Soft magnetic amorphous iron-cobalt alloy with high saturation magnetization

Abstract

The invention relates to the field of metallurgy, in particular to an amorphous magnetically soft alloy based on iron-cobalt, obtained by casting a melt onto the surface of a crystallizer and performing high-speed quenching, which alloy is used as a component of various devices, in particular transformers, motors, generators, the properties of which are based on the electromagnetic induction effect. The method provided by the invention has the technical effects that an extremely high saturation magnetization value of 1.94 to 2.01 T, a coercive force of 6.6 to 10 A / m and a maximum magnetic conductivity of 5000 to 14000 are obtained. The method has the advantages of simple heat treatment mode and low annealing temperature, so that the process cost is remarkably reduced. The technical result is as follows: the soft magnetic material based on soft magnetism of iron and cobalt contains boron, silicon, phosphorus and carbon, and the atomic percent of each component is as follows (at.%): Fe-58.2-68.0; 16.4 to 25.2 parts of CO (carbon monoxide); 13 to 16 parts of B; 0.9 to 1.1 parts of Si; p <-0 >-1.1; and C <-0 >-1.1.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of metallurgy, and in particular to an iron-cobalt based amorphous soft magnetic alloy obtained by casting a melt onto the surface of a crystallizer and subjected to high-speed quenching, which is used as a component of various devices, in particular transformers, electric machines, electric generators, the properties of which are based on the electromagnetic induction effect.

[0002] By quenching a liquid melt on a rapidly rotating copper crystallizer disc, an amorphous structure of the alloy ribbon can be obtained, the cooling rate of which is sufficient to freeze the long-range disordered arrangement of atoms at room temperature.

[0003] The amorphous structure of the iron-cobalt based alloy ribbon, compared to the traditional iron-based amorphous alloy ribbon, provides it with lower power losses, higher saturation magnetization and relatively better glass-forming ability, thus good soft magnetic properties.

[0004] PRIOR ART The patent documents listed below are the closest in composition to the developed iron-cobalt based material, however, they contain additional Cu additives in the chemical composition and are characterized by a nanocrystalline structure. A nanocrystalline soft magnetic material is known, the composition of which is Fe 100-х-у-а Co а Cu х B у (US 8298355 B2, published on February 18, 2010), in which the value of x ranges from 1 to 3 inclusive, the value of y ranges from 10 to 20, and the value of a ranges from 10 to 25, and in the structure part of the grains with a size of 60 nm or less are formed by annealing, and the saturation magnetic induction of the alloy is 1.85 T or higher, and the coercive force is 200 A / m or less.

[0005] The disadvantage of the invention is that the coercive force of the alloy is higher compared to the proposed material.

[0006] An alloy with the composition Fe(100-X-Y-Z)B X P Y Cu Z (RU 2483135 C1, published on May 27, 2013), the main phase of which is amorphous, in which 79≤100-X-Y-Z≤86 at.%, 4≤X≤13 at.%, 1≤Y≤10 at.% and 0.5≤Z≤1.5 at.% of the alloy have a saturation magnetic induction of 1.6 T and a coercive force of 20 A / m. In this case, the method of forming a nanocrystalline structure of the alloy is a heat treatment in the temperature range from T x1 -50°C and T x2 , where T x1 and Tx2 These are the temperatures at which the first and second crystallizations began, respectively.

[0007] The disadvantage of this invention is that it has a lower saturation magnetic induction intensity and a higher coercivity compared to the proposed material.

[0008] The alloy with the closest composition to the proposed alloy is an amorphous alloy based on the iron-cobalt system, whose composition is Fe. а Co b Si c B d Cu e (US 2020 / 0335246 A1, published on October 22, 2020), where a = 60–85, b = 1–20, c = 0–4, d = 12–16, e = 0.5–1.5, and a + b + c + d + e = 100, its saturation magnetic induction intensity is 1.79–1.86T, its coercivity is 1.4–4.3 A / m, and its permeability is 8000–14000. The preferred heat treatment conditions are: temperature 290–370°C, time 5 to 30 min.

[0009] The disadvantage of this invention is its low magnetic induction value. Summary of the Invention

[0010] The technical advantages of this invention are: achieving extremely high saturation magnetization (1.94-2.01 T), coercivity (6.6-10 A / m), and maximum permeability (5000-14000). This invention also features a simple heat treatment method and low annealing temperature, thus significantly reducing processing costs.

[0011] The technical result is achieved through the following scheme: a soft magnetic material based on iron and cobalt, containing boron, silicon, phosphorus, and carbon, with the atomic percentage (at. %) of each component as follows: Iron –58.2–68.0; Cobalt –16.4–25.2; Boron –13–16; Silicon – 0.9 – 1.1; Phosphorus – 0 – 1.1; Carbon –0 –1.1.

[0012] This invention is illustrated with reference to the accompanying drawings, which are as follows: Figure 1 —X-ray diffraction pattern of cast amorphous alloy Fe67.2Co16.8B15Si1 obtained using monochromatic Cu-Kα radiation; Figure 2 —Differential scanning calorimetry results of Fe67.2Co16.8B15Si1 alloy obtained at a heating rate of 0.67 °C / s; Figure 3—X-ray diffraction pattern of annealed amorphous alloy Fe67.2Co16.8B15Si1 obtained using monochromatic Cu-Kα radiation; Figure 4 —Hysteresis loop of Fe67.2Co16.8B15Si1 alloy under heat treatment; Figure 5 — Relationship between coercivity and annealing time of Fe67.2Co16.8B15Si1 alloy; Figure 6 - X-ray diffraction pattern of cast amorphous Fe67.2Co16.8B14Si1C1 alloy obtained using monochromatic Cu-Kα radiation; Figure 7 —Differential scanning calorimetry results of Fe67.2Co16.8B14Si1C1 alloy obtained at a heating rate of 0.67 °C / s; Figure 8 —X-ray diffraction pattern of annealed amorphous Fe67.2Co16.8B14Si1C1 alloy obtained using monochromatic Cu-Kα radiation; Figure 9 —Hysteresis loop of Fe67.2Co16.8B14Si1C1 alloy under heat treatment; Figure 10 — Relationship between coercivity and annealing time of Fe67.2Co16.8B14Si1C1 alloy; Figure 11 —X-ray diffraction pattern of cast amorphous Fe68Co17B13Si1P1 alloy obtained using monochromatic Cu-Kα radiation. Figure 12 Differential scanning calorimetry results of Fe68Co17B13Si1Р1 alloy; Figure 13 —X-ray diffraction pattern of annealed amorphous Fe68Co17B13Si1Р1 alloy obtained using monochromatic Cu-Kα radiation; Figure 14 —Hysteresis loop of Fe68Co17B13Si1Р1 alloy under heat treatment; Figure 15 — Relationship between coercivity and annealing time of Fe68Co17B13Si1P1 alloy. Detailed Implementation

[0013] The alloy composition used in this invention is described by the following formula (unit: at. %): Fe x Co y B a Si b C c P dThe formula is: 58.2≤x≤68.0, 16.4≤y≤25.2, 13≤a≤16, 0.9≤b≤1.1, 0≤c≤1.1, 0≤d≤1.1, 82≤x+y≤85, x+y+a+b+c+d=100. Based on existing research, the main ferromagnetic elements in this material are iron (Fe) and cobalt (Co). Their combination provides enhanced magnetic properties. Their content is determined to achieve a high saturation magnetic induction intensity. Non-metallic elements—boron (B), silicon (Si), and phosphorus (P)—in specified amounts, give the alloy a high tendency to amorphize, thus obtaining a ribbon-like material with an initial amorphous structure.

[0014] In the above embodiments, the method for preparing the iron-cobalt-based amorphous soft magnetic alloy includes the following stages: - Obtain high-purity master alloys from iron, cobalt, boron, silicon, phosphorus, and carbon, with a composition of selected atoms corresponding to the above ranges.

[0015] - The master alloy ingot is prepared in an electric arc melting furnace under an argon atmosphere.

[0016] - The resulting master alloy ingot was remelted in a rapid melt hardening machine. The linear velocity of the crystallizer was 40-50 m / s, and the injection pressure and temperature were (1-3) 10. 5 Pa and 1250-1350°C.

[0017] - Annealing is performed at a temperature of 300-350°C for 5-30 minutes.

[0018] According to the present invention, pure elements iron, cobalt, silicon, boron, and phosphorus are mixed in atomic percentages to obtain a mixture, wherein the starting materials iron, cobalt, silicon, boron, and phosphorus preferably have a purity >99%, and the master alloy is Fe-8-10 wt.% P. It is important to use bulk raw materials; powdered raw materials should be avoided in this invention.

[0019] After obtaining the mixture, it is melted to obtain an alloy ingot. In this invention, the melting is preferably carried out in a vacuum arc melting furnace. The uniformity of the ingot must be controlled, which can be achieved by repeated remelting, approximately five to six times.

[0020] After preparing the alloy ingot, a melting and quenching machine on a rotating copper crystallizing disk is needed to obtain the metal strip. The preferred linear velocity of the rotating disk is 40-50 m / s, and the injection pressure is (1-3) 10. 5The melt temperature is 1250-1350°C. The melt should be poured through a crucible with a linear or circular nozzle; the thickness of the linear nozzle should not exceed 0.5 mm, and the diameter of the circular nozzle should not exceed 0.7 mm. The distance between the edge of the crucible and the surface of the dish should be 0.2 mm. The crucible should be made of a material inert to the molten element.

[0021] When the alloy of the present invention is produced using the above method, a magnetic material with a saturation magnetic flux density of 1.94 T or more and a coercivity of 30 A / m or less can be obtained.

[0022] The magnetic properties of this invention can be improved through a structural relaxation process via annealing. Annealing can be performed in air, in a vacuum, or in an inert gas such as argon or nitrogen. However, it is preferable to perform the annealing in an inert gas environment. Ideally, the highest temperature during annealing should be higher than the initial temperature of the first crystallization stage (T0). X1 Temperature range below 80°C. The constant temperature holding time should be less than 30 minutes.

[0023] When the alloy of the present invention is produced using the above method, magnetic materials with a saturation magnetic flux density of 1.94 T or higher and a coercivity of 8 A / m or lower are readily obtained. Furthermore, the flexural ductility and fully amorphous structure of the material are also maintained.

[0024] Example 1 By atomic percentage (molecular formula: Fe) 67 .2Co 16 .8B 15 Si1) Weigh out raw materials iron, cobalt, silicon and boron with a purity of more than 99.9% and mix them to obtain a mixture; place the mixture in a crucible of an electric arc melting furnace to melt it, and obtain a master alloy ingot by remelting five times.

[0025] The obtained master alloy was remelted in a rapid quenching machine equipped with a copper disc crystallizer to obtain an amorphous alloy ribbon with a width of 1 mm and a thickness of 15 μm. X-ray phase analysis was performed... Figure 1 ) and transmission electron microscopy confirmed that the alloy is mainly amorphous and also contains a small number of nanoscale clusters with a volume fraction of less than 7 nm. These clusters correspond to a FeCo-based body-centered cubic (bcc) solid solution phase.

