US4388367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Perpendicular magnetic recording medium and fabrication
Assignee: Xerox Corp
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Filing: 1981-09-28
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Granted: 1983-06-14
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Expires: 2001-09-28
Abstract
Abstract A method for producing a continuous thin film magnetic medium by electrochemical plating deposition, useful for perpendicular recording. The plated medium comprises a substrate upon which is deposited a thin magnetic layer consisting of acicular shaped crystalline particles with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the particle acicula and the longitudinal axis of the acicular particles oriented substantially normal to the plane of said magnetic layer. The method comprises the steps of providing an electrochemical plating bath solution containing a salt solution of the magnetic elemental component or alloy thereof, e.g., Co salt solution, the bath having a predetermined ion concentration and electrodepositing the elemental component or alloy thereof on the substrate while maintaining the maximum pH value of the salt solution at a point before the precipitation of a secondary precipitate, e.g., Co(OH) 2 , will occur in the bath solution bulk.
Inventors
- 👤 Tu Chen
- 👤 Pietro L. Cavallotti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:46
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8416; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
188 words
A method of producing a continuous thin film magnetic medium comprising a substrate upon which is deposited a thin magnetic layer of Co or alloy thereof, said magnetic layer comprising self-supported, juxtaposed, acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of said magnetic layer, said magnetic acicular particles having a grain boundary of nonmagnetic material separating said magnetic particle acicula from one another, said method comprising the steps of providing an electrochemical plating bath solution containing a Co salt solution having a predetermined Co ++ ion concentration, electrodepositing Co on said substrate, and controlling the precipitation of Co(OH) 2 in said bath solution, the step of controlling comprising the steps of inducing the precipitation of Co(OH) 2 at the grain boundaries of said magnetic acicular particles while maintaining the maximum pH value of the Co salt solution at a point before the precipitation of Co(OH) 2 would occur in the solution bulk.
Claim 2
Independent Claim
188 words
A method of producing a continuous thin film magnetic medium comprising a substrate upon which is deposited a thin magnetic layer of Co or alloy thereof, said magnetic layer comprising self-supported, juxtaposed, acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of said magnetic layer, said magnetic acicular particles having a grain boundary of nonmagnetic material separating said magnetic particle acicula from one another, said method comprising the steps of providing an electrochemical plating bath solution containing a Co salt solution having a predetermined Co ++ ion concentration, electrodepositing Co on said substrate, and controlling the precipitation of Co(OH) 2 in said bath solution, the step of controlling comprising the steps of inducing the precipitation of Co(OH) 2 at the grain boundaries of said magnetic acicular particles while maintaining the maximum pH value of the Co salt solution at a point before the precipitation of Co(OH) 2 would occur in the solution bulk.
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein the Co ++ ion concentration in said bath is in the range of about 0.1 to 2 molar solutions.
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein the pH value of said bath is about 5 to 6.7 or near the maximum pH value before the precipitation of Co(OH) 2 occurs.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein the temperature of said bath is in the range of about room temperature to about 70° C.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein the current density of said bath is in the range of about 1 to 200 mA/cm 2 .
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein the thickness of siad layer is in the range of 0.1 to 2 microns.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein a buffer reagent is employed in said bath.
Claim 9
Dependent Claim
15 words
The method of claim 7 wherein said buffer reagent comprises H 3 BO 3 .
Claim 10
Dependent Claim
31 words
The method of claim 1 wherein an alloying element is added to said Co salt solution bath up to about 20% of the secondary plating element ion in the plating solution.
Claim 11
Dependent Claim
26 words
The method of claim 9 wherein said alloying element is selected from the group consisting of Ni, Cr, Re, Os, Ru, Pd, Mn, Mo and Cu.
Claim 12
Dependent Claim
21 words
The method of claim 1 wherein the length of the length to width ratio of the acicular particles is about 3:1.
