JP2018078275A - METHOD FOR PRODUCING RFeB-BASED MAGNET - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an RFeB-based magnet, in which not only a grain boundary diffusion treatment can be performed so that a heavy rare earth element Ris caused to penetrate in the whole magnet as evenly as possible to thereby produce a magnet that is homogeneous as a whole but also the magnet can be produced without wasting the heavy rare earth element R.SOLUTION: A method for producing an RFeB-based magnet according to the present invention includes: an R-containing-substance adhesion step in which an R-containing slurry 12 obtained by mixing an organic solvent 122 with R-containing powder 121 that contains at least one heavy rare earth element Rselected from among Dy, Tb and Ho, is blown, in a form of dots or a line, onto a surface of a base material 11 including an RFeB-based sintered magnet or RFeB-based hot-plastic worked magnet which contains a rare earth element R, Fe, and B, thereby adhering an R-containing substance 13 to the surface of the base material; and a heating step in which the base material 11 to which the R-containing substance 13 has been adhered is heated to a predetermined temperature at which the heavy rare earth element Rin the R-containing substance 13 diffuses into the base material 11 through grain boundaries of the base material 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing an RFeB-based magnet containing R (rare earth element), Fe (iron) and B (boron). In particular, RFeB-based sintered magnets obtained by orienting raw material powders made of RFeB-based alloy powders in a magnetic field, and hot plastic working after hot pressing on similar raw material powders. Dy (dysprosium), Tb (terbium), and Ho (holmium) through the grain boundary of the crystal grains in the vicinity of the surface of the crystal grains in the RFeB hot plastic working magnet (see Non-Patent Document 1) in which the crystal grains are oriented ) At least one kind of rare earth elements (hereinafter, Dy, Tb and Ho are referred to as “heavy rare earth elements R ^H ”).

  The RFeB-based magnet was discovered by Hayato Sagawa in 1982 and has a feature that many magnetic properties such as residual magnetic flux density are much higher than the conventional permanent magnet. For this reason, RFeB magnets are used in various products such as hybrid and electric vehicle drive motors, motor-assisted bicycle motors, industrial motors, voice coil motors such as hard disks, speakers, headphones, and permanent magnet magnetic resonance diagnostic equipment. Is used.

Early RFeB-based magnets had the disadvantage that the coercive force _HcJ was relatively low among various magnetic properties. After that, the presence of heavy rare earth elements ^RH inside the RFeB-based magnets allowed the coercive force to be reduced. It became clear that improved. The coercive force is a force that can withstand the reversal of magnetization when a magnetic field opposite to the direction of magnetization is applied to the magnet, but the heavy rare earth element R ^H increases the coercive force by preventing this magnetization reversal. It is thought to have an effect to make.

On the other hand, when the content of the heavy rare earth element ^{RH in} the RFeB magnet increases, there arises a problem that the residual magnetic flux density _Br decreases, and thereby the maximum energy product (BH) _max also decreases. In addition, since heavy rare earth elements ^RH are expensive and scarce as resources, and the regions where they are produced are unevenly distributed, it is also possible to supply RFeB-based magnets to the market at low cost and stably. Increasing the ^RH content is undesirable.

Therefore, in order to increase the coercive force while suppressing the content of the heavy rare earth element ^RH , a grain boundary diffusion process is performed (see, for example, Patent Document 1). In the grain boundary diffusion treatment, an ^RH- containing material containing a heavy rare earth element R ^H is attached to the surface of an RFeB-based sintered magnet or RFeB-based hot plastic working magnet, and then heated, thereby allowing the heavy rare earth to pass through the grain boundary. The element ^RH is penetrated into the magnet, and the heavy rare earth element ^RH is diffused only near the surface of each crystal grain. Hereinafter, the RFeB-based sintered magnet or the RFeB-based hot plastic working magnet before the grain boundary diffusion treatment is referred to as a “base material”. The decrease in coercive force is caused by magnetization reversal occurring near the surface of the crystal grain and then spreading to the entire crystal grain. Thus, the concentration of the heavy rare earth element R ^H near the crystal grain surface is increased in this way. Thus, the magnetization reversal can be suppressed and the coercive force can be increased. On the other hand, since the heavy rare earth element R ^H is unevenly distributed only near the surface (grain boundary) of each crystal grain, the overall content can be suppressed, thereby preventing a decrease in residual magnetic flux density and maximum energy product. In addition, RFeB magnets can be supplied to the market at low cost and stably.

