Patent US4722872A successfully refreshed from Google Patents.
US4722872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clad magnetic memory disk substrate
Assignee: Kaiser Aluminum and Chemical Corp
•
Filing: 1986-04-28
•
Granted: 1988-02-02
•
Expires: 2006-04-28
Abstract
Abstract A magnetic memory disk substrate which maintains a high degree of surface smoothness together with high yield strength is prepared by cladding a core material with a cladding layer containing a maximum of about 3% magnesium. The core material is aluminum alloyed with one or more elements such as zinc, magnesium, copper and silicon to produce an improved yield strength. The cladding comprises from about 3% to about 10% per side of the thickness of the entire composite and generally contains further alloying elements for enhanced corrosion resistance. Silicon impurities generally amount to less than 0.5%.
Inventors
- 👤 Edwin J. Westerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:17
CPC Classifications
B; B32; B32B; B32B15/00; B32B15/01; B32B15/016; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; G11B5/73917; G11B5/73919; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12736; Y10T428/12764
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
91 words
A rigid magnetic memory disk substrate comprising: a core comprising an aluminum-base alloy containing from about 3.5% to about 5% magnesium, from about 0.2% to about 0.7% manganese, and from about 0.5% to about 0.25% chromium; and a cladding layer comprising a homogenized aluminum-base alloy containing from about 1.0% to about 2.0% magnesium, from about 0.01% to about 0.2% silicon, from about 0.2% to about 0.7% manganese and from about 0.05% to about 0.25% chromium, said cladding layer comprising from about 6% to about 8% of the thickness of said substrate.
Claim 2
Dependent Claim
91 words
A rigid magnetic memory disk substrate comprising: a core comprising an aluminum-base alloy containing from about 3.5% to about 5% magnesium, from about 0.2% to about 0.7% manganese, and from about 0.5% to about 0.25% chromium; and a cladding layer comprising a homogenized aluminum-base alloy containing from about 1.0% to about 2.0% magnesium, from about 0.01% to about 0.2% silicon, from about 0.2% to about 0.7% manganese and from about 0.05% to about 0.25% chromium, said cladding layer comprising from about 6% to about 8% of the thickness of said substrate.
Claim 3
Dependent Claim
69 words
A rigid magnetic memory disk substrate comprising: (a) a core comprising an aluminum-base alloy containing at least about 3.5% magnesium; (b) a cladding layer comprising an aluminum-base alloy that has been previously homogenized and containing from about 1.0% to 2.0% magnesium and from about 0.01% to less than about 0.5% silicon; and (c) at least one of the aluminum-base alloys further containing from about 0.2% to about 0.7% manganese.
Claim 4
Dependent Claim
69 words
A rigid magnetic memory disk substrate comprising: (a) a core comprising an aluminum-base alloy containing at least about 3.5% magnesium; (b) a cladding layer comprising an aluminum-base alloy that has been previously homogenized and containing from about 1.0% to 2.0% magnesium and from about 0.01% to less than about 0.5% silicon; and (c) at least one of the aluminum-base alloys further containing from about 0.2% to about 0.7% manganese.
Claim 5
Dependent Claim
22 words
A rigid magnetic memory disk substrate according to claim 2 wherein the cladding layer contains from about 0.01% to about 0.2% silicon.
Claim 6
Dependent Claim
25 words
A rigid magnetic memory disk substrate according to claim 2 wherein the aluminum-base alloy core has a yield strength of at least about 14 ksi.
Claim 7
Dependent Claim
35 words
A rigid magnetic memory disk substrate according to claim 2 wherein the thickness of the cladding layer per side of the substrate is from about 3% to about 10% of the thickness of the substrate.
Claim 8
Dependent Claim
23 words
A rigid magnetic memory disk substrate according to claim 2 wherein both aluminum-base alloys contain from about 20% to about 50% cold work.
Claim 9
Dependent Claim
27 words
A rigid magnetic memory disk substrate according to claim 2 wherein at least one of the aluminum-base alloys further contains from about 0.05% to about 0.25% chromium.
Claim 10
Dependent Claim
20 words
A rigid magnetic memory disk substrate according to claim 2 wherein the cladding layer contains less than about 0.5% zinc.
Claim 11
Independent Claim
98 words
A method for preparing a rigid memory disk substrate comprising the steps of: (a) selecting an aluminum-base alloy core material having a yield strength of at least about 8 ksi and containing at least about 3.5% magnesium; (b) selecting and homogenizing a cladding material from an aluminum-base alloy containing from about 1.0% to 3.0% magnesium and from about 0.01% to less than about 0.5% silicon; (c) applying a cladding material to at least one side of the core material; and (d) thereafter rolling and cutting the formed composite into a disk substrate suitable for receiving a magnetizable layer.
Claim 12
Independent Claim
98 words
A method for preparing a rigid memory disk substrate comprising the steps of: (a) selecting an aluminum-base alloy core material having a yield strength of at least about 8 ksi and containing at least about 3.5% magnesium; (b) selecting and homogenizing a cladding material from an aluminum-base alloy containing from about 1.0% to 3.0% magnesium and from about 0.01% to less than about 0.5% silicon; (c) applying a cladding material to at least one side of the core material; and (d) thereafter rolling and cutting the formed composite into a disk substrate suitable for receiving a magnetizable layer.
Claim 13
Dependent Claim
21 words
A method according to claim 9 wherein in step (b) the aluminum-base alloy contains from about 0.01% to about 0.2% silicon.
Claim 14
Dependent Claim
22 words
A method according to claim 9 wherein the cladding material applied in step (c) contains from about 0.05% to about 0.25% chromium.
Claim 15
Dependent Claim
25 words
A method according to claim 9, wherein at least one of the aluminum-base core and aluminum-base cladding material contains from about 0.2% to 0.7% manganese.
Claim 16
Dependent Claim
24 words
A method according to claim 9 wherein from about 20% to about 50% cold work is left in the disk substrate of step (d).
Claim 17
Dependent Claim
23 words
A method according to claim 9 wherein the disk substrate made in step (d) is heated to reduce stresses introduced in step (d).
References Cited (Backward Citations)
US3418090A
Cited
US3471272A
Cited
US3595631A
Cited
US3881883A
Cited
JPS49806A
Cited
US4430387A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |