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High Frequency MN ZN Ferrites and Method of Their Preparation

IP.com Disclosure Number: IPCOM000093511D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Agajanian, AH: AUTHOR [+2]

Abstract

This ferromagnetic material exhibits a high initial permeability at high frequencies. The formulation of the material is: Atom Parts Mol % Weight % Fe 2.0 Fe(2)O(3) 50 Fe(2)O(3) 68.7 Mn 0.8 MnO 40 MnO 24.3 Zn 0.2 ZnO 10 Zno 7.0.

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High Frequency MN ZN Ferrites and Method of Their Preparation

This ferromagnetic material exhibits a high initial permeability at high frequencies.

The formulation of the material is: Atom Parts Mol % Weight %

Fe 2.0 Fe(2)O(3) 50 Fe(2)O(3) 68.7

Mn 0.8 MnO 40 MnO 24.3

Zn 0.2 ZnO 10 Zno 7.0.

Fine-grained, high-purity, reagent grade raw material is mixed and then calcined twice for two hours at a temperature in the range between 600 degrees C to 900 degrees C. Between each calcining treatment, the mix is ball milled for a period of between 16 to 24 hours and screened through a 325 mesh screen. This is then followed by a pressing operation and a sintering treatment.

The latter treatment is performed with the ferrite body being in a platinum boat at a temperature between 1050 degrees C to 1100 degrees C for a period between 2 to 30 hours in an inert gas atmosphere or vacuum. The sintering temperature is gradually reached by raising the temperature of the furnace at a rate of about 60 degrees C per hour. After completing the high-temperature sintering treatment, the ferrite reaction product is cooled to room temperature at a rate of about 100 to 300 degrees C an hour.

The resultant ferrite reaction product is characterized by a saturation magnetization of about 6000 gauss and a uniform grain size of less than 5 microns in diameter. The product mu'fr, where mu' is the initial permeability and fr is the resonance frequency in MHz, of this material is approximately 6400....