Claim 13
Dependent Claim
23 words
The method of claim 1 wherein the diameter of the acicular particles is in the range of about 200 Angstroms to 2000 Angstroms.
Claim 14
Dependent Claim
122 words
A magnetic recording medium comprising a substrate and a magnetic recording layer deposited on said substrate, said layer comprising an electrochemical plating of Co or alloy thereof from a Co salt solution bath wherein the magnetic layer comprises self-supported, juxtaposed acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of the magnetic layer, said magnetic acicular particles having a grain boundary of nonmagnetic material thereby separating magnetic particle acicula from one another, said nonmagnetic material comprising a secondary precipitate developed during the plating of said magnetic layer.
Claim 15
Dependent Claim
122 words
A magnetic recording medium comprising a substrate and a magnetic recording layer deposited on said substrate, said layer comprising an electrochemical plating of Co or alloy thereof from a Co salt solution bath wherein the magnetic layer comprises self-supported, juxtaposed acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of the magnetic layer, said magnetic acicular particles having a grain boundary of nonmagnetic material thereby separating magnetic particle acicula from one another, said nonmagnetic material comprising a secondary precipitate developed during the plating of said magnetic layer.
Claim 16
Independent Claim
194 words
A method of producing a continuous thin film magnetic medium comprising a substrate upon which is deposited a thin magnetic layer, said magnetic layer comprising self-supported, juxtaposed acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of said magnetic layer, said acicular magnetic particles having a grain boundary of nonmagnetic material separating said magnetic particle acicula from one another, said method comprising the steps of providing an electrochemical plating bath solution containing a salt solution of the magnetic elemental component or alloy thereof comprising said magnetic layer, said bath having a predetermined concentration, electrodepositing said elemental component or alloy thereof on said substrate, and controlling the precipitation of a secondary precipitate from the bath solution comprising the steps of inducing precipitation of the secondary precipitate at the grain boundaries of said acicular particles while maintaining the maximum pH value of the salt solution at a point before the precipitation of the secondary precipitate would occur in the solution bulk.
Claim 17
Independent Claim
194 words
A method of producing a continuous thin film magnetic medium comprising a substrate upon which is deposited a thin magnetic layer, said magnetic layer comprising self-supported, juxtaposed acicular shaped crystalline particles of magnetic material with the crystallographic "c" axis of the crystal in each particle oriented parallel to the longitudinal axis of the magnetic particle acicula and the longitudinal axis of said magnetic acicular particles oriented substantially normal to the plane of said magnetic layer, said acicular magnetic particles having a grain boundary of nonmagnetic material separating said magnetic particle acicula from one another, said method comprising the steps of providing an electrochemical plating bath solution containing a salt solution of the magnetic elemental component or alloy thereof comprising said magnetic layer, said bath having a predetermined concentration, electrodepositing said elemental component or alloy thereof on said substrate, and controlling the precipitation of a secondary precipitate from the bath solution comprising the steps of inducing precipitation of the secondary precipitate at the grain boundaries of said acicular particles while maintaining the maximum pH value of the salt solution at a point before the precipitation of the secondary precipitate would occur in the solution bulk.
Claim 18
Dependent Claim
12 words
A magnetic recording medium fabricated according to the method of claim 14.
Claim 19
Dependent Claim
49 words
The method of claim 14 wherein the maintenance of said pH value permits the precipitation of a secondary precipitate in the region of the intergranual boundary of said particles due to a higher pH value in said region compared to said maximum pH value present in said solution bulk.
Claim 20
Dependent Claim
14 words
The method of claim 16 wherein said salt solution comprises a Co salt solution.
Claim 21
Dependent Claim
31 words
The method of claim 17 wherein an alloying element is added to said Co salt solution up to about 20% of the secondary plating element ion in the Co plating solution.
Claim 22
Dependent Claim
26 words
The method of claim 18 wherein said alloying element is selected from the group consisting of Ni, Cr, Re, Os, Ru, Pd, Mn, Mo and Cu.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |