ammonia, aside from controlling the pH, is believed to modify the bath through complex formations and to be part of the reservoir complexes from which deposition occurs.
  • NH OH ammonium hydroxide
  • Amines have been found to be less suitable than ammonia for controlling the bath pH, however, non-complexing bases such as sodium hydroxide (NaOI-I) and potassium hydroxide (KOH) may be used with equal success, provided the amounts added to the citrate baths are of insuflicient quantity to cause precipitation therein.
  • NaOI-I sodium hydroxide
  • KOH potassium hydroxide
  • the ammonia concentration is depleted due to evaporation and, consequently, it is necessary to continuously replenish the bath with ammonium hydroxide to maintain the pH thereof at the preferred 8.5 value.
  • Ammonium is preferably added to the plating bath in the form of ammonium chloride (NH Cl).
  • NH Cl ammonium chloride
  • ammonium ions exert a common ion effect on the ammonia complexes, they are believed to influence the concentration of the ionic species present in the system and thereby effect the structure and magnetic properties of the electrodeposit.
  • Other ammonium salts i.e. ammonium sulfate [(NH SO may be used with equal success provided precipitation does not occur in the bath as a result of the addition.
  • the temperature is then adjusted to a value in the range of 80 C. to 95 C., preferably 90 C., even though the bath may successfully be operated at ordinary room temperature.
  • the bath is then introduced into a conventional rubber-lined steel plating tank, or an equivalent inert container.
  • the carrier, onto which the deposit is to be formed may be of any of a variety of non-magnetic electrically conductive materials such as alloys of copper, aluminum, brass, bronze, etc.
  • the carrier may even be of such materials as glass, plastic, or ceramic, assuming of course that it has previously been provided with a suitable electrically conductive skin covering in a well-known manner.
  • the carrier be a Phosphor-bronze wire having a diameter of approximately 9 mils. It is, of course, necessary that the metallic carrier be cleaned before plating through the use of the conventional alkaline-acidwater methods which are well known in the plating industry.
  • the carrier be exposed as a cathode in the bath for only a short period of time, i.e. from approximately 30 seconds to 3 minutes, preferably in the order of 2 minutes depending upon, of course, the cathode current density to be used in the plating process.
  • the process is made a continuous one whereby the carrier is moved through the bath at a constant speed, by any well known means, with electrical contact at all times maintained with the carrier to supply current thereto.
  • the carrier is preferably centrally encompassed at all times while in the bath by a helicalshaped anode having a coil diameter of approximately one inch and composed of an electrically conductive wire of approximately 50 mils in diameter.
  • anode material may not arbitrarily be made, however, iron-nickel, and iron-nickel-molybdenum may successfully be used provided the anode is bagged in a conventional manner to prevent sludge formations at the anode from entering the bath solution.
  • One of the important factors associated with the choice of anode material is oxidation in the system. When using bath I, ferrous ions are converted to ferric ions due to oxidation of the bath and high concentration of ferric ions therein is to be avoided. Inert anodes such as platinum, or the like, may be used provided they do not lead to excessive oxidation of the system.
  • molybdenum anodes are preferred as they do not have to be bagged and tend to replenish the bath with molybdenum.
  • molybdenum anode it is necessary to continually add molybdate solution to the bath in order to maintain the molybdate concentration constant at the desired value.
  • nickel and iron solutions be continually added to the bath to also maintain the concentrations thereof constant at their respective values during the plating process.
  • the current density involved in the deposition process is not critical and may range, for example, from 150 to 500, preferably 250, amperes per square foot of carrier surface area exposed in bath I and from 200 to 1000, preferably 250, amperes per square foot of carrier surface area exposed in bath II.
  • the current density primarily determines the rate of deposition of the metallic ions onto the cathode. This affects the rate of diffusion into the cathode film which influences the amount of depositing species which must be in equilibrium with the reservoir complexes. Consequently, the bath and current density must be compatible and the current density cannot arbitrarily be chosen. For example, any addition agents in the system are less effective at relatively high current densities and, consequently, larger quantities must be used.
  • the current density is one of the prime factors which determine the structure of the deposit, it is generally necessary to modify the plating system to permit the use of a specific current density.
  • the ferromagnetic element On emergence from the plating bath, the ferromagnetic element is rinsed and dried and is then ready to be operated as a coincident current twistor type of data storage device in the following manner as fully described in the aforementioned copending application:
  • the core along with the ferromagnetic coating, is simultaneously stretched and twisted and the ends thereof are thereafter held in a fixed position.
  • the easy direction of magnetization of the coating is oriented from a direction substantially parallel to the longitudinal axis of the core to one of substantially helical configuration about the body of the core and throughout its length as the threads of a screw.
  • Such a ferromagnetic coating has been found to possess a substantially high positive and negative magnetic remanence and substantially rectangular hysteresis characteristic. Consequently, selected length portions of the coating, in the direction of twist, are allowed to attain one or other of the two stable states, namely, a residual positive or negative remanent induction.
  • a magnetic field along the direction of twist of :H oersteds switches the length portions from one state to another, whereas a field of '-H/ 2 oersteds produces only negligible changes in the remanent induction.
  • a plurality of similar coils of say 20 turns each, are separately wound about the coated wire and are positioned in a spaced side-by-side relationship with respect to one another to define a corresponding plurality of helical-path length portions of ferromagnetic material.
  • Storage of binary information in a select length portion of coating is accomplished by sending a current impulse equal in magnitude to (1 into the conductive wire of the common core and simultaneously sending a current impulse equal in magnitude to (1;) into the select coil in such directions that the vector summation of the magnetic field produced by the two coincident currents are equal in magnitude to 1-H oersteds and is oriented in the same direction as the twist or easy direction of magnetization of the coating.
