Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/62—Record carriers characterised by the selection of the material
  • G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
  • G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
  • G11B5/657—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing inorganic, non-oxide compound of Si, N, P, B, H or C, e.g. in metal alloy or compound
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/48—Coating with alloys
  • C23C18/50—Coating with alloys with alloys based on iron, cobalt or nickel
• • 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
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/9335—Product by special process
  • Y10S428/936—Chemical deposition, e.g. electroless plating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component

Definitions

• the invention is concerned with the composition and production of thin layers, or films, of magnetic alloys having a substantially rectangular hysteretic cycle coated upon discs, drums, tapes, sheets and the like intended to enter in the constitution of magnetic stores of binary data.
• Such a method comprises merging a previously sensibilized substrate within a heated solution of salts of the elements of the layer to produce and of at least one agent for reduction of the metallic ions of said salts, the length of said operation being adjusted to the thickness of the layer which is wanted.
• such a magnetic thin layer or film is comprised of a ternary alloy of cobalt, tungsten and phosphor.
• said alloy comprises, per weight, about 90 to 92 percent of cobalt, about 6 to percent of tungsten and about 0.5 to 3 percent of phosphor; the preferred alloy comprising 91 percent of cobalt, 8 percent of tungsten and 1 percent of phosphor.
• such a layer or film of said ternary alloy is produced from a catalytic bath made of an aqueous solution having an alcaline pH of about 8.4 to 9 and containing salts of cobalt and tungsten and hydrophosphite of sodium, deposition being produced at a temperature substantially comprises between 75 and 85 C. regulated during the operation at a value not varying more than 1 C.
• tungsten as a sodium tungstate salt; and it is also preferred to introduce in said bath, after solving cobalt sulfate therein, Rochelle salt as a complexant agent.
• Said preferred constitution comprises, per weights, 9] percent cobalt, 8 percent tungsten and l percent phosphor, which corresponds in metallic atom composition to 95 percent cobalt, 2.3 percent tungsten and 2.2 percent phosphor.
• Such a layer presents, for a thickness of the order of 5,000 A., a coercive field value substantially equal to 400 OE; the thickness of a layer is, when required, modified at will from a mere adjustment of the length of the deposition operation proper, and the range of thicknesses which are considered as useful for the contemplated application of such layers as integrated parts of binary data magnetic stores, approximately extends from about 3,000 A., wherefor the coercive field is of about 480 OE, up to about 6,000 A., wherefor the coercive field is of about 300 Oersteds.
• Such a range of values of the coercive field of magnetic material films having a substantially rectangular h steretis cycle or characteristic is of special interest for use In mary data information stores because, in addition to a fair protection against the effect of stray demagnetizing magnetic fields on the content of the store, they do not request specially drastic performances for the write or read-in heads by means of which the information is entered in the store.
• Variations of said constitution within the ranges of about 90 to 92 percent weight of cobalt, 6 to 8 percent weight of tungsten and 0.5 to 3 percent weight of phosphor do not largely vary the above given figures, but the useful range of layer or film thicknesses is restricted from use of such modifications if one wish to maintain the possibility of range of the coercive field values.
• the method of production which has proved the more efficient is as follows, wherein, inter alia, the sequence of operations in preparing the autocatalytic bath has proved to be of great importance for the final result, both from the point of view of the reproducibility and from the point of view of performances of the films.
• a substrate which may be indifferently made of dielectric or metallic material is previously sensibilized according to any conventional method in this respect, useless to detail here.
• the autocatalytic chemical bath is prepared as follows: it may be noted that one liter of said bath will permit the straight deposition of the film over 15 dm. of substrate, without addition of any extra bath solution during an operation. The under described components are given for such a one liter of bath.
• the first step of formation of the bath comprises solving 0.426 Mol of cobalt sulfide Co 80,, 7 H O in hot distillated water which is strongly agitated during this operation.
• the second step comprises adding a complexing agent, preferably Rochelle (Sarmete) salt by 1.45 Mol proportion. Let the solution thicken from the addition of the said complexing agent.
• the third step comprises the introduction in the solution of 0.94 Mol of NH OH, corresponding to a pH determination at about a value of 8.5. The solution clears.
• the fourth step comprises solving therein 0.137 Mol of sodium tungstate Na W0
• a solution containing sodium hypophosphite Na H P0 H O is separately prepared, wherein, if estimated useful, 0.94 Mol of NH, Cl is also introduced.
• Said last solution is mixed with the preceding, by volumes containing at most 5 gr. of solid solved in it up to a content of the first solution by 0.38 Mol of sodium hydrophosphite.
• the thus resulting bath is brought to a temperature of C.
• An I autocatalytic reaction develops whereby a layer of the ternary alloy cobalt-tungsten-phosphor is obtained in the above disclosed proportions of its elements. In about 4 minutes, said reaction produces a film having a thickness of the order of 3,000 A. The thickness will reach about 5,000 A. within about 6 minutes and about 6,000 A. within about 8 minutes.
• a magnetic article comprising a substrate coated with a thin magnetic layer of substantially rectangular hysteretic loop from electroless deposition on said substrate of a thin layer of a ternary alloy consisting essentially of about to 92 percent by weight of cobalt, about 6 to 10 percent by weight of tungsten and about 0.5 to 3 percent by weight of phosphor.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Manufacturing Of Magnetic Record Carriers (AREA)
• Magnetic Record Carriers (AREA)
• Chemically Coating (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8648011

Family Applications (1)

Country Status (6)

Citations (2)

• 1968
  • 1968-03-26 FR FR145354A patent/FR1569008A/fr not_active Expired
• 1969
  • 1969-03-10 US US805859A patent/US3647400A/en not_active Expired - Lifetime
  • 1969-03-12 BE BE729758D patent/BE729758A/xx unknown
  • 1969-03-20 GB GB04819/69A patent/GB1203195A/en not_active Expired
  • 1969-03-21 NL NL6904425A patent/NL6904425A/xx unknown
  • 1969-03-25 DE DE19691914984 patent/DE1914984A1/de active Pending

Patent Citations (2)

Also Published As

Similar Documents