US4236945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phosphorus-iron powder and method of producing soft magnetic material therefrom
Assignee: KEYSTONE CARBON COMPANY A PA CORP
•
Filing: 1978-11-27
•
Granted: 1980-12-02
•
Expires: 1998-11-27
Abstract
Abstract A phosphorus-iron powder is disclosed for use in the pressing and sintering of soft magnetic parts. This powder comprises a substantially phosphorous free iron powder blended with a sufficient quantity of ferrophosphorus powder having an average particle size of at least 10 micron and a phosphorus content of from 18 to 30%, to arrive at a phosphorus content for the mixture in a range of from about 0.40 to 1.25%. By pressing the blended mixture to a green density of at least 6.0 grams per cubic centimeter, and sintering the pressed mixture in a nonoxidizing atmosphere at a temperature of at least 1900°F., the part linear shrinkage during sintering is less than 2%.
Inventors
- 👤 Orville W. Reen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:59
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/02; C22C33/0207; C22C33/0214; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
A phosphorus-iron powder for use in the pressing and sintering, at less than 2% linear shrinkage, of soft magnetic parts while retaining the magnetic properties of the parts, comprising a substantially phosphorus free powder containing at least 98% iron blended with a sufficient quantity of ferrophosphorus powder having an average particle size of at least 10 micron and a phosphorus content of from 18 to 30%, to arrive at a phosphorus content for the mixture in the range of from about 0.40 to 1.25% and less than 0.01% carbon or copper impurities in the mixture.
Claim 2
Dependent Claim
95 words
A phosphorus-iron powder for use in the pressing and sintering, at less than 2% linear shrinkage, of soft magnetic parts while retaining the magnetic properties of the parts, comprising a substantially phosphorus free powder containing at least 98% iron blended with a sufficient quantity of ferrophosphorus powder having an average particle size of at least 10 micron and a phosphorus content of from 18 to 30%, to arrive at a phosphorus content for the mixture in the range of from about 0.40 to 1.25% and less than 0.01% carbon or copper impurities in the mixture.
Claim 3
Dependent Claim
25 words
A powder as set forth in claim 1 wherein the phosphorus content for the mixture is in a range of from about 0.45 to 0.75%.
Claim 4
Dependent Claim
124 words
In a process for producing a phosphorus bearing soft magnetic material while retaining the magnetic properties of the parts, which process includes the steps of: blending powder containing at least 98% iron with ferrophosphorus powder having a phosphorus content of from 18 to 30%, into a mixture containing from about 0.40 to 1.25% phosphorus and less than 0.01% carbon or copper impurities, pressing the blended mixture to a green density of at least 6.0 grams per cubic centimeter, and sintering the mixture in a nonoxidizing atmosphere at a temperature of at least 1900° F., wherein the improvement comprises the step of blending ferrophosphorus powder having an average particle size in excess of 10 micron, whereby part linear shrinkage during sintering is less than 2%.
Claim 5
Dependent Claim
124 words
In a process for producing a phosphorus bearing soft magnetic material while retaining the magnetic properties of the parts, which process includes the steps of: blending powder containing at least 98% iron with ferrophosphorus powder having a phosphorus content of from 18 to 30%, into a mixture containing from about 0.40 to 1.25% phosphorus and less than 0.01% carbon or copper impurities, pressing the blended mixture to a green density of at least 6.0 grams per cubic centimeter, and sintering the mixture in a nonoxidizing atmosphere at a temperature of at least 1900° F., wherein the improvement comprises the step of blending ferrophosphorus powder having an average particle size in excess of 10 micron, whereby part linear shrinkage during sintering is less than 2%.
Claim 6
Dependent Claim
25 words
A process as set forth in claim 3 wherein the iron powder is blended with ferrophosphorus powder into a mixture containing 0.45 to 0.75% phosphorus.
References Cited (Backward Citations)
US3836355A
Cited
US4047893A
Cited
US4000980A
Cited
US4090868A
Cited
US4093449A
Cited
US4115158A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-02 | 1984-06-02 | 1984-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-02 | 1988-06-02 | 1988-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-02 | 1992-06-02 | 1992-12-02 | $7700.00 | Window Closed / Lapsed |