WO2022209466A1 - R-t-b系焼結磁石の製造方法 - Google Patents
R-t-b系焼結磁石の製造方法 Download PDFInfo
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- WO2022209466A1 WO2022209466A1 PCT/JP2022/007631 JP2022007631W WO2022209466A1 WO 2022209466 A1 WO2022209466 A1 WO 2022209466A1 JP 2022007631 W JP2022007631 W JP 2022007631W WO 2022209466 A1 WO2022209466 A1 WO 2022209466A1
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- sintering
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- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
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Definitions
- This application relates to a method for manufacturing an RTB based sintered magnet.
- RTB based sintered magnet (R is a rare earth element and always contains at least one selected from the group consisting of Nd, Pr and Ce, T is at least one transition metal and always contains Fe , B is boron) is the main phase of a compound having a R 2 Fe 14 B-type crystal structure, the grain boundary phase located in the grain boundary portion of this main phase, and the compound produced by the influence of trace elements and impurities phase.
- the RTB sintered magnet has a high residual magnetic flux density B r (hereinafter sometimes simply referred to as “B r ”) and a high coercive force H cJ (hereinafter simply referred to as “H cJ ”). It is known as the magnet with the highest performance among permanent magnets.
- VCM voice coil motors
- EV electric vehicles
- HV electric vehicles
- PHV motors for industrial equipment
- household appliances such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV), motors for industrial equipment, and household appliances.
- VCM voice coil motors
- EV electric vehicles
- HV electric vehicles
- PHV motors for industrial equipment
- household appliances such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV), motors for industrial equipment, and household appliances.
- RTB based sintered magnets contribute to energy saving and environmental load reduction through the miniaturization and weight reduction of various motors.
- Such an RTB based sintered magnet is manufactured through processes such as preparing alloy powder, press-molding the alloy powder to produce a compact, and sintering the compact. .
- Patent document 1 discloses an example of such an RTB system sintered magnet.
- H cJ and squareness ratio have increased due to the development of materials and improvements in manufacturing methods for sintered RTB magnets. may decrease.
- B boron
- the embodiment of the present disclosure provides a method for manufacturing RTB based sintered magnets that can solve such problems.
- the method for producing an RTB based sintered magnet of the present disclosure includes a sintering step of sintering a molded body of RTB based alloy powder, wherein the sintering step includes a first step of heating the compact to a first sintering temperature T1 to fabricate a first sintered compact; a cooling step of lowering the temperature of the first sintered compact to a cooling temperature T0; and a second step of heating the first-stage sintered body to a second sintering temperature T2 to fabricate a second-stage sintered body.
- the first sintering temperature T1 and the second sintering temperature T2 are higher than 900°C, and the cooling temperature T0 is 900°C or lower.
- a first sintering time t1 for maintaining the first sintering temperature T1 in the first step is shorter than a second sintering time t2 for maintaining the second sintering temperature T2 in the second step.
- the first sintering temperature T1 and the second sintering temperature T2 are 1000°C or higher and 1100°C or lower.
- the first sintering temperature T1 is 1040°C or higher and lower than 1080°C
- the second sintering temperature T2 is 1020°C or higher and lower than 1060°C.
- the first sintering time t1 is 30 minutes or more and 2 hours or less
- the second sintering time t2 is 1 hour or more and 15 hours or less.
- the first sintering time t1 is half or less of the second sintering time t2.
- the cooling temperature T0 is 700°C or higher and 900°C or lower.
- [B] is the content of B in mass %
- [T] is the content of T in mass %
- FIG. 1 is a flow chart showing the sintering process in the present disclosure.
- FIG. 2 is a diagram schematically showing an example of a temperature profile of objects to be heat-treated (a molded body and a sintered body) in the sintering step of this embodiment.
- FIG. 3 is a diagram schematically showing another example of the temperature profile of the objects to be heat treated (the molded body and the sintered body) in the sintering step of this embodiment.
- FIG. 4 is a diagram schematically showing still another example of the temperature profile of the objects to be heat treated (the molded body and the sintered body) in the sintering step of this embodiment.
- FIG. 5 is a diagram schematically showing still another example of the temperature profile of the objects to be heat treated (the molded body and the sintered body) in the sintering step of this embodiment.
- R is a rare earth element and always contains at least one selected from the group consisting of Nd, Pr and Ce.
