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BELL SYSTEM TECHNICAL JOURNAL 



per cent nickel. On both sides of this range the time necessary for 

 stabilization increased both with increasing and decreasing nickel 

 content. With nickel content of less than 42 per cent and more than 

 88 per cent, approximately, no difference sufficiently large to be 

 attributed to the baking could be observed, even after the alloys had 

 been baked for several weeks. 



20 



40 60 



PER CENT NICKEL 



80 



100 



Fig. 13 — Initial permeabilities for the Fe-Ni series. 



The 78.5 permalloy composition in this series is of special interest 

 because this alloy when air quenched gives the highest initial and 

 maximum permeabilities. The magnetization curves for this com- 

 position are plotted in Fig. 14 for annealed and air-quenched 

 samples, and for a sample of annealed iron. The lower part of this 

 graph is shown in the insert on a larger scale. The curves are plotted 

 for magnetizing forces between and 10 gauss only. In these curves 