There are various methods for attaching the ^RH- containing material to the surface of the base material during the grain boundary diffusion treatment. For example, in Patent Document 1, an ^RH- containing material composed of a mixture of a powder containing a heavy rare earth element ^RH and an organic solvent is discharged from a nozzle toward the surface of the base material, whereby the ^RH- containing material is applied to the surface of the base material. It is described that it adheres.

JP2015-065218A JP 2006-019521 A International Publication WO2011 / 136223

Keiko Hioki, Atsushi Hattori, “Development of Dy-type Nd-Fe-B hot-working magnets using ultra-quenched powders”, Material 52, No. 8, pp. 19-24, General Foundation Forming Material Center, issued in August 2011

In Patent Document 1, in order not to waste heavy rare earth elements ^RH in excess of a necessary amount, a large number of nozzles are arranged opposite to the surface of the base material so that a thicker portion than necessary is not generated. It is said that it is desirable to attach an ^RH- containing material to the surface of the substrate. However, since in practice, possible to eject R ^H inclusions difficult at the same rate from each nozzle (supply amount per unit time), there arises a variation in the supply amount of R ^H inclusions for each nozzle, part In reality, more ^RH- containing materials are attached than necessary. As a result, ^RH penetrates not only in the vicinity of the grain boundary but also in the crystal grains in that portion, and the magnetic properties are deteriorated. Therefore, uniform magnetic characteristics cannot be obtained for the entire magnet. In addition, the heavy rare earth element R ^H is wasted.

The problem to be solved by the present invention is to produce a homogeneous magnet as a whole by allowing the heavy rare earth element R ^H to penetrate as much as possible into the entire base material (magnet) in the grain boundary diffusion treatment, and to produce the heavy rare earth element R ^H It is an object to provide an RFeB-based magnet manufacturing method capable of manufacturing a magnet without wasting power.

The manufacturing method of the RFeB-based magnet according to the present invention made to solve the above problems is as follows.
A heavy rare earth element R ^H composed of at least one of Dy, Tb and Ho is applied to the surface of a base material composed of an RFeB sintered magnet or an RFeB based hot plastic working magnet containing rare earth elements R, Fe and B. An ^RH- containing material adhering step for adhering the ^RH- containing material by spraying the ^RH- containing slurry in which the ^RH- containing powder and the organic solvent are mixed in a dotted or linear manner;
Heating the substrate to which the ^RH- containing material is adhered to a predetermined temperature at which the heavy rare earth element ^RH in the ^RH- containing material diffuses into the substrate through grain boundaries of the substrate; It is characterized by having.

In the production method of the RFeB-based magnet according to the present invention, by spraying the R ^H containing slurry in point-like or linear surface of the base material, the base material surface R ^H content consists slurry R ^H inclusions point-like or It adheres in a linear shape. R ^H inclusions each other of the deposited punctate or linear surface of the base material is not separated from one another (R ^H inclusions between the there is a portion where R ^H inclusions do not adhere) also may punctate Or, the linear ^RH- containing materials are connected to form a dotted or linear shading pattern (a state in which there is a portion with a small amount of ^RH- containing slurry between the dotted or linear portions). Also good. From the standpoint of reducing the amount of heavy rare earth element ^RH used, it is desirable that the ^RH- containing materials are separated from each other.

  The RFeB-based sintered magnet and the RFeB-based hot plastic working magnet contain R, Fe, and B as main constituent elements, but may contain other elements such as Co, Ni, Al, and Cu.

The present inventors have conducted experiments, the R ^H containing slurry rather than the entire substrate surface, the grain boundary diffusion process to R ^H inclusions after having adhered to the substrate surface by blowing a point-like or linear The coercive force of the RFeB magnet subjected to the above was higher than the coercive force of the base material before the grain boundary diffusion treatment. This is because the heavy rare earth element R ^H diffuses in the direction parallel to the substrate surface from the R ^H containing material adhering to the substrate surface in the form of dots or lines in the heating step. This makes it possible to prevent wasteful consumption of the heavy rare earth element ^RH because the coercive force is higher than that of the base material and an excessive amount of ^RH- containing slurry is not used.