  • the core is preferably pulsed to individually develop a magnetic field of :H oersteds in the opposite direction from the magnetic field developed during storage of the function.
  • an electrical signal is or is not available between the ends of the corresponding coil according to whether the binary information 1 or 0, respectively, has been established in the particular length section of the coating as represented by its remanent state.
  • Ferrous Ferric Bath Bath Degrees of twist/inch of storage element length 145 l0. Approx. one-half coincident current in core for storage of binary data 200 1%.... 75 ma. Approx. one-half coincident current in coil for storage of binary data 100 ma 50 ma. Full coincident current in coil for reading of stored binary data W 500 rna. 500 ma. Voltage output across ends of core during reading of binary 1 data- 70 my-.. 75 mv. Signal to noise ratio. 5 Minimum switching ti e- Less than Less than 0.3 micro 0.3 micro sec. sec. Diameter of carrier Approx. Approx.
  • Ferrous Ferric Bath Bath Degrees of twist/inch of storage element length 360 10 Approx. one-half coincident current in core for storage of binary data ma... 60 Approx. one-half coincident current in coil for storage of binary data ma. 55 40 Full coincident current in coil for reading of stored binary data ma.. 300 300 Voltage output across ends of core during reading of binary 1 data m 70 7 Signal to noise ratio 5 75 Minimum switching time fil sec..- 3 3 Diameter of carrier mils 3 3 In each of the storage elements, the coercivity is less than 2 oersteds and the squareness of the hysteresis loop approximately .99.
  • new and improved ferromagnetic data storage elements are fabricated by electroplating a ferromagnetic coating onto an electrically conductive carrier.
  • Such elements in addition to possessing greatly improved magnetic characteristics than heretofore possible, are readily adaptable to be fabricated by mass production techniques thereby maintaining the cost thereof at a minimum, and are ideally suited for incorporation in present day electronic data processors and computers.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sutficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH of approximately 8.5 and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately grams per liter, molybdenum (VI) in a concentration approximately .4 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sufiicient concentration to prevent precipitation of ferrous, nickel, and molybdenum ions.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdate complexes and being of sufiicient concentration to prevent precipitation of said ferrous, nickel, and molybdate ions, said bath having a pH of approximately 8.5.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent consisting of citrate ions in a concentration approximately 104 grams per liter, said bath having a pH of approximately 8.5.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, ammonium ions in a concentration approximately 17 grams per liter, and a complexing agent consisting of citrate ions in a concentration approximately 104 grams per liter, said bath having a pH of approximately 8.5 by the addition of ammonium hydroxide.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of sufiicient concentration to prevent precipitation of ferric, nickel, and. molybdenum (VI) Ions.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH of approximately 8.5 and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdenum (VI) in a concentration approximately .4 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of sufilcient concentration to prevent precipitation of ferric, nickel, and molybdenum ions.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdate complexes and being of sufficient concentration to prevent precipitation of said ferric, nickel, and molybdate ions, said bath having a pH of approximately 8.5.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent consisting of citrate ions in a concentration approximately 42 grams per liter, said bath having a pH of approximately 8.5.
  • An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, ammonium ions in a concentration approximately 17 grams per liter, and a complexing agent consisting of citrate ions in a concentration approximately 42 grams per liter, said bath having a pH .of approximately 8.5 by the addition of ammonium hydroxide.
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents iron ions in a concentration in the range of .7 to 16 grams per liter, nickel ions in a concentration in the range of 3 to grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble iron, nickel, and molybdenum complexes and being of sufficient concentration to prevent precipitation of iron, nickel, and molybdenum ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sufficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier,
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent consisting of citrate ions in a concentration of 88 to 113 grams per liter; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 12 to 34 grams per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and 'being of sufficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aquous electrolytic bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 88 to 113 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferro magnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 12 to 34 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 88 to 113 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferrous chloride, nickel chloride,
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per lited, molybdenum (VI) in a concentration in the range of .l to 1 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of suflicient concentration to prevent precipitation of ferric, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to eifect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent consisting of citrate ions in a concentration of 33 to 104 grams per liter; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish in said coating an easy direction of magnetization which is oriented at an angle
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of suflicient concentration to prevent precipitation of ferric, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufiicient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdate complexes and being of sufficient concentration to prevent precipitation of said ferric, nickel, and molybdate ions, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time suflicient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufiicient to effect the deposition thereon of a ferro magnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount su
  • a process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .l to 1 gram per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time suificient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said
  • a process for fabricating magnetic computing devices comprising the steps of providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 t0 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 'grams per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5 by the addition of ammonium hydroxide; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to efiect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly

Description

United States Patent Office 3,032,485 Patented May 1, 1962 3,032,485 ELECTROLYTIQ BATH FOR USE IN ELEC- TRODEPGSITIGN F FERROMAGNETEC COMPOSlTl0N Ignatius Tsu, Jerome S. Sallo, and Robert D. Fisher, Dayton, Ohio, and Harsnkh J. Modi, West Lafayette, Ind., assignors to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland No Drawing. Filed Oct. 1, 1958, Ser. No. 764,522 25 Claims. (Cl. 204-43) This invention relates generally to the manufacture of ferromagnetic memory elements such as wires, bobbin and torroidal shaped cores, and the like, for use in present day electronic computers and data processors, and more specifically relates to new and improved electrolytic baths for use in the manufacturing of such elements which possess greatly improved magnetic characteristics than heretofore possible.