- T is at least one transition metal and always contains Fe.
- Manufacture of the RTB system sintered magnet in this embodiment is performed as shown in FIG. a first stage step (S10) of heating the molded body to a first sintering temperature T1 to produce a first stage sintered body; a cooling step (S20) for lowering the temperature of the first-stage sintered body to a cooling temperature T0; a second stage step (S30) of heating the first stage sintered body to a second sintering temperature T2 to produce a second stage sintered body; including.
- the first sintering temperature T1 and the second sintering temperature T2 are over 900°C, and the cooling temperature T0 is 900°C or less. Also, in the first step, the first sintering time t1 for holding the first sintering temperature T1 is shorter than the second sintering time t2 for holding the second sintering temperature T2 in the second step.
- RTB based sintered magnets consist of Nd 2 Fe 14 B phase (ferromagnetic) crystal grains as the main phase, and boron (B)-rich B- It is composed of intermetallic compounds such as rich and Nd-rich phases.
- the sintering reaction proceeds by the formation of a liquid phase involving these phases contained in the powder particles that make up the compact. Although the densification reaction does not occur when the amount of the liquid phase is insufficient, the densification reaction rapidly progresses when the amount of the liquid phase increases as the temperature rises. During the sintering process, part of the intermetallic compound in the powder particles melts, resulting in a liquid phase that modifies the surface of the main phase crystal grains or causes reduction of oxides, while bonding and densifying the particles. progressing.
- H cJ and H k /H cJ may unexpectedly decrease due to variations in alloy powder composition and manufacturing conditions. It was also found that this phenomenon is remarkable when the composition ratio of B contained in the RTB system sintered magnet is low. Since it is difficult to avoid variations in the alloy powder composition and manufacturing conditions, it is desired to achieve good H cJ and H k /H cJ even if the alloy powder composition and manufacturing conditions vary. In order to achieve good H cJ and H k /H cJ , it is necessary to densify to a desired density and to have a uniform structure during sintering.
- FIGS. are graphs in which the horizontal axis is time and the vertical axis is temperature, and schematically show an example of the temperature profile of the objects to be heat treated (the molded body and the sintered body) in the sintering process.
- the temperature of the object to be processed is measured by a thermometer such as a thermocouple provided in the sintering device (sintering furnace).
- the actual temperature of the compact or sintered body does not need to be exactly the same as the reading (temperature measurement value) indicated by the thermometer in the sintering furnace, and a deviation of ⁇ 5°C or less between the two shall be acceptable.
- a thick solid line indicates the relationship between temperature and time.
- Time is the elapsed time from the start of the sintering process.
- the unit of elapsed time is, for example, hours, but may be minutes or seconds.
- the temperature as noted above, is a thermometer reading, but is substantially equal to the set temperature specified by the temperature control program.
- the thick solid line in the figure is composed of straight line segments, but the actual temperature or the set temperature may fluctuate curvilinearly.
- the temperature of the object to be processed increases linearly and monotonously from room temperature to the first sintering temperature T1, and the temperature rise rate is constant.
- the temperature increase rate does not have to be constant, and there may be a period during which the temperature increase rate becomes zero.
- the compact may be held at a temperature of, for example, about 200° C. for 1 hour or more and 10 hours or less.
- the graph in the figure shows horizontal straight lines indicating a temperature of 900°C and a temperature of 1000°C.
- both the first sintering temperature T1 and the second sintering temperature T2 are 1000° C. or higher and 1100° C. or lower.
- the first sintering temperature T1 is higher than the second sintering temperature T2, but as shown in FIG. good too.
- the first sintering temperature T1 is, for example, 1040°C or higher and lower than 1080°C
- the second sintering temperature T2 is, for example, 1020°C or higher and lower than 1060°C.
- the first sintering time t1 is 30 minutes or more and 2 hours or less, and the second sintering time t2 is 1 hour or more and 15 hours or less.
- a sintered magnet with good H cJ and H k /H cJ can be provided without a long sintering time. minutes or more and 1 hour or less, and the second sintering time t2 is 1 hour or more and 8 hours or less.
- the first sintering temperature T1 is higher than the second sintering temperature T2 as shown in FIG. 2, it is preferable to set the first sintering time t1 shorter than the second sintering time t2.
- the first sintering time t1 is preferably half or less than the second sintering time t2.
