My country's achievements in magnetic cores

My country's achievements in magnetic cores

my country's achievements in magnetic cores
Since the 1970s, my country has started the research and development of amorphous alloys. After the completion of major scientific and technological projects during the "Sixth Five-Year Plan", "Seventh Five-Year Plan" and "Eighth Five-Year Plan" period, a total of 134 scientific research results have been obtained, and the National Invention Award 2 items, 16 patents, and nearly a hundred alloy varieties. The Central Iron and Steel Research Institute currently has four amorphous alloy strip production lines and one amorphous alloy component iron core production line. Production of various shaped iron-based, iron-nickel-based, cobalt-based and nanocrystalline strips and iron cores, suitable for iron core components of inverter power supplies, switching power supplies, power transformers, leakage protectors, and inductors, with an annual output value of nearly 2000 Ten thousand yuan. During the "Ninth Five-Year Plan", a thousand-ton iron-based amorphous production line is being established, which has entered the ranks of the international advanced level.

The best individual performance levels achieved by amorphous soft magnetic alloys are:
Initial permeability μo = 14 × 104
Cobalt-based amorphous maximum permeability μm = 220 × 104
Co-based amorphous coercivity Hc = 0.001 Oe
Cobalt-based amorphous squareness ratio Br/Bs = 0.995
Cobalt-based amorphous saturation magnetization 4πMs = 18300Gs
Iron-based amorphous resistivity ρ= 270μΩ/cm
Commonly used types of amorphous alloys are: iron-based, iron-nickel-based, cobalt-based amorphous alloys and iron-based nanocrystalline alloys. The national grades and performance characteristics are shown in the table and figure. For the convenience of comparison, the corresponding performances of crystalline alloy silicon steel sheet, permalloy 1J79 and ferrite are also listed. These types of materials have different characteristics and are used in different aspects.

Basic composition and characteristics of grades
1K101 Fe-Si-B series fast quenching soft magnetic base alloy
1K102 Fe-Si-B-C series fast quenched soft magnetic base alloy
1K103 Fe-Si-B-Ni series fast quenched soft magnetic base alloy
1K104 Fe-Si-B-Ni Mo series fast quenched soft magnetic base alloy
1K105 Fe-Si-B-Cr (and other elements) series fast quenching soft magnetic base alloy
1K106 High-frequency and low-loss Fe-Si-B series fast-quenched soft magnet-based alloy
1K107 High frequency and low loss Fe-Nb-Cu-Si-B series fast quenched soft magnet-based nanocrystalline alloy
1K201 High Pulse Permeability Fast Quenching Soft Magnetic Cobalt-based Alloy
1K202 high remanence ratio and fast quenching soft magnetic cobalt-based alloy
1K203 high magnetic induction, low loss, fast quenching soft magnetic cobalt-based alloy
1K204 high frequency low loss fast quenching soft magnetic cobalt-based alloy
1K205 high initial permeability fast quenching soft magnetic cobalt-based alloy
1K206 quenched high permeability soft magnetic cobalt-based alloy
1K501 Fe-Ni-P-B series quick-quenched soft magnet nickel-based alloy
1K502 Fe-Ni-V-Si-B series quick-quenched soft magnet nickel-based alloy
400Hz: silicon steel core amorphous iron core
Power (W) 45 45
Core loss (W) 2.4 1.3
Excitation power (VA) 6.1 1.3
Total weight (g) 295 276

(1) Fe-based amorphous alloys
The iron-based amorphous alloy is composed of 80% Fe and 20% Si, B type metal elements. It has high saturation magnetic induction intensity (1.54T). The loss of iron-based amorphous alloy and silicon steel is compared with the magnetic permeability, excitation current and Iron loss and other aspects are superior to the characteristics of silicon steel sheet, especially low iron loss (1/3-1/5 of oriented silicon steel sheet), replacing silicon steel as a distribution transformer can save energy by 60-70%. The thickness of the iron-based amorphous alloy strip is about 0.03mm, which is widely used in distribution transformers, high-power switching power supplies, pulse transformers, magnetic amplifiers, intermediate frequency transformers and inverter cores, suitable for use at frequencies below 10kHz

