Tongyou Group | Breaking Through Core Technologies in Soft Magnetic Materials and Empowering the Upgrading of the Inductor Industry

Deeply cultivate soft magnetic materials and solidify the foundation of quality.

Soft magnetic composite materials represent one of the key technological barriers in the production of integrated inductors and are a major factor influencing inductor performance. Different magnetic powders, various insulating coating materials and processes, as well as different additives, all significantly affect parameters such as permeability, loss, operating frequency, saturation current, and reliability.

Magnetic powder materials include iron powder, alloy powder, and amorphous/nanocrystalline powders. Pure iron powder is typically prepared by reducing or decomposing Fe(CO)5. Alloy powders and amorphous/nanocrystalline powders are usually produced via atomization methods, which include water atomization, gas atomization, and combined water-gas atomization. Water atomization boasts high production efficiency and relatively low costs; however, alloy powders produced by water atomization exhibit poor sphericity and have a high oxygen content. Gas atomization operates on a principle similar to water atomization and can improve the sphericity of the powder and reduce its oxygen content, though it comes with higher manufacturing costs.

In industry, a combined water-gas atomization process is commonly employed, which leverages the advantages of both water atomization and gas atomization. The cooling rates for water atomization and gas atomization are 10⁴–10⁵ °C/s and 10³–10⁴ °C/s, respectively. As a result, it is impossible to produce spherical amorphous powders with both high saturation magnetization (Bs) and large particle size using this method.

If amorphous/nanocrystalline ribbons are crushed using methods such as ball milling or air-stream grinding, the resulting powders tend to have more sharp edges and corners, which is detrimental to subsequent insulation coating processes. The Japanese company ATMIX employs a rotating water atomization process (SWAP) with a cooling rate exceeding 10⁶°C/s. This method enables the production of FeSiBC (Fe: 79–84 at.%) amorphous powders that feature both large particle size (D50 > 50 μm), high saturation magnetization (Bs: 1.54–1.6 T), and excellent sphericity. In comparison with the preparation techniques and performance of pure iron powders and alloy powders, domestic Chinese companies have now closed the gap with their international counterparts. However, there still remains a gap between domestic non-crystalline and nanocrystalline powders and those produced by the Japanese company ATMIX.

Deeply cultivate magnetic material R&D and strengthen the core of quality.

Insulating coating is a key technology for soft magnetic composite materials and also a major research focus in both academic and industrial circles. It encompasses both inorganic and organic coatings. Insulating coating plays two crucial roles in soft magnetic composite materials:

01 Electrically insulate the metallic magnetic powder to reduce eddy current losses.

02 Binder powder, enhancing formability and the strength of magnetic powder cores.

The advantage of inorganic coating lies in its high insulation performance, excellent thermal stability, and superior heat resistance, enabling it to withstand prolonged high-temperature annealing. In contrast, organic coatings offer good insulation properties and outstanding formability; however, most organic resins begin to decompose when exposed to temperatures exceeding 300°C. Therefore, these two coating technologies each have their own strengths, and in industrial applications, inorganic and organic coatings are typically used simultaneously in a complementary manner.

Since magnetic powder insulation coatings are proprietary core technologies of each company, it’s impossible to directly compare their performance. We can only make judgments based on inductor products.

According to market feedback, companies from Japan, South Korea, the United States, and other countries still outperform domestic enterprises in insulation-coating technology. However, in recent years, domestic inductor manufacturers such as Maxtech, Sunlord Electronics, Bokai New Materials, Tongyou Group, and magnetic-powder producers including Antai Technology, Yue'an New Materials, Mengda New Materials, and Jinan Magnetic Industry have made significant progress in magnetic-powder insulation coating.

Diligently refine soft magnetic technology and solidify the foundation of our products.

The research and development of magnetic powder materials require extensive technical expertise, involving interdisciplinary knowledge from fields such as materials science, physics, and chemical engineering.

Enterprises must continuously pursue technological innovation and process optimization to meet increasingly stringent performance requirements and reduce production costs. At the same time, since the application fields of inductors have varying demands on their performance, R&D personnel must flexibly adjust magnetic powder materials and manufacturing processes according to these different needs, thereby establishing unique technological barriers.

Tongyou Group has been deeply engaged in the field of soft magnetic materials and has filed 14 patent applications in recent years. It has successfully developed high-performance soft magnetic materials with low losses and high permeability. This breakthrough in core technology has laid a solid quality foundation for the group’s inductor products, ensuring from the very beginning outstanding performance in key areas such as stability, inductance value, and service life.