- a cooling step (S20) for lowering the temperature of the first sintered body to the cooling temperature T0 is performed between the first step (S10) and the second step (S30).
- the time t0 during which the temperature of the object to be processed (first-stage sintered body) is 900° C. or less during the cooling process is defined as “cooling time”. Therefore, the cooling time t0 includes a cooling period from 900° C. to the cooling temperature T0 during the cooling from the first sintering time t1, and a cooling temperature from the cooling temperature T0 to 900° C. during the heating from the cooling temperature T0. including the transition time to It is preferable that there is a difference of 50° C.
- the cooling temperature T0 is preferably a temperature lower than the first sintering temperature T1 by 50° C. or more.
- the temperature drop rate during cooling may be lower than the example shown in FIG. 2, for example, as shown in FIG.
- the dependence of the magnet properties on the temperature drop rate during cooling is small. Therefore, from the viewpoint of shortening the time required for the sintering step and improving mass productivity, the temperature drop rate is preferably 3° C./min or more, more preferably 20° C./min or more.
- the cooling temperature T0 may be in the range of 700° C. or higher and 900° C. or lower as long as it is 900° C. or lower, or may be at the room temperature level as shown in FIG. From the viewpoint of shortening the time required for the cooling process and improving mass productivity, the cooling temperature T0 can be set, for example, within the range of 800° C. or higher and 900° C. or lower.
- R is a rare earth element and necessarily contains at least one selected from the group consisting of Nd, Pr and Ce.
- R is a rare earth element and necessarily contains at least one selected from the group consisting of Nd, Pr and Ce.
- R is a rare earth element and necessarily contains at least one selected from the group consisting of Nd, Pr and Ce.
- combinations of rare earth elements represented by Nd--Dy, Nd--Tb, Nd--Dy--Tb, Nd--Pr--Dy, Nd--Pr--Tb and Nd--Pr--Dy--Tb are used.
- R Dy and Tb are particularly effective in improving HcJ .
- other rare earth elements such as La may be contained, and misch metal and didymium can also be used.
- R may not be a pure element, and may contain impurities that are unavoidable in manufacturing within an industrially available range.
- the content is, for example, 27% by mass or more and 35% by mass or less.
- the R content of the RTB based sintered magnet is 31 mass % or less (27 mass % or more and 31 mass % or less, preferably 29 mass % or more and 31 mass % or less).
- the R content of the RTB sintered magnet to 31% by mass or less and the oxygen content to be 400 ppm or more and 4000 ppm or less (preferably 400 ppm or more and 2500 ppm or less, more preferably 400 ppm or more and 2000 ppm or less).
- the generation of oxidized R is reduced. Therefore, higher magnetic properties can be obtained.
- T contains iron (including the case where T consists essentially of iron), and 50% or less of it in mass ratio may be replaced with cobalt (Co) (T consists essentially of iron and cobalt (including cases). Co is effective in improving temperature characteristics and corrosion resistance, and the alloy powder may contain Co in an amount of 10% by mass or less.
- the content of T may account for the remainder of R and B or R and B and M described later.
- the content of B may also be a known content, and the preferred range is, for example, 0.8% by mass to 1.2% by mass. If it is less than 0.9% by mass, high HcJ may not be obtained, and if it exceeds 1.2% by mass, Br may decrease. Note that part of B can be substituted with C (carbon).
- M element can be added to improve HcJ .
- M element is one or more selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Zr, Nb, Mo, In, Sn, Hf, Ta and W .
- the amount of M element to be added is preferably 5.0% by mass or less. This is because if the content exceeds 5.0% by mass, Br may decrease. In addition, unavoidable impurities can also be allowed.
- the content of N (nitrogen) in the RTB sintered magnet is preferably 50 ppm or more and 600 ppm or less.
- the nitrogen content is more preferably 50 ppm or more and 400 ppm or less, most preferably 100 ppm or more and 300 ppm or less. This is because the reduction in magnetic properties due to nitriding can be suppressed while improving the pulverizability.
- the content of C (carbon) in the RTB based sintered magnet is preferably 50 ppm or more and 1300 ppm or less.
- R 28% by mass or more and 35% by mass or less
- B 0.8% by mass or more and 1.2% by mass or less
- T61.5% by mass or more is included
- [B] is the content of B in mass%
- [T] is the content of T in mass%
- Formula 1 satisfy.
- the B content is less than that of a general RTB system sintered magnet.
- a general RTB system sintered magnet has a ratio of [T ] /55.85 ( Fe atomic weight) is less than 14 [B]/10.8 (B atomic weight).
- the step of preparing the coarsely pulverized powder of the RTB-based sintered magnet alloy in the present embodiment includes the step of preparing the RTB-based sintered magnet alloy and grinding the alloy by, for example, a hydrogen pulverization method. and coarsely grinding by
- the following is an example of the manufacturing method of the RTB based sintered magnet alloy.
- an alloy ingot can be obtained by an ingot casting method in which a metal or alloy that has been adjusted in advance to have the composition described above is melted and put into a mold.
- it is represented by the strip casting method or centrifugal casting method in which the molten metal is brought into contact with a single roll, twin rolls, a rotating disk, or a rotating cylindrical mold, etc. and rapidly cooled to produce a solidified alloy that is thinner than the alloy made by the ingot method.
- Alloy flakes can be produced by a quenching method.
- Materials manufactured by either the ingot method or the quenching method can be used in the embodiments of the present disclosure, but they are preferably manufactured by a quenching method such as strip casting.
- the thickness of the quenched alloy produced by the quenching method is usually in the range of 0.03 mm to 1 mm and is in the form of flakes.
- the molten alloy begins to solidify from the surface in contact with the chill roll (roll contact surface), and crystals grow in a columnar shape from the roll contact surface in the thickness direction.
- the quenched alloy is cooled in a shorter time than the alloy (ingot alloy) produced by the conventional ingot casting method (die casting method), so the structure is refined and the crystal grain size is small. In addition, the area of the grain boundary is wide.
- the size (average particle size) of the hydrogen-pulverized powder can be, for example, 1.0 mm or less, preferably 10 ⁇ m or more and 500 ⁇ m or less.
- Example of process for obtaining fine powder> the coarsely pulverized powder is supplied to a jet mill device whose pulverizing chamber is filled with an inert gas, and the coarsely pulverized powder is pulverized to obtain a fine powder.
- a fine powder (RTB alloy powder) having an average particle size of 2.0 ⁇ m or more and 4.5 ⁇ m or less can be obtained.
- the step of obtaining such fine powder can be performed using, for example, a jet milling system.
- the increase in the oxygen content of the RTB based sintered magnet due to the steps after pulverization is preferably 50 ppm or more and 300 ppm or less, more preferably , from 50 ppm to 200 ppm.
- the average particle size of the fine powder in the step of obtaining the fine powder is preferably 2.0 ⁇ m or more and 3.5 m or less. By reducing the average particle size, it is possible to improve the magnetic properties.
- Example of the process of producing a compact of fine powder> In the process of producing the molded body, it is preferable to form the molded body by pressing in an inert gas atmosphere or wet pressing from the viewpoint of suppressing oxidation in magnetic field pressing. Particularly in wet pressing, the surfaces of the particles constituting the compact are coated with a dispersant such as an oil agent, and contact with oxygen and water vapor in the atmosphere is suppressed. Therefore, it is possible to prevent or suppress the particles from being oxidized by the atmosphere before, during or after the pressing process.
- a dispersant such as an oil agent
- the dispersion medium is a liquid in which the alloy powder can be dispersed to obtain a slurry.
- Mineral oil or synthetic oil can be mentioned as a preferred dispersion medium for use in the present disclosure.
- the type of mineral oil or synthetic oil is not specified, but if the kinematic viscosity at normal temperature exceeds 10 cSt, the increase in viscosity will strengthen the bonding force between the alloy powders, and the orientation of the alloy powders during wet compaction in a magnetic field. may adversely affect Therefore, the kinematic viscosity of the mineral oil or synthetic oil at room temperature is preferably 10 cSt or less. If the fraction point of the mineral oil or synthetic oil exceeds 400° C., it becomes difficult to remove the oil after obtaining the molded body, and the amount of residual carbon in the sintered body increases, which may reduce the magnetic properties.
- the fraction point of mineral oil or synthetic oil is preferably 400° C. or less.
- vegetable oil refers to oil extracted from a plant, and the type of plant is not limited to a specific plant.
- a slurry can be obtained by mixing the obtained alloy powder and a dispersion medium.
