JPS61221329A - Production of permanent magnet having axis of easy magnetization in radial direction of plate plane - Google Patents

Abstract

PURPOSE:To produce a permanent magnet which has high magnetic flux density and has the axis of easy magnetization in the radial direction of the plate plane by cooling ultraquickly the melt of an Fe-Cr-Co alloy, forming the melt into an annular or disk shape and subjecting the same to magnetic field annealing then to aging annealing under specific conditions. CONSTITUTION:The Fe-Cr-Co alloy contg., by wt%, 10-40% Cr, 2-40% Co and 0.01-5.00% at least one kind among B, Be, P, Al, Si, Ti, Zr, Hf, V, Nb, Ta, Mo and W and consisting of the balance Fe is melted. Such molten metal is dropped onto a cooling roll under rotation at a high speed by which the molten metal is ultraquickly cooled at a cooling rate of 10<3> deg.C/sec to form a plate material. The plate material is subjected to a soln. heat treatment at 900-1,300 deg.C according to need and is formed to the annular or disk shape. The annular or disk-shaped material is subjected to the magnetic field annealing while the impressing direction of the magnetic field is relatively rotated within the plane parallel with the plate plane in a 600-700 deg.C range and in succesiion the material is subjected to the aging annealing at the lower temp.

Description

[Detailed description of the invention]

Field of Industrial Application) This invention relates to a method of manufacturing a permanent magnet having an axis of easy magnetization in the radial direction of the plate surface, and is particularly suitable for use in applications such as permanent magnets for motors and the like in a ring or disk shape. It is useful.

