Aluminum-nickel-cobalt permanent magnet, preparation method thereof and precision component

Abstract

The invention relates to an aluminum-nickel-cobalt permanent magnet, a preparation method thereof and a precision part. The preparation method of the aluminum-nickel-cobalt permanent magnet comprises the following steps that raw materials are provided according to the stoichiometric ratio of the aluminum-nickel-cobalt permanent magnet, the raw materials are sequentially subjected to smelting treatment and directional solidification casting, and a casting is prepared; the casting is sequentially subjected to homogenization heat treatment, magnetic field heat treatment and tempering aging treatment, and the aluminum-nickel-cobalt permanent magnet is prepared; wherein the homogenizing heat treatment is performed at the temperature of 1200-1350 DEG C in a heat preservation manner; in the step of magnetic field heat treatment, the direction of a magnetic field and the crystal orientation of the casting are in the same direction, and the crystal orientation of the casting is crystal brim in an X-ray diffraction pattern of the casting; 100 gt; and orienting. According to the method, the aluminum-nickel-cobalt permanent magnet which is relatively regular in structure, high in component uniformity and high in performance stability is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of alloys, and in particular to an AlNiCo permanent magnet and a preparation method and precision parts thereof. Background Art

[0002] Alnico permanent magnets have the advantages of high Curie temperature and operating temperature, excellent temperature stability, good mechanical properties and corrosion resistance. They are widely used in various industrial fields, especially in the preparation of high-end precision parts such as parts for aerospace and precision instruments.

[0003] AlNiCo permanent magnet material is an alloy mainly composed of aluminum, nickel, cobalt, iron and other trace metal elements. It is usually obtained by melting the alloy raw materials into molten steel through induction smelting, then pouring it into a sand mold to obtain an alloy ingot, and finally processing it. However, due to the limitations of traditional casting methods, serious component segregation is inevitable in the final product, and it will also cause irregular crystal structure of the casting, which will eventually lead to reduced magnet performance and poor consistency and stability. This is an important technical problem that needs to be solved urgently in the current magnetic material industry.

[0004] Therefore, the existing technology still needs to be improved. Summary of the invention

[0005] Based on this, the present invention provides an aluminum nickel cobalt permanent magnet with a relatively regular structure, high component uniformity and high performance stability, a preparation method thereof, and precision components.

[0006] One aspect of the present invention provides a method for preparing an AlNiCo permanent magnet, comprising the following steps:

[0007] Providing raw materials according to the stoichiometric ratio of Al-Ni-Co permanent magnets, and sequentially subjecting the raw materials to smelting treatment and directional solidification casting to prepare castings;

[0008] The casting is sequentially subjected to homogenization heat treatment, magnetic field heat treatment and tempering aging treatment to prepare an Al-Ni-Co permanent magnet;

[0009] The homogenization heat treatment is carried out at a temperature of 1200°C to 1350°C; in the step of magnetic field heat treatment, the direction of the magnetic field is in the same direction as the crystal orientation of the casting, and the crystal orientation of the casting is the crystal orientation along the X-ray diffraction pattern of the casting. <100> orientation.

[0010] The preparation method provided by the present invention, through sequentially carrying out smelting treatment, directional solidification casting, specific homogenization heat treatment, specific magnetic field heat treatment and tempering aging treatment, can obtain a crystal with good structure and crystal along the <100> On the other hand, by adding a specific homogenization heat treatment step, the degree of component segregation can be significantly reduced, and the internal stress generated in the casting process can be reduced, and the organizational defects inside the casting can be improved to a certain extent. The various process conditions have a coordinated influence to obtain an AlNiCo permanent magnet with a more regular structure and high component uniformity, thereby improving the performance stability of the AlNiCo permanent magnet.

[0011] In some embodiments, the homogenization heat treatment time is 0.5h to 7h; and / or

[0012] The directional solidification casting step is performed using a mold, the temperature of the mold is 1450°C to 1700°C, the mold is provided with a riser, the pouring thickness of the riser is 10mm to 25mm, and the mold is placed on a water cooling plate, the water temperature is 20°C to 40°C.

[0013] In the step of further regulating directional solidification casting, the casting process conditions used in casting are used to promote the crystal along <100> Directional growth.

[0014] In some embodiments, the step of magnetic field heat treatment includes the following conditions:

[0015] First, solution treat at 1220℃~1280℃ for 10min~60min, then cool to 800℃~950℃ at a rate of 1℃ / s~30℃ / s, then cover with insulation cotton and cool to below 500℃ in a magnetic field greater than 0.3T or keep at 780℃~860℃ for 5min~40min, and finally air cool to room temperature in a magnetic field.

[0016] By regulating the conditions of magnetic field heat treatment, the structural uniformity of AlNiCo permanent magnets can be further improved.

[0017] In some embodiments, the tempering and aging treatment step includes the following conditions:

[0018] First, keep it at 620℃~660℃ for 3h~10h, then cool it down to 560℃~600℃ for 10h~15h, then cool it down to 530℃~570℃ for 12h-20h, and finally cool it down to below 150℃ with the furnace.

[0019] Tempering and aging treatment uses a specific three-stage tempering treatment to further improve the composition uniformity of AlNiCo permanent magnets.

[0020] In some of the embodiments, the smelting treatment step is carried out in an induction melting furnace, and the obtained molten steel temperature is 1600°C to 1800°C.

[0021] In some of the embodiments, after the homogenization heat treatment step and before the magnetic field heat treatment step, the step of pre-processing the casting after the homogenization heat treatment is also included, and the pre-processing includes cutting and grinding.

[0022] Pre-processing steps can improve the consistency of product appearance quality.

[0023] In some of the embodiments, the composition of the AlNiCo permanent magnet includes, by mass percentage, 5%-10% Al, 8%-15% Ni, 20%-45% Co, 2%-5% Cu, less than 10% Ti, less than 1.5% Nb, less than 0.3% S, less than 0.3% C, less than 0.5% Si, and the balance Fe.

[0024] Another aspect of the present invention provides an AlNiCo permanent magnet, wherein in the X-ray diffraction pattern of the AlNiCo permanent magnet, the crystals along <100> orientation; and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Al element does not exceed 0.5%, the difference in the percentage of the Ni element does not exceed 1%, the difference in the percentage of the Co element does not exceed 2%, and the difference in the percentage of the Fe element does not exceed 2%;

[0025] Alternatively, the AlNiCo permanent magnet is prepared by the AlNiCo permanent magnet preparation method as described above.

[0026] In some embodiments, the composition of the AlNiCo permanent magnet also includes Ti and Cu elements, and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Ti element does not exceed 0.5%, and the difference in the percentage of the Cu element does not exceed 0.3%.

[0027] According to another aspect of the present invention, there is provided a precision component, wherein the precision component comprises the AlNiCo permanent magnet as described above.

[0028] The aluminum nickel cobalt permanent magnet has a relatively regular structure and high component uniformity, thereby improving the stability of the performance. It is used in the preparation of precision components and can effectively improve the stability of the precision components. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an X-ray diffraction (XRD) pattern of the AlNiCo permanent magnet prepared in Example 1;

[0030] Figure 2 This is the X-ray diffraction (XRD) pattern of the AlNiCo permanent magnet prepared in Comparative Example 1. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. Preferred embodiments of the present invention are provided in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0034] The terms "and / or", "or / and", and "and / or" used herein include any one of two or more related listed items, and also include any and all combinations of the related listed items, wherein the any and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in the present application, the technical solution undoubtedly includes technical solutions connected by "logical and", and also undoubtedly includes technical solutions connected by "logical or".

[0035] In the present invention, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel solutions of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0036] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0037] The temperature parameters in the present invention, if not specifically limited, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, ±1°C are allowed. In the present invention, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ±5°C.

[0038] The mass or weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass or weight described in the description of the embodiments of the present invention may be units known in the chemical industry such as μg, mg, g, and kg.

[0039] An embodiment of the present invention provides a method for preparing an AlNiCo permanent magnet, comprising the following steps S10 to S20.

[0040] S10: providing raw materials according to the stoichiometric ratio of Al-Ni-Co permanent magnets, and sequentially performing smelting treatment and directional solidification casting on the raw materials to prepare castings.

[0041] S20: performing homogenization heat treatment, magnetic field heat treatment and tempering aging treatment on the casting in sequence to prepare an AlNiCo permanent magnet.

[0042] The homogenization heat treatment is carried out at a temperature of 1200°C to 1350°C; in the step of magnetic field heat treatment, the direction of the magnetic field is in the same direction as the crystal orientation of the casting, and the crystal orientation of the casting is the crystal orientation along the X-ray diffraction pattern of the casting. <100> orientation.

[0043] Research has found that the main factors affecting the uniformity and stability of AlNiCo permanent magnets are their intrinsic properties and organizational structure, and the preparation and casting process is the direct cause of the intrinsic properties and organizational structure of the product. Therefore, after a large number of experimental explorations, the present invention provides the above-mentioned preparation method, which obtains a good crystal structure and a crystal structure along the direction of the crystal through sequential smelting treatment, directional solidification casting, specific homogenization heat treatment, specific magnetic field heat treatment and tempering aging treatment. <100> On the other hand, by adding a specific homogenization heat treatment step, the degree of component segregation can be significantly reduced, and the internal stress generated in the casting process can be reduced, and the organizational defects inside the casting can be improved to a certain extent. The various process conditions have a coordinated influence to obtain an AlNiCo permanent magnet with a more regular structure and high component uniformity, thereby improving the performance stability of the AlNiCo permanent magnet.

[0044] “The direction of the magnetic field is in the same direction as the crystal orientation of the casting” can be understood as the two directions are parallel.

[0045] In some embodiments, the homogenization heat treatment time is 0.5h to 7h.

[0046] In some of the embodiments, the smelting process is performed in an induction melting furnace, and the obtained molten steel temperature is 1600°C to 1800°C.

[0047] In some of the embodiments, after the smelting process is completed, the molten steel is further subjected to slag removal to remove impurities.

[0048] In some of the embodiments, the directional solidification casting step is carried out using a mold, the temperature of the mold is 1450℃~1700℃, the mold is provided with a riser, the casting thickness of the riser is 10mm~25mm, and the mold is placed on a water cooling plate, the water temperature is 20℃~40℃.

[0049] In the step of further regulating directional solidification casting, the casting process conditions used in casting are used to promote the crystal along <100> Directional growth.

[0050] In some of the embodiments, the steps of directional solidification casting are: pouring the molten steel into a mold after the smelting treatment, wrapping the mold with an insulating material after the pouring is completed until it is cooled to below 800°C, and then dismantling the mold and removing the riser.

[0051] Specifically, the casting is a block with a length of 10 to 150 mm, a width of 10 to 150 mm, and a height of 10 to 150 mm, or a cylinder with a diameter of 10 to 150 mm and a height of 10 to 200 mm, or a special-shaped piece of similar size.

[0052] In some of the embodiments, the uniform heat treatment is performed in a high temperature furnace. After the treatment, the casting is cooled to below 500° C. in the furnace and then taken out.

[0053] In some of the embodiments, after the step of homogenizing heat treatment and before the step of magnetic field heat treatment, the step of pre-machining the casting after homogenizing heat treatment is further included, and the pre-machining includes cutting and grinding.

[0054] The purpose of pre-processing is to select areas with good columnar crystals and facilitate the product to maintain a good orientation during subsequent magnetic field heat treatment, while improving the consistency of product appearance quality. Cutting and grinding can adopt cutting and grinding processes commonly used in this field without special limitations.

[0055] In some specific examples, the pre-processing steps are as follows: cutting off the bottom portion of the casting close to the cooling plate surface with a height of 3mm to 25mm and the top (excluding the riser) portion away from the water-cooling plate surface with a height of 3mm to 30mm; at the same time, it is necessary to grind according to the required product size specifications, and leave a subsequent processing allowance of 0.2mm to 1.0mm.

[0056] In some embodiments, the step of magnetic field heat treatment includes the following conditions:

[0057] First, solution treat at 1220℃~1280℃ for 10min~60min, then cool to 820℃~950℃ at a rate of 1℃ / s~30℃ / s, then cover with insulation cotton and cool to below 500℃ in a magnetic field greater than 0.3T or keep at 780℃~860℃ for 5min~40min, and finally air cool to room temperature in a magnetic field.

[0058] By regulating the conditions of magnetic field heat treatment, the structural uniformity of AlNiCo permanent magnets can be further improved.

[0059] The thermal insulation cotton can adopt the thermal insulation cotton material commonly used in the field, without any special requirements or restrictions.

[0060] In some embodiments, the tempering and aging treatment step includes the following conditions:

[0061] First, keep it at 620℃~660℃ for 3h~10h, then cool it down to 560℃~600℃ for 10h~15h, then cool it down to 530℃~570℃ for 12h-20h, and finally cool it down to below 150℃ with the furnace.

[0062] Tempering and aging treatment uses a specific three-stage tempering treatment to further improve the composition uniformity of AlNiCo permanent magnets.

[0063] In some of the embodiments, the method further comprises the step of finishing the product after the tempering and aging treatment by grinding and finishing according to the specifications required by the product.

[0064] The finishing process may be a finishing process commonly used in the art without any particular limitation.

[0065] In some of the embodiments, the composition of the AlNiCo permanent magnet includes, by mass percentage, 5%-10% Al, 8%-15% Ni, 20%-45% Co, 2%-5% Cu, less than 10% Ti, less than 1.5% Nb, less than 0.3% S, less than 0.3% C, less than 0.5% Si, and the balance Fe.

[0066] In some of the embodiments, the composition of the AlNiCo permanent magnet includes, by mass percentage, 5%-10% Al, 8%-15% Ni, 20%-45% Co, 2%-5% Cu, greater than 0 and less than 10% Ti, greater than 0 and less than 1.5% Nb, 0-0.3% S, 0-0.3% C, 0-0.5% Si and the balance Fe.

[0067] The mass percentage of Al mentioned above includes 5%, 6%, 7%, 8%, 9%, 10%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0068] The mass percentage of Ni mentioned above includes 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0069] The mass percentage of Co mentioned above includes 20%, 25%, 30%, 35%, 40%, 43%, 44%, 45%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0070] The mass percentage of Cu mentioned above includes 2%, 3%, 4%, 5%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0071] The mass percentage of Ti mentioned above includes 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0072] The mass percentage of Nb mentioned above includes 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0073] Another embodiment of the present invention provides an AlNiCo permanent magnet, wherein in the X-ray diffraction pattern of the AlNiCo permanent magnet, the crystals along <100> orientation; and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Al element does not exceed 0.5%, the difference in the percentage of the Ni element does not exceed 1%, the difference in the percentage of the Co element does not exceed 2%, and the difference in the percentage of the Fe element does not exceed 2%.

[0074] Or another embodiment of the present invention provides an AlNiCo permanent magnet, which is prepared by the AlNiCo permanent magnet preparation method as described above.

[0075] The AlNiCo permanent magnet provided by the present invention has a relatively regular structure, high component uniformity, and low segregation degree of each main element, thereby improving the performance consistency and stability of the AlNiCo permanent magnet.

[0076] In some of the embodiments, the composition of the AlNiCo permanent magnet also includes Ti and Cu elements, and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Ti element does not exceed 0.5%, and the difference in the percentage of the Cu element does not exceed 0.3%.

[0077] According to another aspect of the present invention, a precision component is provided, and the precision component includes the above AlNiCo permanent magnet.

[0078] The aluminum nickel cobalt permanent magnet has a relatively regular structure and high component uniformity, thereby improving the stability of the performance. It is used in the preparation of precision components and can effectively improve the stability of the precision components.

[0079] The above-mentioned precision parts can be various types of precision parts in this field, including but not limited to: parts for instruments and meters, parts for motors, parts for electroacoustic devices, parts for magnetic machinery, etc.

[0080] The present invention will be described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0081] The following are specific embodiments.

[0082] Example 1

[0083] (1) Prepare raw materials according to the following mass percentages: 7.5% Al, 13% Ni, 33.5% Co, 2.8% Cu, 6.7% Ti, 1.0% Nb, 0.25% S, 0.1% C, 0.25% Si and the balance Fe. Place the raw materials in an induction melting furnace for smelting treatment and remove slag to obtain pure molten steel, then pour the molten steel into a high-temperature casting mold: the molten steel temperature is about 1650°C, the casting temperature is about 1600°C, and the casting is placed on a water-cooled plate with a water temperature of 25°C. The periphery of the casting mold is wrapped with aluminum silicate insulation cotton. After the casting is completed, it is cooled to about 500°C to obtain a cylindrical casting with a diameter of 68 mm and a height of 120 mm. The thickness of the riser is about 15 mm. Then the casting mold is removed and the riser is removed.

[0084] (2) The casting is subjected to uniform heat treatment: the casting is subjected to heat preservation treatment in a high-temperature furnace at 1280°C for 2.5 hours, and then slowly cooled to about 300°C in the furnace and taken out, and finally cooled to room temperature; then the 10 mm high part at the bottom (water-cooled plate end) and the 20 mm high part of the top (riser end) of the casting are cut off, and pre-processed by cutting, grinding and other methods according to the required standard samples to obtain pre-processed samples with a diameter and height of 10.5 mm; then magnetic field heat treatment is carried out: first, the casting is solidified at 1250°C. The steel was dissolved and treated for 30 minutes, then cooled to about 900°C at a rate of 10°C / s, then isothermally treated in a 0.35T magnetic field for 30 minutes, and finally air-cooled to room temperature in a magnetic field; tempering and aging treatment was then carried out: first, it was kept at 640°C for 8 hours, then cooled to 590°C and kept for 12 hours, further cooled to 540°C and kept for 13 hours, and finally cooled to below 150°C with the furnace and taken out of the furnace, and finally fine-machining was carried out to obtain an AlNiCo permanent magnet with a diameter and height of 10 mm.

[0085] (3) XRD test was performed on the AlNiCo permanent magnet sample. The X-ray diffraction (XRD) pattern is as follows: Figure 1 As shown, the diffraction intensity ratio of its (200) crystal plane to (110) crystal plane is 10.75, which has good <100> Direction oriented structure.

[0086] Take 3 samples from the upper part, middle part and lower part of the AlNiCo permanent magnet in the height direction, respectively, and record them as: upper-1, upper-2, upper-3, middle-1, middle-2, middle-3, lower-1, lower-2, lower-3; and test the contents of main component elements of the samples respectively, and test the magnetic properties at the same time. The specific test results are shown in Tables 1 and 2 respectively.

[0087] Table 1

[0088]

[0089]

[0090] Table 2

[0091] sample Remanence(kGs) Coercivity(Oe) Maximum magnetic energy product (MGOe) Up -1 10.92 1683 11.63 Up -2 10.96 1688 11.66 Up -3 10.95 1660 11.51 Medium - 1 10.88 1698 11.87 Medium-2 10.92 1689 11.82 Medium-3 10.90 1711 11.65 Next - 1 10.88 1720 11.75 Next - 2 10.81 1702 11.56 Next - 3 10.90 1687 11.92

[0092] Comprehensive Tables 1 to 2 and Figure 1 It can be seen that the preparation method of the present invention can obtain an AlNiCo permanent magnet with a relatively regular structure and high component uniformity, thereby improving the performance stability and consistency of the AlNiCo permanent magnet.

[0093] Example 2

[0094] Example 2 The experimental steps of Example 1 were repeated. It was found that the composition uniformity and magnetic property stability of the prepared AlNiCo permanent magnet were basically consistent with those in Example.

[0095] It can be seen that the preparation method of the present invention has a stable process effect and exhibits good mass production capability.

[0096] Example 3

[0097] The method is basically the same as that of Example 1, except that the uniform heat treatment condition in step (2) is: heat preservation treatment in a high temperature furnace at 1210° C. for 7 hours. The other step conditions are the same as those of Example 1.

[0098] The results show that the prepared AlNiCo permanent magnet has good composition uniformity and magnetic property stability, and is basically consistent with the results of Example 1. The specific test results are shown in Tables 3 and 4.

[0099] Table 3

[0100] sample Al(％) Ni(%) Co(%) Cu(%) Ti(%) Fe(%) Up -1 7.23 13.53 33.75 2.55 5.79 35.75 Up -2 7.34 13.62 33.81 2.56 5.76 35.32 Up -3 7.23 13.55 33.80 2.51 5.78 35.47 Medium - 1 7.33 13.62 34.02 2.52 5.82 35.64 Medium-2 7.25 13.81 33.98 2.55 5.69 35.58 Medium-3 7.35 13.70 34.13 2.56 5.75 35.75 Next - 1 7.31 13.68 34.12 2.55 5.81 34.96 Next - 2 7.34 13.63 34.12 2.52 5.82 35.18 Next - 3 7.28 13.77 33.94 2.57 5.78 35.65

[0101] Table 4

[0102] sample Remanence(kGs) Coercivity(Oe) Maximum magnetic energy product (MGOe) Up -1 10.95 1685 11.88 Up -2 10.94 1676 11.87 Up -3 10.95 1688 11.85 Medium - 1 10.91 1683 11.82 Medium-2 10.92 1681 11.82 Medium-3 10.93 1694 11.85 Next - 1 10.90 1712 11.88 Next - 2 10.91 1720 11.89 Next - 3 10.90 1688 11.82

[0103] Example 4

[0104] The method is basically the same as that of Example 1, except that the uniform heat treatment condition in step (2) is: heat preservation treatment in a high temperature furnace at 1340° C. for 1.2 h. The other step conditions are the same as those of Example 1.

[0105] The results show that the prepared AlNiCo permanent magnet has good composition uniformity and magnetic property stability, and is basically consistent with the results of Example 1. The test results are shown in Tables 5 and 6.

[0106] Table 5

[0107] sample Al(％) Ni(%) Co(%) Cu(%) Ti(%) Fe(%) Up -1 7.41 13.35 34.31 2.53 5.77 35.79 Up -2 7.32 13.48 34.15 2.57 5.89 34.98 Up -3 7.23 13.36 33.88 2.55 5.75 35.63 Medium - 1 7.35 13.22 34.45 2.51 5.83 35.74 Medium-2 7.28 13.82 33.12 2.68 5.67 34.82 Medium-3 7.45 13.71 33.76 2.45 5.70 35.35 Next - 1 7.48 13.34 34.30 2.59 5.57 34.89 Next - 2 7.24 13.34 33.27 2.62 5.66 35.16 Next - 3 7.41 13.27 33.25 2.60 5.91 35.19

[0108] Table 6

[0109] sample Remanence(kGs) Coercivity(Oe) Maximum magnetic energy product (MGOe) Up -1 10.86 1627 11.15 Up -2 10.88 1721 11.23 Up -3 11.11 1666 11.55 Medium - 1 10.89 1655 11.67 Medium-2 10.99 1762 11.12 Medium-3 10.91 1728 11.59 Next - 1 10.88 1694 11.61 Next - 2 11.03 1739 11.06 Next - 3 10.91 1725 11.13

[0110] Comparative Example 1

[0111] Comparative Example 1 is basically the same as Example 1, except that uniform heat treatment is not performed in experimental step (2) of Comparative Example 1, and the conditions of other steps are the same as those of Example 1.

[0112] The X-ray diffraction (XRD) pattern of the AlNiCo permanent magnet sample prepared in Comparative Example 1 is as follows: Figure 2 As shown, the analysis shows that: although there is <100> The diffraction intensity ratio of the (200) crystal plane to the (110) crystal plane is relatively low, only 0.61, indicating a poor orientation.

[0113] The results of the content detection of the main component elements and the magnetic properties test of the AlNiCo permanent magnet sample prepared in Comparative Example 1 are shown in Tables 7 and 8, respectively.

[0114] Table 7

[0115] sample Al(％) Ni(%) Co(%) Cu(%) Ti(%) Fe(%) Up -1 7.02 12.46 36.87 2.03 6.17 36.98 Up -2 6.37 13.59 33.12 2.58 5.01 34.02 Up -3 7.03 14.77 33.67 2.49 4.38 37.84 Medium - 1 6.55 15.91 34.77 1.92 5.08 34.81 Medium-2 7.31 14.87 35.13 2.87 6.87 35.12 Medium-3 7.67 13.02 30.21 3.07 4.19 33.25 Next - 1 6.97 12.17 31.39 3.27 5.98 30.87 Next - 2 6.81 11.36 34.56 2.47 6.98 35.15 Next - 3 7.66 12.11 36.51 2.66 6.12 39.54

[0116] Table 8

[0117] sample Remanence(kGs) Coercivity(Oe) Maximum magnetic energy product (MGOe) Up -1 11.08 1522 9.89 Up -2 10.26 1610 8.67 Up -3 11.35 1313 10.05 Medium - 1 10.16 1389 8.15 Medium-2 9.87 1601 7.69 Medium-3 10.15 1233 8.25 Next - 1 8.96 1732 8.32 Next - 2 9.67 1596 9.13 Next - 3 10.71 1554 7.71

[0118] Compare the data in Tables 1 to 6 and 7 to 8, and compare Figure 1-2 It can be seen that: compared with the technical solution of comparative example 1, the structure of the aluminum nickel cobalt permanent magnet obtained by the technical solution of the present invention is more regular and the composition uniformity is higher. For example, the difference in the percentage of Al in any two partial samples in Example 1 does not exceed 0.5%, while the difference in the percentage of Al in comparative example 1 reaches 1.11%. Furthermore, the performance stability of the aluminum nickel cobalt permanent magnet obtained by the technical solution of the present invention is higher.