Further, according to the inventor's experiment, by setting the area ratio, which is the ratio of the area occupied by the ^RH- containing material, to 31.4% or more of the substrate surface to which the ^RH- containing material is adhered, A coercive force equivalent to that obtained when the ^RH- containing material is adhered to the entire surface of the material can be obtained. This is because, by setting the area ratio to such a value, the heavy rare earth element ^RH spreads throughout the direction parallel to the substrate surface (even where no ^RH- containing material is attached), and the substrate It is thought that this is because the same effect as that obtained when the ^RH- containing material is adhered to the entire surface is obtained. In addition, the region to which the ^RH- containing material is attached in the form of dots or lines does not have to be on the entire surface of the substrate. For example, in the case of a plate-shaped (cuboid) substrate, one surface or two opposing surfaces Conventionally, the ^RH- containing material is generally adhered only to the surface. In such a case, when an ^RH- containing material is attached to one or two surfaces in a dotted or linear manner at an area ratio of 31.4% or more, the entire one or two surfaces contain ^RH. An effect equivalent to the case of attaching an object can be obtained.

The adhesion form of the ^RH- containing material on the surface of the base material is preferably a dot form rather than a linear form in that the amount of heavy rare earth element ^RH used can be further suppressed.

When adhering the R ^H inclusions in dots, it is desirable that their points like R ^H inclusions to be aligned in a straight line. Such arrangement of the ^RH- containing material is such that the ^RH- containing slurry is intermittently discharged from the nozzle while moving the nozzle facing the substrate surface linearly relative to the surface and parallel to the surface. By doing so, it can be easily formed.

Patent Document 3 describes that an ^RH- containing slurry is applied to the surface of a substrate using a screen printing technique. In this method, the screen is stretched on the surface of the substrate, the ^RH- containing slurry is supplied onto the screen, and the screen surface is rubbed with a squeegee so that the ^RH- containing slurry in the screen can permeate. Through which the ^RH- containing slurry is applied to the substrate surface. However, the method of Patent Document 3 is based on the assumption that the surface of the base material is a flat surface, and it is difficult to apply the ^RH- containing slurry to the surface of the base material that is a curved surface. In the manufacturing method of the RFeB-based magnet according to the present invention contrast, R ^H by blowing-containing slurry to a point or linear, surface plane of the substrate, R to the surface even with either curved ^H Inclusions can be deposited. In particular, the method for producing an RFeB magnet according to the present invention can suitably attach the ^RH- containing material when the surface of the base material, which has been difficult to apply by the method of Patent Document 3, is a curved surface. The curved surface to which the ^RH- containing material is attached may be either a convex surface or a concave surface. When the surface of the substrate has both a convex surface and a concave surface, the ^RH- containing material may be attached to both of them, or the ^RH- containing material may be attached to only one of them.

According to the method for producing an RFeB magnet according to the present invention, a heavy rare earth element ^RH is made to penetrate into the entire base material (magnet) as evenly as possible in the grain boundary diffusion treatment, and a homogeneous magnet as a whole is produced. A magnet can be manufactured without wasting the rare earth element ^RH .

Schematic which shows one Embodiment of the manufacturing method of the RFeB type magnet which concerns on this invention. The schematic block diagram of the ^RH containing slurry supply apparatus used in embodiment of the manufacturing method of the RFeB type magnet which concerns on this invention. The top view which shows the example of the pattern which arrange | positions a ^RH containing material on the surface of a base material. The top view which shows the example of the pattern which arrange | positions a ^RH containing material on the surface of a base material. The photograph which shows the example which made ^RH containing material adhere to the surface of a base material. The top view which shows the pattern used in Example 9, and arrange | positions the ^RH containing material on the surface of a base material. In Example 9, the photograph which shows the state which made the ^RH containing material adhere to the (a) convex surface and (b) concave surface of a base material.