- the mixing ratio of the alloy powder and the dispersion medium is not particularly limited, but the concentration of the alloy powder in the slurry is preferably 70% or more (that is, 70% or more by mass) by mass. This is because, at a flow rate of 20 to 600 cm 3 /sec, the alloy powder can be efficiently supplied into the cavity and excellent magnetic properties can be obtained.
- the concentration of the alloy powder in the slurry is preferably 90% or less in mass ratio.
- the method of mixing the alloy powder and the dispersion medium is not particularly limited. The alloy powder and the dispersion medium may be separately prepared, weighed in predetermined amounts, and mixed.
- a container containing a dispersion medium is placed at the alloy powder discharge port of the pulverizer such as a jet mill, and the alloy powder obtained by pulverization may be collected directly into the dispersion medium in the container to obtain a slurry.
- the inside of the vessel is also filled with an atmosphere of nitrogen gas and/or argon gas, and the obtained alloy powder is recovered directly into the dispersion medium without exposing it to the atmosphere to form a slurry.
- a compact having a predetermined size and shape can be obtained by molding the slurry thus obtained with a known wet press apparatus. This compact is sintered to obtain a sintered body.
- the compact is sintered to obtain a sintered body.
- the sintering step in this embodiment is a first stage step (S10) of heating the molded body to a first sintering temperature T1 to produce a first stage sintered body; a cooling step (S20) for lowering the temperature of the first-stage sintered body to a cooling temperature T0; a second stage step (S30) of heating the first stage sintered body to a second sintering temperature T2 to produce a second stage sintered body; including.
- the compact may be sintered using a vacuum or an inert gas such as helium or argon.
- Magnetic properties can be improved by heat treatment.
- heat treatment conditions such as heat treatment temperature and heat treatment time, known conditions can be adopted.
- the sintered body is subjected to heat treatment at a temperature equal to or lower than the first sintering temperature T1 and the first sintering temperature T2 (for example, 400° C. to 800° C.) for 1 hour or more.
- the RTB system sintered magnet thus obtained is subjected to a grinding/polishing process, a surface treatment process, and a magnetization process, as required, to obtain the final RTB system sintered magnet. magnet is complete.
- the method for producing an RTB based sintered magnet of the present disclosure includes adding a heavy rare earth element RH (RH is at least one of Tb, Dy, and Ho) from the surface of the sintered body to the inside. Diffusion includes a diffusion process. By diffusing the heavy rare earth element RH from the surface of the sintered body into the interior, the coercive force can be efficiently increased.
- RH is at least one of Tb, Dy, and Ho
- Experimental example 1 R-T-B based sintered magnets are about No. Each element was weighed so that the composition shown in 1 was obtained, and the alloy was cast by a strip casting method to obtain an alloy in the form of flakes. After hydrogen embrittlement was applied to the resulting flake-shaped alloy in a pressurized hydrogen atmosphere, dehydrogenation treatment was performed by heating and cooling in vacuum to obtain a coarsely pulverized powder. Next, the obtained coarsely pulverized powder was pulverized using an air jet pulverizer (jet mill apparatus) to obtain an alloy powder having a D50 of 3.6 ⁇ m.
- an air jet pulverizer jet mill apparatus
- a so-called orthogonal magnetic field forming apparatus in which the magnetic field application direction and the pressure direction are perpendicular to each other was used.
- the obtained compact was sintered under the conditions shown in Table 2. No. in Table 2. 1-4 are No. in Table 1.
- the first sintered body is produced by heating the compact produced so as to have the composition of 1. (first stage step), the temperature of the first sintered body is cooled to the cooling temperature T0: room temperature (about 30 ° C.) by rapid cooling (10 ° C./min or more), and the first sintered body after cooling is 2
- a second sintered body is produced by heating at a sintering temperature of 1040° C. for a second sintering time t2: 4 hours (second step).
- Other No. is similarly described.
- No. No.
- 1-1 to 1-3 have only one sintering step. After sintering, the RTB sintered magnet is held at 900° C. for 2 hours, then cooled to room temperature, then held at 500° C. for 2 hours, and then subjected to heat treatment by cooling to room temperature. -B system sintered magnets (No. 1-1 to 1-9) were obtained.
- Table 1 shows the components of the obtained RTB based sintered magnet.
