Types, characteristics and application scope of soft magnetic materials

            Soft magnetic materials refer to those materials where magnetization occurs at HC not greater than 1000A/m, and such materials are called soft magnets. Typical soft magnetic materials can achieve maximum magnetization with minimum external magnetic field. A magnetic material having low coercivity and high magnetic permeability. Soft magnetic materials are easy to be magnetized and demagnetized, and are widely used in electrical and electronic equipment. The most widely used soft magnetic materials are iron silicon alloy (silicon steel sheet) and all kinds of soft magnetic ferrite. The magnetic hysteresis loop is narrow and steep, the magnetization process is nearly reversible, the hysteresis loss is small, the magnetic permeability is high, the coercivity is low. Such as silicon steel sheet, industrial pure iron, pure carbon steel, etc.
            Magnetic materials with low coercivity, also known as high magnetic conductivity materials. In the power industry for the manufacture of electrical machinery, transformers and other electrical equipment core. In the electronic industry for the manufacture of various magnetic components, widely used in television, radio and communication, etc. This kind of material has the characteristics of high saturation flux density, high permeability, long and narrow hysteresis loop, small area, small hysteresis loss, small remanence and coerced force. Small eddy current loss and hysteresis loss are required for AC applications. Commonly used are pure iron, low carbon steel, silicon steel sheet, permo alloy, ferrite and so on.
(1) pure iron, low carbon steel: high magnetic permeability, good processing performance. But the eddy current loss is large, only suitable for DC core.
(2) silicon steel sheet, silicon steel belt: high resistivity, small eddy current loss. But the quality is brittle, the processing performance is poor. Laminated sheets or rolled into rings, dipping insulating paint between sheets or forming an oxide layer to reduce eddy current loss.
(3) Permalloy: a general term for Fe-Ni alloy, which has high magnetic permeability. Used for precision instruments, recording heads, etc., or where small size is required.
(4) ferrite: with Fe2O3 as the main component, mixed with Mn-Zn