EP0369097B1 - Magnetische Stoffe, enthaltend Seltenerdelemente, Eisen, Stickstoff und Wasserstoff - Google Patents

Magnetische Stoffe, enthaltend Seltenerdelemente, Eisen, Stickstoff und Wasserstoff Download PDF

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Publication number
EP0369097B1
EP0369097B1 EP89104753A EP89104753A EP0369097B1 EP 0369097 B1 EP0369097 B1 EP 0369097B1 EP 89104753 A EP89104753 A EP 89104753A EP 89104753 A EP89104753 A EP 89104753A EP 0369097 B1 EP0369097 B1 EP 0369097B1
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Prior art keywords
hydrogen
nitrogen
atomic percent
alloy
gas
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French (fr)
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EP0369097A1 (de
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Takahiko Iriyama
Kurima Kobayashi
Hideaki Imai
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Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Asahi Chemical Industry Co Ltd
Asahi Kasei Kogyo KK
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0433—Nickel- or cobalt-based alloys
    • C22C1/0441—Alloys based on intermetallic compounds of the type rare earth - Co, Ni
    • 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
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0553—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 obtained by reduction or by hydrogen decrepitation or embrittlement
    • 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
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2

Definitions

  • the present invention relates to magnetic materials comprising at least one rare earth element, iron, nitrogen and hydrogen and bonded or sintered magnets obtained therefrom and processes for preparing the same.
  • Magnetic materials and permanent magnets are one of the important electric and electronic materials employed in a wide range of from small magnets for various motors and actuators to large magnets for magnetic resonance imaging equipment.
  • Sm-Co samarium-cobalt
  • Nd-Fe-B neodymium-iron-boron
  • the Sm-Co permanent magnets are now practically used and one composition of them having a high efficiency shows a high maximum energy product [herein “(BH) max "] of 29.6 MGOe and a Curie temperature (herein “Tc”) of 917 °C.
  • (BH) max a high maximum energy product
  • Tc Curie temperature
  • permanent magnets of the Nd-Fe-B system are provided and the saturation magnetization (herein “4 ⁇ Is" or " ⁇ s") of one composition in single crystal reaches 16 KG with a (BH) max of about 40MGOe, but the Tc is as low as 312 °C and the resistance to oxidation is not sufficient.
  • the incorporation of Co with the Nd-Fe-B system is tried to increase the Tc but with a decreased intrinsic coersive force (herein “iHc"). Further, the incorporation of Co and Al or Ga with the Nd-Fe-B system is tried to give a permanent magnet having a Tc of 500 °C and a (BH) max of 35 to 40 but the resistance to oxidation is still not enough, and for practical purposes the treatment such as ion coating and plating is required.
  • iron nitride having a high 4 ⁇ Is in the form of a thin film for magnetic recording media or magnetic head materials For example, permanent magnets from iron alloys with rare earth metals and nitrogen have been proposed in CHEMICAL ABSTRACT, Vol. 103, No. 26, December 30, 1985, Columbus, Ohio, U.S.A., HITACHI METALS, LTD.
  • iron nitride has a low iHc and is difficult to be used as a bulk permanent magnetic material.
  • R-Fe rare earth-iron
  • the incorporation of hydrogen with the R-Fe alloys is studied and the increase in 4 ⁇ Is is observed but such R-Fe alloys containing hydrogen which can be used as permanent magnetic materials have not been obtained.
  • the magnetic properties of the magnetic materials, bonded magnets and sintered magnets include, herein, saturation magnetisation (herein “4 ⁇ Is” or “ ⁇ s”), residual magnetization (herein “Br”), intrinsic coercive force (Herein “iHc”), magnetic anisotropy, magnetic anisotropy energy (herein “Ea”), loop rectangularity (herein “Br/4 ⁇ Is”), maximum energy product (herein “(BH) max "), Curie temperature (herein “Tc”) and rate of thermal demagnetization.
  • an object of the present invention to provide magnetic materials having a high magnetic anisotropy and iHc as well as a high 4 ⁇ Is which can be used as a bulk permanent magnetic material.
  • Another object is to provide magnetic materials having a good resistance to oxidation and to deterioration of the magnetic properties.
  • Still another object is to provide a process for preparing such a magnetic material and a sintered and a bonded magnet making use of it.
  • a further object is to provide sintered magnets having high magnetic properties which do not require the annealing of the as sintered magnets.
  • FIG. 1 is a flow chart showing one typical embodiment of the processes for making permanent magnets.
  • FIGS. 2-(a) to 2-(c), FIGS. 3-(a) to 3-(c), FIGS. 4-(a) to 4-(c), FIGS. 5-(a) to 5-(c) and FIGS. 6-(a) to 6-(c) are X-ray powder diffraction patterns of the magnetic materials at each of the preparation steps i.e., (a) the starting alloys (b) the starting alloys after annealing and (c) the alloys after the absorption of nitrogen and hydrogen according to the present invention.
  • FIG. 7 shows a crystal structure of the starting rhombohedral R2Fe17 alloy wherein R is at least one rare earth element selected from the group consisting of Ce, Pr, Nd, Sm and Gd.
  • FIGS. 8-(a) to 8-(e) show variations of the number of the hydrogen absorbed, the lattice constants of a-axis and c-axis, the ratios of lattice constants of c-axis to a-axis, the half maximum line breadth of (204) and (300) reflections and the magnetic properties, respectively, with the increase in the number of the nitrogen absorbed per unit of Sm2Fe17 when the rhombohedral Sm2Fe17 alloy powder having an average particle diameter of 40 »m was contacted at 465 °C with a mixed gas of ammonia and hydrogen by varying the partial pressure of the ammonia from 0 to 0.5 atm and the partial pressure of the hydrogen from 1 to 0.5 atm with a total pressure of 1 atm to conduct the absorption of nitrogen and hydrogen in the alloy powder ⁇ ⁇ and ⁇ // were measured at 15KOe as in Example 12.
  • FIGS. 9-(a) to 9-(c) show distributions and concentrations of the nitrogen absorbed in the same rhombohedral Sm2Fe17 alloy powder as employed above by electron probe micro analysis.
  • the hatched portions schematically show the distribution of the nitrogen absorbed. From FIGS. 9-(a) and 9-(c) it can be understood that the concentration of the nitrogen absorbed is uniform and the as is as high as 140 emu/g when a mixed gas of ammonia having a partial pressure of 0.35 and hydrogen having a partial pressure of 0.65 is employed in the absorption of nitrogen and hydrogen in the alloy powder.
  • FIG. 10 shows Curie temperatures and decomposition temperatures in air of R2Fe17N 4.0 H 0.5 wherein R is Ce, Nd, Sm, Gd, Dy, Y and didymium.
  • the Curie temperatures of these magnetic materials are all above 470 °C and especially those of Nd and Sm are above 500 °C.
  • the decomposition temperatures in air of Ce, Nd and Sm are above 600 °C.
  • 5 samples were prepared and measured for each R and the mean value was employed.
  • the decomposition temperatures the errors in measurement were not small and the error lines were drawn in taking into account the errors.
  • FIG. 11 shows the oxidation resistance in air at 150 °C of the Sm2Fe17N 4.0 H 0.5 alloy powder having an average particle size of 40 »m in terms of the increase in weight as a function of a period of time tested in comparison with the Nd15Fe77B8 alloy powder (product of Sumitomo Special Metals Co., Ltd., "NEOMAX-35”) and the Sm1Co5 alloy powder (product of Research Chemicals).
  • FIG. 12 shows the deterioration in air at 150 °C of the magnetic properties of the Sm2Fe17N 4.0 H 0.5 alloy powder having an average particle size of 40 »m in terms of the ratios of the Br to the initial Br° and those of the iHc to the initial iHc° as a function of a period of time tested.
  • the weight of the Nd15Fe77B8 alloy powder is increased by about 4.5 % by weight and that of the Sm1Co5 alloy powder is increased by about 1 % by weight.
  • the weight of the Sm2Fe17N 4.0 H 0.5 alloy powder is increased by only 0.6 % by weight.
  • the Nd15Fe77B8 alloy powder maintains only about 10 % of the magnetic properties and the Sm1Co5 alloy powder maintains about 70 % of the Br and about 40 % of the iHc.
  • the Sm2Fe17N 4.0 H 0.5 alloy powder of the present invention has about 120 % of the Br and about 110 % of the iHc which are rather increased compared to the initial values due to the effect of annealing.
  • FIGS. 13-(a) to 13-(d) show the microstructure, by electron probe micro analysis, having a composition formula of Sm2Fe17N 4.0 H 0.5 Zn 4.7 at the initial stage of sintering prepared by mixing Sm2Fe17N 4.0 H 0.5 alloy powder having an average particle size of 15 »m with Zn (in an amount corresponding to Zn 4.7 of the above formula) having an average particle size of 8 »m in a ball mill for one hour in a nitrogen atmosphere immediately before sintering and sintering the mixture by raising the temperature at a rate of about 10 °C per minute up to 440 °C and cooling the sintered mixture to 20 °C immediately after reaching 440 °C.
  • FIG. 13-(a) is a scanning electron micrograph of the heat treated body and FIG. 13-(b) is an X-ray composition micrograph of the heat-treated body.
  • white regions are the Sm1Fe3 composition phase but most regions which are gray are uniform and can be identified by analysis as the Sm2Fe17 composition phase.
  • FIGS. 13-(c) and (13)-d are Fe and Zn characteristic X-ray micrographs of the heat-treated body, respectively, and white spots correspond to the presence of Fe and Zn elements, respectively.
  • the additive of the present invention quickly diffuses into the grain boundaries and forms a reaction phase with the major phase.
  • FIG. 14-(a) to 14-(d) show the microstructure, by electron probe micro analysis, of the sintered body of a compositioin formula of Sm2Fe17N 4.0 H 0.5 Zn 4.7 having a (BH) max of 11.8MGOe prepared by sintering a mixture of Sm2Fe17N 4.0 H 0.5 Zn 4.7 alloy powder obtained by further pulverizing the Sm2Fe17N 4.0 H 0.5 Zn 4.7 having an average particle size of 15 »m as employed above to an average particle size of 5 »m and the Zn powder as employed above at 480 °C for one hour.
  • FIG. 14-(a) is a scanning electron micrograph of the sintered body, FIG.
  • FIGS. 14-(b) is an X-ray composition micrograph of the sintered body and FIGS. 14-(c) and 14-(d) are Fe and Zn characteristic X-ray micrographs of the sintered body, respectively. As may be observed from FIGS. 14-(a) to 14-(d), Zn is precipitated in the grain boundaries in the microstructure of the sintered body.
  • FIG. 15 is an X-ray powder diffraction pattern of the alloy powder of, by atomic percent, 8.3Sm-70.6Fe-18.0N-3.1H as obtained in Example 1 of the present invention.
  • FIG. 16 is a magnetization versus temperature curve for the alloy powder of, by atomic percent, 8.3Sm-70.6Fe-18.0N-3.1H as obtained in Example 1 of the present invention.
  • FIGS. 17-(a) and 17-(b) are X-ray powder diffraction patterns of the starting alloy powder having a composition formula of Sm2F17 after the annealing and the alloy powder after the absorption of nitrogen and hydrogen, respectively, as obtained in Example 23 of the present invention.
  • FIG. 18 is a X-ray powder diffraction pattern of the alloy powder of, by atomic present, 8.8Sm-69.9Fe-18.3N-3.0H composition as obtained in Example 25 of the present invention.
  • FIG. 19 shows the relation of numbers of the nitrogen and hydrogen per unit of Sm2Fe17N x H y Zn 2.2 with the (BH) max of the sintered magnet as obtained in Example 31 of the present invention.
  • the rare earth elements R which can be employed in the present invention include light and heavy rare earth elements including Y and may be employed alone or in combination. More specifically, R includes Nd, Pr, La, Ce, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y and mixtures of two or more rare earth elements such as mischmetal and didymium. More preferably, R is at least one member selected from the group consisting of Nd, Pr, Ce, Sm, Gd, didymium, and alloys of Sm-Nd, Sm-Ce, Sm-Dy, Sm-Gd, Sm-Pr and Sm-Y.
  • rare earth elements R which can be employed in the present invention may not always be pure and may contain impurities which are inevitably entrained in the course of production.
  • the amount of R which can be employed in the present invention is typically 5 to 20 atomic percent, and a preferred amount of R is 8 to 9.5 atomic percent. When the amount of R is less than 5 atomic percent, the iHc is decreased. On the other hand, with amounts of R of more than 20 atomic percent, the 4 ⁇ Is is decreased.
  • the amount of nitrogen which can be employed in the present invention is typically 5 to 30 atomic percent, a preferred amount of nitrogen is 13 to 18 atomic percent.
  • the amount of nitrogen is less than 5 atomic percent, the magnetic anisotropy is decreased and as a result, the iHc is extremely decreased.
  • amounts of nitrogen of more than 30 atomic percent decrease the iHc and the 4 ⁇ Is as well as the magnetic anisotropy which are not suitable for practical permanent magnets.
  • the amount of hydrogen which can be employed in the present invention is typically 0.01 to 25 atomic percent, a preferred amount of hydrogen is 2 to 5 atomic percent. When the amount of hydrogen is less than 0.01 atomic percent, the magnetic properties are low. On the other hand, amounts of hydrogen of more than 25 atomic percent decrease the iHc as well as the magnetic anisotropy and require a treatment under pressure for the absorption of hydrogen.
  • the major component of the magnetic materials of the present invention is iron and the amount of iron is typically 40 to 89.9 atomic percent, preferably 50 to 86 atomic percent. A more preferred amount of iron is 69 to 72 atomic percent since the magnetic materials of the present invention are prepared by the absorption of nitrogen and hydrogen in an alloy of the rhombohedral R2Fe17 structure wherein R is at least one rare earth element selected from the group consisting of Ce, Pr, Nd, Sm and Gd or of the hexagonal R2Fe17 structure wherein R is at least one rare earth element selected from the group consisting of Tb, Dy, Ho, Er, Eu, Tm, Yb, Lu and Y as the basic composition.
  • the iron can be substituted by cobalt in an amount of at most 50 atomic percent of the iron.
  • At least one additive M is incorporated with the magnetic material of formula (I) of the present invention.
  • Exemplary additives M include metals such as Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, Ce, Sm and Fe, any alloys or mixtures thereof, oxides such as MgO, Al2O3 and Sm2O3; fluorides such as AlF3, ZnF2; carbides such as SiC and TiC; nitrides such as AlN and Si3N2; and any alloys or mixtures of the metals, the oxides, the fluorides, the carbides and the nitrides.
  • metals such as Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, Ce, Sm and Fe, any alloys or mixtures thereof, oxides such as MgO, Al2O3 and Sm2O3; fluorides such as AlF3, ZnF2; carbides such as SiC and TiC; nitrides such as AlN and Si3N2; and any alloys or mixture
  • additives M preferred are Zn, Ga, Al, In and Sn, any alloys or mixtures thereof; and any alloys or mixtures of at least one member selected from the group consisting of Zn, Ga, Al, In and Sn and at least one member selected from the group consisting of Si, Sic, Si3N2, MgO, Sm2O3 and TiC.
  • the amount of the additive M is typically 0.1 to 40 atomic percent and a preferred amount of the additive M is 5 to 15 atomic percent.
  • the amount of the additive is less than 0.1 atomic percent, the increase in iHc is small.
  • the amount of the additive M is more than 40 atomic percent, the decrease in 4 ⁇ Is is remarkable.
  • Iron and at least one rare earth element are alloyed by high frequency melting, arc melting or melt spinning in an inert gas atmosphere such as argon to give a starting alloy. It is preferred that the amount of the rare earth element is 5 to 25 atomic percent and the amount of the iron is 75 to 95 atomic percent. When the amount of the rare earth element is less than 5 atomic percent, a large amount of ⁇ -Fe phase is present in the alloy and accordingly, high iHc cannot be obtained. Also, when the amount of the rare earth is more than 25 atomic percent, high 4 ⁇ Is cannot be obtained.
  • Cobalt and/or at least one additive M can also be alloyed together with the iron and the rare earth element in the preparation of the starting alloy.
  • the amount of the cobalt does not exceed 50 atomic percent of the iron.
  • additive M is alloyed with the rare earth element and iron, it is preferred that the amount of the rare earth element is 5 to 25 atomic percent, that of the iron is 75 to 90 atomic percent and that of additive M is 0.1 to 50 atomic percent. Also when cobalt is alloyed with the additive M, rare earth element and iron, it is preferred that the amount of the cobalt does not exceed 50 atomic percent of the iron.
  • the iron tends to precipitate in the solidification of the alloy from a melt state, which causes decrease in the magnetic properties, particularly the iHc.
  • annealing is effective for making such an iron phase disappear, rendering the alloy composition uniform and improving the crystallinity of the alloy.
  • the annealing is preferably conducted at a temperature of 500 °C to 1300 °C for one hour to two weeks.
  • the alloys prepared by the high frequency melting or the arc melting are better in crystallinity and have higher 4 ⁇ Is than those prepared by the melt spinning.
  • the alloys of the present invention can also be prepared by the melt spinning and the crystal size of the alloy according to this method are fine and can be about 0.2 »m depending upon the conditions employed. However, when the cooling rate is high, the alloy becomes amorphous and the 4 ⁇ Is and iHc after the subsequent absorption of nitrogen and hydrogen do not so increase as by the high frequency melting or the arc melting. Thus in this case annealing is preferred.
  • the starting alloy is coarsely pulverized in a jaw crusher, a stamp mill or coffee mill in an inert atmosphere such as nitrogen and argon to such an average particle size that has reactivity to nitrogen and hydrogen and does not cause the progress of oxidation, i.e., typically 40 »m to 300 »m.
  • the pulverization can be carried out by alternatingly repeating the absorption of hydrogen in the sarting alloy with hydrogen gas at a temperature of 200 °C to 400 °C and the desorption of the hydrogen absorbed in an inert atmosphere such as argon at 600 °C to 800 °C. Since the starting alloy containing hydrogen becomes harder and the stretching of crystal lattices is caused by the alternating repetition of the absorption and desorption of hydrogen in the starting alloy, the pulverization can be spontaneously effected with the suppression of decrease in crystallinity to any desired particle size, as small as, for example, 4 »m, depending upon the number of the alternating repetition.
  • the methods for the absorption of nitrogen and hydrogen in the starting alloy which can be employed in the present invention include contacting the starting alloy powder with ammonia gas or a mixed gas of ammonia and at least one gas selected from the group consisting of hydrogen, helium, neon, argon and nitrogen at elevated temperatures at a pressure of 1 to 10 atm in one step; contacting the starting alloy powder with hydrogen gas or a mixed gas of hydrogen and at least one gas selected from the group consisting of helium, neon, argon and nitrogen at elevated temperatures to conduct the absorption of hydrogen and contacting the hydrogen-absorbed alloy powder with ammonia gas or a mixed gas of ammonia and at least one gas selected from the group consisting of hydrogen, helium, neon, argon and nitrogen at elevated temperature at a pressure of 1 to 10 atm to conduct the absorption of nitrogen in the hydrogen-absorbed alloy powder in two steps; and contacting the starting alloy powder with nitrogen gas, ammonia gas or a mixed gas of nitrogen or ammonia and at least one gas selected from the group consisting of helium