- the sum of each composition, oxygen content, and carbon content in Table 1 does not equal 100 mass%. This is because impurity elements other than the elements listed in the table are included. The same applies to other tables.
- ⁇ when the formula 1 is satisfied, it is described as “ ⁇ ”, and when it is not satisfied, it is described as “x”.
- An RTB sintered magnet was machined to prepare a sample of 7 mm length, 7 mm width and 7 mm thickness, and measured with a BH tracer to determine the magnetic properties.
- the inventive example has H cJ ⁇ 1646 kA/m and H k /H cJ ⁇ 90.1%, which is better H cJ and H k /H cJ compared to the comparative example.
- An RTB based sintered magnet having
- the comparative examples No. 1-1 to 1-3
- the H cJ decreased greatly (No. 1-1) and coarse grains occurred ( No. 1-3). Therefore, there is a possibility that the magnetic properties may unexpectedly deteriorate due to variations in manufacturing conditions.
- Experimental example 2 No. in Table 4.
- a compact was produced in the same manner as in Experimental Example 1, except that each element was weighed so as to obtain compositions of 2 to 4.
- the compact thus obtained was sintered under the conditions shown in Table 5.
- the RTB based sintered magnets after sintering were heat treated in the same manner as in Experimental Example 1 to obtain RTB based sintered magnets (No. 2-1 to 2-6).
- Table 4 shows the components of the obtained RTB based sintered magnet. As shown in Tables 4 and 5, No. 2-1 and 2-2 are No. in Table 4. 2, and No. The compositions of 2-3 and 2-4 are No. in Table 4. 3, and No. The compositions of 2-5 and 2-6 are No. in Table 4. 4 composition. Magnetic properties and H k /H cJ of the resulting RTB based sintered magnet were determined in the same manner as in Experimental Example 1. Table 6 shows the results.
- Experimental example 3 No. in Table 7.
- a compact was produced in the same manner as in Experimental Example 1, except that each element was weighed so as to obtain a composition of No. 5.
- the compact thus obtained was sintered under the conditions shown in Table 8.
- Table 7 shows the components of the obtained RTB based sintered magnet. Diffusion treatment was performed on the obtained RTB based sintered magnet. Specifically, atomized powder (106 ⁇ m or less) of Nd: 0.3% by mass, Pr: 76.4% by mass, Tb: 13.4% by mass, Cu: 4.7% by mass, and Ga: 5.2% by mass Got ready. Next, an adhesive containing a sugar alcohol was applied to the entire surface of the RTB sintered magnet by a dipping method.
- the atomized powder was adhered to the RTB sintered magnet coated with the adhesive in an amount of 2 mass % with respect to the mass of the RTB sintered magnet.
- the atomized powder and the RTB based sintered magnet were heated at 920° C. for 10 hours to carry out a diffusion process, followed by cooling. After that, heat treatment was performed at 480° C. for 3 hours using a heat treatment furnace.
- the magnetic properties and H k /H cJ of the RTB system sintered magnet obtained after diffusion were determined in the same manner as in Experimental Example 1. Table 9 shows the results.
- the invention examples yield RTB sintered magnets having better H cJ and H k /H cJ than the comparative examples.
- the manufacturing method of the RTB-based sintered magnet of the present disclosure can be applied to various motors such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV), motors for industrial equipment, and household appliances. It can be used as a permanent magnet used in a wide variety of applications such as.
- VCM voice coil motors
- EV electric vehicles
- HV PHV
- PHV motors for industrial equipment
- household appliances can be used as a permanent magnet used in a wide variety of applications such as.
