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US3607462A Expired / Lapsed US ⏱️ 0.0 years remaining

Process of magnetic particle preparation

Assignee: Spang Industries Inc
•
Filing: 1968-03-21
•
Granted: 1971-09-21
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Expires: 1988-03-21
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Abstract

Abstract Magnetic particle cores suitable for phase shifting applications having a permeability substantially above 275 and core losses below 0.24 ohms per henry per unit of inductance at 1,800 Hertz are produced by a novel combination of steps including one or more of the following: reduction of prepowder anneal additives, selective distribution of magnetic particle sizes, adding flexibility to the electrical insulation applied to the magnetic particles, elevated pressure compacting, surface etching of the pressure compacted core after hydrogen anneal, and an oxidation heat treatment following surface etching. Surface etching and oxidation combine to increase the breakstrength and improve other properties of various permeability cores, for example, from 125 through 300 permeability.

Inventors

  • 👤 Alfred M Laing

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 18:51
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 20 words
The process of claim 1 in which the magnetic powder consists essentially of molybdenum, nickel, and iron in alloy form.
Claim 2
Dependent Claim 42 words
The process of claim 1 in which the magnetic powder is blended with about 0.02 percent to about 0.03 percent by weight uncalcined kaolin before annealing the magnetic powder and the annealing is carried out at a temperature of about 1,250* F.
Claim 3
Dependent Claim 33 words
The process of claim 1 in which an electrical insulation coating is applied to the annealed powder from a slurry including a metallic silicate and an aqueous suspension of an inert metallic oxide.
Claim 4
Dependent Claim 58 words
The process of claim 1 in which the magnetic powder is electrically insulated by applying a plurality of coatings of a slurry including a metallic silicate, an aqueous suspension of an inert metallic oxide, and a ceramic clay with intermediate drying of each coating and in which the plasticizer coating is applied to a dried electrical insulation coating.
Claim 5
Dependent Claim 30 words
The process of claim 1 in which the electrical insulation is applied in a plurality of individual coatings and in which the plasticizer is added witH an electrical insulation coating.
Claim 6
Dependent Claim 37 words
The process of claim 2 further including the step of compacting the electrically insulated magnetic powder with plasticizer at a pressure of about 135 tons to about 150 tons per square inch to form a magnetic core.
Claim 7
Dependent Claim 27 words
The process of claim 7 further including the step of annealing the compacted magnetic core between about 1,000* F. and about 1,500* F. in a nonoxidizing atmosphere.
Claim 8
Dependent Claim 26 words
The process of claim 8 further including the step of surface etching of the annealed magnetic core to minimize skin welding effect resulting from pressure compacting.
Claim 9
Dependent Claim 39 words
The process of claim 9 further including the step of oxidizing the surface etched magnetic core by heating the magnetic core above about 225* F. but not higher than about 1, 000* F. in an atmosphere containing free oxygen.
Claim 10
Dependent Claim 27 words
The process of claim 10 in which the surface etched magnetic core is heated in the atmosphere containing free oxygen to a temperature above about 600* F.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1974-09-20 1975-03-22 1975-09-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1978-09-20 1979-03-22 1979-09-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1982-09-20 1983-03-22 1983-09-21 $7700.00 Window Closed / Lapsed

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