In most electronic computer and data processor applications, it is generally highly desirable that the magnetic memory elements be relatively small in size, require negligible expenditure of time and effort in order to be electrically connected in circuit, be physically sturdy and economical to manufacture utilizing mass production techniques, possess relatively high magnetic remanence and relatively low magnetic coercivity properties, be readily adaptable to fast switching operations measured in fractions of microseconds, and additionally, possess substantially rectangular hysteresis characteristics resulting in substantially high signal-to-noise ratios.
Various attempts have heretofore been made to produce such magnetic memory elements for information storage purposes by electroplating an electrically conductive carrier with a relatively thin coating of an alloy having magnetic properties. Even though present day electroplating techniques possess practically unlimited potentialities in the manufacture of such elements, to date however, to the knowledge of applicants there is yet to be produced thereby any memory element which possesses all of the above-mentioned characteristics.
Consequently, the primary object of the present invention is to devise a new and improved aqueous electrolytic bath for utilization in the process of electrodeposition of a ferromagnetic coating onto an electrically conductive carrier whereby magnetic memory elements are produced which possess all of the above-mentioned characteristics.
Briefly, in accordance with the present invention, such a bath includes as essential constituents iron ions in a concentration in the range of .7 to 16 grams per liter, nickel ions in a concentration in the range of 3 to grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent.
More specifically, the plating bath preferably contains simple salts of iron, nickel, and molybdenum in complexed form wherein iron is initially added as either a ferrous salt such as ferrous chloride (FeCl -4H O) or as a ferric salt such as ferric chloride (FeCl -6H O). From the standpoint of economic availability, the chlorides of iron are preferred, however, any salt of iron may be used provided the anion does not cause precipitation in the overall system.
Nickel is preferably added to the plating bath as a simple nickel chloride salt (NiCl -6H O). However, following the addition, several nickel species may appear as free nickel ions, nickel amine complexes, nickel chelates, nickel addition agent complexes, and nickel complexes with other added metal salts. Nickel may be added in the form of other salts, as an illustrative example nickel sulfate (NiSO -6H O) provided precipitation does not occur. The form in which nickel exists in a given system depends upon many factors such as the nickel concentration, pH, ammonium ion concentration, chelating agent concentration, iron concentration, addition agent concentration, complexing agent concentration, temperature, and concentration of other metal salts. It is by varying these factors that a wide range of magnetic properties is obtained. In addition, the nickel species in the bulk of the solution are not necessarily the same as the nickel species occurring in the so-called double layer at the cathode. It is the latter species from which deposition actually occurs and which is of major importance in determining the magnetic properties of the deposit.
Molybdenum ing bath and it is preferably added to the bath in the form of sodium molybdate (Na MoO -2H O). However, molybdenum may be added in the form of other compounds provided they cause no precipitation in the overall system. For example, molybdenum may be added in the form of molybdic acid (H2MOO4), phosphomolybdic acid (P O 24MoO -XH O), potassium molybdate ammonium molybdate [(NH MoO -2H O], ammonium heptamolybdate [(NH4)6M0I1O24'4H2O], molybdenum trioxide (M00 etc. However, the concentration of molybdenum (V1) is critical and the optimum concentration depends upon the overall conditionof the system. In fact, in the preferred bath if the molybdate concentration is excessive, for example an ionic concentration thereof in excess of approximately 2 grams per litter, little or no deposit results. Molybdate in such bath has been found to effect the plating bath similarly to addition agents in that, for example, molybdate lowers the discharge potential of the plating process and is believed to lcjo$plex with the iron and/ or nickel constituents in the Due to the fact that even the hydroxides of iron begin to precipitate even in acid solutions, it is desirable to utilize a complexing agent to maintain the plating bath in solution. The preferred complexing agent for this purpose is ammonium citrate [(NH HC H O However, any material which forms a complex with the iron ions of sufiicient solubility and stability is a suitable complexing agent. For example, complexing agents which may be used with equal success are sodium citrate and potassium citrate (K C H5Oq2H2O). Various acids such as citric acid (H3C6H507'XH2O), glycolic acid (C H O -XH O), aspartic acid (C H O N-XH O), and the sodium salt of ethylenediaminetetraacetic acid etc. may be used, provided there is no breakdown of the complex for example anodic oxidation during the plating process which might form oxidation. products at the anode thus modifying the plating bath and, consequently, modifying the magnetic properties of the cathode deposit.
In the present invention, it is believed that the essential function of the complexing agent is to provide a (VI) has an appreciable effect in the platsoluble reservoir of iron, nickel, and/or molybdenum (VI) ions from which are formed, through dynamic equilibria, the species from which the deposition actually occurs. The complexing agent must be of a concentration in the bath to supply the iron, nickel and molybdenum (VI) species rapidly enough through equilibria to provide a suitable concentration of species for deposition, and yet, not rapidly enough to form an appreciable amount of other species whose solubility limits are exceeded to cause precipitation in the bath. Since the complexing agent partially determines the concentration of the reactive species present in the plating bath, the choice of the particular complexing agent has an effect on the composition and structure, and consequently the magnetic properties of the cathode deposit, which influence may be modified by the other constituents of the plating system. In the preferred ferrous plating bath, it is desirable that a minimum molar ratio of l to 1 be maintained between the relative citrate and ferrous ion concentrations.
