Iron-silicon-aluminum Soft Magnet (Fe-Si-Al), commonly referred to as Kool Mμ or Sendust in the market, is one of the soft magnetic materials with the best overall performance. Although the production processes are relatively mature, the production costs remain high.
Definition of Iron-Silicon-Aluminum Soft Magnet
The soft magnet comprises aluminum, silicon, and iron and boasts a substantial maximum magnetic induction (Bmax) of 10,500 Gauss. Its core loss is significantly lower than iron powder cores and high-flux materials. It has low magnetostriction (resulting in low noise).
It is a low-cost energy storage material that is free from thermal aging. This makes it suitable for replacing iron powder cores while maintaining stable performance at high temperatures.
Characteristics of Iron-Silicon-Aluminum Soft Magnet
| Low Losses: Due to its unique composition and microstructure, they exhibit lower core losses at high frequencies, which is crucial for reducing energy consumption in electromagnetic devices.
| High Saturation Magnetic Induction: Iron-silicon-aluminum soft magnets’ saturation magnetic induction (Bs) typically ranges from 1.4 to 1.6 T, making it excellent for applications requiring high magnetic flux density.
| Good Temperature Stability: They maintain stable magnetic performance over a wide temperature range (-40°C to +150°C), suitable for various environmental conditions.
| High Resistivity: These magnets have high resistivity, which helps to minimize eddy current losses and further improves the material’s efficiency.
| Mechanical Properties: They exhibit good mechanical properties, with a density of approximately 7.0 g/cm³, moderate hardness, and ease of processing into various shapes and sizes of magnetic cores.
Chemical Properties of Iron-Silicon-Aluminum Soft Magnet
| Oxidation Resistance: The aluminum component in the soft magnetic powder can form a dense oxide film, effectively preventing the material from oxidizing at high temperatures, thereby extending its service life.
| Corrosion Resistance: The oxide film formed on the surface provides good corrosion resistance, making it suitable for use in humid or corrosive environments.
Combining Iron-Silicon-Aluminum Soft Magnets with Permanent Magnets
Iron-silicon-aluminum soft magnets and permanent magnets have different magnetic performance characteristics, and their combined use can leverage each other’s advantages in specific applications. For instance, in high-frequency transformers or inductors:
Iron-silicon-aluminum soft magnet can be used in coils to reduce eddy current and core losses at high frequencies, improving efficiency.
Permanent magnets can generate a constant magnetic field, used in magnetic separation and information storage applications.
Application Areas of Iron-Silicon-Aluminum Soft Magnet
They are widely used in various high-frequency electromagnetic devices, such as switch-mode power supplies, inverters, transformers, and inductors. Its excellent magnetic properties and low loss characteristics make it an ideal choice for these applications.
Iron-Silicon-Aluminum Magnetic Cores: These magnetic cores are commonly used in power supplies. They are easily identifiable by their black coating, with model numbers and letters printed on the side. Iron-silicon-aluminum magnetic cores have high saturation magnetic induction, high initial permeability, and very low core losses, widely used in power inductors, power factor correction inductors, common mode filtering inductors, and choke coils.
They are also used in the production of motors, sensors, and other electronic components to enhance the overall performance and reliability of devices.
Impact of Processing Technology on the Performance of Iron-Silicon-Aluminum Soft Magnet
As the particle size of the FeSiAl powder decreases, the effective permeability of the magnetic powder core decreases, while the quality factor increases.
With an increase in the binder content, the quality factor of the magnetic powder core increases, leading to a reduction in effective permeability.
The magnetic powder core formed by pressing can have its magnetic properties improved through annealing heat treatment. Properly increasing the heat treatment temperature can enhance both effective permeability and quality factor.
Samples cooled slowly after heat treatment exhibit slightly higher effective permeability and quality factor compared to samples cooled rapidly.
Magnet Manufacturer
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