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Abstract
Description
・成形体を第1焼結温度T1に加熱して第1段焼結体を作製する第1段工程(S10)と、
・第1段焼結体の温度を冷却温度T0に下げる冷却工程(S20)と、
・第1段焼結体を第2焼結温度T2に加熱して第2段焼結体を作製する第2段工程(S30)と、
を含む。
Rは希土類元素であり、Nd、PrおよびCeからなる群から選択される少なくとも1つを必ず含む。好ましくは、Nd-Dy、Nd-Tb、Nd-Dy-Tb、Nd-Pr-Dy、Nd-Pr-Tb、Nd-Pr-Dy-Tbで示される希土類元素の組合せを用いる。
R:28質量%以上35質量%以下、
B:0.8質量%以上1.2質量%以下、
T61.5質量%以上を含み、[B]を質量%で示すBの含有量、[T]を質量%で示すTの含有量とするとき、14[B]/10.8<[T]/55.85 式1
を満足する。
本実施形態におけるR-T-B系焼結磁石用合金の粗粉砕粉を準備する工程は、R-T-B系焼結磁石用合金を準備する工程と、この合金を例えば水素粉砕法などによって粗く粉砕する工程とを含み得る。
本実施形態における微粉末を得る工程では、粉砕室が不活性ガスで満たされたジェットミル装置に前記粗粉砕粉を供給して前記粗粉砕粉の粉砕を行い、微粉末を得る。この工程では、例えば、平均粒度が2.0μm以上4.5μm以下の微粉末(R-T-B系合金粉末)を得ることができる。このような微粉末を得る工程は、例えば、ジェットミル粉砕システムを用いて実行することができる。
成形体を作製する工程において、磁場中プレスでは酸化抑制の観点から不活性ガス雰囲気中によるプレスまたは湿式プレスによって成形体を形成する方が好ましい。特に湿式プレスは成形体を構成する粒子の表面が油剤などの分散剤によって被覆され、大気中の酸素や水蒸気との接触が抑制される。このため、プレス工程の前後あるいはプレス工程中に粒子が大気によって酸化されることを防止または抑制することができる。
分散媒は、その内部に合金粉末を分散させることによりスラリーを得ることができる液体である。
得られた合金粉末と分散媒とを混合することでスラリーを得ることができる。
次に、成形体を焼結して焼結体を得る。本実施形態における焼結工程は、前述したように、
・成形体を第1焼結温度T1に加熱して第1段焼結体を作製する第1段工程(S10)と、
・第1段焼結体の温度を冷却温度T0に下げる冷却工程(S20)と、
・第1段焼結体を第2焼結温度T2に加熱して第2段焼結体を作製する第2段工程(S30)と、
を含む。
R-T-B系焼結磁石がおよそ表1のNo.1に示す組成となるように、各元素を秤量してストリップキャスト法により鋳造し、フレーク状の合金を得た。得られたフレーク状の合金を水素加圧雰囲気で水素脆化させた後、真空中で加熱、冷却する脱水素処理を施し、粗粉砕粉を得た。次に、得られた粗粉砕粉に対して気流式粉砕機(ジェットミル装置)を用いて粉砕し、D50が3.6μmの合金粉末を得た。
表4のNo.2~4の組成となるように、各元素を秤量する以外は、実験例1と同様な方法で成形体を作製した。得られた前記成形体を表5に示す条件で焼結を行った。焼結後のR-T-B系焼結磁石に対して、実験例1と同様に熱処理を施しR-T-B系焼結磁石(No.2-1~2-6)を得た。
表7のNo.5の組成となるように、各元素を秤量する以外は、実験例1と同様な方法で成形体を作製した。得られた前記成形体を表8に示す条件で焼結を行った。得られたR-T-B系焼結磁石の成分を表7に示す。得られたR-T-B系焼結磁石に対し、拡散処理を行った。具体的には、Nd:0.3質量%、Pr:76.4質量%、Tb:13.4質量%、Cu:4.7質量%、Ga5.2質量%のアトマイズ粉(106μm以下)を準備した。次に、R-T-B系焼結磁石にディッピング法により糖アルコール類を含有する粘着剤をR-T-B系焼結磁石の全面に塗布した。粘着剤を塗布したR-T-B系焼結磁石に前記アトマイズ粉をR-T-B系焼結磁石の質量に対し2mass%付着させた。次に、熱処理炉を用いて920℃で10時間の条件で前記アトマイズ粉及び前記R-T-B系焼結磁石を加熱して拡散工程を実施した後、冷却した。その後、熱処理炉を用いて480℃で3時間の条件で熱処理を実施した。得られた拡散後のR-T-B系焼結磁石を実験例1と同様にして磁気特性およびHk/HcJを求めた。結果を表9に示す。
Claims (7)
- R-T-B系合金粉末(Rは希土類元素であり、Nd、PrおよびCeからなる群から選択される少なくとも1つを必ず含み、Tは遷移金属の少なくとも1つでありFeを必ず含む、Bはホウ素である)の成形体を焼結する焼結工程を含み、
前記焼結工程は、
前記成形体を第1焼結温度T1に加熱して第1段焼結体を作製する第1段工程と、
