Please enable JavaScript.
Coggle requires JavaScript to display documents.
CHAPTER 4a (MPI) - Part 8,9,10,11,12 - Coggle Diagram
CHAPTER 4a (MPI) - Part 8,9,10,11,12
Magnetic
Domains
Ferromagnetic materials get their magnetic properties not only because their atoms carry a magnetic moment but because of the material is made up of a small regions
In each domain, all of the atomic dipoles are coupled together in a prefer direction. This alignment develops as the materials develops its crystalline structure during solidification from the molten state
-
This can be done by placing the material in strong external magnetic field / by passing electric current to pass through the material
-
The more domains that are aligned, the stronger the magnetic field in the material
When all of the domain are aligned, the material is said to be magnetically saturated. When a material is magnetically saturated, there is no additional amount of external magnetization force as it will caused & increase internal level of magnetization
-
Permeability (m)
is a material property that describes the ease which magnetic flux is establish in a component.
It is the ratio of the flux density (B) created within the material to magnetizing field (H) (m = B/H)
-
The maximum permeability is the point where the slope of B-H curve for the unmagnetized material is the greatest
-
Overview-leakage field
Occurs when the magnetic field is forced out into the air by the distortion of the field within a material
When a ferromagnetic material is magnetized, magnetic discontinuities which lie normal to the field direction resulting in formation of strong leakage field / flux leakage
The leakage field can be detected by only used the finely divided magnetic particle which collect at the surface defect