Ammonia is preferably added to the plating bath in the form of ammonium hydroxide (NH OH) to control the pH thereof. Even though it is possible to utilize the plating baths, in accordance with the present invention, to prepare cathode deposits having magnetic properties without the addition of ammonia, it is desirable that the baths have a pH within the range of 7.5 to 9.5, preferably 8.5. Ammonia, aside from controlling the pH, is believed to modify the bath through complex formations and to be part of the reservoir complexes from which deposition occurs. Amines have been found to be less suitable than ammonia for controlling the bath pH, however, non-complexing bases such as sodium hydroxide (NaOI-I) and potassium hydroxide (KOH) may be used with equal success, provided the amounts added to the citrate baths are of insuflicient quantity to cause precipitation therein. As the plating bath is operated within a temperature range of 80 C. to 95 0., preferably 90 C., the ammonia concentration is depleted due to evaporation and, consequently, it is necessary to continuously replenish the bath with ammonium hydroxide to maintain the pH thereof at the preferred 8.5 value.
Ammonium is preferably added to the plating bath in the form of ammonium chloride (NH Cl). As the ammonium ions exert a common ion effect on the ammonia complexes, they are believed to influence the concentration of the ionic species present in the system and thereby effect the structure and magnetic properties of the electrodeposit. Other ammonium salts i.e. ammonium sulfate [(NH SO may be used with equal success provided precipitation does not occur in the bath as a result of the addition.
Shown below in charts I and II, are two forms of new and improved aqueous electrolytic baths having preferred constituent concentrations in accordance with the teachings of the present invention, for use in the process of deposition of an iron-nickel-molybdenum coating on an electrically conductive carrier, in which process the carrier is subjected as a cathode to electrolytic action in the bath, during which the coating formed thereon possesses greatly improved magnetic characteristics. It is to be noted that in the upper half of each chart, is given the concentration of each compound in the actual bath measured in grams per liter of aqueous solution; in the lower half of each chart, is the concentration given in grams per liter of aqueous solution of each constituent present in solution as contributed by each compound. In each instance, the minimum, optimum, and maximum concentrations for each constituent is given in tabular form. It is to be understood of course that the upper and lower concentration limits of each compound and constituent of the bath are not critical in that they specifically define limits above and below which is a definite zone of demarcation of all useful magnetic properties possessed by the cathode deposit.
Plating Bath Compounds Mini- Opti- Maximum mum mum Ferrous Chloride (FeCl2-4H2O) 45 50 55 Nickel Chloride (NlCl2-6H2O) 10 20 40 Sodium Molybdate ENazMoOr-ZHzO) .5 1 3 Ammonium Citrate (N H4) 2HC6H5O7] Ammonium Chloride (N HiCl) 35 50 100 Plating Bath Constituents Mini- Opti- Maximum mum mum Ferrous Ion Concentration 12 14 16 Nickel Ion Concentration- 3 5 10 Molybdenum (VI) Concentr 1 .4 1 Citrate Ion Concentration 88 104 113 Ammonium Ion Concentration 12 17 34 Plating Bath Compounds Mini- Opti- Maximum mum mum Ferric Chloride (Ft-101361120) 4 6 15 Nickel Chloride (NiClz-fiHzO) 10 20 40 Sodium Molybdate iNazMoOi-2Hz0) .5 1 3 Ammonium Citrate (N HO2HCGHEO1] 4O 50 125 Ammonium Chloride (N H401) 25 5O 75 Plating Bath Constituents Mini- Opti- Maximum mum mum Ferric Ion Concentration 7 1 3 Nickel Ion Concentration 3 5 10 Molybdenum (VI) Concentration 1 .4 1 Citrate Ion Concentration 33 42 104 Ammonium Ion Concentration-.- 8 17 25 Even though the new and improved aqueous electrolytic baths, just described, find utility in any of the numerous present day electroplating process, a preferred process will be described utilizing the baths of the present invention whereby magnetic data storage devices of the twistor type, such as that shown and described in copending application Serial No. 696,987, by J. R. Anderson, et al., filed November 18, 1957, and assigned to the present assignee, are fabricated and exhibit improved magnetic characteristics than heretofore possible.
After the electrolytic bath has been prepared, either I or II, and the pH adjusted to a value in the range of 7.5 to 9.5, preferably 8.5, the temperature is then adjusted to a value in the range of 80 C. to 95 C., preferably 90 C., even though the bath may successfully be operated at ordinary room temperature. The bath is then introduced into a conventional rubber-lined steel plating tank, or an equivalent inert container. The carrier, onto which the deposit is to be formed, may be of any of a variety of non-magnetic electrically conductive materials such as alloys of copper, aluminum, brass, bronze, etc. In fact the carrier may even be of such materials as glass, plastic, or ceramic, assuming of course that it has previously been provided with a suitable electrically conductive skin covering in a well-known manner. However, in the fabrication of the twistor types of bistable magnetic data storage devices, as disclosed in the aforementioned copending application, it is preferred that the carrier be a Phosphor-bronze wire having a diameter of approximately 9 mils. It is, of course, necessary that the metallic carrier be cleaned before plating through the use of the conventional alkaline-acidwater methods which are well known in the plating industry.
In the twistor type of device it is desirable to secure a relatively thin deposit on the carrier in the order of one ten-thousandth of an inch so as to maintain eddy current losses therein at a minimum during operation of the device, and yet be thick enough to insure adequate output and not fracture when torsional stresses are applied thereto as described in the copending application. Consequently, it is desirable that the carrier be exposed as a cathode in the bath for only a short period of time, i.e. from approximately 30 seconds to 3 minutes, preferably in the order of 2 minutes depending upon, of course, the cathode current density to be used in the plating process. To accomplish this, the process is made a continuous one whereby the carrier is moved through the bath at a constant speed, by any well known means, with electrical contact at all times maintained with the carrier to supply current thereto. The carrier is preferably centrally encompassed at all times while in the bath by a helicalshaped anode having a coil diameter of approximately one inch and composed of an electrically conductive wire of approximately 50 mils in diameter.