[Conventional technology] Ring-shaped or disk-shaped permanent magnets that are radially anisotropic or multipolar magnetized have conventionally been produced mainly by compression sintering using fine powder of ferrite or rare earth magnets, or by plastic molding. It was manufactured by etc. However, although the thus obtained material had a large coercive force Bo, a high magnetic flux density Br could not be obtained because the material had a low density and was a compound. Furthermore, since the manufacturing method was originally isotropic, the axis of easy magnetization was not easily fixed. On the other hand, in order to increase Ha in alloy magnets with high Br, Fe-Or-00 alloys in particular are subjected to magnetic field treatment, but when such treatment is performed,
Having a direction close to the magnetic field direction (001>Separated into two phases with a long axis in the axial direction. Therefore, such a material can be said to be a permanent magnet with -axis anisotropy. C) Problem to be solved by the invention) Magnetic flux density It is an object of the present invention to provide an advantageous method for manufacturing a permanent magnet having a high magnetization and an axis of easy magnetization in the radial direction of the plate surface. +Means for solving the iui point) The inventors have conducted intensive research to solve the above problem, and as a result, have obtained the knowledge described below. (1) In order to obtain a high Br, ferrite magnets and rare earth magnets with low density are disadvantageous, and alloy magnets are more suitable. Such alloy magnets are hard and brittle, so it is extremely difficult to make them into a plate using normal rolling methods. However, by using a direct plate manufacturing method using liquid ultra-quenching, it is possible to easily obtain a ribbon. can. (2) In order to arrange the easy axis of magnetization in the radial direction of the plate surface, it is necessary that the easy axis of magnetization be included within the plate surface. (100) planes gather in parallel to , and therefore there are many easy magnetization axes (100>(010>) within the plate surface, which is also advantageous in this respect. (8) Easy magnetization axes in the radial direction In order to shape the material, it is sufficient to control the growth direction of the different phases due to two-phase separation.In other words, it is sufficient to perform two-phase separation annealing in a rotating magnetic field or without rotating the material in a magnetic field. This invention is based on the knowledge that Or: 1 G to 40 wt%
(hereinafter simply shown in %), Co: 2 to 40% and B
*Be, P, AZ, Si, Ti,
Zr, Hf, V. An alloy plate containing 0.01 to 5.00% of at least one selected from Nb*Ta, Mo, and W, and the remainder having a composition of substantially Fe, is optionally 90%
After solution treatment at a temperature range of 0 to 1300°C, it is formed into a ring or disc shape, and then a magnetic field is applied to the molded plate in a plane parallel to the plate surface at a temperature range of aOO to 700°C. This is a method for manufacturing a permanent magnet having an axis of easy magnetization in the radial direction of the plate surface, which comprises performing magnetic field annealing while relatively rotating the application direction, and then performing aging annealing at a temperature lower than the magnetic field annealing temperature. In this invention, as an alloy plate, a molten metal having the above composition is supplied onto a cooling body whose cooling surface is updated at high speed, and lO
Thickness O, obtained by rapid solidification at a cooling rate of ℃/S or more.
Sheets of Oa to 1.00as are particularly advantageously suited. This invention will be explained in detail below. First, the research results that formed the basis of this invention will be explained. After the 240r-15Co-9W-Fe alloy was melted, it was continuously supplied to the contact portion of rotating twin rolls and rapidly solidified to create a thin plate with a thickness of 0.50 mm. A ring-shaped sample with an outer diameter of 39w5 and an inner diameter of IQm was punched out from this thin plate, held at 660°C for 10 minutes in a rotating magnetic field with a strength of 10 koe, in a unidirectional magnetic field, and in no magnetic field, and then 24 at 610”C without applying a magnetic field
The rings were cooled at 10°C/h to 500'C for 24 hours and then subjected to age annealing at 50.0'C for 24 hours. , b and C. Figure a shows the case of annealing in a rotating magnetic field, figure C shows the case of annealing in a unidirectional magnetic field, and figure C shows the case of no magnetic field annealing. magnetic field, H/ is parallel to the magnetic field, H
Indicates that it is perpendicular to the deflecting magnetic field. As is clear from the figure, particularly excellent characteristics are obtained when a rotating magnetic field is applied. Next, 24 (3r -1s Co -4W -Fe alloy was melted and poured into a mold, and the obtained slab
After heating at ℃ for 80 minutes, hot rolling was performed to obtain a thin plate with a thickness of QJ15m. This thin plate was then subjected to solution treatment at 1280°C, and samples punched into rings with an outer diameter of 80 rings and an inner diameter of 10 rings were annealed in a magnetic field and a non-magnetic field, and then subjected to age annealing in the same manner as described above. The results of the investigation on the magnetic properties measured after the test are shown in Figures 2a-O, respectively. In the figure, Hrot' H7 and H-work are as described above, R// indicates the rolling direction, and R-work indicates the rolling direction. As is clear from the figure, the magnetic properties are significantly improved by applying a rotating magnetic field. On the other hand, in the case of unidirectional magnetic field annealing, the coercive force differs greatly between H/ and H process, and a large coercive force cannot be obtained in non-magnetic field annealing. As a result of repeated research based on the above-mentioned basic data, the inventors determined that by regulating the manufacturing conditions as follows,
It was confirmed that a permanent magnet with an axis of easy magnetization in the radial direction of the plate surface could be produced. α) Component composition of the material Or: IQ-40% Qr effectively contributes as an α phase stabilizing element. However, if the content is less than 10%, the alpha phase will become unstable, while if it exceeds 40%, the alpha phase will form and become brittle, so it was limited to a range of 10-40%. Co: 2-40% ○O is useful as a source of ferromagnetic phase formation after two-phase separation, but if it is less than 2%, high coercive force cannot be obtained, while if it exceeds 40%, it becomes brittle and Since it is also uneconomical, the content was limited to a range of 2 to 40%. B+ Be, P, Al, Si, Tit Zr+
Hf* L Nb, Ta, M. and W: 0.01 to 5.0 θ% Each of the above-mentioned elements contributes effectively as an element that promotes stabilization of the α phase, and their effects are equal. However, whether used alone or in combination, the content is 0.
If it is less than 0.01%, the effect of the addition is poor;
If it exceeds 0%, the saturation magnetic flux density will decrease, resulting in a decrease in the residual magnetic flux density and the maximum energy product (BH)! n
(2) Two-phase separation annealing in a rotating magnetic field The molten alloy produced to the above-mentioned preferred composition is ingot-formed and rolled. It is made into a thin plate by the liquid ultra-quenching method or the liquid ultra-quenching method described below. Then, after forming it into a ring or disk shape by punching, etching, or wire cutting, the direction of application of the magnetic field is rotated in a rotating magnetic field, that is, in a plane parallel to the plate surface, or the magnetic field is applied. The annealing treatment is performed under the condition that the direction is fixed and the molded plate is rotated. Through such annealing treatment, the alloy structure is separated into two phases: α phase and α2 phase, but at this time, the long axis direction is affected by the direction of the magnetic field, so the long axis extends radially, which is called radial anisotropy. is formed. If the annealing temperature exceeds 700°C, there is a high possibility that the alloy will exceed the Curie point, and the effect of magnetic field annealing will be lost. On the other hand, if the annealing temperature is below 600°C, two-phase separation will not occur or will take a long time. , magnetic field annealing is 600-7
The test was carried out in a temperature range of 00'C. (8) Age Annealing The thin plate subjected to the magnetic field annealing described above needs to be subjected to age annealing in order to expand the compositional difference between the α1 phase and the α phase and to further improve the magnetic properties. At this time, if annealing is performed for a long time at the same temperature as the two-phase separation annealing temperature mentioned above, the separated α, phase or α2 phase will become too coarse and lose shape anisotropy. It is necessary to carry out the operation at a temperature lower than the above temperature. In this way, a permanent magnet having a ring-shaped or disk-shaped material having an axis of easy magnetization in the radial direction of the plate surface can be obtained. (4) Solution treatment A plate-shaped permanent magnet with radial anisotropy can be obtained by the process consisting of the above-mentioned component composition - two-phase separation annealing and temporary annealing in a rotating magnetic field. It is more advantageous to perform solution treatment prior to two-phase separation annealing in a magnetic field. This solution treatment is performed to transform the material into a single tank, but if the treatment temperature is less than 900℃, it will take a long time for solution treatment, while if it exceeds 1300℃, the plate surface will melt. Therefore, it is necessary to carry out the process at a temperature range of 900 to 1300°C. Further, as the alloy plate which is the material of the present invention, a thin plate obtained by a liquid ultra-quenching method is particularly suitable. This is because when the liquid super-quenching method is applied, 1) the α phase is supercooled and a single α tank can be easily obtained without solution treatment, and 2) solution treatment at high temperature. is not required, so two-phase separation annealing can be performed with fine crystal grains intact. ■) The plate surface orientation of the obtained ribbon is (1o o) (ovw
>, and has many advantages such as the presence of many axes of easy magnetization on the plate surface. However, if the cooling rate is lower than 103° C./B, partial transformation will be induced after direct sheet production and a single α tank will not be obtained, so the cooling rate needs to be 108° C./S or higher. Also, if the thickness of the ribbon is made thinner than Q, Q5m111, the plate will have many defects and sufficient properties will be obtained, whereas if it is made thicker than l, QQs+1, unsolidified parts will remain inside even after plate making. Since it is difficult to obtain a cooling rate of 10"C/S or higher, it is preferable that the thickness of the quenched ribbon be approximately 0.05 to 1.001Is. (Function) Two-phase separation annealing is performed in a rotating magnetic field. By doing this, a structure in which the separated phase grows radially becomes a structure, and radial anisotropy is obtained.C Example] Example 1 280r -15Co -3AZ -2Ti -Fe(
A 10 kg ingot having a composition of 73 alloy was produced and hot-rolled into a plate with a thickness of a and a m, and then roughly cold-rolled in the direction perpendicular to the longitudinal direction of the hot-rolled plate.
The thickness of the board was made as thick as a parrot. This plate was immediately punched into a disc with a diameter of 20 mm without being subjected to solution treatment.
Annealed at 660 °C for 80 minutes in a rotating magnetic field of 0 koe,
Then, after reducing the magnetic field to zero, the temperature was further increased to 580℃ and 560℃.
, 540°C, and 620°C for 1 hour, respectively, and then annealed at 500°C for 5 hours. Table 1 below shows the results of an investigation of the magnetic properties of the thus obtained disks, in comparison with those obtained by annealing in a non-rotating, unidirectional magnetic field. Table 1 Example 2 A molten alloy having a composition of 2 B Or -1400-2No -Fe was supplied from its injection nozzle to the contact area of rotating twin rolls, and rapidly solidified at a cooling rate of 10°C/S. , finished into a thin plate with a thickness of 0.501111. After punching a ring with an outer diameter of a om and an inner diameter of 1 OIIS from this thin plate, it was held at 650°C for 160 minutes in a rotating magnetic field, a unidirectional magnetic field, and no magnetic field, respectively, and then the magnetic field was removed. 24 hours at 600℃ without adding
Next, cool down to 500°C at a rate of 10°C/h, and then
Aging annealing was performed at 00"C for 24 hours. The measurement results of the coercive force of each ring obtained are summarized in Table 2. Table 2 Example 8 240r -15 (30-4V -Fe ) alloy The molten metal was finished into a thin plate with a thickness of Q and 4Qtll by the twin roll method.After punching out a disk with an outer diameter of aosm from this thin plate,
Table 8 shows the coercive force of each disk obtained by holding it for 680° C. 12O in a rotating magnetic field of 10 koe, in a unidirectional magnetic field, and in no magnetic field. Table 8 Example 4 An alloy composition of 24Cr-15Co-4W-Fe was melted in a melting furnace and poured into a mold. 1 piece of the obtained slab
After heating to 300°C, it was rolled to a thickness of Q, (15m. After solution treatment was applied to this rolled plate at 11,300°C,
After punching out a ring with outer diameter SOW and inner diameter IQsm,
Magnetic field annealing was performed at 660°C for 110 minutes in a rotating magnetic field of 10 kOe, followed by annealing at 610°C for 110 minutes without applying a magnetic field.
The rings were then cooled to 500°C at a rate of 10"C/h for 24 hours, and then subjected to age annealing at 500°C for 124 hours. The coercive force of the ring thus obtained is shown in the table 6. For comparison, the ring was annealed in a rotating magnetic field. Table 4 also shows the measurement results of the coercive force of the samples annealed in a unidirectional magnetic field and in no magnetic field. Table 4 Example 5 Molten alloy having a composition of 220r -15Co -5V -Fe From this, an ingot of 10J9 was produced.
After heating to 00°C for 180 minutes, hot rolling was performed to a thickness of 0.40m, and solution treatment was performed at 1250'C. Then, after punching out a disk with an outer diameter of 3Qw, it was heated at 650°C for 2 hours in a rotating magnetic field of 10 koe, in a unidirectional magnetic field, and in no magnetic field.
Hold for 0 minutes, then heat to 600'C without applying a magnetic field.
After cooling to 500° C. at a rate of 10° C./s for 24 hours, aging annealing was performed at 500° C. for 12 hours. Table 5 shows the measurement results regarding the coercive force of each disc obtained. Table 5 Effects of invention C) Thus, according to this invention, it is possible to obtain a permanent magnet that has anisotropy in the radial direction within the plate plane, which was considered difficult in the past, especially when a quenched ribbon is used as the blade material. Solution treatment can also be omitted, resulting in process and energy savings6.

