36 



BELL SYSTEM TECHNICAL JOURNAL 



properties of an alloy containing 15 per cent cobalt and 18 per cent 

 tungsten reproduced from Roster's published data. The alloy was 

 initially quenched from a temperature of 1300° C, and subsequently 



13.000 



Z 11,000 



9000 



7000 



4 6 8 



PER CENT COBALT CONTENT 



Fig. 17 — Effect of different combinations of cobalt and molybdenum on the 

 coercive force and residual induction of iron-cobalt-molybdenum alloys in the heat- 

 treated condition — Koster'". 



aged at temperatures from 300 to 800° C. The best results are ob- 

 tained by aging at temperatures between 700° C. and 800° C. 



The precipitation of the second phase in a typical iron-cobalt- 

 molybdenum alloy is illustrated by a comparison of Figs. 19 and 20. 

 The section in Fig. 19, which is for the alloy after quenching from 1300° 

 C, shows a typical solid solution structure with a small number of 

 rounded inclusions resulting either from the deoxidation of the melt or 

 from incomplete solution at the high temperature. In Fig. 20, a section 



