FACTORS AFFECTING MAGNETIC QUALITY 



283 



15 20 30 50 



PER CENT REDUCTION IN THICKNESS 



Fig. a — Dependence of the grain size of iron on the amount of deformation and on the 

 temperature of anneal. Kenyan. 



90" 



5.0 2.5 2.5 5.0 



COERCIVE FORCE, He, IN OERSTEDS 



lO^xlO.O 



5.0 2.5 2.5 5.0 



RESIDUAL INDUCTION, Br, IN GAUSSES 



7.5 10-0 X103 



40 30 20 10 10 20 30 40 



PERMEABILITY, /i, (FOR MEDIUM FIELDS) 



Fig. 34 — Variation of magnetic properties with the direction of measurement in a sheet 

 of iron-nickel alloy (40% Ni) severely rolled (98.5%) and annealed at 1100°C. 



The eflfect of size of a magnetic specimen is often of importance. This is 

 well known in the study of thin films, a,nd fine powders in which the smallest 