The choice of anode material may not arbitrarily be made, however, iron-nickel, and iron-nickel-molybdenum may successfully be used provided the anode is bagged in a conventional manner to prevent sludge formations at the anode from entering the bath solution. One of the important factors associated with the choice of anode material is oxidation in the system. When using bath I, ferrous ions are converted to ferric ions due to oxidation of the bath and high concentration of ferric ions therein is to be avoided. Inert anodes such as platinum, or the like, may be used provided they do not lead to excessive oxidation of the system. It has been found that in each of baths I and II, molybdenum anodes are preferred as they do not have to be bagged and tend to replenish the bath with molybdenum. However, even when a molybdenum anode is used, it is necessary to continually add molybdate solution to the bath in order to maintain the molybdate concentration constant at the desired value. Additionally, it is necessary that nickel and iron solutions be continually added to the bath to also maintain the concentrations thereof constant at their respective values during the plating process.
The current density involved in the deposition process is not critical and may range, for example, from 150 to 500, preferably 250, amperes per square foot of carrier surface area exposed in bath I and from 200 to 1000, preferably 250, amperes per square foot of carrier surface area exposed in bath II. The current density primarily determines the rate of deposition of the metallic ions onto the cathode. This affects the rate of diffusion into the cathode film which influences the amount of depositing species which must be in equilibrium with the reservoir complexes. Consequently, the bath and current density must be compatible and the current density cannot arbitrarily be chosen. For example, any addition agents in the system are less effective at relatively high current densities and, consequently, larger quantities must be used. As the current density is one of the prime factors which determine the structure of the deposit, it is generally necessary to modify the plating system to permit the use of a specific current density.
On emergence from the plating bath, the ferromagnetic element is rinsed and dried and is then ready to be operated as a coincident current twistor type of data storage device in the following manner as fully described in the aforementioned copending application:
The core, along with the ferromagnetic coating, is simultaneously stretched and twisted and the ends thereof are thereafter held in a fixed position. As a result of the stretching and twisting, the easy direction of magnetization of the coating is oriented from a direction substantially parallel to the longitudinal axis of the core to one of substantially helical configuration about the body of the core and throughout its length as the threads of a screw. Such a ferromagnetic coating has been found to possess a substantially high positive and negative magnetic remanence and substantially rectangular hysteresis characteristic. Consequently, selected length portions of the coating, in the direction of twist, are allowed to attain one or other of the two stable states, namely, a residual positive or negative remanent induction. A magnetic field along the direction of twist of :H oersteds switches the length portions from one state to another, whereas a field of '-H/ 2 oersteds produces only negligible changes in the remanent induction. A plurality of similar coils, of say 20 turns each, are separately wound about the coated wire and are positioned in a spaced side-by-side relationship with respect to one another to define a corresponding plurality of helical-path length portions of ferromagnetic material. Storage of binary information in a select length portion of coating is accomplished by sending a current impulse equal in magnitude to (1 into the conductive wire of the common core and simultaneously sending a current impulse equal in magnitude to (1;) into the select coil in such directions that the vector summation of the magnetic field produced by the two coincident currents are equal in magnitude to 1-H oersteds and is oriented in the same direction as the twist or easy direction of magnetization of the coating.
During reading of the selected length portion of the coating, the core is preferably pulsed to individually develop a magnetic field of :H oersteds in the opposite direction from the magnetic field developed during storage of the function. In response to the read impulse, an electrical signal is or is not available between the ends of the corresponding coil according to whether the binary information 1 or 0, respectively, has been established in the particular length section of the coating as represented by its remanent state.
Listed below in chart form are the electrical operational characteristics of two twistor data storage elements fabricated by the previously described plating process which utilize each of the unique ferrous and ferric baths previously described and differ only in wire size of carrier.
Ferrous Ferric Bath Bath Degrees of twist/inch of storage element length. 145 l0. Approx. one-half coincident current in core for storage of binary data 200 1%.... 75 ma. Approx. one-half coincident current in coil for storage of binary data 100 ma 50 ma. Full coincident current in coil for reading of stored binary data W 500 rna. 500 ma. Voltage output across ends of core during reading of binary 1 data- 70 my-.. 75 mv. Signal to noise ratio. 5 Minimum switching ti e- Less than Less than 0.3 micro 0.3 micro sec. sec. Diameter of carrier Approx. Approx.
9 mils. 9 mils.
Ferrous Ferric Bath Bath Degrees of twist/inch of storage element length 360 10 Approx. one-half coincident current in core for storage of binary data ma... 60 Approx. one-half coincident current in coil for storage of binary data ma. 55 40 Full coincident current in coil for reading of stored binary data ma.. 300 300 Voltage output across ends of core during reading of binary 1 data m 70 7 Signal to noise ratio 5 75 Minimum switching time fil sec..- 3 3 Diameter of carrier mils 3 3 In each of the storage elements, the coercivity is less than 2 oersteds and the squareness of the hysteresis loop approximately .99. Consequently, it can thus be seen that by the use of the unique aqueous electrolytic baths, in accordance with the present invention, new and improved ferromagnetic data storage elements are fabricated by electroplating a ferromagnetic coating onto an electrically conductive carrier. Such elements, in addition to possessing greatly improved magnetic characteristics than heretofore possible, are readily adaptable to be fabricated by mass production techniques thereby maintaining the cost thereof at a minimum, and are ideally suited for incorporation in present day electronic data processors and computers.
While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art of electrodeposition of ferromagnetic materials, that changes and modifications may be made Without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.
What is claimed is:
1. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sutficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions.
2. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH of approximately 8.5 and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately grams per liter, molybdenum (VI) in a concentration approximately .4 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sufiicient concentration to prevent precipitation of ferrous, nickel, and molybdenum ions.
3. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdate complexes and being of sufiicient concentration to prevent precipitation of said ferrous, nickel, and molybdate ions, said bath having a pH of approximately 8.5.
4. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent consisting of citrate ions in a concentration approximately 104 grams per liter, said bath having a pH of approximately 8.5.
5. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration approximately 14 grams per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, ammonium ions in a concentration approximately 17 grams per liter, and a complexing agent consisting of citrate ions in a concentration approximately 104 grams per liter, said bath having a pH of approximately 8.5 by the addition of ammonium hydroxide.
6. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of sufiicient concentration to prevent precipitation of ferric, nickel, and. molybdenum (VI) Ions.
7. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath having a pH of approximately 8.5 and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdenum (VI) in a concentration approximately .4 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of sufilcient concentration to prevent precipitation of ferric, nickel, and molybdenum ions.
8. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdate complexes and being of sufficient concentration to prevent precipitation of said ferric, nickel, and molybdate ions, said bath having a pH of approximately 8.5.
9. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, and a complexing agent consisting of citrate ions in a concentration approximately 42 grams per liter, said bath having a pH of approximately 8.5.
10. An aqueous electrolytic bath for use in the process of deposition of a ferromagnetic coating on an electrically conductive carrier in which process said carrier is subjected as a cathode to electrolytic action in said bath, said bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration approximately 1 gram per liter, nickel ions in a concentration approximately 5 grams per liter, molybdate ions in a concentration approximately .7 gram per liter, ammonium ions in a concentration approximately 17 grams per liter, and a complexing agent consisting of citrate ions in a concentration approximately 42 grams per liter, said bath having a pH .of approximately 8.5 by the addition of ammonium hydroxide.
11. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents iron ions in a concentration in the range of .7 to 16 grams per liter, nickel ions in a concentration in the range of 3 to grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble iron, nickel, and molybdenum complexes and being of sufficient concentration to prevent precipitation of iron, nickel, and molybdenum ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy di' rection of magnetization which is oriented at an angle with respect to said longitudinal axis.
12. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and being of sufficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount suificient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
13. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent consisting of citrate ions in a concentration of 88 to 113 grams per liter; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
14. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 12 to 34 grams per liter, and a complexing agent capable of forming soluble ferrous, nickel, and molybdenum (VI) complexes and 'being of sufficient concentration to prevent precipitation of ferrous, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
15. A process for fabricating magnetic computing devices comprising the steps of: providing an aquous electrolytic bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
16. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferrous chloride, nickel chloride, and sodium molybdate and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 88 to 113 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferro magnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
17. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 12 to 34 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 88 to 113 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
18. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferrous chloride, nickel chloride,
and sodium molybdate and including as essential constituents ferrous ions in a concentration in the range of 12 to 16 grams per liter, nickel ions in a concentration in the range of 3 to grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, ammonium ions in a concentration in the range of 12 to 34 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 88 to 113 grams per liter, said bath having a pH in the range of 7.5 to 9.5 by the addition of ammonium hydroxide; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to eifect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount suificient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
19. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per lited, molybdenum (VI) in a concentration in the range of .l to 1 gram per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of suflicient concentration to prevent precipitation of ferric, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to eifect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
20. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, and a complexing agent consisting of citrate ions in a concentration of 33 to 104 grams per liter; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
21. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath having a pH in the range of 7.5 to 9.5 and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .1 to 1 gram per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdenum (VI) complexes and being of suflicient concentration to prevent precipitation of ferric, nickel, and molybdenum (VI) ions; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufiicient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount suflicient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
22. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent capable of forming soluble ferric, nickel, and molybdate complexes and being of sufficient concentration to prevent precipitation of said ferric, nickel, and molybdate ions, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time suflicient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount suflicient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
23. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufiicient to effect the deposition thereon of a ferro magnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
24. A process for fabricating magnetic computing devices comprising the steps of: providing an aqueous electrolytic bath including as essential constituents ferric ions in a concentration in the range of .7 to 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdenum (VI) in a concentration in the range of .l to 1 gram per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time suificient to effect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said carrier, by an amount sufiicient to establish in said coating an easy direction of magnetization which is oriented at an anglewith respect to said longitudinal axis.
25. A process for fabricating magnetic computing devices comprising the steps of providing an aqueous electrolytic bath containing ferric chloride, nickel chloride, and sodium molybdate and including as essential constituents ferric ions in a concentration in the range of .7 t0 3 grams per liter, nickel ions in a concentration in the range of 3 to 10 grams per liter, molybdate ions in a concentration in the range of .3 to 2 'grams per liter, ammonium ions in a concentration in the range of 8 to 25 grams per liter, and a complexing agent consisting of citrate ions in a concentration in the range of 33 to 104 grams per liter, said bath having a pH in the range of 7.5 to 9.5 by the addition of ammonium hydroxide; subjecting an elongated electrically conductive carrier as a cathode to electrolytic action in said bath for a time sufficient to efiect the deposition thereon of a ferromagnetic coating which has the property of providing a particularly oriented easy direction of magnetization when stressed; and applying a torsional stress to said coating, relative to a longitudinal axis of said car- 14 rier, by an amount sufficient to establish in said coating an easy direction of magnetization which is oriented at an angle with respect to said longitudinal axis.
