What is soft magnetic material ?

Soft magnetic materials refer to a category of magnetic materials with coercive force lower than 1000 A/m, featuring low coercivity and high magnetic permeability. Their core characteristics include easy magnetization, easy demagnetization and high saturation magnetic flux density. They have narrow hysteresis loops and low hysteresis loss, making them ideal for scenarios requiring frequent magnetization and demagnetization.

I. Main Types

1. Metallic Soft Magnetic Materials

Electromagnetic Pure Iron: Carbon content below 0.04%, featuring high saturation magnetic flux density and excellent cold workability. Its thermal conductivity decreases while hardness and brittleness increase. Widely used as iron cores for motors, transformers, relays, instrument transformers and switches.

Iron-Nickel Alloys (Permalloy): Possess extremely high magnetic permeability and low coercivity under weak magnetic fields, yet are sensitive to stress. Applied in devices operating below 1 MHz within weak magnetic fields.

Iron-Aluminum Alloys: High resistivity and light weight with relatively low magnetic permeability. Higher aluminum content leads to increased hardness, brittleness and reduced ductility. Suitable for devices working in both weak and strong magnetic fields.

Iron-Silicon Alloys (Silicon Steel Sheets): High resistivity and low eddy current loss, but brittle with poor machinability. Dominantly used for iron cores of transformers and motors, ranking the most widely used soft magnetic material worldwide.

Metallic Soft Magnetic Powder Cores: Combine high saturation magnetic flux density of metals and low loss advantages of ferrites, capable of stable operation under medium and high-frequency alternating magnetic fields. It boasts promising market prospects and is closely linked to the new energy industry.

2. Ferrite Soft Magnetic Materials

Mainly composed of ferric oxide, blended with Mn-Zn or Ni-Zn raw materials, and manufactured into Mn-Zn ferrites and Ni-Zn ferrites via powder metallurgy. They feature high resistivity and low high-frequency loss, but have low saturation magnetic flux density and poor temperature stability. Mostly applied in low-power magnetic components working at medium and high frequencies, such as equipment for television, broadcasting and communication industries.

3. Amorphous and Nanocrystalline Soft Magnetic Materials

Amorphous Alloys: Also known as metallic glass, they have no long-range ordered crystal grains. They deliver high magnetic permeability and resistivity, low coercivity and insensitivity to stress, free from magnetocrystalline anisotropy caused by crystal structures, along with outstanding corrosion resistance and high mechanical strength. They have much lower Curie temperature than crystalline soft magnetic materials, which greatly cuts down power energy loss.

Nanocrystalline Alloys: Composed of crystalline phases below 50 nanometers and amorphous grain boundary phases, they achieve superior comprehensive properties over traditional crystalline and amorphous alloys. With high magnetic permeability, low coercivity, low core loss, high saturation magnetic flux density and excellent stability, they have developed rapidly and become strong competitors of ferrite soft magnetic materials in recent years.

II. Application Fields

As essential basic materials for electric energy transmission, conversion and signal processing, soft magnetic materials have been widely applied across modern industrial sectors:

Power Electronics & Energy Industry: Serve as core magnetic cores for transformers, motors, inductors and filters, extensively adopted in photovoltaic inverters, energy storage systems and UPS power supplies.

Information & Communication Industry: Soft magnetic ferrites are key raw materials for magnetic antennas, power converters and filters used in 5G base stations, smartphones, NFC devices and wireless charging equipment.

New Energy Vehicle Industry: Applied in on-board chargers (OBC), DC-DC converters and motor drive systems. Their low-loss property effectively improves overall vehicle energy efficiency.

Consumer Electronics & Household Appliances: Massively used for inductors and transformer cores in laptops, mobile phones, inverter air conditioners and other daily electronic products.

Emerging Industries: Growing market demand is seen in robots, aerospace equipment, medical instruments, data center servers and AI GPU related devices.