MAGNETIC MATERIALS IN RELATION TO STRUCTURE 



29 



characteristics, and becomes agglomerated as is well known in the case 

 of iron and of nickel. In this form it has a minimum embrittling effect 

 since contact between metallic crystallites exists over the greater pro- 

 portion of the interface. The structure is illustrated in Fig. 14. If 

 sufficient manganese is present, alloys containing fairly high percent- 

 ages of sulfur can not only be hot worked, but are malleable when cold. 



Fig. 13 — Structure of an iron-nickel alloy containing 80 per cent nickel to which 

 had been added 0.12 per cent sulphur and 1.05 per cent manganese. The sulfide 

 constituent exists along the crystallite boundaries as gra\ish rounded inclusions. 

 Mag. 2000 X . 



The production of magnetic dusts is unique as a metallurigcal process 

 since the metallurgist is concerned with adding elements yielding a 

 product which can be pulverized to a fine dust. Generally, the met- 

 allurgist exercises his greatest ingenuity to produce ductility and 

 malleability in the end product. 



