Question

Magnetic materials properties: e.g. permeability, retentivity, coercivity, B-H curve, hysteresis and iron losses.

Soft magnetic materials: soft iron, silicon steel, mu-metal.

Hard magnetic materials: ferrites.

A. From the list of magnetic materials above select one soft magnetic material and one hard magnetic material. Sketch the B-H curves (hysteresis loops) of both selected materials. 

B. Give an example of where each one is used and state which of its properties makes it useful for the purpose.

 

 

Answer 1

Cobalt

Retentivity: 0.82-1.6T

Coercivity: 10-900

B-H Curve

Hysteresis loop

Iron is commonly used as magnetic materials in generators and motors.

Cobalt is a necessary component in rechargeable batteries. For example, in electric cars

Iron

Retentivity: Iron gets magnetized quickly but loses its magnetism as soon the inducing magnet is removed.

Coercivity: Iron has a very low coercivity

B-H Curve

Iron Hysteresis loop