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US 4,017,265 AGranted
Ferromagnetic memory layer, methods of making and adhering it to substrates, magnetic tapes, and other products
OwnerDavid W. Taylorinventor
Life of this patent
Estimating the term…
Abstract
A thin, ferromagnetic layer which can be continuous, substantially pit-free and uniform, said layer having high bit density capabilities consisting essentially of cobalt in the form of close packed hexagonal crystals. A substrate is treated with a catalytic activator upon which is deposited an electroless conductive layer, such as copper; the cobalt layer is deposited by electroplating on the conductive layer. The ferromagnetic layer has a nominal coercivity of about 200 to about 500 oersteds and exhibits no anisotropy in the plane of deposition.
Claims40
A magnetic memory member comprising;
- a. a substrate;
- b. a flexible synthetic polymer layer superimposed on a surface thereof, said layer having cyano groups, having a solvent-dispersed phase of catalytic nuclei of platinum, palladium, copper, silver or gold on its surface and concurrently therewith dispersed in the body of the resin;
- c. a conductive layer of copper or nickel adhering to said nuclei;
- and
- d. a magnetic layer integrally secured to said conductive layer;
- said magnetic layer consisting essentially of substantially pure closely packed hexagonal cobalt which is thin, uniform, continuous and substantially pit-free, having a thickness of about 0.05 to 0.5 microns and a smooth surface approximating optical reflectivity;
- a nominal coercivity of about 200 to about 500 Oersteds;
- an inductance of about 6,000 to 16,000 Gauss and a ratio of remnant to saturation induction greater than 0.8 and approaching unity at the extreme, the magnetic memory member having improved information density, frequency response and data rate capability without reduction of output amplitude.
5 more elements
A method of making a magnetic memory member by depositing a conductive layer coating on a substrate, making said conductive layer coating cathodic and electrodepositing a magnetic metal thereon, the improvement comprising:
- a. applying to said substrate as a coating a solution of synthetic polymer containing a cyano group, the solution having one solvent therefore which is a high boiling solvent which is less solvent in water than water is in the solvent, the resin solution containing dissolved therein a platinum, palladium, copper or silver salt;
- b. drying the coating until there remains a limited residual amount of the solvent;
- c. applying to the coated substrate a solution containing a reductant which is absorbed by the coating to reduce the platinum, palladium, copper or silver ions substantially to their metal form, thereby creating catalytic nuclei in and on the coating surface;
- d. applying an electroless solution of copper or nickel ions to chemically plate the copper or nickel in a substantially continuous layer, which tenaciously adheres to the coated substrate at the catalytic nuclei sites, the limited residual amount of solvent being an adequate amount to absorb the reductant;
- and
- e. electrodepositing thereon a layer of substantially pure closely packed hexagonal cobalt which is thin, continuous, uniform and substantially pit-free from an ageous plating solution containing the cobalt, said layer having a thickness of about 0.05 to 0.5 microns;
- a smooth surface approximating optical reflectivity;
- a nominal coercivity of about 200 to 500 Oersteds;
- an inductance of about 6,000 to 16,000 Gauss and a ratio of remnant induction to saturation induction greater than 0.8 and approaching unity at the extreme, thereby forming a magnetic memory member having improved information density, frequency response and data rate capability without reduction of output amplitude.
6 more elements
A method of making a magnetic memory member by depositing a conductive layer coating on a substrate, making said conductive layer coating cathodic and electrodepositing a magnetic metal thereon, the improvement comprising:
- a. applying to said substrates as a coating a solution of synthetic polymer containing a cyano group, the solution having one solvent therefore which is a high boiling solvent which is less solvent in water than water is in the solvent, the resin solution containing dissolved therein a reductant which is absorbed by the coating;
- b. drying the coating until there remains a limited residual amount of solvent;
- c. applying an aqeous solution of platinum, palladium or silver salt whereby the palladium, platinum or silver ions are reduced to their metal form by said reductant thereby creating catalytic nuclei in and on the coating surface;
- d. applying an electroless solution of copper or nickel ions to chemically plate the copper or nickel in a substantially continuous layer, which tenaciously adheres to the coated substrate at the catalytic nuclei sites, the limited residual amount of solvent being an adequate amount to absorb the reductant;
- and
- e. electrodepositing thereon a layer of substantially pure, closely packed hexagonal cobalt which is thin, continuous, uniform and substantially pit-free from an aqueous plating solution containing the cobalt, said layer having a thickness of about 0.05 to 0.5 microns;
- a smooth surface approximating optical reflectivity;
- a nominal coercivity of about 200 to 500 Oersteds, an inductance of about 6,000 to 16,000 Gauss and a ratio of remnant induction to saturation induction greater than 0.8 and approaching unity at the extreme, thereby forming a magnetic memory member having improved information density, frequency response and data rate capability without reduction of output amplitude.
5 more elements
A method of making a magnetic memory member by depositing a conductive layer coating on a substrate, making said conductive layer coating cathodic and electrodepositing a magnetic metal thereon, the improvement comprising:
- a. applying to said substrate as a coating a solution of synthetic polymer containing a cyano group, the solution having one solvent therefore which is a high boiling solvent which is less solvent in water than water is in the solvent, the resin solution containing dissolved therein (1) a gold or silver salt, or (2) a palladium or platinum salt,
- b. drying the coating until there remains a limited residual amount of solvent;
- c. applying an electroless solution of copper ions containing a reductant thereto whereby the gold or silver salts are reduced, or applying an electroless solution of nickel ions containing a reductant whereby the palladium or platinum is reduced, thereby creating catalytic nuclei to tenaciously retain the chemically plated copper or niclel, respectively to form a substantially continuous layer of copper or nickel, the limited residual amount of solvent being an adequate amount to absorb the reductant;
- and
- d. electrodepositing thereon a layer of substantially pure closely packed hexagonal cobalt which is thin, continuous, uniform and substantially pit-free from an aqeous plating solution containing the cobalt, said layer having a thickness of about 0.05 to 0.5 microns;
- a smooth surface approximating optical reflectivity;
- a nominal coercivity of about 200 to 500 Oersteds;
- an inductance of about 6,000 to 16,000 Gauss and a ratio of remnant to saturation induction greater than 0.8 and approaching unity at the extreme, thereby forming a magnetic memory member having improved information density, frequency response and data rate capability without reduction of output amplitude.
5 more elements
Dependencies are inferred from the claim text.