References Cited in the file of this patent UNITED STATES PATENTS 1,837,355 Burns et al. Dec. 22, 1931 2,507,400 Marinis May 9, 1950 2,599,178 Holt et al June 3, 1952 FOREIGN PATENTS 18,378 Australia Oct. 22, 1929 OTHER REFERENCES Bobeck: Bell System Technical Journal, November 1957, vol. XXXVI, pp. 1319-1340.

Claims (1)

11. A PROCESS FOR FABRICATING MAGNETIC COMPUTING DEVICES COMPRISING THE STEPS OF: PROVIDING AN AQUEOUS ELETROLYTIC BATH HAVING A PH IN THE RANGE OF 7.5 TO 9.5 AND INCLUDING AS ESSENTIAL CONSTITUENTS IRON IN A CONCENTRATION IN THE RANGE OF .7 TO 16 GRAMS PER LITER, NICKEL IONS IN A CONCENTRATION IN THE RANGE OF 3 TO 10 GRAMS PER LITER, MOLYBDENUM (VI) IN A CONCENTRATION IN THE RANGE OF .1 TO 1 GRAM PER LITER, AND A COMPLEXING AGENT CAPABLE OF FORMING SOLUBLE IRON, NICKEL, AND MOLYBDENUM COMPLEXES AND BEING OF SUFFICIENT CONCENTRATION TO PREVENT PRECIPITATION OF IRON, NICKEL, AND MOLYBDENUM IONS; SUBJECTING AN ELONGATED ELECTRICALLY CONDUCTIVE CARRIER AS A CATHODE TO ELECTROLYTIC ACTION IN SAID BATH FOR A TIME SUFFICIENT TO EFFECT THE DEPOSITION THEREON OF A FERROMAGNETIC COATING WHICH HAS THE PROPERTY OF PROVIDING A PARTICULARLY ORIENTED EASY DIRECTION OF MAGNETIZATION WHEN STRESSED; AND APPLYING A TORSIONAL STRESS TO SAID COATING, RELATIVE TO A LONGITUDINAL AXIS OF SAID CARRIER, BY AN AMOUNT SUFFICIENT TO ESTABLISH IN SAID COATING AN EASY DIRECTION OF MAGNETIZATION WHICH IS ORIENTED AT AN ANGLEE WITH RESPECT TO SAID LONGITUDINAL AXIS.
US764522A 1958-10-01 1958-10-01 Electrolytic bath for use in electrodeposition of ferromagnetic compositions Expired - Lifetime US3032485A (en)

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NL243931D NL243931A (en) 1958-10-01
US764522A US3032485A (en) 1958-10-01 1958-10-01 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
US827412A US2945217A (en) 1958-10-01 1958-11-07 Magnetic data storage devices
US773843A US3032486A (en) 1958-10-01 1958-11-14 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
US803585A US3031386A (en) 1958-10-01 1959-04-02 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
DEN17319A DE1216647B (en) 1958-10-01 1959-09-30 Bath for the galvanic deposition of a ferromagnetic coating
FR806358A FR1241315A (en) 1958-10-01 1959-09-30 Electrolytic baths for the production of ferro-magnetic coating
GB33301/59A GB896263A (en) 1958-10-01 1959-10-01 Aqucous electrolytic bath for the deposition of ferro-magnetic coatings
CH7910659A CH393026A (en) 1958-10-01 1959-10-06 Electrolytic bath for the production of ferromagnetic coating

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US764522A US3032485A (en) 1958-10-01 1958-10-01 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
US827412A US2945217A (en) 1958-10-01 1958-11-07 Magnetic data storage devices
US773843A US3032486A (en) 1958-10-01 1958-11-14 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
US803585A US3031386A (en) 1958-10-01 1959-04-02 Electrolytic bath for use in electrodeposition of ferromagnetic compositions

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US773843A Expired - Lifetime US3032486A (en) 1958-10-01 1958-11-14 Electrolytic bath for use in electrodeposition of ferromagnetic compositions
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3239437A (en) * 1960-07-28 1966-03-08 Atomic Energy Authority Uk Methods of depositing magnetic alloy films
US3271274A (en) * 1962-10-31 1966-09-06 Sperry Rand Corp Electrodeposition of a ternary alloy of nickel, iron and molybdenum
US3354059A (en) * 1964-08-12 1967-11-21 Ibm Electrodeposition of nickel-iron magnetic alloy films
US4473447A (en) * 1981-08-10 1984-09-25 Man Maschinenfabrik Augsburg-Nurnberg Ag Method of manufacturing absorption layers for solar energy systems and bath therefor
US20060254924A1 (en) * 2004-01-16 2006-11-16 Canon Kabushiki Kaisha Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution
WO2015039647A1 (en) * 2013-09-18 2015-03-26 Harting Kgaa Galvanic bath

Families Citing this family (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB895247A (en) * 1958-03-12 1962-05-02 Nat Res Dev Improvements relating to magnetic storage devices
US3569946A (en) * 1958-09-25 1971-03-09 Burroughs Corp Magnetic material and data store
NL236551A (en) * 1959-02-26
US3134965A (en) * 1959-03-03 1964-05-26 Ncr Co Magnetic data-storage device and matrix
US3051891A (en) * 1959-03-18 1962-08-28 Gen Dynamics Corp Tank circuit
US3258752A (en) * 1959-06-08 1966-06-28 Manufacture of storage devices
US3154767A (en) * 1960-02-08 1964-10-27 Gen Dynamics Corp Storage wire erase
US3234525A (en) * 1960-03-28 1966-02-08 Gen Electric Thin film devices
NL263978A (en) * 1960-04-28
NL265014A (en) * 1960-05-19
US3031648A (en) * 1960-05-25 1962-04-24 Ncr Co Magnetic data storage device
US3077021A (en) * 1960-05-27 1963-02-12 Ibm Method of forming memory arrays
US3011158A (en) * 1960-06-28 1961-11-28 Bell Telephone Labor Inc Magnetic memory circuit
