soft magnetic materials

soft magnetic materials

Silicon steel

Silicon steel is an alloy. The iron-silicon alloy formed by adding a small amount of silicon (generally below 4.5%) to pure iron is called silicon steel. This type of iron core has the highest saturation magnetic induction value of 20,000 Gauss; Good magnetoelectric properties, easy mass production, cheap price, little influence of mechanical stress, etc., have been widely used in the power electronics industry, such as power transformers, distribution transformers, current transformers and other iron cores.

Silicon steel is the material with the largest output and usage in soft magnetic materials. It is also the material with the largest amount of magnetic materials used in power transformers. It is especially suitable for low frequency and high power. Commonly used are cold-rolled silicon steel sheet DG3, cold-rolled non-oriented electrical steel strip DW, and cold-rolled oriented electrical steel strip DQ, which are suitable for medium and small power low-frequency transformers, choke coils, and reactors in various electronic systems and household appliances. , Inductor core, this kind of alloy has good toughness, and can be processed by punching, cutting, etc. The core has laminated and wound types. However, the loss increases sharply at high frequencies, and the general use frequency does not exceed 400Hz.

From the perspective of application, two factors should be considered in the selection of silicon steel: magnetism and cost. For small motors, reactors and relays, pure iron or low-silicon steel sheets can be selected; for large motors, high-silicon hot-rolled silicon steel sheets, single-oriented or non-oriented cold-rolled silicon steel sheets can be selected; single-oriented cold-rolled silicon steel sheets are often used for transformers piece. When used under power frequency, the thickness of commonly used strips is 0.2~0.35mm; when used under 400Hz, the thickness of 0.1mm is often selected. The thinner the thickness, the higher the price.

1J22 soft magnetic alloy

1J22 is an iron-cobalt-vanadium soft magnetic alloy with high saturation magnetic induction. Among the existing soft magnetic materials, the alloy has the highest saturation magnetic induction (2.4T), high Curie point (980°C), and the largest saturation magnetostriction coefficient ( 60~100×10-6). Due to the high saturation magnetic induction, the size can be greatly reduced when making a motor with the same power, and when it is used as an electromagnet, it can generate a large attraction force under the same cross-sectional area. Due to the high Curie point, the alloy can work at a higher temperature where other soft magnetic materials have been completely demagnetized, and maintain good magnetic stability. Due to the large magnetostriction coefficient, it is extremely suitable as a magnetostrictive transducer, with high output energy and high working efficiency.

Mainly used in:

Mobile phone: Soft magnets can be used for micro-vibration motors, wireless charging, cameras and other components.
High-performance generators: military high-performance generators require 1J22 materials to improve the performance of generators.
High-end relay: A relay is an electrical appliance that turns on or off a circuit according to changes in physical quantities such as voltage, current, temperature, speed, or time. Some relays use soft magnetic materials.
Transducer: A device that converts electrical energy and sound energy into each other. As electronic devices become smaller and smaller, transducers require more advanced magnetic materials.


Permalloy often refers to iron-nickel alloys, and the nickel content is in the range of 30-90%. It is a very widely used soft magnetic alloy. Through appropriate technology, the magnetic properties can be effectively controlled, such as initial permeability of more than 100,000, maximum permeability of more than one million, coercive force as low as two thousandths Oersted, close to 1 or close to Zero square coefficient, permalloy with face-centered cubic crystal structure has good plasticity, and can be processed into ultra-thin strips of 1 micron and various usage forms. Commonly used permalloys are 1J50, 1J79, 1J85 and so on.

The saturation magnetic induction of 1J50 is slightly lower than that of silicon steel, but its magnetic permeability is dozens of times higher than that of silicon steel, and its iron loss is also 2~3 times lower than that of silicon steel. Made into a higher frequency (400~8000Hz) transformer, the no-load current is small, suitable for making a small higher frequency transformer below 100 watts.

1J79 has good comprehensive performance and is suitable for high-frequency and low-voltage transformers, leakage protection switch cores, common-mode inductor cores and current transformer cores.

The initial magnetic permeability of 1J85 can reach more than 100,000, which is suitable for low-frequency or high-frequency input and output transformers, common-mode inductors and high-precision current transformers with weak signals.

Amorphous alloys

Silicon steel and permalloy soft magnetic materials are crystalline materials, atoms are arranged regularly in three-dimensional space to form a periodic lattice structure, there are grains, grain boundaries, dislocations, interstitial atoms, magnetic crystal anisotropy, etc. Defects are not good for soft magnetic properties. From the perspective of magnetic physics, an amorphous structure with irregular arrangement of atoms, no periodicity and no grain boundaries is ideal for obtaining excellent soft magnetic properties.

