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BELL SYSTEM TECHNICAL JOURNAL 



erties similar, but somewhat inferior to, those of magnetic dust cores -'' 

 which are described in a later section of the paper. 



Iron- Cobalt Alloys 

 Iron-cobalt alloys in the region of 50 per cent cobalt are of impor- 

 tance for magnetic purposes because of the high values of flux densities 

 obtained with medium magnetizing forces. The desirable magnetic 

 properties of the alloy containing 50 per cent cobalt were first reported 

 by one ^^ of the authors. A very complete investigation of alloys over 

 the whole range of cobalt contents has been described by Elmen '' 

 from whose paper the curves shown in Fig, 10 are taken. With 



10 20 30 



H IN OERSTEDS 

 40 50 60 70 



80 90 100 



1500 



24000 



20000 



16000 



12000 



- 8000 



4000 



8000 



6000 



4000 



2000 



Fig. 10 — Magnetization curve and permeability curve for 50 50 iron-cohalt alloy 



Elmcni". 



magnetizing forces from 5 to over 1500 oersteds the intrinsic induction 

 is greater than that obtained with iron. 



Because of anomalies in properties of the alloys in the region of 50 

 per cent cobalt, the structural features of the alloys become of interest. 

 In addition to the maximum in intrinsic induction, the electrical con- 



