Magnetic material with low coercive force, also known as high magnetic permeability material. In the power industry, it is used to manufacture iron cores for electrical equipment such as motors and transformers. It is used in the electronics industry to manufacture various magnetic components, and is widely used in television, broadcasting and communications. This kind of material has the characteristics of high saturation magnetic flux density, high magnetic permeability, narrow and long hysteresis loop, small area, small hysteresis loss, small remanence and coercive force. When used in AC occasions, the eddy current loss and hysteresis loss are required to be small. Commonly used are pure iron, low carbon steel, silicon steel sheet, permalloy, ferrite and so on.
(1) Pure iron and low carbon steel: high magnetic permeability and good processing performance. However, the eddy current loss is large, so it is only suitable for DC iron core.
(2) Silicon steel sheet and silicon steel strip: high resistivity and low eddy current loss. But the quality is brittle and the processability is poor. Sheets are stacked or rolled into rings, and insulating varnish is dipped between the sheets or an oxide layer is formed to reduce eddy current loss.