Amorphous soft magnetic alloy materials

Amorphous soft magnetic alloy materials and its industrial status and development prospect  

Nano (ultramicrocrystal) soft magnetic alloy material  

Fe-based nanocrystalline alloys are composed of iron, silicon, boron and a small amount of copper, molybdenum and niobium, among which copper and niobium are essential elements for obtaining nanocrystalline structure.  They are first made into amorphous strips and then properly annealed to form a mixture of microcrystalline and amorphous structures.  Although cheap, this material has excellent magnetic properties and is almost comparable to the best cobalt based amorphous alloys, but does not contain expensive cobalt. It is an ideal material for industrial and civil high frequency transformers, transformers and inductors, as well as the replacement of Permalle and ferrite.  

The advantages of amorphous soft magnetic alloy materials  

Excellent magnetism:  Compared with traditional metal magnetic materials, amorphous alloy is an excellent soft magnetic material with high magnetic conductivity more than 10 times that of ferrite and low loss (1/5-1/10 of silicon steel sheet and 1/2-1/5 of ferrite loss) due to its disordered atomic arrangement, no anisotropy of crystal and high resistivity.  Instead of silicon steel, permalloy and ferrite as transformer core, transformer, sensor, etc., can greatly improve transformer efficiency, reduce volume, reduce weight, reduce energy consumption.  In fact, the magnetic properties of amorphous alloys are by far the most important application field of amorphous alloys.  

The production of amorphous alloy is directly spray belt after steelmaking, only one step to produce a thin strip finished products, saving a lot of precious energy, while no pollutant emissions, is very beneficial to environmental protection.  It is because of the energy saving in the manufacturing process of amorphous alloy, and its excellent magnetic properties, reduce the loss in the process of transformer use, so it is called the green material and the material of the 21st century.  

Application of amorphous soft magnetic alloy materials  

Power Electronics Technology field:  

High power medium and high frequency transformer  

Inverter transformer  

High power switching power supply transformer  

Communication technology:  

Programmable switch power supply  

Data exchange interface component  

Pulse transformer  

UPS power filter and storage power supply, power factor correction choke, standard choke  

Anti-electromagnetic interference components:  

Ac power supply, SCR, EMI differential mode, common mode inductor, output filter inductor  

Switching power supply:  

Magnetic saturation reactor  

Magnetic amplifier  

Spike suppressor  

choke  

Sensors:  

Current and voltage transformers  

Zero sequence current transformer  

Leakage switch transformer  

Anti-theft sensor label  

At present, the products of amorphous soft magnetic alloy are mainly used in transformer core, high-power inverter transformer and reactor core, various forms of switching power transformer and inductor core, various sensors core, etc.  

In the low frequency electromagnetic components, fe-based amorphous alloy is widely used, and it has achieved good results in the application of power distribution transformers, and has become the largest production of amorphous alloy.  It can replace cobalt-based amorphous alloy and fe-Ni high magnetic conductivity alloy in medium and high frequency field.  

The biggest application of nanocrystalline alloy is the core of power transformer.  Power transformer is a special transformer used for measuring current and electric energy on transmission and transformation lines.  

From the current domestic and foreign applications and future development, a large number of amorphous alloys are still used in power system:  

A. Distribution transformer core.  Fe-base amorphous alloy core has high saturation magnetic induction intensity, low coercivity, low loss (equivalent to 1/3 ~ 1/5 of silicon steel sheet), low excitation current and good temperature stability, so that the no-load loss of amorphous alloy transformer in operation is much lower than that of silicon steel transformer.  This situation is especially applicable to the rural power grid with long no-load time and low power efficiency.  

B. Core of power transformer.  A large number of power transformers are used in substations, and they have very strict requirements on core materials. They not only require high magnetic indicators (such as high permeability, high saturation magnetic induction, low loss, etc.), but also require the whole magnetization curve of core materials to meet certain conditions, so as to ensure the accuracy of transformers in the whole measurement range.  In recent years, amorphous microcrystalline alloy has been widely used as the core of transformer and achieved very ideal results.  

C, switching power supply transformer and inductor core.  Conventional power supplies convert alternating current to direct current at 50 hz (called power frequency).  Because of the low working frequency, the transformer is large in size, high in energy consumption and low in efficiency.  Switching power supply is a new power supply technology developed since the 1970s, it uses more than 20 kilohertz working frequency, greatly reduced the volume of the transformer, reduce the weight, improve the efficiency.  In the switching power supply using amorphous alloy as core components are: main transformer, control transformer, common mode inductor, noise filter, filter inductor, energy storage inductor, reactor, magnetic amplifier, peak suppressor, saturation inductor, pulse compressor, switching tube protection inductor, etc..  

D. Core of leakage switch transformer.  Leakage switch is installed in front of electrical appliances, used to protect electrical appliances and people's electrical safety device.  When the equipment insulation is poor or the human body is shocked, the signal will be induced in the secondary coil of the transformer. After processing, the switch will jump off and the circuit will be cut off to protect the electrical appliances or human safety.  Permo alloy (fe-Ni alloy) was used as the core of the transformer in the past.  Since the 1980s, amorphous alloy began to be used as the core of transformer in leakage switches, and the current domestic consumption is great.  

In the field of power electronics, nanocrystalline soft magnetic alloy is the best choice of soft magnetic material for high power switching power supply because of its high saturation magnetic induction and low high frequency loss and good thermal stability.  The transformer with nanocrystalline core can convert power up to 500kW, and its volume is more than 50% less than that of power ferrite transformer.  

In civilian product, frequency conversion technology is helpful for saving electric energy, reduce volume and weight, being popularized in great quantities.  However, the negative effect cannot be ignored. If the inverter lacks the necessary interference suppression link, a large number of high-order harmonics will be injected into the power grid, which will reduce the total power factor of the power grid.  One of the most effective ways to reduce the pollution of power grid is to add power factor correction (PFC) to the frequency converter, in which the key component is the inductor core with low high-frequency loss and high saturation magnetic induction.  Iron - based amorphous alloys have obvious advantages in such applications and will play an important role in the greening of frequency conversion home appliances.  At present, the use of amorphous PFC inductor in variable frequency air conditioning has become a hot spot.