前記第1段焼結体の温度を冷却温度T0に下げる冷却工程と、
前記第1段焼結体を第2焼結温度T2に加熱して第2段焼結体を作製する第2段工程と、
を含み、
前記第1焼結温度T1および前記第2焼結温度T2は、900℃超であり、
前記冷却温度T0は、900℃以下であり、
前記第1段工程において前記第1焼結温度T1に保持する第1焼結時間t1は、前記第2段工程において前記第2焼結温度T2に保持する第2焼結時間t2よりも短い、R-T-B系焼結磁石の製造方法。 - 前記第1焼結温度T1および前記第2焼結温度T2は、1000℃以上1100℃以下である、請求項1に記載のR-T-B系焼結磁石の製造方法。
- 前記第1焼結温度T1は、1040℃以上1080℃未満であり、
前記第2焼結温度T2は、1020℃以上1060℃未満である、請求項1または2に記載のR-T-B系焼結磁石の製造方法。 - 第1焼結時間t1は、30分以上2時間以下であり、
第2焼結時間t2は、1時間以上15時間以下である、請求項1から3のいずれか1項に記載のR-T-B系焼結磁石の製造方法。 - 前記第1焼結時間t1は前記第2焼結時間t2の半分以下の時間である、請求項1から4のいずれか1項に記載のR-T-B系焼結磁石の製造方法。
- 前記冷却温度T0は、700℃以上900℃以下である、請求項1から5のいずれか1項に記載のR-T-B系焼結磁石の製造方法。
- 前記合金粉末の組成は、R:28質量%以上35質量%以下、B:0.8質量%以上1.20質量%以下、T61.5質量%以上を含み、[B]を質量%で示すBの含有量、[T]を質量%で示すTの含有量とするとき、14[B]/10.8<[T]/55.85
を満足する、請求項1から6のいずれか1項に記載のR-T-B系焼結磁石の製造方法。
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10303008A (ja) * | 1997-04-23 | 1998-11-13 | Hitachi Metals Ltd | R−Fe−B系希土類焼結磁石およびその製造方法ならびにそれを用いた超電導磁気軸受装置 |
JP2004103659A (ja) * | 2002-09-05 | 2004-04-02 | Hitachi Metals Ltd | 機械強度に優れた希土類焼結磁石およびその製造方法 |
JP2004111481A (ja) * | 2002-09-13 | 2004-04-08 | Sumitomo Special Metals Co Ltd | 希土類焼結磁石およびその製造方法 |
WO2009075351A1 (ja) * | 2007-12-13 | 2009-06-18 | Showa Denko K.K. | R-t-b系合金及びr-t-b系合金の製造方法、r-t-b系希土類永久磁石用微粉、r-t-b系希土類永久磁石 |
JP2015113525A (ja) * | 2013-12-11 | 2015-06-22 | ▲煙▼台正海磁性材料股▲ふん▼有限公司 | 高保磁力磁石の調製方法 |
JP2019169560A (ja) * | 2018-03-22 | 2019-10-03 | 日立金属株式会社 | R−t−b系焼結磁石の製造方法 |
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10303008A (ja) * | 1997-04-23 | 1998-11-13 | Hitachi Metals Ltd | R−Fe−B系希土類焼結磁石およびその製造方法ならびにそれを用いた超電導磁気軸受装置 |
JP2004103659A (ja) * | 2002-09-05 | 2004-04-02 | Hitachi Metals Ltd | 機械強度に優れた希土類焼結磁石およびその製造方法 |
JP2004111481A (ja) * | 2002-09-13 | 2004-04-08 | Sumitomo Special Metals Co Ltd | 希土類焼結磁石およびその製造方法 |
WO2009075351A1 (ja) * | 2007-12-13 | 2009-06-18 | Showa Denko K.K. | R-t-b系合金及びr-t-b系合金の製造方法、r-t-b系希土類永久磁石用微粉、r-t-b系希土類永久磁石 |
JP2015113525A (ja) * | 2013-12-11 | 2015-06-22 | ▲煙▼台正海磁性材料股▲ふん▼有限公司 | 高保磁力磁石の調製方法 |
JP2019169560A (ja) * | 2018-03-22 | 2019-10-03 | 日立金属株式会社 | R−t−b系焼結磁石の製造方法 |
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