  • the one step method is preferred since the absorption of nitrogen and hydrogen can be completed in 10 to 20 minutes.
  • the two step methods it is easier to firstly conduct the absorption of hydrogen in the alloy powder and secondly conduct the absorption of nitrogen in the hydrogen-absorbed alloy powder.
  • the amounts of the nitrogen and hydrogen absorbed in the starting alloy can be controlled by the kind of the contacting gas selected or the mixing ratio of ammonia and hydrogen employed and the temperature chosen, the pressure applied and the contacting period of time employed.
  • a mixed gas of ammonia and hydrogen When the one step method is employed, it is preferred to use a mixed gas of ammonia and hydrogen.
  • the mixing ratio of ammonia and hydrogen may vary depending upon the contacting conditions and it is preferred that the partial pressure of ammonia is 0.02 to 0.75 atm and the partial pressure of hydrogen is 0.98 to 0.25 atm with a total pressure of the mixed gas of 1 atm.
  • the contacting temperature is typically 100 °C to 650 °C. When the contacting temperature is below 100 °C, the rate of the absorption of nitrogen and hydrogen is small.
  • the alloy powder after the absorption of nitrogen and hydrogen is further finely pulverized in a vibrating ball mill in an inert atmosphere such as nitrogen, helium, neon and argon typically to an average particle size of 1 to 10 »m.
  • the effect of additive M is most remarkably exhibited when the additive M is added to the alloy powder after the absorption of nitrogen and hydrogen and the mixture is mixed and finely pulverized in a vibrating ball mill in an inert atmosphere such as nitrogen, helium, neon, argon to an average size of 1 to 10 »m.
  • an inert atmosphere such as nitrogen, helium, neon, argon to an average size of 1 to 10 »m.
  • the alloy powder after the absorption of nitrogen and hydrogen undergoes the change in particle size and morphology as well as the mixing with additive M and as a result, the microstructure of the sintered magnet after the additive is allowed to react with the major phase and/or after the additive is dispersed in the grain boundaries undergoes the influence of the conditions in this step.
  • the additive When the average particle size reaches about 0.2 »m, the additive easily reacts with the major phase at sintering and accordingly the magnetic properties do not much improve. Also, average particle sizes of smaller than about 0.2 »m easily undergo oxidation and their handling becomes difficult. On the other hand, when the average particle size reaches about 20 to 30 um, a number of magnetic domains are gathered within each grain and resultedly the effect of additive M is small and the iHc cannot be improved by sintering.
  • the amount of additive M is typically 0.1 to 40 atomic percent.
  • the amount of additive M is 5 to 15 atomic percent, the magnetic properties, especially the (BH) max of the sintered magnet is improved.
  • the amount of additive M is 0.1 to 5 atomic percent, the decrease in the 4 ⁇ Is is small and the iHc is improved to some extent compared to that of the alloy powder without additive M.
  • amounts of the additive of 15 to 30 atomic percent give a sintered magnet having a comparatively high iHc and a good loop rectangularity and a decreased 4 ⁇ Is.
  • the amount of the additive is 30 to 40 atomic percent, the iHc of the sintered magnet is greatly increased but the magnetization is small and thus a special magnet is provided. Further when the amount of additive M is above 40 atomic percent, the 4 ⁇ Is of the sintered magnet becomes too small for practical purposes.
  • the alloy powder of the present invention has higher magnetic properties than conventional rare earth magnetic materials, a stronger magnetic field at the pressing is preferably employed.
  • the alloy powder as obtained above can be molded into a bonded magnet by mixing it with, as a binder agent, a thermoplastic resin such as polyamide, polybutylene terephthalate, polyphenylene sulfide as liquid crystal polymer and subjecting the mixture to infection-molding in a magnetic field; by mixing it with, as a binder agent, a thermosetting resin such as epoxy resin, phenolic resin and synthetic rubber and subjecting the mixture to compression-molding in a magnetic field; or compression-molding it in a magnetic field to give a shaped article, coating or impregnating the shaped article with, as a binder agent, the thermosetting resin or incorporating a solution of the thermoplastic resin with the shaped article and drying the shaped article thus obtained.
  • a thermoplastic resin such as polyamide, polybutylene terephthalate, polyphenylene sulfide as liquid crystal polymer and subjecting the mixture to infection-molding in a magnetic field
  • a thermosetting resin such as
  • sintering can be conducted by the conventional methods such as atmospheric heating, hot pressing and hot isostatic pressing.
  • atmospheric heating hot pressing and hot isostatic pressing.
  • the hot pressing in a hot atmosphere which does not require a large apparatus as employed by the hot isostatic pressing and can improve the magnetic properties of the sintered magnet will now be described.
  • the magnetic material of the present invention can be obtained by the absorption of nitrogen and hydrogen in the alloy, desired magnetic properties cannot be obtained unless the sintered magnet maintains the predetermined amounts of nitrogen and hydrogen in its structure. Accordingly it is preferred to conduct the sintering in a mixed gas of ammonia and hydrogen or argon or nitrogen or a mixed gas of nitrogen and hydrogen or argon at a temperature of 100 °C to 650 °C typically for 30 minutes to 4 hours, preferably for 1 to 2 hours. Of these mixed gases, a mixed gas of ammonia and hydrogen is more preferred for controlling the nitrogen and hydrogen absorbed in the structure of the sintered magnet.
  • the magnetic material of the present invention is stable and thus any atmosphere of the sintering can be employed to give good magnetic properties of the sintered magnet.
  • the sintering temperature is above 650 °C, in general, the decomposition of the magnetic material of the present invention progresses independently of the sintering atmosphere employed to precipitate ⁇ -Fe phase and changes the amounts of the nitrogen and hydrogen initially absorbed.
  • the pressure of the hot pressing depends upon the material of the die employed and is sufficiently around 10 ton/cm2.
  • additive M when additive M is employed, the sintering conditions vary depending on the type of additive M employed. For example, when Zn having a melting point near 420 °C is employed as additive M, the dispersion of Zn in the grain boundaries becomes remarkable at a temperature near 420 °C but the magnetic properties is not much improved by this dispersion alone although amounts of Zn of 30 to 40 atomic percent increase the iHc with decreased 4 ⁇ Is, accordingly with not-improved final (BH) max .
  • Magnetization can be conducted by exposing the sintered body or the bonded magnet of the present invention to an external magnetic field.
  • the direction of the magnetic field is the same as that of easy magnetization of the sintered body or the bonded magnet.
  • a static magnetic field can be generated by an electromagnet or a pulsed magnetic field can be generated by a capacitor discharge magnetizer.
  • the magnetic field strength for sufficiently conducting the magnetization is typically above 15KOe and preferably above 30KOe.
  • annealing is effective.
  • the crystallinity of magnetic materials could be said to have a close relation with the magnetic properties of the magnetic materials.
  • the crystallinity is nearer to completeness, i.e., as the disorder in crystal structure is less or the defect in crystals are less, the 4 ⁇ Is and the magnetic anisotropy are more increased.
  • the crystallinity of the magnetic materials of the present invention is increased, the magnetic properties can further be improved.
  • annealing is a preferred means for increasing the crystallinity for practical purposes.
  • the annealing of the starting alloy when carried out before the absorption of nitrogen and hydrogen in the alloy, it is preferred to carry out the annealing at a temperature of 500 °C to 1300 °C in an inert gas atmosphere such as argon and nitrogen or in a hydrogen atmosphere for one hour to two weeks.
  • an inert gas atmosphere such as argon and nitrogen
  • the annealing temperature is typically 100 °C to 650 °C, preferably 150 °C to 500 °C. When the annealing temperature is below 100 °C, the effect of annealing does not appear. On the other hand, annealing temperatures above 650 °C tend to evaporate nitrogen and hydrogen. Any non-oxidizing atmosphere can be employed and the atmosphere containing hydrogen, argon, nitrogen or ammonia is more effective. When the annealing is carried out at a temperature below 450 °C, air is effective as the annealing atmosphere.
  • the quantitative analysis of the rare earth element and the iron in the alloy powder of the present invention was conducted by dissolving the alloy powder in nitric acid and subjecting the solution obtained to inductively coupled plasma emission spectrometry by a spectrometer (manufactured by Seiko Instruments & Electronics Ltd.), and the quantitative analysis of the nitrogen and hydrogen absorbed was conducted by subjecting the alloy powder of the present invention to an inert gas fusion in impulse furnace-thermal conductivity analysis by an analyzer (manufactured by Horiba, Ltd., "EMGA-2000").
  • the 4 ⁇ Is, iHc, temperature dependency of magnetization and Curie temperature of the alloy powder of the present invention were measured by a vibrating sample magnetometer (manufactured by Toei Industry Co., Ltd.).
