Hard and Soft Ferromagnetic Materials and Applications:
Magnetic material are further classified into two types
1. Metallic magnetic materials: Which are made up of metals
2. Ceramic magnetic materials (ferrites): Which are the compounds of metals and nonmetals.
Based on their properties each type is classified into Hard and Soft magnetic materials. A magnetic material that retains magnetic field is called magnet.
Metallic Magnetic Materials:
They are classified into two types.
(1) Soft ferromagnetic materials:
They is also called “permeable magnetic materials” since they allow the flux lines to pass through very easily. They can be easily magnetized and demagnetized. When a soft ferromagnetic material is magnetized it is called soft magnet.
E.g. Soft iron, steel. Properties:
1. They posses high permeability
2. They posses high susceptibility
3. They posses low coercivity
4. They posses low retentivity
5. Low magnetization force is enough for saturation
6. Since the area under the Hysteresis curve is very small, the energy loss per cycle is small.
1. They are used in electromagnets
2. They are used in ac current machinery
3. They are used in Communication equipments
4. They are used in audio and video transformers
(2) Hard ferromagnetic materials:
They are also called as “permanent magnetic materials” because of their ability to retain magnetic field even after the magnetizing force is withdrawn. They are called “hard magnetic materials” because they cannot be magnetized and demagnetized very easily. When a Hard magnetic material is magnetized it is called Hard magnet. E.g. Alnico, Nickel.
(compared to soft magnetic materials)
1. They posses low permeability
2. They posses low susceptibility
3. They posses high coercivity
4. They posses high retentivity
5. Since the area enclosed by the Hysteresis curve is large, the energy loss per cycle is high.
6. High magnetization force is needed for saturation.
1. They are used in digital computers
2. They are used for making permanent magnets
3. They are used in transducers
4. They are used in magnetic tapes.