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BELL SYSTEM TECHNICAL JOURNAL 



has been reported " for iron prepared in this manner. In Fig. 4 is re- 

 produced a curve from the unpublished work of Cioffi showing the enor- 

 mous improvement in magnetic softness achieved by the hydrogen 

 treatment. 



0.2 



0.4 



0.6 



H 



0.8 



1.0 



"ig. 4 — The permeability of a laboratory sample of hydrogen treated ir<iii conipari'd 

 with that of untreated iron — Cioffi". 



The mechanism of the purification is outlined by the reactions in 

 Fig. 2. The carbon is eliminated as a hydrocarbon gas, probably 

 methane; the oxygen as water vapor; the nitrogen as ammonia or as 

 nitrogen gas due to thermal dissociation of nitrides; the sulfur as 

 hydrogen sulfide; and the phosphorus probably as phosphine. The 

 most probable explanation to account for the purification is that, at the 