  • An alloy ingot of, by atomic percent, 10.5Sm-89.5Fe composition i.e., a composition formula of Sm2Fe17 was prepared by the arc melting of Sm having a purity of 99.9 % by weight and Fe having a purity of 99.9 % in a water-cooled copper boat in an argon atmosphere.
  • the alloy ingot thus obtained was annealed at 1200 °C for 3 hours in an argon atmosphere, and then coarsely crushed in a jaw crusher in a nitrogen atmosphere and subsequently finely pulverized to an average particle size of 100 »m in a coffee mill in a nitrogen atmosphere.
  • the alloy powder thus obtained was placed in a tubular furnance and a mixed gas of ammonia gas having a partial pressure of 0.4 atm and hydrogen gas having a partial pressure of 0.6 atm was introduced into the tubular furnace and the temperature of the furnace was raised to 450 °C at a rate of 15 °C/minute and kept at 450 °C while continuing the introduction of the mixed gas for 30 minutes to effect the absorption of nitrogen and hydrogen in the alloy powder, and then the temperature of the furnace was cooled to 20 °C at a rate of 15 °C/minute in the mixed gas atmosphere to give alloy powder of, by atomic percent, 8.3Sm-70.6Fe-18.0N-3.1H composition.
  • Fig. 15 is an X-ray powder diffraction pattern by the radiation of Ni-filtered CuK ⁇ of this alloy powder.
  • the alloy powder thus obtained was compression-molded in a magnetic field of 15KOe under a pressure of 2 ton/cm2.
  • the molded article thus obtained was magnetized in a pulse magnetic field of 50 KOe and the magnetic properties were as follows; 4 ⁇ Is 13.3 KG Ea 9.8 x 106 erg/g iHc 1100 Oe
  • the alloy powder is a magnetic material having a high 4 ⁇ Is and a high Ea.
  • the alloy powder was further finely pulverized to an average particle size of 5 »m in a vibrating ball mill in a nitrogen atmosphere and then compression-molded using copper powder as the binder agent in the same manner as described above, the iHc was improved to be 5100 Oe.
  • Fig. 16 shows Curie temperature (Tc) of this alloy powder.
  • Tc was 560 °C which was remarkably increased from Tc of 95 °C of the intermetallic compound having a composition formula of Sm2Fe17.
  • alloy powder containing nitrogen and hydrogen The same procedures for obtained alloy powder containing nitrogen and hydrogen as in Example 1 were repeated except that the partial pressures of ammonia gas and hydrogen gas were changed to 0.1 atm and 0.9 atm ; 0.2 atm and 0.8 atm ; and 0.5 atm and 0.5 atm, respectively.
  • alloy powder of, by atomic percent, 9.1Sm-76.9Fe-9.0N-5.0H, 8.7Sm-74.2Fe-13.1N-4.0H and 8.0Sm-67.8Fe-23.3N-0.9H compositions, respectively was obtained.
  • the alloy powder compositions and their magnetic properties are shown in Table 1 below.
  • Example 1 The same procedures for obtaining alloy powder as in Example 1 were repeated except using hydrogen gas alone at a pressure of 1 atm instead of the mixed gas.
  • the magnetic properties of the hydrogen-absorbed alloy powder are shown in Table 1 below.
  • Example 1 The same procedures for obtaining alloy powder as in Example 1 were repeated except that the partial pressures of the ammonia and the hydrogen in the mixed gas were changed to 0.6 atm and 0.4 atm, respectively. As the result, the alloy powder of, by atomic percent, 6.5Sm-55.0Fe-38.2N-0.3H composition was obtained. The magnetic properties of the alloy powder thus obtained are shown in Table 1 below.
  • Example 2 The same procedures for obtaining alloy powder containing nitrogen and hydrogen and having an average particle size of 100 »m as in Example 1 were repeated except that as the starting alloys, 7.2Sm-92.8Fe, 14.4Sm-85.6Fe and 20.2Sm-79.8Fe were employed, respectively, instead of the 10.5Sm-89.5Fe.
  • the alloy powder compositions and their magnetic properties after absorption of nitrogen and hydrogen are shown in Table 2. Table 2 Example No.
  • Example 2 The same procedures for obtaining alloy powder as in Example 1 were repeated except that the absorption of nitrogen and hydrogen in the alloy was carried out in a mixed gas of ammonia having a partial pressure of 0.05 atm and argon having a partial pressure of 0.95 atm with a total pressure of 1 atm at 490 °C for 5 minutes.
  • Example 8 The same procedures as in Example 8 were repeated except that the contact temperature and time with the mixed gas were changed to 450 °C and 20 minutes, respectively, in the absorption of nitrogen and hydrogen in the alloy powder.
  • Example 2 The same procedures for obtaining alloy powder as in Example 1 were repeated except that the absorption of nitrogen and hydrogen in the alloy was carried out in a mixed gas of ammonia having a partial pressure of 0.2 atm, hydrogen having a partial pressure of 0.3 atm and argon having a partial pressure of 0.5 atm with a total pressure of 1 atm at 450 °C for 30 minutes.
  • Example 2 About 1 g of the same starting alloy powder having an average particle size of 100 »m as in Example 1 was packed in a cylindrical stainless steel pressure resistant vessel having an inner diameter of 30 mm and a height of 150 mm. After the vessel was vacuumed, ammonia gas of 2 atom and hydrogen gas of 3 atm were filled in the vessel with a total pressure of 5 atm at 20 °C. Then the vessel was placed in an electric furnace at 400 °C for 30 minutes to carry out the absorption of nitrogen and hydrogen in the alloy. The total pressure in the vessel at the heating at 400 °C was 7.2 atm. Then the vessel was cooled to 20 °C and the alloy powder was taken out of the vessel and subjected to analysis.
  • Example 2 The same procedures for obtaining alloy powder containing nitrogen and hydrogen and having an average article size of 100 »m as in Example 1 were repeated except that Ce, Nd, Pr, Gd, Dy and Y, each having a purity of 99.9 % by weight and didymium were employed, respectively, instead of the Sm.
  • the alloy powder compositions and their magnetic properties before and after the absorption of nitrogen and hydrogen are shown in Table 4.
  • the magnetic anisotropy was evaluated in terms of the ratio ( ⁇ ⁇ / ⁇ // ) of magnetization in the direction of hard magnetization ( ⁇ ⁇ ) to that in the direction of easy magnetization ( ⁇ // ) at 15 Koe.
  • Alloy ingots were prepared by the high frequency melting of Sm, Dy, Y, Gd, Ce or Nd and Fe, each having a purity of 99.9% by weight in an argon atmosphere, followed by molding the melt in an iron mold. Then the alloy ingots were annealed at 1200 °C for 2 hours in an argon atmosphere to render the alloy compositions uniform.
  • the starting alloy compositions thus obtained are shown in Table 5.
  • the alloys were finely pulverized to an average particle size of 100 »m in a coffee mill in a nitrogen atmosphere and subjected to the absorption of nitrogen and hydrogen in the alloy powder in the same manner as in Example 1 to give magnetic materials whose alloy compositions are shown in Table 5. Also the magnetic properties of the magnetic materials thus obtained are shown in Table 5.
  • Example 2 The same starting alloy powder having an average particle size of 100 »m as obtained in Example 1 was placed in a tubular furnace and hydrogen gas having a pressure of 1 atm alone was introduced into the tubular furnace and the temperature of the furnace was raised to 450 °C at a rate of 15 °C/minute and kept at 450 °C while continuing the introduction of hydrogen for one hour to effect the absorption of hydrogen alone in the alloy powder and then a mixed gas of ammonia gas having a partial pressure of 0.4 atm and hydrogen gas having a partial pressure of 0.6 atm with a total pressure of 1 atm was introduced into the tubular furnace kept at 450 °C, instead of the hydrogen gas, for 30 minutes to effect the absorption of nitrogen in the hydrogen-absorbed alloy powder, and then the alloy powder was cooled to 20 °C at a rate of 15 °C/minute in the same mixed gas atmosphere to give alloy powder of, by atomic percent, 8.3Sm-70.6Fe-17.5N-3.6H composition.
  • the magnetic properties of the alloy powder thus obtained were as
  • Example 2 The same starting alloy powder having an average particle size of 100 »m as obtained in Example 1 was placed in a tubular furnace and nitrogen gas having a pressure of 1 atm alone was introduced into the tubular furnace and the temperature of the furnace was raised to 550 °C at a rate of 15 °C/minute and kept at 550 °C which continuing the introduction of nitrogen for 8 hours to effect the absorption of nitrogen alone in the alloy powder and subsequently a mixed gas of hydrogen gas having a partial pressure of 0.5 atm and nitrogen gas having a partial pressure of 0.5 atm with a total pressure of 1 atm was introduced into the tubular furnace cooled to and kept at 450 °C, instead of the nitrogen gas, for 30 minutes to effect the absorption of hydrogen in the nitrogen absorbed-alloy powder, and then the alloy powder was cooled to 20 °C at a rate of 15 °C/minute in the same mixed gas atmosphere to give alloy powder of, by atomic percent, 8.4Sm-71.9Fe-15.6N-4.1H composition.
  • An alloy of, by atomic percent, 10.5Sm-89.5Fe composition was prepared by the high frequency melting of Sm and Fe each having a purity of 99.9 % by weight in an argon atmosphere, followed by pouring the melt in an iron mold and then annealing the ingot thus obtained at 1250 °C for 3 hours in an argon atmosphere.
  • the alloy thus obtained was coarsely crushed in a jaw crusher in a nitrogen atmosphere and finely pulverized in a coffee mill in a nitrogen atmosphere to an average particle size of 100 »m.
  • This alloy powder is designated Powder A.
  • Powder A was sealed in an autoclave provided with a pressure valve and a pressure gauge. After the autoclave was vacuumed, a mixed gas of hydrogen gas and ammonia gas was introduced into the autoclave.
  • the inner pressure of the autoclave was 9.0 atm with a partial pressure of the ammonia of 3.0 atm and a partial pressure of the hydrogen of 6.0 atm.
  • the autoclave was heated in a heating furnace for 465 °C for 30 minutes to effect the absorption of nitrogen and hydrogen in the alloy powder and subsequently slowly cooled to 20 °C to give alloy powder of, by atomic percent, 8.3Sm-70.6Fe-16.5N-4.6H composition.
  • the magnetic properties of the alloy powder were as follows; 4 ⁇ Is 13.1 KG Ea 9.6 x 106 erg/g iHc 1050 Oe
  • Powder A as obtained in Example 20 was placed at the position whose temperature was 550 °C in a tubular furnace having such a temperature distribution that the temperature of the center of the furnace was 1500 °C and the temperature was rapidly decreased in the direction of both ends of the furnace with the temperature of one end equal to 20 °C.
  • the magnetic properties of the alloy powder were as follows; 4 ⁇ Is 11.8 KG Ea 7.3 x 106 erg/g iHc 570 Oe
  • An alloy ingot having a composition formula of Sm2Fe10 was prepared by the high frequency melting in the same manner as in Example 20.
  • the alloy ingot thus prepared was pulverized in a coffee mill in a nitrogen atmosphere and sieved to give alloy powder having an average particle size of less than 74 »m.
  • This powder was dispersed in methylethyl ketone, spread on a stainless steel plate having a diameter of 15 cm and dried in air to give a target.
  • radio frequency-sputtering was carried in a sputtering device (manufactured by ULVAC Co., "SH-450") to give a thin film of Sm-Fe having a thickness of 0.8 »m on an alumina substrate having a thickness of 0.48 mm and an area of 3.81 cm x 3.81 cm under the following conditions ; Distance between Substrate and Target 8 cm Sustrate temperature 600 °C to 650 °C Atmosphere & Pressure Argon about 40 mTorr Radio Frequency Power 350 W
  • the thin film was sealed in a quartz tube and heated in an argon atmosphere at 800 °C for one hour and subsequently sealed in a tubular furnace. Then a mixed gas of ammonia gas having a partial pressure of 0.35 atm and hydrogen gas having a partial pressure of 0.65 atm with a total pressure of 1 atm was introduced into the tubular furnace and the temperature of the tubular furnace was raised to 450 °C at a rate of 15 °C/minute and kept at 450 °C while continuing the introduction of the mixed gas for 15 minutes to effect the absorption of nitrogen and hydrogen in the thin film, and then the temperature of the tubular furnace was cooled to 20 °C at a rate of 15 °C/minute in the mixed gas atmosphere to give a magnetic film having a composition formula of Sm2Fe11N1H 0.1 .
  • An alloy ingot having a composition formula of Sm2Fe17 was prepared by the arc melting of Sm having a purity of 99.9 % by weight and Fe having a purity of 99.9 % by weight in a water-cooled copper boat in an argon atmosphere.
  • the alloy ingot thus obtained was annealed at 900 °C for 7 days in an argon atmosphere, and then coarsely crushed in a jaw crushed in a nitrogen atmosphere and subsequently finely pulverized to an average particle size of 105 »m in a coffee mill in a nitrogen atmosphere.
  • the alloy powder thus obtained was further finely pulverized to an average particle size of 4.6 »m in a vibrating mill in a nitrogen atmosphere and subsequently subjected to annealing at 900 °C for 6 hours in an argon atmosphere.
  • FIG. 17-(a) is an X-ray powder diffraction pattern by the radiation of Ni-filtered CuK ⁇ of this alloy powder after annealing. It can be observed that the peak is sharp and the crystallinity is sufficiently high.
  • the alloy powder obtained after annealing was placed in a tubular furnace and a mixed gas of ammonia gas having a partial presure of 0.4 atm and hydrogen gas having a partial pressure of 0.6 atm with a total pressure of 1 atm was introduced into the tubular furnace and the temperature of the tubular furnace was raised to 450 °C at a rate of 15 °C./minute and kept at 450 °C while continuing the introduction of the mixed gas for 30 minutes to effect the absorption of nitrogen and hydrogen in the alloy, and then the alloy powder was cooled to 20 °C at a rate of 15 °C/minute in the same mixed gas to give an alloy powder of, by atomic percent, 8.3Sm-70.5Fe-18.3N-2.9H composition.
  • FIG. 17-(b) is an X-ray powder diffraction pattern by the radiation of Ni-filtered CuK ⁇ line of this alloy powder.
  • the magnetic properties of the alloy powder thus obtained were as follows; 4 ⁇ Is 13.8 KG Ea 11.4 x 106 erg/g iHc 6800 Oe
  • the alloy powder thus obtained is a magnetic material having a high Ea as well as a high 4 ⁇ Is.
  • An alloy ingot of, in atomic percent, 10.2Sm-1.0Dy-88.8Fe was prepared by the arc melting of Sm, Dy and Fe, each having a purity of 99.9 % by weight in a water-cooled copper boat in an argon atmosphere.
  • the alloy ingot thus obtained was annealed at 1200 °C for 2 hours in an argon atmosphere, and then coarsely crushed in a jaw crusher in a nitrogen atmosphere and subsequently finely pulverized to an average particle size of 117 »m in a coffee mill in a nitrogen atmosphere.
  • the alloy powder thus obtained was further finely pulverized to an average particle size of 3.8 »m in a jet mill in a nitrogen atmosphere and subsequently subjected to the same annealing as in Example 23, followed by carrying out the absorption of nitrogen and hydrogen in the alloy powder in the same manner as in Example 23 to give an alloy powder of, by atomic percent, 8.0Sm-0.8Dy-70.0Fe-18.5N-2.7H whose magnetic properties were as follows; 4 ⁇ Is 13.9 KG Ea 11.2 x 106 erg/g iHc 6830 Oe
  • An alloy ingot having a composition formula of Sm2Fe 15.9 was prepared by the arc melting of Sm having a purity of 99.9 % by weight and Fe having a purity of 99.9 % by weight in a water-cooled copper boat in an argon atmosphere.
  • the alloy ingot thus obtained was annealed at 900 °C for 7 days in an argon atmosphere, and then coarsely crushed in a jaw crusher in a nitrogen atmosphere and subsequently finely pulverized to an average particle size of 110 »m in a coffee mill in a nitrogen atmosphere.
  • the alloy powder thus obtained which is designated Powder B was placed in a tubular furnace and hydrogen gas having a pressure of 1 atom alone was introduced into the tubular furnace and the temperature of the tubular furnace was raised to 300 °C at a rate of 15 °C/minute and kept at 300 °C while continuing the introduction of the hydrogen gas for 30 minutes to carry out the absorption of hydrogen in the alloy.
  • the amount of hydrogen absorbed was 1.23 hydrogen atom per Sm atom.
  • the alloy powder thus obtained was further finely pulverized in a vibrating ball mill in a nitrogen atmosphere to an average particle size of 3.8 »m.
  • the alloy powder was placed in a tubular furnace and a mixed gas of ammonia gas having a partial pressure of 0.4 atom and hydrogen gas having a partial pressure of 0.6 atm with a total pressure of 1 atm was introduced into the tubular furnace at and the temperature of the tubular furnace was raised to 450 °C at a rate of 15 °C/minute and kept at 450 °C while continuing the intrduction of the mixed gas 30 minutes to effect the absorption of nitrogen and hydrogen in the alloy, and then the alloy powder was cooled to 20 °C at a rate of 15 °C/minute in the same mixed gas atmosphere to give an alloy powder of, by atomic percent, 8.8Sm-69.9Fe-18.6N-2.7H composition whose magnetic properties were as follows; 4 ⁇ Is 13.5 KG Ea 10.9 x 106 erg/g iHc 5600 Oe
  • the alloy powder thus obtained is a magnetic material having a high Ea as well as a high 4 ⁇ Is.
  • FIG. 18 is an X-ray powder diffraction pattern by the radiation of Ni-filtered CuK ⁇ of this alloy powder.
  • Powder B as obtained in Example 25 was placed in a tubular furnace and hydrogen gas at a pressure of 1 atm was introduced into the tubular furnace and the temperature of the tubular furnace was raised to 300 °C at a rate of 15 °C/minute and kept at 300 °C while continuing the introduction of the hydrogen gas for 10 minutes to effect the absorption of hydrogen in the alloy (i.e., hydrogen absorption procedure) and then the introduction of the hydrogen was stopped and the temperature of the tubular furnace was raised to 700 °C at a rate of 15 °C/minute in an argon atmosphere to effect the desorption of hydrogen in the alloy (i.e., hydrogen desorption procedure).
  • the fine pulverization of the alloy powder was conducted by alternatingly repeating the hydrogen absorption procedure and the hydrogen desorption procedure until the average particle size reached 4.1 »m.
  • Example 25 Then the absorption of nitrogen and hydrogen in the alloy was carried out under the same conditions as in Example 25 to give alloy powder of, by atomic percent, 8.8Sm-69.9Fe-18.3N-3.0H composition.
  • the X-ray powder diffraction pattern by the radiation of Ni-filtered CuK ⁇ of the alloy powder was similar to that of FIG. 18.
  • the magnetic properties of the alloy powder were as follows; 4 ⁇ Is 13.6 KG Ea 11.3 x 106 erg/g iHc 6200 Oe
  • Example 25 Separately the absorption of nitrogen and hydrogen in Power B as obtained in Example 25 was carried out under the same conditions as in Example 25 and then the alloy powder thus obtained was finely pulverized to an average particle size of 3.7»m in a vibrating ball mill in a nitrogen atmosphere to give alloy powder of, by atomic percent, 8.8Sm-70.4Fe-18.0N-2.8H composition.
  • the magnetic properties of the alloy powder thus obtained were as follows; 4 ⁇ Is 11.2 KG Ea 7.8 x 106 erg/g iHc 4800 Oe
  • Example 25 When Power B as obtained in Example 25 was finely pulverized to an average particle size of 3.7 »m in a vibrating ball mill in a nitrogen atmosphere and then the absorption of nitrogen and hydrogen in the alloy powder was carried out in the same manner as in Example 25 to give alloy powder of, by atomic percent, 8.9Sm-70.7Fe-17.7N-2.7H composition.
  • the magnetic properties of the alloy powder were as follows; 4 ⁇ Is 12.0 KG Ea 7.6 x 106 erg/g iHc 2200 Oe
  • a starting alloy of, by atomic percent, 10.5Sm-89.5Fe composition Using an apparatus for carrying out the quenching of alloy melt by ejecting the alloy melt on to a rotating copper roll having a diameter of 25 cm and a width of 2 cm, a starting alloy of, by atomic percent, 10.5Sm-89.5Fe composition.
