Patent US3909240A successfully refreshed from Google Patents.
US3909240A
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Method of producing acicular metal crystals
Assignee: Graham Magnetics Inc
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Filing: 1973-09-28
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Granted: 1975-09-30
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Expires: 1993-09-28
Abstract
Abstract Improved processes and products based on the discovery that metal atoms in complex relationship with complexing agents can be used to moderate the formation of organic salt seed crystals which promote an exceptionally well-ordered acicular growth of organometallic salts such as oxalates of the metal. Some acicular, i.e. needle-like, products have particular utility for being reduced to ferromagnetic metal particles which retain a surprisingly large degree of acicularity and possess extraordinarily favorable properties for use in magnetic recording applications.
Inventors
- 👤 Robert J Deffeyes
- 👤 Wesley R Tyler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:43
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/41; C07C51/412; B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/20; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70636; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31786
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
135 words
IN A PROCESS FOR MAKING METAL POWDERS COMPRISING THE STEPS OF REACHING METAL IONS WITH AN ORGANIC ACID FROM A LIQUID MEDIUM, PRECIPITATIMG AN ORGANOMETALLIC SALT, AND REDUCING THE SALT TO A POWDER, THE IMPROVEMENT COMPRISING THE STEPS OF A INITIATING THE PRECIPITATION BY FORMING SEED CRYSTALS OF SAID ORGANIC ACID AND CATIONS OF A SEED METAL, AND FORMING TAKING PLACE IN THE PRESENCE OF A QUANTITY OF A COMPLEXING AGENT FOR SAID SEED METAL, SAID COMPLEXING AGENT FORMING MEANS TO FACILITATE A PREFERENTIAL CRYSTAL GROWTH OF SAID ACICULAR ORGANOMETALLIC SALT CRYSTALS ALONG THE LONG AXIS THEREOF, B. UTILIZING SAID SEED CRYSTALS AS GROWTH INITIATING SITES FOR FORMATION OF SAID ACICULAR ORGANOMETALLIC SALTS OR AS INTERMEDIATE SEED CRYSTALS SUBSEQUENTLY USED TO FORM SAID ORGANOMETALLIC SALTS C. AND REDUCING SAID ORGANOMETALLIC SALTS TO A METAL POWDER.
Claim 2
Dependent Claim
135 words
IN A PROCESS FOR MAKING METAL POWDERS COMPRISING THE STEPS OF REACHING METAL IONS WITH AN ORGANIC ACID FROM A LIQUID MEDIUM, PRECIPITATIMG AN ORGANOMETALLIC SALT, AND REDUCING THE SALT TO A POWDER, THE IMPROVEMENT COMPRISING THE STEPS OF A INITIATING THE PRECIPITATION BY FORMING SEED CRYSTALS OF SAID ORGANIC ACID AND CATIONS OF A SEED METAL, AND FORMING TAKING PLACE IN THE PRESENCE OF A QUANTITY OF A COMPLEXING AGENT FOR SAID SEED METAL, SAID COMPLEXING AGENT FORMING MEANS TO FACILITATE A PREFERENTIAL CRYSTAL GROWTH OF SAID ACICULAR ORGANOMETALLIC SALT CRYSTALS ALONG THE LONG AXIS THEREOF, B. UTILIZING SAID SEED CRYSTALS AS GROWTH INITIATING SITES FOR FORMATION OF SAID ACICULAR ORGANOMETALLIC SALTS OR AS INTERMEDIATE SEED CRYSTALS SUBSEQUENTLY USED TO FORM SAID ORGANOMETALLIC SALTS C. AND REDUCING SAID ORGANOMETALLIC SALTS TO A METAL POWDER.
Claim 3
Dependent Claim
24 words
A process as defined in claim 1 wherein said acicular organometallic salt product is formed in the same medium as are said seed crystals.
Claim 4
Dependent Claim
34 words
A process as defined in claim 1 wherein said acicular organometallic salt product is formed in said medium comprising substantially less complexing agent than does said medium in which said seed crystals are formed.
Claim 5
Dependent Claim
58 words
A process as defined in claim 1 wherein the predominant of the metallic portion of said organometallic salts is formed of atoms selected from the group of metals consisting of cobalt, iron and nickel, of mixtures thereof, and of any of said metals with other elements in quantities sufficient to render ferromagnetic the reduction products of said salts.
Claim 6
Dependent Claim
58 words
A process as defined in claim 2 wherein the predominant of the metallic portion of said organometallic salts is formed of atoms selected from the group of metals consisting of cobalt, iron and nickel, of mixtures thereof, and of any of said metals with other elements in quantities sufficient to render ferromagnetic the reduction products of said salts.
