Permalloy transformer core price

Permalloy metal core: various types of Permalloy materials have their own typical magnetic properties that are superior to silicon steel materials and ferrites, and have higher temperature stability and aging stability.   High initial permeability Permalloy material (IJ79, IJ85, IJ86) cores are often used to make current transformers and small signal transformers; high rectangular Permalloy material (IJ51) cores are often used to make magnetic amplifiers and two-stage pulse transformers; low remanence Permalloy material (IJ67h)   Cores are often used to make small and medium power unipolar pulse transformers   2. Amorphous core:   ⑴ Iron-based amorphous core:   It has the highest saturation magnetic induction intensity (1.451.56T) among almost all amorphous alloy cores, and also has high permeability, low coercivity, low loss, low excitation current and good temperature stability and aging stability.   Mainly used to replace silicon steel sheets, as various forms and different power power distribution transformers, medium frequency transformers, the operating frequency ranges from 50Hz to 10KHz; as the core of high-power switching power supply reactor, the use frequency can reach 50KHz.   ⑵ Iron-nickel based amorphous core:   Medium to low saturation magnetic induction intensity (0.75T), high magnetic permeability, low coercivity, wear resistance and corrosion resistance, good stability. Commonly used to replace Permalloy core as the zero-sequence current transformer core in leakage switch.   ⑶ Cobalt-based amorphous core:   It has the highest magnetic permeability among all amorphous alloy cores, and also has medium to low saturation magnetic induction intensity (0.65T), low coercivity, low loss, excellent wear resistance and corrosion resistance, good temperature stability and aging stability, and impact and vibration resistance. It is mainly used to replace Permalloy core and ferrite core to make high-frequency transformers, filter inductors, magnetic amplifiers, pulse transformers, pulse compressors, etc. in high-end fields (military)   Permalloy is essentially an iron-nickel (FeNi) alloy with very low coercivity, but high saturation magnetic density Bs, magnetic permeability and Curie temperature, close to pure iron. Multi-element Permalloy, the initial relative magnetic permeability can reach 30000~80000, but the resistivity is low, about 10-7Ω-m, it can be processed into extremely thin sheets, so it can be used at working frequencies up to (20~30)kHz. Permalloy thin strips with a thickness of 0.02mm are commonly used in domestic engineering, and there are also 0.005mm thick thin strips, but because the surface of the thin strip must be insulated during the winding process of the magnetic core, its filling factor is greatly reduced, so it is rarely used in engineering. When the application frequency exceeds 30kHz, due to the low resistivity of Permalloy, its loss will increase significantly. High magnetic permeability alloy (Permalloy) High magnetic permeability alloy refers to iron-nickel alloys with high initial and maximum magnetic permeability, and most of the trade names are called "Permalloy".   In addition to high magnetic permeability, Permalloy has relatively low loss, especially good environmental adaptability and stable performance. Although it is expensive, it is still used in power supplies with relatively strict conditions. The main type of Permalloy is iron-nickel alloy, which is composed of nickel (35% to 85%), iron and added molybdenum, copper, tungsten, etc. It was basically finalized in the 1940s and was widely used in the 1970s and 1980s, forming dozens of models, which are generally classified according to the nickel content. Low nickel alloys with a nickel content of 30% to 50% are low nickel alloys, such as China's 1J30, 1J34, 1J50, 1J51, etc. High nickel alloys with a nickel content of 65% to 85% are high nickel alloys, such as China's 1J66, 1J79, 1J80, 1J88, etc. According to the needs of power supplies, various types of Permalloy strips have been developed. There are materials with rectangular, non-rectangular, and linear (constant magnetic conductivity) hysteresis loops. They can be rolled into various specifications with thicknesses from 0.20mm to 0.005mm (5μm). Generally, 0.20mm thick Permalloy is used for 50Hz, and 0.005mm thick Permalloy is used for 500kHz to 1MHz, covering the entire frequency range from industrial frequency to medium frequency to high frequency, and has long broken through the old concept that it can only be used below 20kHz. Like silicon steel and soft ferrites, Permalloy has also been developing rapidly in the past decade. One is to add chromium and other elements to iron-nickel alloys with low nickel content to achieve magnetic conductivity with high nickel content, thereby reducing costs. The reported Ni38Cr8Fe alloy has a magnetic permeability of 100,000 to 300,000 at H=0.4A/m, which is close to the level of high nickel content alloys. What is more outstanding is that in recent years, domestic and foreign companies have successively launched Permalloy products with high initial magnetic permeability of 200,000 to 300,000 and maximum magnetic permeability of 350,000 to 500,000. Another breakthrough is the manufacturing process of Permalloy thin strips, which are rolled into ultra-thin strips with a thickness of 0.01mm to 0.005mm, expanding the frequency application range. When Bm is 0.1T, the loss of 0.126W/g at 500kHz, 0.392W/g at 1MHz, 6.79W/g at 5MHz, and 23.1W/g at 10MHz for 0.005mm thick Ni80Mo5 Permalloy ultra-thin strips. It can be used in power transformers above 1MHz.   Powder cores   1. Magnetic powder cores   Magnetic powder cores are a kind of soft magnetic material made by mixing ferromagnetic powder particles and insulating media. Since the ferromagnetic particles are very small (0.5 to 5 microns for high frequency) and separated by non-magnetic electrical insulating film materials, on the one hand, eddy currents can be isolated and the material is suitable for higher frequencies; on the other hand, due to the gap effect between particles, the material has low magnetic permeability and constant magnetic permeability characteristics; and because the particle size is small, skin phenomenon basically does not occur, and the change of magnetic permeability with frequency is relatively stable. It is mainly used for high-frequency inductance. The magnetic and electrical properties of magnetic powder cores mainly depend on the magnetic permeability of the powder material, the size and shape of the powder, their filling factor, the content of the insulating medium, the molding pressure and the heat treatment process.   Commonly used magnetic powder cores are iron powder cores, Permalloy powder cores and Sendust powder cores.   The calculation formula for the effective magnetic permeability μe and inductance of the magnetic core is: μe = DL/4N2S × 109   Where: D is the average diameter of the magnetic core (cm), L is the inductance (share), N is the number of winding turns, and S is the effective cross-sectional area of ​​the magnetic core (cm2).   (1) Iron powder core   Common iron powder cores are made of carbon-based ferromagnetic powder and resin carbon-based ferromagnetic powder. The price is the lowest among powder cores. The saturation magnetic induction value is about 1.4T; the magnetic permeability ranges from 22 to 100; the initial magnetic permeability μi has good stability with frequency; the DC current superposition performance is good; but the loss is high at high frequency. Changes in the initial magnetic permeability of the iron powder core with the DC magnetic field strength Changes in the initial magnetic permeability of the iron powder core with frequency   (2) Permalloy powder core   Permalloy powder cores mainly include molybdenum permalloy powder cores (MPP) and high flux powder cores (High Flux).   MPP is composed of 81% Ni, 2% Mo and Fe powder. The main features are: saturation magnetic induction value is about 7500Gs; the magnetic permeability range is large, from 14 to 550; it has the lowest loss among powder cores; it has excellent temperature stability and is widely used in space equipment, open-air equipment, etc.; the magnetostriction coefficient is close to zero, and no noise is generated when working at different frequencies. Mainly used in high-quality Q filters below 300kHz, inductive load coils, resonant circuits, LC circuits with high temperature stability requirements, output inductors, power factor compensation circuits, etc., commonly used in AC circuits, and the most expensive among powder cores.   High flux powder core HF is composed of 50% Ni and 50% Fe powder. The main features are: saturation magnetic induction value is around 15000Gs; magnetic permeability ranges from 14 to 160; it has the highest magnetic induction intensity and the highest DC bias capability among powder cores; and the core size is small. Mainly used in line filters, AC inductors, output inductors, power factor correction circuits, etc., commonly used in DC circuits, and is more used in high DC bias, high DC and low AC. The price is lower than MPP.   (3) Kool Mμ Cores   Kool Mμ Cores are composed of 9% Al, 5% Si, and 85% Fe powder. It is mainly used to replace iron powder core, with 80% lower loss than iron powder core, and can be used at frequencies above 8kHz; saturation magnetic induction is about 1.05T; magnetic permeability ranges from 26 to 125; magnetostriction coefficient is close to 0, no noise is generated when working at different frequencies; it has higher DC bias capability than MPP; and has the best performance-price ratio. It is mainly used in AC inductors, output inductors, line filters, power factor correction circuits, etc. Sometimes it is also used as a transformer core instead of air-gap ferrite.   