  • the melting of Sm and Fe, each having a purity of 99.9 % by weight before quenching was effected by packing the Sm and Fe in a quartz nozzle by the high frequency melting in an argon atmosphere and the ejecting pressure was 1Kg/cm2 with the distance between the roll and nozzle of 1 mm.
  • the rotating speed of the roll was varied as shown in Table 7 and the thin samples thus obtained were pulverized to an average particle size of about 30 »m in a coffee mill in a nitrogen atmosphere and then the absorption of nitrogen and hydrogen in the alloy powder was carried out in the same manner as in Example 1.
  • the starting alloy when the starting alloy is prepared by the melt spinning, magnetic powder materials having very high iHc (except the rotating speed of 6000 r.p.m.) can be obtained in the present invention.
  • the rotating speed of the roll when the rotating speed of the roll is in the range of 500 to 3000 r.p.m. in the preparation of starting alloys by the melt spinning, the starting alloys obtained are crystalline.
  • the rotating speed of the roll is 6000 r.p.m. in the preparation of a starting alloy by the melt spinning, the starting alloy obtained is amorphous which might render the iHc not so high.
  • Example 8 The same alloy powder having an average particle size of 100 »m after the absorption of nitrogen and hydrogen as obtained in Example 1 was subjected to annealing under the conditions as shown in Table 8.
  • the magnetic properties of the alloy powder after annealing are shown in Table 8. As would be clear from Table 8, the annealing under these conditions is effective for improving the magnetic properties. The change in the alloy powder compositions before and after the annealing could not be observed.
  • the alloys having the compositions as shown in Table 9 were prepared by the arc melting of Sm, Fe and Co, each having a purity of 99.9 % by weight in a water-cooled boat in an argon atmosphere, and then coarsely crushed in a jaw crusher in a nitrogen atmosphere and subsequently finely pulverized to an average particle size of 100 »m in a coffee mill in a nitrogen atmosphere.
  • the alloy powder thus obtained was placed in a tubular furnace and a mixed gas of ammonia gas having a partial pressure of 0.67 atm and hydrogen gas having a partial pressure of 0.33 atm with a total pressure of 1 atm was introduced into the tubular furnace and the temperature of the tubular furnace was raised to 470 °C at a rate of 15 °C/minute and kept at 470 °C while continuing the introduction of the mixed gas for 60 minutes to effect the absorption of nitrogen and hydrogen in the alloy and the alloy powder was cooled to 20 °C at a rate of 15 °C/minute in the same mixed gas to give alloy powder having the compositions shown in Table 9.
  • the magnetic properties of the alloy powder are shown in Table 9.
  • Example 2 About 1 g of the same alloy powder having an average particle size of 5 »m and an iHc of 5100 Oe as obtained in Example 1 was packed in a WC mold having a rectangular hole of 5 mm x 10 mm for hot pressing, oriented in a magnetic field of 15 KOe and pressed under a pressure of 1 ton/cm2. Then the mold was fixed in a hot-pressing device and subjected to hot-pressing under the conditions shown in Table 10 to effect the sintering of the alloy powder.
  • Example 23 The same alloy having a composition formula of Sm2Fe17 and an average particle size of 105 »m as obtained in Example 23 was subjected to the absorption of nitrogen and hydrogen in a mixed gas of ammonia and hydrogen with various partial pressures to give alloy powder.
  • a mixed gas of ammonia and hydrogen with various partial pressures to give alloy powder.
  • To the alloy powder thus obtained 2.2 of Zn per unit cell of Sm2Fe17N x H y was added and the mixture was finely pulverized in a vibrating ball mill for one hour in nitrogen atmosphere to give alloy powder having an average particle size of 5 »m and a composition formula of Sm2Fe17N x H y Zn 2.2 as shown in FIG. 19.
  • the alloy powder was molded into a plate of 5 mm x 10 mm x 2 mm by a uniaxial magnetic press in a magnetic field of 15 KOe under a pressure of 1 ton/cm2 and the plate was sintered in a mixed gas of ammonia having a partial pressure of 0.2 atm and hydrogen having a partial pressure of 0.8 atm with a total pressure of 1 atm at 480 °C for 2 hours under a pressure of 10 ton/cm2.
  • the sintered body thus obtained was magnetized in a magnetic field of about 60 KOe to give a sintered magnet.
  • FIG. 19 clearly shows a close relation of the amounts of nitrogen and hydrogen absorbed with (BH) max as the magnetic property.
  • (BH) max is highest, and even when x is varied from 3.0 to 5.0 and y is varied from 0.1 to 1.0, (BH) max is comparatively high.
  • Example 23 The same alloy having a composition formula of Sm2Fe17 and an average particle size of 105 »m as obtained in Example 23 was subjected to the absorption of nitrogen and hydrogen in the same manner as in Example 23 to give alloy powder having a composition formula of Sm2Fe17N 4.0 H 0.5 .
  • Zn was added in an amount of 2.2 per unit cell of Sm2Fe17N 4.0 H 0.5 and the mixture was finely pulverized in a vibrating mill for one hour in a nitrogen atmosphere to give alloy powder having an average particle size of 5 »m and a composition formula of Sm2Fe17N 4.0 H 0.5 Zn 2.2
  • the alloy powder thus obtained was molded into a plate of 10 mm x 5 mm x 2 mm by a uniaxial magnetic field press in a magnetic field of 15 KOe under a pressure of 1 ton/cm2 and the plate was sintered in a mixed gas of ammonia having a partial pressure of 0.2 atm and hydrogen having a partial pressure of 0.8 atm with a total pressure of 1 atm at 470 °C under a pressure of 10 ton/cm2 for a period of time shown in Table 11.
  • Table 11 Magnetic Properties Alloy Powder before Sintering Sintered Body Sintering Time (hour) 1 2 4 iHc (Oe) 3000 4800 6700 5300 4 ⁇ Is (KG) 11.5 10.6 10.0 9.0 Loop Rectangularity (Br/4 ⁇ Is) 0.780 0.900 0.914 0.870 (BH) max (MGOe) - 12.0 15.0 8.0
  • Example 32 To the same alloy powder having a composition formula of Sm2Fe17N 4.0 H 0.5 as obtained in Example 32 Zn was added in an amount of 2 and 7 per unit cell of Sm2Fe17N 4.0 H 0.5 , respectively, and the mixtures were finely pulverized in a vibrating ball mill in a nitrogen atmosphere for 4 hours and 1 hour, respectively, and the alloy powder was molded into plates and in the same manner as in Example 32 to give sintered bodies.
  • Table 12 Magnetic Properties Sm2Fe17N 4.0 H 0.5 Zn2 Sm2Fe17N 4.0 H 0.5 Zn7 Pulverization(4 hrs.) Pulverization(1 hr.) Alloy Powder before Sintering Sintered Body Alloy Powder before Sintering Sintered Body iHc (Oe) 4500 10800 3000 11700 4 ⁇ Is (KG) 10.6 9.0 8.9 7.7 Rectangu- (Br/4 ⁇ Is) larity 0.80 0.92 0.77 0.95 (BH) max (MGOe) - 9.8 - 9.4
  • An alloy of, by atomic percent, 10.6Sm-77.8Fe-11.6Zn composition was prepared by high frequency melting of Sm, Fe and Zn, each having a purity of 99.9 % by weight.
  • the alloy thus obtained was annealed at 900 °C for 24 hours and then the annealed alloy was crushed and finely pulverized to an average particle size of 100 »m and subjected to the adsorption of nitrogen and hydrogen in the alloy in the same manner as in Example 1.
  • the magnetic properties of the finely pulverized alloy powder are set forth in Table 13.
  • the alloy powder was further finely pulverized in a vibrating ball mill to an average particle size of about 6 »m in a nitrogen atmosphere.
  • the magnetic properties of the alloy powder thus obtained are set forth in Table 13.
  • the powder having an average particle size of about 6 »m was compression-molded by a uniaxial magnetic field press in a magnetic field of 15 KOe under a pressure of 1 ton/cm2 to form a plate of 10mm x 5 mm x 2 mm.
  • the plate was sintered by the hot-pressing in a WC mold at 470 °C under a pressure of 12 ton/cm2 for 90 minutes in an atmosphere of ammonia having a partial pressure of 0.2 atom and hydrogen having a partial pressure of 0.8 atm with a total pressure of 1 atm.
  • the magnetic properties of the sintered body thus obtained are set forth in Table 13.
  • the alloy powder thus obtained was molded and sintered by the hot pressing in the same manner as in Example 34 to give a sintered body.
  • Example 32 To the same alloy powder having a composition formula of Sm2Fe17N 4.0 H 0.5 as obtained in Example 32 the additives as set forth in Table 14 were added and the mixtures were finely pulverized in a vibrating ball mill for one hour in a nitrogen atmosphere, molded and sintered for 2 hours in the same manner as in Example 32 to give sintered magnets.
  • Example 32 To the same alloy powder having a composition formula of Sm2Fe17N 4.0 H 0.5 as obtained in Example 32, 7.0 and 11.5 of Zn per unit cell of Sm2Fe17N 4.0 H 0.5 having an average particle size of 8 »m were added, respectively, mixed in a nitrogen atmosphere for 30 minutes, molded into a plate in the same manner as in Example 32 and sintered by the hot pressing in a mixed gas of ammonia having a partial pressure of 0.35 atm and hydrogen having a partial pressure of 0.65 atm with a total pressure of 1 atm at 465 °C for one hour to give sintered magnets.
  • Example 32 The same alloy powder having a composition formula of Sm2Fe17N 4.0 H 0.5 and an average particle size of 105 »m as obtained in Example 32 was finely pulverized to an average particle size of about 0.2 »m in a vibrating ball mill in a nitrogen atmosphere, and 2 g of the alloy powder thus obtained was mixed with 0.4 g of an epoxy adhesive (product of Konishi Co., "Bondquick 5") in a mortar to give viscous powder. Then the viscous powder was placed in a ceramic vessel of 10 mm x 5 mm x 5 mm and hardened in a magnetic field of 15 KOe at 20 °C for about one hour to give a bonded magnet (a).
  • an epoxy adhesive product of Konishi Co., "Bondquick 5
  • the same alloy powder as described above was compression-molded in a magnetic field of 15 KOe under a pressure of 10 ton/cm2 to give a molded article having a weight of 0.5 g. Then the molded article was impregnated with 5 % by weight of polyisoprene dissolved in toluene and sufficiently dried to give a bonded magnet (b).

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Claims (29)

  1. Magnetisches Material, das durch die Formel



            RαFe(100-α-β-γ)NβHγ   (I)



    wiedergegeben wird, worin
       R für wenigstens ein Seltenerd-Element einschließlich Y steht;
       α 5 bis 20 Atomprozent bedeutet,
       β 5 bis 30 Atomprozent bedeutet, und
       γ 0,01 bis 10 Atomprozent bedeutet und deiner ist als β.
  2. Magnetisches Material nach Anspruch 1, das darin eingearbeitet einen durch M wiedergegebenen Zusatzstoff enthalt und eine durch die Formel



            RαFe(100-α-β-γ-δ)NβHγMδ   (II)



    wiedergegebene Zusammensetzung aufweist, worin
       R, α, β, und γ dieselbe Bedeutung haben, wie sie in Anspruch 1 definiert wurde;
       M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, MgO, Al₂O₃, Sm₂O₃, AlF₃, ZnF₂, SiC, TiC, AlN und Si₃N₄ bestehenden Gruppe;
       δ 0,1 bis 40 Atomprozent bedeutet; und
       (100-α-β-γ-δ) nicht weniger als 40 Atomprozent ist.
  3. Magnetisches Material nach Anspruch 1 oder 2, worin das magnetische Material eine Kristallstruktur des rhomboedrischen Systems oder des hexagonalen Systems aufweist.
  4. Magnetisches Material nach einem der Ansprüche 1 bis 3, worin R wenigstens eine Komponente aus der aus Nd, Pr, Ce, Sm, Gd, Didym und Legierungen aus Sm-Nd, Sm-Ce, Sm-Dy, Sm-Gd, Sm-Pr und Sm-Y bestehenden Gruppe ist.
  5. Magnetisches Material nach einem der Ansprüche 1 bis 4, worin die Menge an Fe 50 bis 86 Atom-% beträgt.
  6. Magnetisches Material nach einem der Ansprüche 1 bis 5, worin Fe durch Co in einer Menge nicht über 50 Atom-% Fe substituiert ist.
  7. Magnetisches Material nach einem der Ansprüche 2 bis 6, worin M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Zn, Ga, Al, In, Sn und Si bestehenden Gruppe.
  8. Verfahren zur Herstellung eines magnetischen Materials, das den Schritt umfaßt, daß man eine Legierung einer Zusammensetzung - angegeben in Atom-% - 5 bis 25 R - 95 bis 75 Fe mit einem Stickstoff enthaltenden Gas und einem Wasserstoff enthaltenden Gas oder mit einem Ammoniak enthaltenden Gas bei einer Temperatur von 100 °C bis 650 °C unter Zustandebringen der Absorption von Stickstoff und Wasserstoff in der Legierung in Kontakt bringt, worin
    - das Stickstoff enthaltende Gas Stickstoffgas oder eine Gasmischung aus Stickstoff und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon-, Wasserstoff- und Ammoniak-Gas bestehenden Gruppe;
    - das Wasserstoff enthaltende Gas Wasserstoffgas oder eine Gasmischung aus Wasser-stoff und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon- und Stickstoff-Gas bestehenden Gruppe;
    - das Ammoniak enthaltende Gas Ammoniakgas oder eine Gasmischung aus Ammoniak und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon-, Wasserstoff- und Stickstoff-Gas bestehenden Gruppe;
    unter Erhalt eines magnetischen Materials, das durch die Formel



            RαFe(100-α-β-γ)NβHγ   (I)



    wiedergegeben wird, worin
       R für wenigstens ein Seltenerd-Element einschließlich Y steht;
       α 5 bis 20 Atomprozent bedeutet,
       β 5 bis 30 Atomprozent bedeutet, und
       γ 0,01 bis 10 Atomprozent bedeutet und kleiner ist als β.
  9. Verfahren nach Anspruch 8, welches außerdem das Mischen des erhaltenen magnetischen Materials der Formel (I) mit wenigstens einem durch M wiedergegebenen Zusatzstoff umfaßt, unter Erhalt eines magnetischen Materials, das durch die Formel