NL267166A (en) * 1960-07-19
US3351771A (en) * 1960-09-21 1967-11-07 Rca Corp Parametric subharmonic oscillator
NL269912A (en) * 1960-10-05
US3381138A (en) * 1960-12-20 1968-04-30 Kokusai Denshin Denwa Co Ltd Parametron element using ferromagnetic thin film
NL286609A (en) * 1961-12-12
US3255033A (en) * 1961-12-28 1966-06-07 Ibm Electroless plating of a substrate with nickel-iron alloys and the coated substrate
NL287699A (en) * 1962-01-12
NL292139A (en) * 1962-05-21
US3319315A (en) * 1962-11-21 1967-05-16 Tech Met Corp Method of preparing magnetic memory device
DE1292991B (en) * 1963-02-04 1969-04-17 Siemens Ag Process for the production of a thin magnetizable layer on a particularly smooth metallic base plate by vacuum vapor deposition, cathode sputtering or electrolytic deposition
US3264621A (en) * 1963-03-25 1966-08-02 Burroughs Corp Magnetic data store
US3280012A (en) * 1963-04-29 1966-10-18 Ncr Co Method of making magnetic device
DE1259666B (en) * 1963-11-29 1968-01-25 Ibm Process for the galvanic deposition of a non-magnetostrictive nickel-iron alloy coating
GB1099493A (en) * 1964-04-11 1968-01-17 Nat Res Dev Method for the construction of ferrite memory stores
FR143854A (en) * 1965-04-02
US3460953A (en) * 1966-05-27 1969-08-12 Pennsalt Chemicals Corp Process for depositing brasslike coatings and composition therefor
US3825478A (en) * 1972-10-30 1974-07-23 Oxy Metal Finishing Corp Electrolyte and method for electrodepositing microporous chromium-nickel composite coatings
JPS5582793A (en) * 1978-12-18 1980-06-21 Ibm Nickelliron plating method
US4279707A (en) * 1978-12-18 1981-07-21 International Business Machines Corporation Electroplating of nickel-iron alloys for uniformity of nickel/iron ratio using a low density plating current
US4450051A (en) * 1981-01-13 1984-05-22 Omi International Corporation Bright nickel-iron alloy electroplating bath and process
GB8923156D0 (en) * 1989-10-13 1989-11-29 Emi Plc Thorn Improvements in or relating to methods of manufacturing electromagnetic articles

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1837829A (en) * 1929-02-13 1929-10-22 Thegeneral Electric Company Limited Improvements inthe manufacture of nickel iron alloys
US1837355A (en) * 1926-09-08 1931-12-22 Bell Telephone Labor Inc Electrodeposition of alloys
US2507400A (en) * 1943-08-02 1950-05-09 Sk Wellman Co Method of electroplating with iron and cobalt
US2599178A (en) * 1950-03-10 1952-06-03 Wisconsin Alumni Res Found Electrodeposition of alloys of molybdenum with cobalt, nickel, and iron

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2112084A (en) * 1934-11-01 1938-03-22 Westinghouse Electric & Mfg Co Magnetic material and method of producing the same
US2706329A (en) * 1951-05-12 1955-04-19 Michigan Bumper Corp Electrically deposited core iron
US2822326A (en) * 1955-03-22 1958-02-04 Rockwell Spring & Axle Co Bright chromium alloy plating
US2834725A (en) * 1956-12-27 1958-05-13 Ibm Cobalt-nickel electroplating solution
US2840517A (en) * 1957-07-10 1958-06-24 Rockwell Spring & Axle Co Nickel-iron-zinc alloy electroplating

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1837355A (en) * 1926-09-08 1931-12-22 Bell Telephone Labor Inc Electrodeposition of alloys
AU1837829A (en) * 1929-02-13 1929-10-22 Thegeneral Electric Company Limited Improvements inthe manufacture of nickel iron alloys
US2507400A (en) * 1943-08-02 1950-05-09 Sk Wellman Co Method of electroplating with iron and cobalt
US2599178A (en) * 1950-03-10 1952-06-03 Wisconsin Alumni Res Found Electrodeposition of alloys of molybdenum with cobalt, nickel, and iron

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3239437A (en) * 1960-07-28 1966-03-08 Atomic Energy Authority Uk Methods of depositing magnetic alloy films
US3271274A (en) * 1962-10-31 1966-09-06 Sperry Rand Corp Electrodeposition of a ternary alloy of nickel, iron and molybdenum
DE1241226B (en) * 1962-10-31 1967-05-24 Sperry Rand Corp Bath and process for the galvanic deposition of magnetizable nickel-iron-molybdenum alloy coatings
US3354059A (en) * 1964-08-12 1967-11-21 Ibm Electrodeposition of nickel-iron magnetic alloy films
US4473447A (en) * 1981-08-10 1984-09-25 Man Maschinenfabrik Augsburg-Nurnberg Ag Method of manufacturing absorption layers for solar energy systems and bath therefor
US20060254924A1 (en) * 2004-01-16 2006-11-16 Canon Kabushiki Kaisha Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution
US7641783B2 (en) 2004-01-16 2010-01-05 Canon Kabushiki Kaisha Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution
WO2015039647A1 (en) * 2013-09-18 2015-03-26 Harting Kgaa Galvanic bath

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US3032486A (en) 1962-05-01
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US2945217A (en) 1960-07-12
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FR1241315A (en) 1960-12-21
DE1216647B (en) 1966-05-12

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