Claim 7
Dependent Claim
58 words
A process as defined in claim 3 wherein the predominant of the metallic portion of said organometallic salts is formed of atoms selected from the group of metals consisting of cobalt, iron and nickel, or mixtures thereof, and of any of said metals with other elements in quantities sufficient to render ferromagnetic the reduction products of said salts.
Claim 8
Dependent Claim
37 words
A process as defined in claim 1 wherein the acicular organometallic produce is largely formed of particles having a length of at least about 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 9
Dependent Claim
37 words
A process as defined in claim 2 wherein the acicular organometallic product is largely formed of particles having a length of at least about 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 10
Dependent Claim
36 words
A process as defined in claim 3 wherein the acicular organometallic product is largely formed of particles having a length of at least 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 11
Dependent Claim
37 words
A process as defined in claim 4 wherein the acicular organometallic product is largely formed of particles having a length of at least about 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 12
Dependent Claim
37 words
A process as defined in claim 5 wherein the acicular organometallic product is largely formed of particles having a length of at least about 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 13
Dependent Claim
37 words
A process as defined in claim 6 wherein the acicular organometallic product is largely formed of particles having a length of at least about 0.5 microns and a length to diameter ratio of at least about 8:1.
Claim 14
Dependent Claim
20 words
A process as defined in claim 3 wherein nickel comprises at least 8 percent of metal in said organometallic salt.
Claim 15
Dependent Claim
20 words
A process as defined in claim 4 wherein nickel comprises at least 8 percent of metal in said organometallic salt.
Claim 16
Dependent Claim
20 words
A process as defined in claim 7 wherein nickel comprises at least 8 percent of metal in said organometallic salt.
Claim 17
Dependent Claim
43 words
A process as defined in claim 1 wherein the complexing agent is selected from the group consisting of ammonium salts or organic compounds selected from those bearing at least two reactive groups selected from the group consisting of hydroxyl, amino and carboxylic groups.
Claim 18
Dependent Claim
43 words
A process as defined in claim 16 wherein the complexing agent is selected from the group consisting of ammonium salts or organic compounds selected from those bearing at least two reactive groups selected from the group consisting of hydroxyl, amino and carboxylic groups.
Claim 19
Dependent Claim
43 words
A process as defined in claim 3 wherein the complexing agent is selected from the group consisting of ammonium salts or organic compounds selected from those bearing at least two reactive groups selecTed from the group consisting of hydroxyl, amino and carboxylic groups.
Claim 20
Dependent Claim
27 words
A process as defined in claim 1 wherein said organo-metallic salt is a metal oxalate wherein at least 50 percent by weight of said metal is cobalt.
Claim 21
Dependent Claim
26 words
A process as defined by claim 19 wherein said organometallic salt is formed as an acicular fasces comprising numerous distinctive rod-like configurations of even greater acicularity.
Claim 22
Dependent Claim
34 words
A process as defined in claim 1 wherein said liquid medium comprises water and a water-soluble organic solvent, said solvent providing means to reduce the solubility of said organometallic salt in said liquid medium.
Claim 23
Dependent Claim
34 words
A process as defined in claim 2 wherein said liquid medium comprises water and a water-soluble organic solvent, said solvent providing means to reduce the solubility of said organometallic salt in said liquid medium.
Claim 24
Dependent Claim
34 words
A process as defined in claim 3 wherein said liquid medium comprises water and a water-soluble organic solvent, said solvent providing means to reduce the solubility of said organometallic salt in said liquid medium.
Claim 25
Dependent Claim
34 words
A process as defined in claim 4 wherein said liquid medium comprises water and a water-soluble organic solvent, said solvent providing means to reduce the solubility of said organometallic salt in said liquid medium.
Claim 26
Dependent Claim
34 words
A process as defined in claim 7 wherein said liquid medium comprises water and a water-soluble organic solvent, said solvent providing means to reduce the solubility of said organometallic salt in said liquid medium.
Claim 27
Dependent Claim
27 words
A process as defined in claim 6 wherein said organometallic salt is a metal oxalate wherein at least 50 percent by weight of said metal is cobalt.
Claim 28
Dependent Claim
49 words
A process as defined in claim 26 wherein said metal is thermally reduced to a metal powder having a squareness of at least 0.72 magnetic moment of at least 110 coercivity of at least 500 and an increase in coercivity between 25* and -195*F of less than 100 percent.
Claim 29
Dependent Claim
14 words
A process as defined in claim 20 wherein said organometallic salt is an oxalate.
Claim 30
Dependent Claim
19 words
A process as defined in claim 3 wherein said metal product has a AH/H ratio of less than 0.75.
Claim 31
Dependent Claim
27 words
A process as defined in claim 28 wherein said organometallic salt is a metal oxalate wherein at least 50 percent by weight of said metal is cobalt.
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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |