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ELABORATION AND STUDY OF SOFT MAGNETIC MATERIALS OBTAINED BY RAPID SOLIDIFICATION AND BY CHEMICAL VAPOUR DEPOSITION FOR APPLICATIONS AT MEDIUMAND HIGH FREQUENCIES

Objective

The basic aim of the project is the laboratory scale development of high quality iron-based soft magnetic alloys, for prospective use in medium and high-frequency devices (400 Hz - 1 Mhz).
Preparation, characterization and study of nonconventional low loss soft magnetic alloys, to be prospectively employed in efficient electrical devices operating at medium and high frequencies, have been undertaken. A 3-fold approach to the problem has been pursued, with respect to the following materials: amorphous iron based and cobalt based alloys, iron silicide 6.5 wt% rapidly solidified alloys, iron silicide 6.5 w% laminations, silicon enriched by means of chemical vapour deposition. The obtained materials, whose magnetic performances have been optimised after preparation by means of suitable thermal/thermomagnetic treatments, have been exhaustively characterized from a structural, mechanical and magnetic point of view. The relationships existing between the intrinsic and structural properties on the one hand and the magnetic and mechanical properties on the other hand have been identified. The final materials, tested under a wide range of exciting frequencies, exhibit excellent soft magnetic behaviour, which favourably compares with that of top quality conventional commercial alloys.

Areas of possible exploitation include: distribution transformers; variable speed motors; magnetic cores; sensors and transducers; shielding; pulsed power applications.
Basically, such alloys will be required to have high saturation induction, high permeability, low losses, medium to low magnetostriction and good mechanical properties, in order to compare favourably with current materials. Applications might include medium and high-frequency transformers, actuators, inverter transformers, switched-mode power supplies, saturable reactor cores, magnetic switches.

The following key objectives are envisaged :

(i) elaboration by planar flow casting of thin (<= 20 degreesm) FeB-based amorphous ribbons, having low losses at high frequencies (10 Khz - 1 Mhz)

(ii) elaboration by planar flow casting of crystalline high Si ribbons (4.5 wt%
(iii) elaboration by CVD of Si (or Al enriched conventional grain-oriented FeSi laminations, with properties optimized at medium and, if possible, power frequencies

(iv) assessment of the microstructural properties of the elaborated alloys

(v) comprehensive magnetic characterization

(vi) theoretical assessment of magnetic vs. microstructural properties.

On the project is intended to enhance European know-how in the field of innovative soft magnetic materials.

Coordinator

Istituto Elettrotecnico Nazionale Galileo Ferraris
Address
Corso Massimo D'azeglio 42
10125 Torino
Italy

Participants (4)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
Avenue Des Martyrs 25
38042 Grenoble
Institut National des Sciences Appliquees de Lyon (INSA)
France
Address
20 Avenue Albert Einstein
69621 Villeurbanne
Institut National des Sciences Appliquées de Toulouse (INSA)
France
Address
Complexe Scientifique De Rangueil
31077 Toulouse
Università degli Studi di Torino
Italy
Address
Via Pietro Giuria 5-7
10125 Torino