[0119] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing an AlNiCo permanent magnet, characterized in that: The steps include: Providing raw materials according to the stoichiometric ratio of Al-Ni-Co permanent magnets, and sequentially subjecting the raw materials to smelting treatment and directional solidification casting to prepare castings; The casting is subjected to homogenization heat treatment, magnetic field heat treatment and tempering aging treatment in sequence to prepare an Al-Ni-Co permanent magnet; The homogenization heat treatment is carried out at a temperature of 1200°C to 1350°C; in the step of magnetic field heat treatment, the direction of the magnetic field is in the same direction as the crystal orientation of the casting, and the crystal orientation of the casting is the crystal orientation along the X-ray diffraction pattern of the casting. <100> orientation.

2. The method for preparing an AlNiCo permanent magnet according to claim 1, characterized in that: The homogenization heat treatment time is 0.5h to 7h; and / or The directional solidification casting step is performed using a mold, the temperature of the mold is 1450°C to 1700°C, the mold is provided with a riser, the pouring thickness of the riser is 10mm to 25mm, and the mold is placed on a water cooling plate, the water temperature is 20°C to 40°C.

3. The method for preparing an AlNiCo permanent magnet according to claim 2, characterized in that: The step of magnetic field heat treatment includes the following conditions: First, solution treat at 1220℃~1280℃ for 10min~60min, then cool to 800℃~950℃ at a rate of 1℃ / s~30℃ / s, then cover with insulation cotton and cool to below 500℃ in a magnetic field greater than 0.3T or keep at 780℃~860℃ for 5min~40min, and finally air cool to room temperature in a magnetic field.

4. The method for preparing an AlNiCo permanent magnet according to any one of claims 1 to 2, characterized in that: The steps of the tempering aging treatment include the following conditions: First, keep it at 620℃~660℃ for 3h~10h, then cool it down to 560℃~600℃ for 10h~15h, then cool it down to 530℃~570℃ for 12h-20h, and finally cool it down to below 150℃ with the furnace.

5. The method for preparing an AlNiCo permanent magnet according to any one of claims 1 to 2, characterized in that: The smelting treatment step is carried out in an induction melting furnace, and the obtained molten steel temperature is 1600°C to 1800°C.

6. The method for preparing an AlNiCo permanent magnet according to any one of claims 1 to 2, characterized in that: After the homogenization heat treatment step and before the magnetic field heat treatment step, the method further includes a step of pre-processing the casting that has undergone the homogenization heat treatment, wherein the pre-processing includes cutting and grinding.

7. The method for preparing an AlNiCo permanent magnet according to any one of claims 1 to 2, characterized in that: The components of the AlNiCo permanent magnet include, in percentage by mass: 5%-10% Al, 8%-15% Ni, 20%-45% Co, 2%-5% Cu, less than 10% Ti, less than 1.5% Nb, less than 0.3% S, less than 0.3% C, less than 0.5% Si and the balance Fe.

8. An AlNiCo permanent magnet, characterized in that: In the X-ray diffraction diagram of the AlNiCo permanent magnet, the crystals along <100> orientation; and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Al element does not exceed 0.5%, the difference in the percentage of the Ni element does not exceed 1%, the difference in the percentage of the Co element does not exceed 2%, and the difference in the percentage of the Fe element does not exceed 2%; Or, the AlNiCo permanent magnet is prepared by the method for preparing an AlNiCo permanent magnet according to any one of claims 1 to 7.

9. The AlNiCo permanent magnet according to claim 8, characterized in that: The components of the AlNiCo permanent magnet also include Ti and Cu elements, and in any two parts of the AlNiCo permanent magnet, the difference in the percentage of the Ti element does not exceed 0.5%, and the difference in the percentage of the Cu element does not exceed 0.3%.

10. A precision component, characterized in that: The precision component includes the AlNiCo permanent magnet as described in any one of claims 8 to 9.

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