Introduction
Sendust alloy refers to the high permeability soft magnetic alloy with sendust as the main component element, also known as sendust alloy.
A brief history
In 1931, Japan’s increase in costs first studied the magnetic properties of Fe-Si-Al alloys with different silicon and aluminum contents. . Because of the high content of silicon and aluminum, the resistivity is also high (≈100μΩ·cm), and the eddy current loss is low. The alloy has good oxidation and corrosion resistance, high hardness (HV≈500) and wear resistance, and its magnetism is not very sensitive to stress. In 1936 they reported a Fe-Si-Al alloy containing 9.6% Si and 5.4% Al and named Sendust. This alloy has poor workability and can only be used for castings. In 1976, Japan's Yamamoto and others added 2 to 4% Ni to this alloy and improved the processability and magnetic properties by magnetic field heat treatment, and named it super Fe-Si-Al alloy (super sendust). In 978, Japan Arai and others used liquid fast Cold technology produces Fe-Si-Al alloy microcrystalline ribbons with a thickness of 20～110m. The magnetic and process properties are improved. The magnetocrystalline anisotropy and saturation magnetostriction of Fe-Si-Al alloy are close to zero, so The initial permeability and maximum permeability are very high, and the coercive force and hysteresis loss are very low.
Features
Since the magnetocrystalline anisotropy constant and the saturation magnetostriction are close to zero, the soft magnetic properties of the sendust soft magnetic alloy are very good; the initial permeability is about It is 18.75mH/m, the maximum permeability is 137.5mH/m, the coercivity is 3.2A/m, and the magnetic saturation value is 1.10T. In addition, due to the high content of silicon and aluminum, the alloy has high resistivity, low eddy current loss, high hardness of the alloy, good wear resistance, and also has good anti-oxidation and corrosion resistance and low stress sensitivity.
Manufacturing method
The sendust soft magnetic alloy is brittle and hard, suitable for casting production. It can also crush the castings into powder to make powder magnetic cores. The Fe-Si-Al microcrystalline alloy strip made by melt rapid quenching technology has improved magnetic properties and process performance.
Application
Fe-Si-Al alloy is mainly used for recording and video recording heads.
Soft magnetic alloy
Soft magnetic alloy is a kind of alloy with high permeability and low coercivity in a weak magnetic field. This type of alloy is widely used in the radio electronics industry, precision instrumentation, remote control and automatic control systems. Together, it is mainly used in two aspects: energy conversion and information processing. It is an important material in the national economy.
Classification
There are many types of soft magnetic alloys. According to the different elements of the alloy, they can be divided into electromagnetic pure iron (industrial pure iron), iron-silicon alloy, iron-nickel alloy, iron-aluminum alloy , Iron-silicon aluminum alloy and iron-cobalt alloy, etc. If the magnetic properties of the alloy are different, it can be divided into high magnetic saturation alloy, high permeability alloy, high squareness ratio alloy, electrical steel, constant permeability alloy, high △B alloy, corrosion-resistant soft magnetic alloy and thermomagnetic compensation alloy. Etc. According to the internal structure of the alloy, it can be divided into crystalline soft magnetic alloy, amorphous soft magnetic alloy and nanocrystalline soft magnetic alloy.