2) Fe-Ni based-amorphous alloy
The iron-nickel-based amorphous alloy is composed of 40% Ni, 40% Fe and 20% metal elements. It has a medium saturation magnetic induction intensity (0.8T), a high initial permeability and a high maximum permeability And high mechanical strength and excellent toughness. It has low iron loss at medium and low frequencies. The heat treatment in air will not oxidize, and a good rectangular loop can be obtained after magnetic field annealing. The price is 30-50% cheaper than 1J79. The application range of iron-nickel-based amorphous alloy corresponds to that of medium-nickel permalloy, but its iron loss and high mechanical strength are far superior to crystalline alloys; instead of 1J79, it is widely used in leakage switches, precision current transformer cores, and magnetic Shield and so on. The iron-nickel-based amorphous alloy is the earliest developed in China and is currently the most widely used amorphous variety in the domestic amorphous alloys. The annual output is about 200 tons. The iron oxide-nickel-based amorphous alloy (1K503) does not occur in the air heat treatment. Invention patents and US patent rights.

3) Iron-based nanocrystalline alloy (Nanocrystalline alloy)
The iron-based nanocrystalline alloy is an amorphous material formed by the rapid solidification process by adding a small amount of Nb, Cu, Si, and B elements to the alloy composed mainly of iron elements. This amorphous material is heat-treated Microcrystals with a diameter of 10-20 nm can be obtained, which are dispersed on an amorphous matrix and are called microcrystals, nanocrystalline materials or nanocrystalline materials. Nanocrystalline materials have excellent comprehensive magnetic properties: high saturation magnetic induction (1.2T), high initial permeability (8×104), low Hc (0.32A/M), low high-frequency loss under high magnetic induction (P0 .5T/20kHz=30W/kg), the resistivity is 80μΩ/cm, which is higher than that of Permalloy (50-60μΩ/cm). After longitudinal or transverse magnetic field treatment, high Br (0.9) or low Br value (1000Gs) can be obtained. ). It is the material with the best comprehensive performance on the market; applicable frequency range: 50Hz-100kHz, best frequency range: 20kHz-50kHz. Widely used in high-power switching power supplies, inverter power supplies, magnetic amplifiers, high-frequency transformers, high-frequency converters, high-frequency choke cores, current transformer cores, leakage protection switches, and common-mode inductor cores.

Comparison of the characteristics of commonly used soft magnetic cores
1. Comparison of the characteristics of magnetic powder core and ferrite: MPP core: use ampere-turns <200, 50Hz~1kHz, μe: 125 ~ 500; 1 ~ 10kHz; μe: 125 ~ 200;> 100kHz: μe: 10 ~ 125
HF core: Use ampere-turns <500, can be used on a larger power supply, not easy to be saturated under a larger magnetic field, and can ensure the minimum DC drift of the inductance, μe: 20 ~ 125
Iron powder core: using ampere-turns> 800, can not be saturated under high magnetization field, can ensure the best inductance value of AC and DC superposition stability. The frequency characteristic is stable within 200kHz; but the high frequency loss is large, suitable for use below 10kHz.
FeSiAlF magnetic core: instead of iron powder core, the operating frequency can be greater than 8kHz. The DC bias capability is between MPP and HF.
Ferrite: Low saturation magnetic density (5000Gs), minimum DC bias capability 3. Comparison of the characteristics of silicon steel, permalloy and amorphous alloy:
Silicon steel and FeSiAl materials have high saturation magnetic induction values ​​Bs, but their effective magnetic permeability values ​​are low, especially in the high frequency range;
Permalloy has high initial permeability, low coercivity and loss, and stable magnetic properties, but Bs is not high enough. When the frequency is greater than 20kHz, the loss and effective permeability are not ideal, the price is more expensive, and the processing and heat treatment are complicated;
Cobalt-based amorphous alloy has high magnetic permeability, low Hc, low loss in a wide frequency range, close to zero saturation magnetostriction coefficient, insensitive to stress, but low Bs value and expensive;
The iron-based amorphous alloy has a high Bs value and a low price, but the effective magnetic permeability value is low.
The permeability and Hc value of the nanocrystalline alloy are close to crystalline high permalloy and cobalt-based amorphous, and the saturation magnetic induction Bs is equivalent to that of medium nickel permalloy. The heat treatment process is simple, and it is an ideal low-cost high-performance soft magnetic Materials; Although the Bs value of nanocrystalline alloys is lower than that of iron-based amorphous and silicon steel, their high-frequency loss under high magnetic induction is much lower than them, and they have better corrosion resistance and magnetic stability. Compared with ferrite, nanocrystalline alloy has 2 to 3 times higher working magnetic induction on the basis of lower loss when it is lower than 50kHz, and the magnetic core volume can be more than doubled.


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