II) Tape-wound core   1. Silicon steel sheet core   Silicon steel sheet 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 core has the highest saturation magnetic induction value of 20000Gs; because they have good magnetoelectric properties, are easy to mass produce, cheap, and have little mechanical stress, they are widely used in the power electronics industry, such as power transformers, distribution transformers, current transformers and other cores. It is the material with the largest output and usage among soft magnetic materials. It is also the material with the largest usage among magnetic materials for 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 and chokes, reactors, and inductor cores in various electronic systems and household appliances. This type of alloy has good toughness and can be processed by punching, cutting, etc. The core has stacked and wound types. However, the loss increases sharply at high frequencies, and the general use frequency does not exceed 400Hz. From the application point of view, the selection of silicon steel should consider two factors: 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. When used at power frequency, the thickness of the commonly used strip is 0.2~0.35 mm; when used at 400Hz, 0.1 mm is often selected. The thinner the thickness, the higher the price.   2. Permalloy   Permalloy often refers to an iron-nickel alloy with a nickel content in the range of 30~90%. It is a widely used soft magnetic alloy. Through appropriate processes, magnetic properties can be effectively controlled, such as an initial magnetic permeability of more than 105, a maximum magnetic permeability of more than 106, a coercive force as low as 2‰ Oersted, and a rectangular coefficient close to 1 or close to 0. Permalloy with a face-centered cubic crystal structure has good plasticity and can be processed into 1μm ultra-thin strips and various usage forms. Commonly used alloys include 1J50, 1J79, 1J85, etc. The saturation magnetic induction intensity of 1J50 is slightly lower than that of silicon steel, but the magnetic permeability is dozens of times higher than that of silicon steel, and the iron loss is 2~3 times lower than that of silicon steel. Made into a transformer with a higher frequency (400~8000Hz), the no-load current is small, and it is suitable for making small higher frequency transformers below 100W. 1J79 has good comprehensive performance and is suitable for high-frequency 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 100,000 105, which is suitable for low-frequency or high-frequency input and output transformers, common-mode inductors and high-precision current transformers for weak signals.   3. Amorphous and Nanocrystalline Soft Magnetic Alloys   Silicon steel and Permalloy soft magnetic materials are both crystalline materials. The atoms are arranged regularly in three-dimensional space to form a periodic lattice structure. There are defects such as grains, grain boundaries, dislocations, interstitial atoms, and magnetocrystalline anisotropy, which are not conducive to soft magnetic properties. From the perspective of magnetic physics, the amorphous structure with irregular atomic arrangement and no periodicity and grain boundaries is very ideal for obtaining excellent soft magnetic properties. Amorphous metals and alloys are a new material field that came out in the 1970s. Its preparation technology is completely different from the traditional method. Instead, it adopts ultra-rapid cooling and solidification technology with a cooling rate of about one million degrees per second. From molten steel to thin strip finished products, it is formed in one step, which reduces many intermediate processes compared to the general cold-rolled metal thin strip manufacturing process. This new process is called a revolution in traditional metallurgical processes. Due to ultra-rapid cooling and solidification, the atoms do not have time to arrange and crystallize in an orderly manner when the alloy solidifies. The solid alloy obtained is a long-range disordered structure without the grains and grain boundaries of crystalline alloys. It is called an amorphous alloy and is called a revolution in metallurgical materials. This amorphous alloy has many unique properties, such as excellent magnetism, corrosion resistance, wear resistance, high strength, hardness and toughness, high resistivity and electromechanical coupling performance. Due to its excellent performance and simple process, it has become the focus of research and development in the material science community 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 have gradually replaced silicon steel, Permalloy and ferrite to flood the market.