[Brief explanation of the drawing]

FIG. 1 and FIGS. 2a, b, and c are demagnetization curve diagrams of each ring obtained by annealing in a rotating magnetic field, a unidirectional magnetic field, and no magnetic field, respectively.

Claims (1)

[Claims] 1. Cr: 10-40 wt% Co: 2-40 wt% and B, Be, P, Al, Si, Ti, Zr, Hf, V, N
After forming an alloy plate containing 0.01 to 5.00 wt% of at least one selected from b, Ta, Mo, and W, with the remainder substantially having a composition of Fe, into a ring or disk shape, The molded plate is subjected to magnetic field annealing in a temperature range of 600 to 700°C while relatively rotating the direction of application of the magnetic field in a plane parallel to the plate surface, followed by aging annealing at a temperature lower than the magnetic field annealing temperature. A method for producing a permanent magnet having an axis of easy magnetization in the radial direction of the plate surface. 2. The alloy plate has a thickness of 0.05 to 0.05 and is obtained by supplying the molten metal having the above composition onto a cooling body whose cooling surface renews and moves at high speed, and rapidly solidifying it at a cooling rate of 10^3°C/s or more. 1.00m
2. The method according to claim 1, wherein the thin plate has a thickness of m. 3. Cr: 10-40 wt% Co: 2-40 wt% and B, Be, P, Al, Si, Ti, Zr, Hf, V, N
b, at least one selected from Ta, Mo, and W: 0.01 to 5.00 wt%, and the balance is substantially Fe.
After solution treatment at a temperature range of 00 to 1300°C, it is formed into a ring or disk shape, and then heated to a temperature of 600 to 700°C.
The formed plate is subjected to magnetic field annealing while relatively rotating the direction of application of the magnetic field in a plane parallel to the plate surface, and then subjected to aging annealing at a temperature lower than the magnetic field annealing temperature. A method for manufacturing a permanent magnet having an axis of easy magnetization in the radial direction of the plate surface.