1 to 7, an embodiment of a method for manufacturing an RFeB magnet according to the present invention will be described.
FIG. 1 is a schematic diagram showing the steps of a method for manufacturing an RFeB magnet according to this embodiment. First, a substrate 11 made of an RFeB sintered magnet or an RFeB hot plastic working magnet is prepared by a known method (a). The RFeB-based sintered magnet may be produced by a pressing method in which the raw RFeB-based alloy powder is pressed while being oriented by a magnetic field and then sintered, or as described in Patent Document 2, the RFeB-based alloy powder May be produced by a PLP (Press-less process) method in which the material is oriented by a magnetic field in a mold without being pressed and then sintered as it is. The RFeB-based hot plastic working magnet can be manufactured by the method described in Non-Patent Document 1. As shown in FIG. 1, the shape of the base material 11 was changed to a rectangular parallelepiped shape (reference numeral 111), an overall one having a bow shape (reference numeral 112), and a curved surface having an upward convex shape on only one surface of the rectangular parallelepiped. Various shapes such as one having a shape (reference numeral 113, hereinafter referred to as “one-sided bow shape”) can be taken. The base material having a curved surface, such as the base materials denoted by reference numerals 112 and 113, is manufactured by the PLP method using a mold corresponding to the shape, and is subjected to machining for forming those shapes. This is desirable in that it does not need to be performed (only the surface finishing is required).

Next, an ^RH- containing slurry 12 is prepared (b). The ^RH- containing slurry is prepared by mixing the ^RH alloy powder 121 containing the heavy rare earth element ^RH and the organic solvent 122. As the ^RH alloy powder 121, a TbNiAl alloy powder containing Tb, Ni, and Al at a mass ratio of 92: 4: 4 was used in the examples described later. Here, Dy or Ho may be used instead of Tb, or two or more of Dy, Tb and Ho may be used. Ni and Al have a role to lower the melting point of the alloy, but are not essential in the present invention. Therefore, the ^RH alloy powder 121 may be a metal containing only the heavy rare earth element ^RH , or one containing elements other than Ni and / or Al. As the organic solvent 122, in the examples described later, a mixture of two types of silicones having different viscosities (so-called silicone grease and silicone oil) was used to adjust the viscosity. The viscosity of the organic solvent 122 is such that the ^RH- containing slurry 12 can be ejected from the nozzle 21 described below, and adjacent points or lines when sprayed on the surface of the substrate 11 in the form of dots or lines. It was adjusted so that it would not flow on the surface so as to bond. An organic solvent other than silicone may be used.

Next, the ^RH- containing slurry 12 is sprayed onto the surface of the base material 11 in the form of dots or lines by the ^RH- containing slurry supply device 20 shown in FIG. 2 (FIG. 1 (c)). R ^H containing slurry supply device 20, and sends the one nozzle 21, a storage tank 22 for storing the R ^H containing slurry, to intermittently nozzle 21 by suction R ^H containing slurry 12 from the reservoir tank 22 R ^{The H-} containing slurry delivery device 23, the base material holding part 24 that holds the base material 11 so as to face the nozzle 21, and the moving part 25 that moves the relative positions of the nozzle 21 and the base material holding part 24 in the horizontal direction. With.

The ^RH- containing slurry delivery device 23 has a pneumatic or electromagnetic solenoid actuator. When a signal is transmitted from the controller of the ^RH- containing slurry delivery device 23 to the actuator, the valve element or the piston moves. The ^RH containing slurry is extruded to the nozzle 21. A piezoelectric element (piezoelectric element) can also be used as the actuator. These examples are blown onto the point-like surface of any R ^H containing slurry 12 substrate 11, the R ^H containing slurry from the nozzle 21 by opening a valve, for example, as R ^H containing slurry delivery apparatus 23 By using what is continuously fed, the ^RH- containing slurry 12 can be sprayed linearly on the surface of the substrate 11.

  Although the moving part 25 uses what moves the base material holding part 24 in this embodiment, what moves the nozzle 21 and what moves both the nozzle 21 and the base material holding part 24 may be used. In the following, the description of “moving the nozzle 21” means that the position of the nozzle 21 relative to the base material 11 held by the base material holding part 24 is moved, and the nozzle 21 and the base material holding part. The case where any one of 24 is moved is included. The moving unit 25 exemplified here has a mechanism for moving the base material holding unit 24 in two directions, ie, a horizontal X direction and a horizontal Y direction perpendicular to the X direction. Thus, the substrate holding part 24 can be moved to an arbitrary position within a predetermined planar range.

The surface of the substrate 11 to which the ^RH- containing slurry 12 is attached may be a flat surface or a curved surface.

If the organic solvent 122 is volatile, the ^RH- containing slurry 12 sprayed on the surface of the substrate 11 evaporates and the solid solvent remains on the surface of the substrate 11. Is non-volatile, it remains on the surface of the substrate 11 as an ^RH- containing slurry. In any case, the ^RH- containing material 13 containing the heavy rare earth element ^RH is attached to the surface of the base material 11 in the form of dots or lines. When the ^RH- containing slurry is sprayed on the surface of the base material 11 in the form of dots or lines, if the points or lines are separated to some extent, the points or lines of the ^RH- containing material 13 attached to the surface of the base material 11 are also obtained. They are separated from each other and spaced apart.

The base material 11 to which the ^RH- containing material 13 is attached is heated to a predetermined temperature together with the ^RH- containing material 13 (d). The predetermined temperature is a temperature at which the heavy rare earth element R ^H in the R ^H containing material 13 diffuses into the base material 11 through the grain boundary of the base material 11, and is typically 700 to 1000 ° C. Thus, after diffusing the heavy rare earth element R ^H into the base material 11 through the grain boundary, the heavy rare earth element R ^H remains on the surface of the base material 11 if necessary, or an aging treatment (treatment at a relatively low temperature of about 500 ° C.). An RFeB magnet, which is the final product, is obtained by performing a grinding process and a magnet forming process for removing the residue of the ^RH- containing material 13.

3 and 4 show examples of patterns in which the ^RH- containing material 13 is arranged on the surface of the substrate 11. FIG. 3 shows an example in which the ^RH- containing material 13 is a dot-like shape that is circular in plan view. The ^RH- containing material 13 is arranged in a square lattice shape in the example of FIG. The ^RH- containing material 13 may be arranged in a rectangular lattice instead of a square lattice. In such an arrangement, the ^RH containing slurry 13 is sprayed intermittently and periodically on the surface of the base material 11 while moving the nozzle 21 in the vertical direction or the horizontal direction of the figure, thereby arranging the rows of the ^RH containing materials 13. After forming one row, the nozzle 21 is moved in a direction perpendicular to the row, and the same operation is repeated to form the row. On the other hand, in the example of FIG. 3 (b), the ^RH inclusions 13 are arranged in one row at equal intervals in the vertical direction in the figure, and the positions are shifted by a half cycle between adjacent rows in the horizontal direction. Is provided. This arrangement is hereinafter referred to as a “staggered” arrangement. Such an arrangement is basically formed by the same method as in (a), but when the ^RH- containing slurry 12 is sprayed on the second and subsequent rows, the position is shifted by 1/2 cycle in the row direction. Can be formed.

The example of FIG. 3C is a modification of (a), and the interval between the ^RH- containing materials 13 in the same column is shorter than the interval between the columns. Such an arrangement is close to a linear arrangement, but since there is a gap between the ^RH- containing materials 13 in the same row, the amount of heavy rare earth element ^RH used should be less than that of the linear arrangement. Can do. In the example of FIG. 3 (d), rows are formed in the vertical and horizontal directions of the figure at the same interval as the distance in which three ^RH containing materials 13 are arranged in the vertical and horizontal directions. The interval between these rows may be a size other than the three ^RH- containing materials 13.

The example of FIG.3 (e) arrange | positions the ^RH containing material 13 randomly (randomly). In the example of FIG. 3 (f), the dotted ^RH- containing material 13 is formed on the surface of the base material 11 more densely than the other examples, and the ^RH- containing materials 13 are in contact with each other.

FIG. 4 shows an example in which an ^RH- containing material 13 other than a circle is used in plan view. FIG. 4A shows a square ^RH- containing material 13. Depending on the shape of the nozzle 21, the ^RH- containing material 13 can take various planar shapes such as a rectangle, other quadrangle, a polygon other than a quadrangle such as a triangle and a hexagon, and an ellipse, in addition to a square. In the example of FIG. 4B, the shape of the ^RH- containing material 13 in a plan view is linear, and a large number of the linear ^RH- containing materials 13 are arranged in parallel.

In FIG. 5, the example which made the ^RH containing material 13 adhere to the surface of the base material 11 is shown with a photograph. In this example, a nozzle 21 having an inner diameter of 0.12 mm was used. The used ^RH alloy powder 121 is a powder of TbNiAl alloy containing the above-mentioned Tb, Ni and Al in a mass ratio of 92: 4: 4, and the organic solvent 122 is a silicone grease and silicone oil in a mass ratio of 10: The ^RH- containing slurry 12 is a mixture of the ^RH alloy powder 121 and the organic solvent 122 at a mass ratio of 75:25. Many of the ^RH- containing materials 13 attached to the surface of the substrate 11 have almost the same diameter, and the value of the diameter is 0.68 mm. On the entire surface of the substrate 11, 16 mg / cm ² of ^RH- containing material 13 was adhered per unit area. The area ratio, which is the ratio of the ^RH- containing material 13 in the entire surface of the substrate 11, is 31.4%.

Next, the results of measuring the magnetic properties of the samples of Examples and Reference Examples manufactured under a plurality of conditions in this embodiment will be shown. In this experiment, each sample was produced using a single-sided bow-shaped substrate (reference numeral 113 in FIG. 1) having the same size and produced in the same lot. In each sample of the example, a circular ^RH- containing material was attached in a dot shape to the arcuate curved surface of the substrate in plan view. In the reference example, by using the screen printing method described in Patent Document 3, the ^RH- containing material was uniformly adhered to the entire plane by applying the ^RH- containing slurry to the plane facing the arcuate curved surface. The reason why the ^RH- containing slurry was applied to the flat surface in the reference example is that it is difficult to apply the ^RH- containing slurry to the curved surface by the screen printing method. The heating temperature in the grain boundary diffusion treatment is 900 ° C. Other manufacturing conditions differ depending on the sample and will be described below.

Table 1 shows the contents of different production conditions for each sample and the magnetic properties at room temperature for each sample. Here, the dot interval c and the gap d in the table are as shown in FIG. 3A when the arrangement of the ^RH- containing material 13 is a square lattice, and as shown in FIG. 3B when it is a staggered pattern. , The distance between one ^RH- containing material 13 and the ^RH- containing material 13 adjacent to the ^RH- containing material 13 and the size of the gap (the portion where the ^RH- containing material 13 does not exist). The coating amount refers to the coating amount per unit area of the surface on which the ^RH- containing material 13 is applied. The area ratio refers to the ratio of the area occupied by the ^RH- containing material on the surface of the substrate to which the ^RH- containing material is attached.

From these experimental results, it can be said that a coercive force higher than the coercive force of 13 kOe of the substrate is obtained in any of the examples. Further, in Examples 1 to 4, 7, and 8 having an area ratio larger than 31.4%, a coercive force higher than that of Reference Example 1 was obtained, and equivalent to Reference Example 2 having a larger coating amount than those Examples. The coercive force of is obtained. In particular, in Examples 1 to 4, a coercive force equal to or higher than that of the reference example in which the ^RH- containing material 13 was uniformly applied to the surface of the base material was obtained despite the fact that a gap was provided between the dots. It is noted that.

Next, Example 9 using a base material having a bow shape as a whole (the one shown in FIG. 1 (a) denoted by reference numeral 112) will be described. In Example 9, among the two curved surfaces of the bow-shaped base material 112, both the convex surface 1121 and the concave surface 1122 (see FIG. 1 (a)) have R ^H so that the pattern shown in FIG. Inclusion material 13 was deposited. In this pattern, placing dots of R ^H inclusions 13 in a row in the vertical direction in FIG. 6 (y-direction) to the distance c (the gap between the dots d), a row of dots of the R ^H inclusions 13 6 Are arranged at intervals a in the horizontal direction (x direction). The basic position of dots in the y direction is shifted by (c / 8) between adjacent dot rows. Therefore, in the columns separated by 8 periods in the x direction, the dots are arranged at the same position in the y direction. However, the dots of the ^RH- containing material 13 are arranged at positions shifted by (c / 2) in the y direction from the basic position every four rows (only the row indicated by the alternate long and short dash line in FIG. 6). Yes. This disturbs the row of dots extending in the direction inclined by arctan (1/8) (about 7 °) from the x direction formed when dots are arranged only at the basic position so that the dots are dispersed. Can be arranged.