Amorphous metals and alloys are a new field of materials that emerged in the 1970s. Its preparation technology is completely different from the traditional method, but adopts the ultra-rapid solidification technology with a cooling rate of about 1 million degrees per second, from molten steel to the finished thin strip, which is more than the general cold-rolled metal thin strip manufacturing process. Many intermediate processes are reduced, and this new process is called a revolution to the traditional metallurgical process. Due to ultra-rapid cooling and solidification, when the alloy is solidified, the atoms have no time to arrange and crystallize in an orderly manner. The obtained solid alloy has a long-range disordered structure, and there are no grains and grain boundaries of the crystalline alloy. It is called an amorphous alloy and is called a metallurgical material. A revolution in learning.

This amorphous alloy has many unique properties, such as excellent magnetic properties, corrosion resistance, wear resistance, high strength, hardness and toughness, high electrical resistivity and electromechanical coupling performance, etc. Because of its excellent performance and simple process, it has become the focus of research and development in the field of material science at home and abroad since the 1980s. At present, the United States, Japan, and Germany have a complete production scale, and a large number of amorphous alloy products gradually replace silicon steel, permalloy and ferrite and rush to the market.
Commonly used types of amorphous alloys are: iron-based, iron-nickel-based, cobalt-based amorphous alloys and iron-based nanocrystalline alloys.

Fe-based amorphous alloys

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

Fe-Ni based-amorphous alloy

Iron-nickel-based amorphous alloy is composed of 40%Ni, 40%Fe and 20%Si, and B-type metal elements. It has a medium saturation magnetic induction [0.8T], a high initial permeability and a high maximum Magnetic permeability as well as high mechanical strength and excellent toughness. It has low iron loss at medium and low frequencies. There is no oxidation after heat treatment in air, and a good rectangular loop can be obtained after annealing in a magnetic field. 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; it is widely used in leakage switches, precision current transformer cores, magnetic shielding, etc. Iron-nickel-based amorphous alloy is the earliest developed in China, and it is also the most widely used amorphous variety in China’s amorphous alloys, with an annual output of nearly 200 tons. Iron-nickel-based amorphous alloy (1K503), which does not undergo heat treatment in air, has won national invention patents and US patent rights.

Co based-amorphous alloy

Cobalt-based amorphous alloy is composed of 80% Co and 20% Si, B-type metal elements. It has extremely high magnetic permeability among all amorphous alloys, and has low saturation magnetic induction, low coercive force, Low loss, excellent wear resistance and corrosion resistance, good temperature stability and aging stability, shock and vibration resistance. It is generally used in transformers and inductors in military power supplies with strict requirements, replacing Permalloy and ferrite, but the price is high.

Nanocrystalline alloy

Nanocrystalline special amorphous alloy. Iron-based nanocrystalline alloy is an amorphous material formed by a rapid solidification process of an alloy composed of iron as the main element and a small amount of Nb, Cu, Si, and B elements. This kind of amorphous material can obtain microcrystals with a diameter of 10-20 nanometers after heat treatment, which are dispersed on the amorphous substrate, and are called microcrystals, nanocrystalline materials or nanocrystalline materials.

Nanocrystalline materials have excellent comprehensive magnetic properties: high saturation magnetic induction (1.2T), high initial magnetic permeability (80,000), low Hc (0.32A/M), and low high frequency loss under high magnetic induction (P0. 5T/20kHz=30 W/kg), the resistivity is 80 micro-ohm centimeters, which is higher than permalloy (50-60 micro-ohm centimeters), and high Br (0.9) or low Br value can be obtained by longitudinal or transverse magnetic field treatment (1000Gs).

Nanocrystalline is the material with the best comprehensive performance on the market; applicable frequency range: 50Hz-100kHz, optimal frequency range: 20kHz-50kHz. Widely used in high-power switching power supply, inverter power supply, magnetic amplifier, high-frequency transformer, high-frequency converter, high-frequency choke core, current transformer core, leakage protection switch, common mode inductor core.

Shanghai HY Industry Co., Ltd has international first-class material production equipment such as high temperature alloy isothermal forging production line, CONSARC vacuum melting furnace, VAR vacuum arc remelting furnace etc., with strong professional ability and highly responsible management team. We are a member of China Application of nuclear energy materials, Member of the International Council of the Aeronautical Sciences,China Electronic Materials Industry Association Magnetic Materials Branch. Years of experience in special alloy. When you have superalloy material inquiry, please contact us without hesitation. Shanghai HY Industry Co., Ltd is Corrosion & fatigue nickel alloy professional manufacturer,We will provide you with sincere and thoughtful service.

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