[0026] Heating the amorphous alloy strip to 340°C, compared to Figure 2 The first stage crystallization temperature T X1The annealing temperature was lower than 80°C. The annealing heating rate was 150°C / min, and the temperature was held at this temperature for 2 min, after which the sample was removed from the furnace and air-cooled. The annealed sample was then subjected to X-ray diffraction and transmission electron microscopy for structural observation. Based on the results, it was confirmed that the alloy retained the structure obtained during the quenching process. Figure 3 In a magnetic field of 800 kA / m, the magnetic flux density (saturation magnetic induction) is designated as B. s ( Figure 4 Saturation magnetic induction intensity B s The coercivity is 2.00 T, and the coercivity is H. c 9.5 A / m Figure 5 The permeability μ at a frequency of 1 kHz and a magnetic field of 5 A / m e It is 13500.

[0027] Example 2 By atomic percentage (molecular formula: Fe) 67.2 Co 16.8 B 14 Si1C1) Weigh out raw materials iron, cobalt, silicon, boron and carbon with a purity of over 99.9% and mix them to obtain a mixture; place the mixture in a crucible of an electric arc melting furnace to melt it, and obtain a master alloy ingot by remelting five times.

[0028] The molten alloy was quenched using a single-roll melt quenching machine to obtain an amorphous alloy ribbon with a width of 1 mm and a thickness of 18 μm. X-ray diffraction and transmission electron microscopy confirmed that the alloy structure was entirely amorphous. Figure 6 ).

[0029] The amorphous alloy strip was heated to 310°C, compared to Figure 7 Crystallization temperature T X1 The annealing process was carried out at a low temperature of 80°C. The heating rate during the annealing process was 150°C / min, and the temperature was maintained at this condition for 5 min. After removal from the furnace, the product was air-cooled. X-ray diffraction was used to determine the final product. Figure 8 The structure was observed using transmission electron microscopy, and the annealed samples were analyzed. The results confirmed that the alloy retained the structure obtained during quenching. Under a magnetic field of 800 kA / m (saturation magnetization), the magnetic flux density was designated as B. s ( Figure 9 Saturation magnetization B s The coercivity is 1.99 T, and the coercivity H is 1.99 T. c 8.0 A / m Figure 10 The permeability μ at a frequency of 1 kHz and a magnetic field of 5 A / m e It is 5800.

[0030] Example 3 By atomic percentage (molecular formula: Fe) 68 Co 17 Si1B 13 P1) Weigh out raw materials of iron, cobalt, silicon, and boron with a purity exceeding 99.9% and mix them with a pre-melted master alloy of Fe-8.8 wt.% P to obtain a mixture. Place the mixture in a crucible of an electric arc melting furnace and melt it until the chemical composition is homogeneous. Repeatedly remelt the master alloy and flip the ingot five times.

[0031] The obtained master alloy was quenched using a rotating copper crystallizing disk, resulting in an amorphous alloy ribbon 1 mm wide and 18 μm thick. X-ray diffraction and transmission electron microscopy confirmed that the alloy structure was entirely amorphous. Figure 11 ).

[0032] The amorphous alloy strip was heated to 305°C, compared to Figure 12 Crystallization temperature T X1 The annealing temperature was lower than 80°C. The annealing heating rate was 150°C / min, and the temperature was held at this level for 15 min, after which the alloy was removed from the furnace and air-cooled. The structure after annealing was analyzed by X-ray diffraction and transmission electron microscopy. Based on the results, it was confirmed that the alloy maintained the obtained structure during quenching. Figure 13 Under a magnetic field of 800 kA / m (saturation induction), the magnetic flux density is specified as B. s ( Figure 14 Saturation magnetic flux density B s The coercivity is 1.98 T, and the coercivity is H. c 7.0 A / m ( Figure 15 The permeability μ at a frequency of 1 kHz and a magnetic field of 5.0 A / m. e It is 5800.

Claims

1. A soft magnetic amorphous material based on iron and cobalt, containing boron, silicon, phosphorus, and carbon, with the following atomic percentages for each component: Iron –58.2–68.0; Cobalt –16.4–25.2; Boron –13–16; Silicon – 0.9 – 1.1; Phosphorus – 0 – 1.1; Carbon –0 –1.1.

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