WO2017069131A1 - 磁性材料の製造方法 - Google Patents
磁性材料の製造方法 Download PDFInfo
- Publication number
- WO2017069131A1 WO2017069131A1 PCT/JP2016/080883 JP2016080883W WO2017069131A1 WO 2017069131 A1 WO2017069131 A1 WO 2017069131A1 JP 2016080883 W JP2016080883 W JP 2016080883W WO 2017069131 A1 WO2017069131 A1 WO 2017069131A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- powder
- surface oxide
- iron
- iron powder
- magnetic material
- Prior art date
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/12—Metallic powder containing non-metallic particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/145—Chemical treatment, e.g. passivation or decarburisation
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/012—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials adapted for magnetic entropy change by magnetocaloric effect, e.g. used as magnetic refrigerating material
- H01F1/015—Metals or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—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
- 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
- H01F41/026—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 protecting methods against environmental influences, e.g. oxygen, by surface treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—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
- 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
- H01F41/0266—Moulding; Pressing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C2202/00—Physical properties
- C22C2202/02—Magnetic
Definitions
- the present invention relates to a method for manufacturing a magnetic material.
- a magnetic refrigeration system that is clean and highly energy efficient has been proposed as a refrigeration technology that reduces the environmental burden without using chlorofluorocarbon-based gases that cause environmental problems.
- a magnetic refrigeration material plays the role of a refrigerant.
- a magnetic material capable of obtaining a large magnetic entropy change near room temperature is used.
- a La (Fe, Si) 13 -based compound having a NaZn 13 type crystal structure is known as a magnetic material exhibiting characteristics suitable for such magnetic refrigeration.
- a La (Fe, Si) 13- based compound can obtain a large change in magnetic entropy, and is advantageous in practical use since inexpensive Fe is the main constituent element.
- Patent Documents 1 and 2 Regarding the method for producing a La (Fe, Si) 13 -based compound, the raw materials are integrated using an arc melting method or the like, followed by a heat treatment held at 1050 ° C. for 10 days, whereby a NaZn 13 type crystal structure phase is obtained. It has been reported that a magnetic material having a main phase can be obtained (see Non-Patent Document 1).
- Patent Document 3 proposes a method of solidifying by a roll quenching method
- Patent Document 4 proposes a method of forcibly cooling molten metal. In these methods, even if the homogenization heat treatment of the intermediate material can be shortened, it is still unavoidable to pass through the intermediate material.
- Patent Document 5 the inclusion of boron B or carbon C in the raw material composition increases the amount of NaZn 13 type crystal structure phase generated in the intermediate material, which facilitates subsequent homogenization heat treatment.
- the alloy produced by this method needs to add B to about 1.8 atomic% or more and 5.4 atomic% or less in order to obtain a good effect, and secondary formation such as Fe 2 B phase is required. There is a problem that the phase deteriorates the characteristics.
- Patent Document 6 Attempts have also been made to obtain a final NaZn 13 type crystal structure phase without using an intermediate material by using a metal reaction that does not go through a liquid phase.
- Patent Document 6 a Fe—Si alloy and lanthanum oxide are reacted.
- an alkaline earth metal that is extremely active in oxygen, such as Ca for reduction, which complicates safety management.
- washing with water is essential to desorb the Ca oxide after the reaction, there is a possibility of causing rust on the surface of the produced La (Fe, Si) 13 -based compound.
- Patent Document 7 proposes a method in which pressurization and pulse energization are simultaneously performed and sintering is performed by energization heating. In this method, a sample containing a relatively large number of La (Fe, Si) 13 -based compounds can be produced in a short time without going through an intermediate material.
- Japanese Unexamined Patent Publication No. 2002-356748 Japanese Unexamined Patent Publication No. 2003-96547 Japanese Unexamined Patent Publication No. 2004-100043 Japanese Unexamined Patent Publication No. 2006-265631 Japanese Unexamined Patent Publication No. 2004-99928 Japanese Unexamined Patent Publication No. 2006-274345 Japanese Patent No. 4237730
- an object of one aspect of the present invention is to provide a method for producing a magnetic material by which a magnetic material having a high content of NaZn 13 type crystal structure phase can be obtained by solid phase reaction. .
- a surface oxide reduction process for reducing the surface oxide of the iron powder A powder molded body obtained by mixing the surface oxide-reduced iron powder obtained by the surface oxide reduction step and the compound powder A composed of La element and Si element, and compacting the obtained mixed powder.
- a method for producing a magnetic material comprising: a sintered body forming step of producing a sintered body by a solid phase reaction in a vacuum atmosphere from a powder molded body obtained by the powder molded body forming step.
- the manufacturing method of the magnetic material of the present embodiment can include the following steps.
- a surface oxide reduction process for reducing and removing the oxide on the surface of the iron powder, which is one of the raw material powders, is provided.
- the specific means for reducing the oxide on the iron powder surface is not particularly limited.
- the surface oxide reduction process can include the following steps.
- the surface oxide reduction process it is possible to obtain a surface oxide-reduced iron powder by reducing and removing the surface oxide formed on the surface of the iron powder supplied as the starting material powder by performing the following steps: it can.
- An iron powder placement step for placing iron powder in the heating chamber of the electric furnace.
- Evacuation step to evacuate the heating chamber after the iron powder placement step.
- the inside of the heating chamber is heated to a processing temperature of 400 ° C. or higher and 1000 ° C. or lower, and the iron powder is exposed to hydrogen gas to reduce the surface of the iron powder. Get the surface reduction treatment step.
- iron powder can be placed in the heating chamber of the electric furnace.
- the electric furnace used at this time is not particularly limited, but the inside of the heating chamber, that is, the inside of the furnace can be evacuated and hydrogen gas can be supplied so that the evacuation step and the surface reduction treatment step can be performed.
- An electric furnace that can be used is preferable.
- the inside of the heating chamber of the electric furnace can be evacuated.
- the ultimate vacuum in the electric furnace is not particularly limited. For example, it is sufficient if it can be reached by a rotary pump, and it is preferably 1 Pa or less, and more preferably 1.0 ⁇ 10 ⁇ 1 Pa or less.
- the surface reduction treatment step can be performed after the target vacuum degree is reached in the vacuum exhaust step.
- the inside of the heating chamber of the electric furnace is heated to a processing temperature of 400 ° C. or more and 1000 ° C. or less, hydrogen gas is supplied into the heating chamber of the electric furnace, and the iron powder is brought into contact with the hydrogen gas.
- hydrogen gas is supplied into the heating chamber of the electric furnace, and the iron powder is brought into contact with the hydrogen gas.
- the surface of the iron powder can be reduced, and the surface oxide of the iron powder can be reduced.
- the treatment temperature is preferably 400 ° C. or higher and 1000 ° C. or lower, more preferably 500 ° C. or higher and 700 ° C. or lower, and further preferably 600 ° C. or higher and 650 ° C. or lower.
- the iron powders are sintered with each other, and the particle size of the iron powder may be coarsened.
- the timing of supplying the hydrogen gas is not particularly limited, and for example, it can be changed from exhaust to hydrogen gas supply at the start of temperature rise. However, when the temperature in the heating chamber is low, the reduction reaction does not proceed sufficiently. Therefore, after starting the temperature increase, the exhaust is continued until the process temperature is reached, and after reaching the process temperature, the supply of hydrogen gas is started. It is preferable to do.
- the hydrogen gas to be supplied may be a single hydrogen molecule gas, or a mixed gas of hydrogen molecules and an inert element.
- argon or helium can be used as the inert element.
- the hydrogen gas to be supplied is preferably a single hydrogen molecule gas so that the reduction reaction proceeds sufficiently for the surface oxide on the iron powder surface.
- the supply form of the hydrogen gas after the supply of the hydrogen gas to the electric furnace is started is not particularly limited.
- the gas can be continuously supplied into the electric furnace to form a hydrogen gas stream in the electric furnace.
- the atmosphere in the electric furnace is changed to a hydrogen-containing atmosphere, the supply can be stopped.
- a desired pressure for example, atmospheric pressure
- the pressure in the electric furnace can be monitored, and the hydrogen gas can be supplied again at an arbitrary timing according to the fluctuation of the pressure in the electric furnace.
- the time in which the inside of the electric furnace is a hydrogen-containing atmosphere and is maintained at the processing temperature is not particularly limited, the amount of iron powder disposed in the electric furnace, the degree of surface oxide formation, etc. Can be selected.
- the treatment time is preferably 1 hour or longer so that the surface oxide on the surface of the iron powder can be sufficiently reduced.
- the upper limit of the treatment time is not particularly limited, but it is preferably 2 hours or less in consideration of productivity and the like.
- the heating can be stopped and the temperature can be cooled to or near room temperature.
- the iron powder that has been subjected to the reduction treatment that is, the iron powder that has been subjected to the surface oxide reduction treatment, can be taken out from the heating chamber and supplied to the powder compact forming process described later.
- the surface oxide reduction process can include the following steps.
- the surface oxide reduction process by performing the following steps, it is possible to obtain a surface oxide-reduced iron powder in which the surface oxide formed on the surface of the electrolytic iron supplied as a starting material is reduced and removed. .
- An iron ingot forming step in which electrolytic iron is dissolved and degassed to form an iron ingot.
- electrolytic iron can be dissolved and deaerated to form an iron ingot.
- dissolving and deaerating electrolytic iron is not specifically limited, For example, melt
- an iron ingot with a reduced oxygen content can be formed.
- the obtained iron ingot is ground to obtain the iron powder that has been subjected to the surface oxide reduction treatment.
- the method and conditions for grinding the iron ingot in the grinding step are not particularly limited, and can be carried out so as to obtain a surface oxide-reduced iron powder having a desired particle size.
- an iron ingot can be ground with a drill bit.
- the surface-oxide-reduced iron powder obtained by the grinding step can be supplied to the powder molded body forming step described later.
- the surface oxide reduction process has been described with reference to two embodiments.
- the configuration of the surface oxide reduction process is not limited to the above-described form, and the surface oxide of the iron powder can be reduced and removed. If it is a method, various methods can be used.
- the surface oxide-reduced iron powder has a standard dimension specified in JISZ8801 (1982). A powder that has passed through a 106 ⁇ m sieve is preferred.
- the surface oxide-reduced iron powder used in the powder molding formation process is a compound powder to be described later in consideration of the promotion of the solid phase reaction when the sintered body formation process is performed after the powder molding formation process. It is because it is preferable that it is a particle size comparable as A.
- the compound powder A is preferably a powder that has passed through a sieve having a reference dimension of 106 ⁇ m as defined in JISZ8801 (1982) as will be described later, the surface-oxide-reduced iron powder used in the powder molding forming process as described above. Is preferably a powder that has passed through a sieve having a reference dimension of 106 ⁇ m as defined in JISZ8801 (1982).
- the surface oxide-reduced iron powder to be used in the powder molded body forming process described later is a surface-oxidized surface powder that has passed through a sieve having a reference dimension defined by JISZ8801 (1982) of the surface oxide-reduced iron powder. It is more preferable that the iron powder has been subjected to a material reduction treatment.
- the surface oxide-reduced iron powder to be used in the powder molding forming process described later is a surface-oxidized surface powder that has passed through a sieve having a standard dimension defined by JISZ8801 (1982) of the surface oxide-reduced iron powder. It is more preferable that the iron powder has been subjected to a material reduction treatment.
- the size of the powder affects the element diffusion distance and speed, so that the reaction proceeds sufficiently in the sintered body forming process, so that at least the above-mentioned reference dimension is 106 ⁇ m. This is because coarse particles can be removed by sieving.
- iron powder that has been screened with a screen having a finer reference size than a screen having a reference size of 32 ⁇ m is not practical because it may contain a large amount of powder that undergoes an ignition-like oxidation reaction.
- the particle size of the surface oxide-reduced iron powder obtained by the surface oxide reduction step is preferably a powder that has passed through a sieve having a reference dimension defined in JISZ8801 (1982) of 106 ⁇ m as described above. However, at the stage immediately after finishing the surface oxide reduction treatment, it may be out of the above range. In this case, the surface oxide-reduced iron powder after the surface oxide reduction step can be screened using a sieve having a predetermined reference dimension so that the particle size falls within the above particle size range.
- the iron powder supplied into the heating chamber of the electric furnace Is preferably composed of powder that passes through the sieve having the predetermined reference dimension.
- the grinding step a surface oxide-reduced iron powder having a particle size passing through a sieve having a predetermined reference dimension is obtained. It is preferable to grind the iron ingot.
- the surface oxide-reduced iron powder obtained by the surface oxide reduction step and the LaSi compound compound powder A composed of La element and Si element are mixed, and the resulting mixture is obtained.
- the powder can be compacted to form a powder compact.
- Compound powder A can be composed of La element and Si element as described above.
- Such a compound powder A includes, for example, a powder of lanthanum alone and silicon so that a bulk material having a composition that matches the ratio of La and Si contained in the mixed powder of iron powder and compound powder A can be obtained.
- a single powder is weighed and then dissolved and mixed, and the resulting bulk material is pulverized.
- the bulk material may be composed of a single compound, but may be composed of a plurality of compound phases.
- the compound powder A can be formed into a powder form by once forming a bulk material and then pulverizing it.
- the size of the compound powder A is not particularly limited, but for example, it is preferable that the powder passes through a sieve having a reference dimension of 106 ⁇ m as defined in JISZ8801 (1982).
- a sintered body of a magnetic material having a high content of NaZn 13 type crystal structure phase can be formed by a solid phase reaction. Since the size of the powder affects the element diffusion distance and speed, the compound powder A is sieved with a standard dimension of 106 ⁇ m as defined in JISZ8801 (1982) in order to allow the reaction to proceed sufficiently in the sintered body forming process. It is preferable that the powder has passed through.
- the compound powder A is more preferably a powder obtained by pulverizing the above bulk material and having passed through a sieve having a reference dimension defined in JISZ8801 (1982) of 53 ⁇ m.
- the compound powder A is more preferably a powder obtained by pulverizing the above bulk material and having passed through a sieve having a standard dimension defined by JISZ8801 (1982) of 32 ⁇ m.
- the size of the powder affects the element diffusion distance and speed, so that the reaction proceeds sufficiently in the sintered body forming process, so at least the reference dimension is 106 ⁇ m. This is because coarse particles can be removed by sieving.
- the compound powder A which has been screened by a sieve having a reference dimension finer than 32 ⁇ m, is not practical because it may contain a large amount of powder that undergoes an ignition-like oxidation reaction.
- the mixed powder in the powder molded body forming step, can be prepared by weighing and mixing the surface oxide-reduced iron powder and the compound powder A at a predetermined ratio.
- the composition of the mixed powder is not particularly limited, but the ratio of La element is 7.1 atomic% or more and 9.3 atomic% or less, and the ratio of Fe element is 76.1 atomic% or more and 84.5 atoms. It is preferable to mix so that the ratio of Si element is 8.4 atomic% or more and 16.7 atomic% or less.
- a magnetic material having a high content of NaZn 13 type crystal structure phase can be produced.
- the NaZn 13 type crystal structure phase can be suitably produced the La (Fe, Si) 13 type compounds.
- the La element ratio in the mixed powder is preferably 7.1 atomic% or more.
- the La element ratio in the mixed powder is preferably 9.3 atomic% or less.
- the magnetocaloric effect increases as the ratio of the Fe element in the mixed powder and the Fe element in the Si element increases.
- the amount is preferably 1 atomic percent or more, and the Si element ratio is preferably 16.7 atomic percent or less.
- the ratio of Fe element among Fe element and Si element becomes too high, an impurity phase is easily generated. Therefore, the ratio of Fe element is 84.5 atomic% or less as described above.
