Magnetic Materials

What materials are most frequently used for magnetic cores? What can coils can be wound on to make electromagnets?

Common Materials

This table describes some of the more common "soft" magnetic materials. These retain only a very small residual magnetism after the magnetizing force (coil) is removed. They would not make "hard" or permanent magnets, but would be extremely useful for motors and solenoids and other magnetic circuits.

Magnetic Materials

Material	Form	Apprx % Composition					Permeability at B=20 gauss	Maximum permeability	Saturation flux density B gauss
Material	Form	Fe	Ni	Co	Mo	Other	Permeability at B=20 gauss	Maximum permeability	Saturation flux density B gauss
Cold rolled steel	Sheet	98.5	---	---	---	---	180	2,000	21,000
Iron	Sheet	99.91	---	---	---	---	200	5,000	21,500
Purified iron	Sheet	99.95	---	---	---	---	5,000	180,000	21,500
4% Silicon-iron Grain-oriented¹	Sheet Sheet	96 97	--- ---	--- ---	--- ---	4 Si 3 Si	500 1,500	7,000 30,000	19,700 20,000
45 Permalloy	Sheet	54.7	45	---	---	---	2,500	25,000	16,000
45 Permalloy²	Sheet	54.7	45	---	---	---	4,000	50,000	16,000
Hipernik	Sheet	50	50	---	---	---	4,500	70,000	16,000
Monimax	Sheet	---	---	---	---	---	2,000	35,000	15,000
Sinimax	Sheet	---	---	---	---	---	3,000	35,000	11,000
78 Permalloy	Sheet	21.2	78.5	---	---	0.3 Mn	8,000	100,000	10,700
4-79 Permalloy	Sheet	16.7	79	---	4	0.3 Mn	20,000	100,000	8,700
Mu metal	Sheet	18	---	---	---	---	20,000	100,000	6,500
Supermalloy	Sheet	15.7	---	---	---	---	100,000	800,000	8,000
Permendur	Sheet	49.7	---	---	---	---	800	5,000	24,500
2V Permendur	Sheet	49	---	---	---	---	800	4,500	24,000
Hiperco	Sheet	64	---	---	---	---	650	10,000	24,200
2-81 Permalloy	Insulated powder	17	---	---	---	---	125	130	8,000
Carbonyl iron	Insulated powder	99.9	---	---	---	---	55	132	---
Ferroxcube III	Sintered powder		---	---	---	---	1,000	1,500	2,500

Notes:

Properties in direction of rolling.
Similar properties for Nicaloi, 4750 alloy, Carpenter 49, Armco 48.
At saturation.
Q, quench or controlled cooling.