In Example 9, the diameter of the nozzle 21 was 0.21 mm, whereby the diameter of the dots of the ^RH- containing material 13 formed on the surface of the substrate 112 was 0.8 mm. The distance between the dots in the y direction was 2 mm, the gap d between the dots in the y direction was 1.2 mm, and the distance a between the rows of dots extending in the x direction was 0.6 mm. The coating amount of the ^RH- containing material 13 on the surface of the base material 112 is 16 mg / cm ² , and the area ratio occupied by the ^RH- containing material 13 on the surface of the base material 112 is 31.6%. The ^RH- containing material 13 used is the same as in Examples 1-8.

FIG. 7 is a photograph showing a state in which dots of the ^RH- containing material 13 are attached to the (a) convex surface 1121 and (b) concave surface 1122 of the substrate 112. Thus, after depositing the dots of the ^RH- containing material 13 on both the convex surface 1121 and the concave surface 1122, the sample of Example 9 was obtained by heating to a temperature of 900 ° C. as in Examples 1-8. . When the magnetic characteristics of the obtained sample were measured, the residual magnetic flux density B _r is 13.9 kg, the coercive force H _cj is called 22.3KOe, values comparable to other examples were obtained.

Although was deposited R ^H inclusions 13 in both the convex 1121 and the concave 1122 of the substrate 112 is arcuate in Example 9, only the convex surface 1121, or only the concave 1122 is adhered to R ^H inclusions 13 May be. Further, the dot pattern of the ^RH- containing material 13 attached to the convex surface 1121 and the concave surface 1122 is not limited to the example shown in FIG. 6, and can take various forms such as the examples shown in FIG. 3 and FIG. 4. . Alternatively, the dot pattern of the ^RH- containing material 13 shown in FIG. 6 may be applied to a substrate having another shape, such as a flat substrate or a single-sided arcuate substrate. Furthermore, the dots of the ^RH- containing material 13 can be attached to the convex surface and / or the concave surface of the substrate having various shapes in a pattern other than that shown in FIG.

DESCRIPTION OF SYMBOLS 11, 111, 112, 113 ... Base material 1121 ... Convex surface 1122 ... Concave surface 12 ... ^RH containing slurry 121 ... ^RH alloy powder 122 ... Organic solvent 13 ... ^RH containing material 20 ... ^RH containing slurry supply apparatus 21 ... Nozzle 22 ... Storage tank 23 ... RH-containing slurry delivery device 24 ... Base material holding part 25 ... Moving part

Claims (7)

A heavy rare earth element R ^H composed of at least one of Dy, Tb and Ho is applied to the surface of a base material composed of an RFeB sintered magnet or an RFeB based hot plastic working magnet containing rare earth elements R, Fe and B. An ^RH- containing material adhering step for adhering the ^RH- containing material by spraying the ^RH- containing slurry in which the ^RH- containing powder and the organic solvent are mixed in a dotted or linear manner;
Heating the substrate to which the ^RH- containing material is adhered to a predetermined temperature at which the heavy rare earth element ^RH in the ^RH- containing material diffuses into the substrate through grain boundaries of the substrate; A method for producing an RFeB-based magnet, comprising: 2. The method for producing an RFeB magnet according to claim 1, wherein a plurality of dotted or linear ^RH- containing materials are adhered to the surface of the base material in a state of being separated from each other. The RFeB system according to claim 1 or 2, wherein an area ratio, which is a ratio of an area occupied by the ^RH- containing material, on the surface of the base material to which the ^RH- containing material is attached is 31.4% or more. Magnet manufacturing method. The method for producing an RFeB-based magnet according to any one of claims 1 to 3, wherein the ^RH- containing material is adhered to the surface of the base material in the form of dots. The method for producing an RFeB-based magnet according to claim 4, wherein the ^RH- containing materials in the form of dots attached to the surface of the base material are arranged in a straight line. The method for producing an RFeB magnet according to any one of claims 1 to 5, wherein a surface of the base material to which the ^RH- containing material is attached is a curved surface.   The method according to claim 6, wherein the curved surface is a concave surface.