- the ratio of Si element is preferably 8.4 atomic% or more.
- the ratio of La element is more preferably 7.1 atomic% to 7.5 atomic%, and the ratio of Fe element is 81.5 atomic% to 83.0 atomic%. More preferably, the ratio of Si element is more preferably 9.2 atomic% or more and 11.1 atomic% or less.
- the specific method of mixing the iron powder and the compound powder A is not particularly limited, and any means can be used as long as both powders can be mixed substantially uniformly.
- a powder molded body can be obtained by compacting the obtained mixed powder.
- the method of compacting is not particularly limited, and a powder compact can be obtained by filling the compacted powder into a compactor and molding it by pressing. Specifically, for example, after the mixed powder is put into a die, the upper and lower sides are closed with a punch, and a load is applied to the punch to obtain a pellet-shaped powder molded body.
- the applied load is not particularly limited. If the load is large, the porosity in the sample after sintering can be reduced, but if it is too large, the punch and die are plastically deformed and the load is not evenly distributed. For this reason, it is preferable to select the pressure at the time of molding according to the material of the used punch or die, the porosity required for the sintered body, and the like.
- a sintered body In the sintered body forming step, a sintered body can be produced from the powder molded body obtained in the powder molded body forming step by a solid phase reaction in a vacuum atmosphere.
- the powder molded body is heated in a vacuum at a temperature of 1050 ° C. or higher and 1140 ° C. or lower to advance reactive sintering.
- the chamber can be evacuated before the temperature rises after placing the powder compact in the heating furnace.
- the chamber can be evacuated before the temperature rises after placing the powder compact in the heating furnace.
- the sintered body formation step is performed in a vacuum atmosphere, By heating in an environment in which oxygen intrusion is suppressed, the effect of removing oxides on the surface of the iron powder appears clearly. That is, the formation reaction of the NaZn 13 type crystal structure phase can be promoted.
- the degree of vacuum at room temperature is not particularly limited, and may be less than 0.1 MPa, which is atmospheric pressure, but may be 1 ⁇ 10 ⁇ 3 Pa or more and 1 ⁇ 10 ⁇ 1 Pa or less. Preferably, it is 5 ⁇ 10 ⁇ 3 Pa or more and 1 ⁇ 10 ⁇ 2 Pa or less.
- the chamber is evacuated to atmospheric pressure or lower as described above, and the degree of vacuum is not particularly limited, but when the degree of vacuum is lower than 1 ⁇ 10 ⁇ 1 Pa, oxygen is contained in the chamber.
- the vacuum degree is preferably 1 ⁇ 10 ⁇ 1 Pa or less because water and moisture may remain so as to affect the sintering reaction.
- a non-general exhaust system having a high capacity is required, so that 1 ⁇ 10 ⁇ 3 Pa or more is preferable. In particular, 5 ⁇ 10 ⁇ 3 Pa or more is practical for achieving a degree of vacuum.
- the inside of the chamber is described as being evacuated here, for example, the powder molded body can be vacuum-sealed in a glass tube or the like and heated. In this case, when vacuum-sealing, the inside of the glass tube can be evacuated to make the inside of the glass tube have a desired degree of vacuum.
- the powder molding can be heated after the temperature in the chamber is set to a predetermined degree of vacuum or the temperature rise is started while exhausting the chamber.
- the ultimate temperature at the time of heating is preferably 1050 ° C. or higher and 1140 ° C. or lower as described above.
- the peritectic decomposition temperature decreases as the Fe concentration increases, in the La (Fe, Si) 13 compound, the composition ratio of Fe and Si is 1050 in the region where the Fe concentration is higher than 0.91: 0.09.
- the peritectic decomposition reaction occurs even at 0 ° C., and when the composition ratio of Fe and Si is around 0.88: 0.12, the reaction is promoted and the production efficiency is improved when the temperature is increased to 1140 ° C.
- the heat treatment temperature can be set to 1050 ° C. or higher and 1140 ° C. or lower, and the heat treatment temperature can be selected according to the composition of the magnetic material to be prepared.
- the heat treatment temperature by the 1050 ° C. or higher 1140 ° C. or less, by solid-phase reaction it is possible to form a high content fraction of NaZn 13 type crystal structure phase sintered body. Therefore, unlike the case of forming via the liquid phase, there is no intermediate material generation, so there is no need to apply heat treatment for a long time as in the prior art, and the production efficiency of the NaZn 13 type crystal structure phase is increased. Can be increased.
- the holding time after reaching the heat treatment temperature is not particularly limited, and can be arbitrarily selected according to the size of the powder molded body. For example, a preliminary test or the like can be performed, and the selection can be made according to the generation ratio of the ratio of the NaZn 13 type crystal structure phase in the obtained sintered body.
- the kind of furnace at the time of implementing a sintered compact formation process is not specifically limited, What is necessary is just a furnace which can be heated by the desired temperature in the pressure reduction atmosphere below atmospheric pressure.
- the method of raising the temperature in a reduced-pressure atmosphere below atmospheric pressure is also possible in a heat treatment furnace that can evacuate the core tube, and as described above, the powder molded body is vacuum-sealed in a quartz tube and a tubular furnace or the like Even if it is kept for a predetermined time in the soaking zone, it can be realized.
- the production ratio of the NaZn 13 type crystal structure phase can be reduced. It can be increased efficiently in a short time. Therefore, the production efficiency of a magnetic material exhibiting excellent characteristics as a magnetic refrigeration material can be increased.
- the sintered body obtained in the sintered body forming step may contain the second phase as long as the volume fraction is a small amount of 10% or less.
- a magnetic material was manufactured by the following procedure and evaluated. (Surface oxide reduction process) 100 g of commercially available iron powder (manufactured by Kojundo Chemical Laboratory Co., Ltd., particle size 53 ⁇ m or less, purity 3N) was spread on an alumina dish having a diameter of 8 cm and placed in the soaking zone of the heating chamber of the electric furnace (iron powder placement step) ).
- the inside of the heating chamber of the electric furnace was evacuated to 1 ⁇ 10 ⁇ 1 Pa with a rotary pump (vacuum evacuation step).
- the temperature increase was started, and the temperature was increased to 600 ° C., which is the target temperature, in 1 hour from the start of the temperature increase.
- hydrogen was introduced under the condition that the inside of the heating chamber became equal to the atmospheric pressure, and the iron powder placed in the heating chamber was exposed to hydrogen gas for 1 hour (surface reduction treatment step). The hydrogen gas was continuously supplied so that the pressure in the heating chamber became equal to the atmospheric pressure during the surface reduction treatment step after the supply of hydrogen gas was started.
- the electric furnace heater is shut off while the introduction of hydrogen gas into the heating chamber is continued, and the hydrogen supply in the chamber is stopped when the temperature in the heating chamber drops to room temperature.
- Iron powder with reduced oxide iron powder with reduced surface oxide treatment
- compound powder A was prepared.
- compound powder A a LaSi compound powder containing La and Si and having a composition ratio of 1: 1 was prepared by the following procedure.
- the LaSi compound powder was prepared by weighing La metal (manufactured by Japan Yttrium Co., Ltd.) and Si powder (manufactured by Kojundo Chemical Laboratory Co., Ltd., purity 4N) so as to have a mass ratio of 1: 1 and arc melting.
- the LaSi compound was obtained by pulverizing with an agate mortar and pestle in the air.
- the obtained LaSi compound powder was passed through a standard sieve having a standard dimension of 32 ⁇ m as defined in JISZ8801 (1982), and only the powder particles that passed through the mesh were used as compound powder A.
- the surface oxide-reduced iron powder obtained in the surface oxide reduction step and the above-mentioned compound powder A are mixed so as to have a composition ratio of La 1 + d (Fe 0.90 Si 0.10 ) 13 and mixed.
- a powder was prepared.
- the excess d from the stoichiometric ratio of La was 0.3. This is because even when inevitable La oxidation occurs, La (Fe 0.90 Si 0.10 ) 13 is adjusted so that there is an element amount sufficient to constitute it.
- 0.3 g of the obtained mixed powder is put into a through-hole (diameter: 8 mm) of a die made of non-magnetic steel, and the upper and lower sides are suppressed with a homogeneous steel punch, and a surface pressure equivalent to 100 MPa is applied from both ends with a hand press.
- the pellet which is a molding was produced. (Sintered body forming process)
- the pellet obtained in the powder molding process is wrapped in a 0.05 mm thick Mo foil, placed in a quartz tube closed at one end, and then the inside is evacuated to 5 ⁇ 10 ⁇ 3 Pa. A vacuum ampoule was formed by sealing.
- the prepared vacuum ampule was placed in a muffle furnace, heated to 1130 ° C., which is a heat treatment temperature for reactive sintering, in 2 hours from the start of the temperature rise, and then held at the heat treatment temperature for 12 hours.
- composition of the gray portion 11 in FIG. 1 was analyzed using an energy dispersive X-ray analyzer attached to SEM (manufactured by Bruker: model Quantax 700). As a result, the composition ratio of La, Fe and Si was La (Fe 0.9 Si 0. 1) consistent with 13, have been identified as NaZn 13 type crystal structure phase.
- the white part 12 was La rich phase and the black part 13 was Fe phase.
- the NaZn 13 type crystal structure phase is formed as the main phase, and the size of the Fe phase is greatly reduced compared to 53 ⁇ m of the iron powder used as the starting material powder. It could be confirmed.
- the surface oxide reduction step was carried out according to the following procedure, and the same procedure as in Example 1 was performed except that the obtained surface oxide reduction-treated iron powder was used.
- the magnetic material was manufactured in the same manner as in the powder molding body forming step and the sintered body forming step.
- the obtained ground particles were passed through a standard sieve having a standard dimension of 53 ⁇ m as defined in JISZ8801 (1982), and only the powder particles that passed through the mesh were subjected to a powder molding forming process as iron powder that had been subjected to surface oxide reduction treatment.
- Example 2 the surface was polished in the same manner as in Example 1 and the reflected electron image of the scanning electron microscope was observed. An observation image is shown in FIG.
- Example 2 when the composition of the gray portion 21 in FIG. 2 was analyzed using an energy dispersive X-ray analyzer, the composition ratio of La, Fe and Si was La (Fe 0.9 Si 0 .1 ) Consistent with 13 , identified as NaZn 13 type crystal structure phase.
- the white part 22 was La rich phase and the black part 23 was Fe phase.
- the residual Fe phase was small, and it was confirmed that most were NaZn 13 type crystal structure phases.
- FIG. 3 shows the result of powder X-ray diffraction measurement for the samples obtained in Example 1 and Example 2 in order to compare the constituent amounts of the Fe phase and the NaZn 13 type crystal structure phase.
- the bar line shown in the lower part of FIG. 3 shows model pattern figures of NaZn 13 type La (Fe, Si) 13 and ⁇ -Fe calculated from the crystal structure.
- Example 1 the ratio of the phase fraction of La (Fe, Si) 13 and ⁇ -Fe was 99.0: 1.0, and in Example 2, 97.7: 2.3. It was confirmed that good NaZn 13 type La (Fe, Si) 13 was produced.
- Example 1 In the point where the same iron powder as in Example 1 (manufactured by High-Purity Chemical Laboratory, particle size of 53 ⁇ m or less, purity 3N) was subjected to a powder molded body forming step without being subjected to a surface oxide reduction step, and in a sintered body forming step A specimen 1 was produced in the same manner as in Example 1 except that the sintering was performed using electric current pressure sintering.
- the degree of vacuum in the chamber before sintering is 2 ⁇ 10 ⁇ 2 Pa
- the applied pressure is 38 MPa
- 300 A is energized in the cross-sectional sample space having a diameter of 10 mm, and the temperature is raised to 1120 ° C. After reaching the maximum temperature, the energization amount was set to 0 and heating was stopped immediately.
- the types of phases in the image of FIG. 4 are the same as in the case of Example 1 and Example 2, but compared with the case of Example 1 and Example 2, the black NaZn 13 type crystal structure phase is black. It can be seen that the amount of ⁇ -Fe phase is large.
- Comparative Example 2 In Comparative Example 2, the same iron powder as in Example 1 (manufactured by High-Purity Chemical Laboratory, particle size of 53 ⁇ m or less, purity 3N) was subjected to a powder molded body forming step without being subjected to a surface oxide reduction step, and Specimen 2 was produced in the same manner as in Example 1 except that the holding time after reaching the heat treatment temperature of 1130 ° C. was 48 hours in the knot forming step.
- FIG. 6 shows the result of the powder X-ray diffraction measurement performed on the obtained specimen 2. Compared with the specimen 1, the residual Fe decreased, and the ratio of the phase fraction of La (Fe, Si) 13 and ⁇ -Fe was 92.7: 7.3.
- FIG. 7 shows an SEM image of the specimen 2.
- the structure of the black ⁇ -Fe phase is partially coarsened to 53 ⁇ m or more with respect to the white La-rich phase, and Fe grain growth occurs.
- the cause of such a change is that the diffusion of elements between LaSi grains and Fe grains does not proceed because the oxide layer around the Fe grains becomes a barrier, and during that time, coarsening of Fe grains occurs due to the so-called Ostwald growth mechanism. Because of this.
- Comparative Example 3 In Comparative Example 3, a specimen 3 was produced in the same manner as in Example 1 except that the quartz tube was not sealed in the sintered body formation step and heated in an air atmosphere.
- FIG. 8 shows the result of the powder X-ray diffraction measurement performed on the obtained specimen 3.
- FIG. 9 shows an SEM image of the specimen 3.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Power Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Environmental & Geological Engineering (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
La(Fe,Si)13系化合物の製造方法に関しては、アーク溶解法等を用いて原料の一体化を行い、続いて1050℃で10日間保持する熱処理を行うことによって、NaZn13型結晶構造相を主相とする磁性材料が得られることが報告されている(非特許文献1参照)。
鉄粉末の表面酸化物を低減する表面酸化物低減工程と、
前記表面酸化物低減工程により得られた表面酸化物低減処理済み鉄粉末と、La元素及びSi元素により構成される化合物粉末Aとを混合し、得られた混合粉末を圧粉成型する粉末成型体形成工程と、
前記粉末成型体形成工程により得られた粉末成型体から、真空雰囲気中での固相反応により焼結体を作製する焼結体形成工程と、を有する磁性材料の製造方法を提供する。
(表面酸化物低減工程)
本発明の発明者らは、固相反応により、NaZn13型結晶構造相の含有分率の高い磁性材料が得られる、磁性材料の製造方法について鋭意検討を行った。
(粉末成型体形成工程)
粉末成型体形成工程では、表面酸化物低減工程により得られた表面酸化物低減処理済み鉄粉末と、La元素及びSi元素により構成されるLaSi化合物の化合物粉末Aとを混合し、得られた混合粉末を圧粉成型し、粉末成型体を形成することができる。
(焼結体形成工程)
焼結体形成工程では、粉末成型体形成工程で得られた粉末成型体から、真空雰囲気中での固相反応により焼結体を作製することができる。
[実施例1]
以下の手順により磁性材料を製造し、その評価を行った。
(表面酸化物低減工程)
市販の鉄粉末(株式会社高純度化学研究所製、粒径53μm以下、純度3N)100gを直径8cmのアルミナ皿の上に拡げ、電気炉の加熱チャンバの均熱帯に配置した(鉄粉末配置ステップ)。
(粉末成型体形成工程)
まず、化合物粉末Aを準備した。化合物粉末Aとしては以下の手順によりLaと、Siとを含有し、その組成比が1:1のLaSi化合物粉末を準備した。
(焼結体形成工程)
粉末成型体形成工程で得られたペレットを厚さ0.05mmのMoフォイルで包み込み、一端の閉じた石英管中に入れた後、内部を5×10-3Paまで排気し、排気口側を封じ切ることにより真空アンプルを形成した。
[実施例2]
表面酸化物低減工程を以下の手順により実施し、得られた表面酸化物低減処理済み鉄粉末を用いた点以外は実施例1と同様にして、すなわち、表面酸化物低減工程以外は、実施例1の粉末成型体形成工程、及び焼結体形成工程と同様にして磁性材料の製造を行った。
(表面酸化物低減工程)
まず、市販の電解鉄(昭和電工株式会社製 商品名:アトミロン)15gをアルゴン中アーク溶解により溶解脱気し、ボタン状インゴットを成形した(鉄インゴット形成ステップ)。
[比較例1]
実施例1と同じ鉄粉末(高純度化学研究所製、粒径53μm以下、純度3N)を表面酸化物低減工程に供することなく粉末成型体成形工程に供した点、及び焼結体形成工程において通電加圧焼結を用いて焼結を行った点以外は実施例1と同様にして、供試体1を作製した。
[比較例2]
比較例2は、実施例1と同じ鉄粉末(高純度化学研究所製、粒径53μm以下、純度3N)を表面酸化物低減工程に供することなく粉末成型体成形工程に供した点、及び焼結体形成工程において、熱処理温度である1130℃に到達した後の保持時間を48時間とした点以外は、実施例1と同様にして、供試体2を作製した。
[比較例3]
比較例3は、焼結体形成工程において、石英管を封じず、大気雰囲気のまま加熱した点以外は実施例1と同様にして供試体3を作製した。
Claims (4)
- 鉄粉末の表面酸化物を低減する表面酸化物低減工程と、
前記表面酸化物低減工程により得られた表面酸化物低減処理済み鉄粉末と、La元素及びSi元素により構成される化合物粉末Aとを混合し、得られた混合粉末を圧粉成型する粉末成型体形成工程と、
前記粉末成型体形成工程により得られた粉末成型体から、真空雰囲気中での固相反応により焼結体を作製する焼結体形成工程と、を有する磁性材料の製造方法。 - 前記表面酸化物低減工程は、
電気炉の加熱チャンバ内に前記鉄粉末を配置する鉄粉末配置ステップと、
前記鉄粉末配置ステップ後、前記加熱チャンバ内を真空排気する真空排気ステップと、
前記真空排気ステップ後、前記加熱チャンバ内を400℃以上1000℃以下の処理温度まで加熱し、かつ前記鉄粉末を水素ガスに曝露することで前記鉄粉末の表面還元処理を行い、前記表面酸化物低減処理済み鉄粉末を得る表面還元処理ステップと、を有する請求項1に記載の磁性材料の製造方法。 - 前記表面酸化物低減工程は、
電解鉄を溶解脱気して鉄インゴットを形成する鉄インゴット形成ステップと、
前記鉄インゴット形成ステップで得られた鉄インゴットを研削して前記表面酸化物低減処理済み鉄粉末を得る研削ステップと、を有する請求項1に記載の磁性材料の製造方法。 - 前記粉末成型体形成工程において、前記表面酸化物低減処理済み鉄粉末と、前記化合物粉末Aとを、
前記混合粉末中のLa元素の比率が7.1原子%以上9.3原子%以下、
Fe元素の比率が76.1原子%以上84.5原子%以下、
Si元素の比率が8.4原子%以上16.7原子%以下となるように混合する請求項1乃至3のいずれか一項に記載の磁性材料の製造方法。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017546556A JP6440282B2 (ja) | 2015-10-19 | 2016-10-18 | 磁性材料の製造方法 |
US15/767,427 US11056254B2 (en) | 2015-10-19 | 2016-10-18 | Method of manufacturing magnetic material |
EP16857444.0A EP3367395B1 (en) | 2015-10-19 | 2016-10-18 | Method for manufacturing magnetic material |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015-205863 | 2015-10-19 | ||
JP2015205863 | 2015-10-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2017069131A1 true WO2017069131A1 (ja) | 2017-04-27 |
Family
ID=58557043
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2016/080883 WO2017069131A1 (ja) | 2015-10-19 | 2016-10-18 | 磁性材料の製造方法 |
Country Status (4)
Country | Link |
---|---|
US (1) | US11056254B2 (ja) |
EP (1) | EP3367395B1 (ja) |
JP (1) | JP6440282B2 (ja) |
WO (1) | WO2017069131A1 (ja) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113292335A (zh) * | 2021-07-02 | 2021-08-24 | 燕山大学 | 一种纯相钛酸亚铁的制备方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005113209A (ja) * | 2003-10-08 | 2005-04-28 | Hitachi Metals Ltd | 磁性粒子とその製造方法、及び磁性粒子ユニット |
JP2006316324A (ja) * | 2005-05-13 | 2006-11-24 | Toshiba Corp | 磁性材料の製造方法 |
JP2015506090A (ja) * | 2011-11-22 | 2015-02-26 | インスティテュート オブ フィジックス, チャイニーズ アカデミー オブ サイエンシーズ | 接着La(Fe,Si)13系磁気熱量材料及びその製造方法と用途 |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3715582B2 (ja) | 2001-03-27 | 2005-11-09 | 株式会社東芝 | 磁性材料 |
US6676772B2 (en) | 2001-03-27 | 2004-01-13 | Kabushiki Kaisha Toshiba | Magnetic material |
JP3967572B2 (ja) | 2001-09-21 | 2007-08-29 | 株式会社東芝 | 磁気冷凍材料 |
US7186303B2 (en) | 2002-08-21 | 2007-03-06 | Neomax Co., Ltd. | Magnetic alloy material and method of making the magnetic alloy material |
JP3630164B2 (ja) | 2002-08-21 | 2005-03-16 | 株式会社Neomax | 磁性合金材料およびその製造方法 |
JP3947066B2 (ja) | 2002-09-05 | 2007-07-18 | 株式会社Neomax | 磁性合金材料 |
JP4413804B2 (ja) | 2005-03-24 | 2010-02-10 | 株式会社東芝 | 磁気冷凍材料及びその製造方法 |
JP2006274345A (ja) | 2005-03-29 | 2006-10-12 | Hitachi Metals Ltd | 磁性合金粉末およびその製造方法 |
CN100519807C (zh) * | 2005-04-05 | 2009-07-29 | 日立金属株式会社 | 磁性合金以及制备该磁性合金的方法 |
WO2008099234A1 (en) * | 2007-02-12 | 2008-08-21 | Vacuumschmelze Gmbh & Co. Kg. | Article for magnetic heat exchange and method of manufacturing the same |
JP5059929B2 (ja) | 2009-12-04 | 2012-10-31 | 住友電気工業株式会社 | 磁石用粉末 |
JP2016080883A (ja) | 2014-10-17 | 2016-05-16 | ヤマハ株式会社 | 楽器 |
-
2016
- 2016-10-18 WO PCT/JP2016/080883 patent/WO2017069131A1/ja active Application Filing
- 2016-10-18 US US15/767,427 patent/US11056254B2/en active Active
- 2016-10-18 JP JP2017546556A patent/JP6440282B2/ja active Active
- 2016-10-18 EP EP16857444.0A patent/EP3367395B1/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005113209A (ja) * | 2003-10-08 | 2005-04-28 | Hitachi Metals Ltd | 磁性粒子とその製造方法、及び磁性粒子ユニット |
JP2006316324A (ja) * | 2005-05-13 | 2006-11-24 | Toshiba Corp | 磁性材料の製造方法 |
JP2015506090A (ja) * | 2011-11-22 | 2015-02-26 | インスティテュート オブ フィジックス, チャイニーズ アカデミー オブ サイエンシーズ | 接着La(Fe,Si)13系磁気熱量材料及びその製造方法と用途 |
Non-Patent Citations (1)
Title |
---|
See also references of EP3367395A4 * |
Also Published As
Publication number | Publication date |
---|---|
JPWO2017069131A1 (ja) | 2018-09-27 |
EP3367395A4 (en) | 2019-08-21 |
EP3367395B1 (en) | 2022-06-29 |
US20180301254A1 (en) | 2018-10-18 |
EP3367395A1 (en) | 2018-08-29 |
JP6440282B2 (ja) | 2018-12-19 |
US11056254B2 (en) | 2021-07-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5477282B2 (ja) | R−t−b系焼結磁石およびその製造方法 | |
JP5999106B2 (ja) | R−t−b系焼結磁石の製造方法 | |
EP2511920B1 (en) | Process for production of rare earth anisotropic magnet | |
CN101404195A (zh) | 用于制备稀土永磁体的方法 | |
JP5609783B2 (ja) | 希土類−遷移金属系合金粉末の製造方法 | |
WO2010113465A1 (ja) | R-t-b-m系焼結磁石用合金及びその製造方法 | |
JPH09143636A (ja) | 希土類−鉄−窒素系磁石合金 | |
JP2005223263A (ja) | 希土類永久磁石の製造方法及び得られた希土類永久磁石 | |
Patissier et al. | Fast synthesis of LaFe13− xSix magnetocaloric compounds by reactive Spark Plasma Sintering | |
Gutfleisch et al. | Phase transformations during the disproportionation stage in the solid HDDR process in a Nd16Fe76B8 alloy | |
JP6440282B2 (ja) | 磁性材料の製造方法 | |
EP3855459B1 (en) | Sintered magnet manufacturing method | |
KR101483319B1 (ko) | 희토류금속 수소화물 제조 방법 및 이를 사용한 희토류금속-천이금속 합금 분말 제조 방법 | |
US6352597B1 (en) | Method for producing a magnetic alloy powder | |
JP7196666B2 (ja) | 希土類磁石用焼結体およびその製造方法 | |
JP7156226B2 (ja) | 希土類磁石の製造方法 | |
JP7287215B2 (ja) | 希土類磁石用焼結体の製造方法 | |
JPH09157803A (ja) | 希土類−鉄系合金 | |
JP4288637B2 (ja) | 永久磁石用希土類系合金粉末の製造方法 | |
KR101546037B1 (ko) | 마그네슘계 수소저장재료 및 이의 제조방법 | |
JP2838616B2 (ja) | 希土類系永久磁石用合金粉末の製造方法 | |
JP2838617B2 (ja) | 希土類系永久磁石用合金粉末の製造方法 | |
RU2648335C1 (ru) | Способ получения магнитотвердого материала | |
JP5088277B2 (ja) | 希土類−鉄−窒素系合金粉末の製造方法 | |
JP7363059B2 (ja) | 熱電変換材料の製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 16857444 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 15767427 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref document number: 2017546556 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2016857444 Country of ref document: EP |