            RαFe(100-α-β-γ-δ)NβHγMδ   (II)



    wiedergegeben wird, worin
       R, α, β, und γ dieselbe Bedeutung haben, wie sie in Anspruch 8 definiert wurde;
       M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, MgO, Al₂O₃, Sm₂O₃, AlF₃, ZnF₂, SiC, TiC, AlN und Si₃N₄ bestehenden Gruppe;
       δ 0,1 bis 40 Atomprozent bedeutet; und
       (100-α-β-γ-δ) nicht weniger als 40 Atomprozent ist.
  10. Verfahren zur Herstellung eines magnetischen Materials, das durch die Formel



            RαFe(100-α-β-γ-δ)NβHγMδ   (II)



    wiedergegeben wird, worin
       R für wenigstens ein Seltenerd-Element einschließlich Y steht;
       M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, MgO, Al₂O₃, Sm₂O₃, AlF₃, ZnF₂, SiC, TiC, AlN und Si₃N₄ bestehenden Gruppe;
       α 5 bis 20 Atomprozent bedeutet;
       β 5 bis 30 Atomprozent bedeutet;
       γ 0,01 bis 10 Atomprozent bedeutet und Kleiner ist als β;
       δ 0,1 bis 40 Atomprozent bedeutet; und
       (100-α-β-γ-δ) nicht weniger als 40 Atomprozent ist,
    wobei das Verfahren den Schritt umfaßt, daß man eine Legierung einer Zusammensetzung - angegeben in Atom-% - 5 bis 25 R - 95 bis 75 Fe - 0,1 bis 40 M mit einem Stickstoff enthaltenden Gas und einem Wasserstoff enthaltenden Gas oder mit einem Ammoniak enthaltenden Gas bei einer Temperatur von 100 °C bis 650 °C unter Zustandebringen der Absorption von Stickstoff und Wasserstoff in der Legierung in Kontakt bringt, worin
    - das Stickstoff enthaltende Gas Stickstoffgas oder eine Gasmischung aus Stickstoff und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon-, Wasserstoff- und Ammoniak-Gas bestehenden Gruppe;
    - das Wasserstoff enthaltende Gas Wasserstoffgas oder eine Gasmischung aus Wasser-stoff und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon- und Stickstoff-Gas bestehenden Gruppe; und
    - das Ammoniak enthaltende Gas Ammoniakgas oder eine Gasmischung aus Ammoniak und wenigstens einem Gas ist, das gewählt ist aus der aus Helium-, Neon-, Argon-, Wasserstoff- und Stickstoff-Gas bestehenden Gruppe.
  11. Verfahren nach einem der Ansprüche 8 bis 10, worin das Ammoniak enthaltende Gas eine Gasmischung aus Ammoniakgas und Wasserstoffgas ist, worin die Gasmischung einen Partialdruck von Ammoniakgas von 0,02 bis 0,75 atm und einen Partialdruck von Wasserstoffgas von 0,98 bis 0,25 atm aufweist, mit der Maßgabe, daß der Gesamtdruck der Gasmischung 1 atm ist.
  12. Verfahren nach einem der Ansprüche 8 bis 10, worin der Schritt der Absorption von Stickstoff und Wasserstoff in der Legierung in der Weise durchgeführt wird, daß man bei einer Temperatur von 100 °C bis 650 °C die Legierung in gleich welcher Reihenfolge erstens mit einem Stickstoff enthaltenden Gas oder einem Ammoniak enthaltenden Gas und zweitens mit einem Wasserstoff enthaltenden Gas oder erstens mit einem Wasserstoff enthaltenden Gas und zweitens mit einem Stickstoff enthaltenden Gas oder einem Ammoniak enthaltenden Gas in Kontakt bringt.
  13. Verfahren nach einem der Ansprüche 8 bis 10, worin die Schritte der Absorption von Stickstoff und Wasserstoff in der Legierung bei einem Druck von 1 bis 10 atm durchgeführt werden.
  14. Verfahren nach einem der Ansprüche 8 bis 13, welches außerdem den Schritt des Pulverisierens der Legierung auf eine Größe von 40 bis 300 »m in einer Inertgas-Atmosphäre vor der Absorption von Stickstoff und Wasserstoff in der Legierung umfaßt.
  15. Verfahren nach einem der Ansprüche 8 bis 13, welches außerdem den Schritt des Glühens der Legierung bei einer Temperatur von 500 °C bis 1.300 °C in einer Inertgas-Atmosphäre vor der Absorption von Stickstoff und Wasserstoff umfaßt.
  16. Verfahren nach Anspruch 15, welches außerdem den Schritt des Pulverisierens der Legierung auf eine Größe von 40 bis 300 »m in einer Inertgas-Atmosphäre nach dem Glühen der Legierung und vor der Absorption von Stickstoff und Wasserstoff in der Legierung umfaßt.
  17. Verfahren nach einem der Ansprüche 8 bis 10, welches außerdem vor der Absorption von Stickstoff und Wasserstoff in der Legierung die Schritte des In-Kontakt-Bringens der Legierung mit Wasserstoffgas bei einer Temperatur von 200 °C bis 400 °C unter Erreichen der Absorption von Wasserstoff und des Erwärmens der Wasserstoff absorbiert enthaltenden Legierung bei einer Temperatur von 600 °C bis 800 °C in einer Inertgas-Atmosphäre unter Erreichen der Desorption des absorbierten Wasserstoffs umfaßt, wodurch bewirkt wird, daß die Legierung vor der Absorption von Stickstoff und Wasserstoff in der Legierung pulverisiert wird.
  18. Verfahren nach Anspruch 17, worin die Schritte abwechselnd wenigstens zweimal wiederholt werden.
  19. Verfahren nach einem der Ansprüche 8 bis 18, welches außerdem den Schritt des Glühens der Legierung bei einer Temperatur von 100 °C bis 650 °C in einer nichtoxidierenden Atmosphäre nach der Absorption von Stickstoff und Wasserstoff in der Legierung umfaßt.
  20. Verfahren nach einem der Ansprüche 8 bis 18, welches außerdem den Schritt des Glühens der Legierung bei einer Temperatur von 100 °C bis 450 °C an Luft nach der Absorption von Stickstoff und Wasserstoff in der Legierung umfaßt.
  21. Verfahren nach einem der Ansprüche 8 bis 20, worin die Legierung eine aus der Schmelze abgeschreckte Legierung ist.
  22. Verfahren nach einem der Ansprüche 8 bis 21, worin Fe in der Legierung durch Co in einer Menge nicht über 50 Atom-% Fe substituiert ist.
  23. Sintermagnet mit wenigstens einem magnetischen Material, das aus der Gruppe gewählt ist, die besteht aus einem magnetischen Material, das durch die Formel



            RαFe(100-α-β-γ)NβHγ   (I)



    wiedergegeben wird, worin
       R für wenigstens ein Seltenerd-Element einschließlich Y steht;
       α 5 bis 20 Atomprozent bedeutet;
       β 5 bis 30 Atomprozent bedeutet; und
       γ 0,01 bis 10 Atomprozent bedeutet, und Kleiner ist als β,
    und einem magnetischen Material, das durch die Formel



            RαFe(100-α-β-γ-δ)NβHγMδ   (II)



    wiedergegeben wird, worin
       R, α, β, und γ dieselbe Bedeutung haben, wie sie für Formel (I) definiert wurde;
       M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, MgO, Al₂O₃, Sm₂O₃, AlF₃, ZnF₂, SiC, TiC, AlN und Si₃N₄ bestehenden Gruppe;
       δ 0,1 bis 40 Atomprozent bedeutet; und
       (100-α-β-γ-δ) nicht weniger als 40 Atomprozent ist.
  24. Sintermagnet nach Anspruch 23, welcher die magnetischen Materialien der Formeln (I) und (II) umfaßt, wobei der Sintermagnet eine Einphasen-Struktur aufweist, worin die einzige Phase aus einer Mischung der magnetischen Materialien der Formeln (I) und (II) gebildet ist, oder eine Zweiphasen-Mikrostruktur aufweist, worin die größere Phase aus einer größeren Menge des magnetischen Materials der Formel (I) im zentralen Teil des Korns des Sintermagneten gebildet ist und die Kleinere Phase aus einer größeren Menge des Zusatzstoffes M des magnetischen Materials der Formel (II) gebildet ist, die in die Korn-Grenzbereiche der größeren Phase eindiffundiert ist.
  25. Sintermagnet nach Anspruch 23 oder 24, worin Fe in dem wenigstens einen magnetischen Material durch Co in einer Menge nicht über 50 Atom-% Fe substituiert ist.
  26. Sintermagnet nach Anspruch 23 oder 24, worin das magnetische Material eine Kristallstruktur des rhomboedrischen Systems oder des hexagonalen Systems aufweist.
  27. Gebondeter Magnet, der gebildet ist aus Teilchen wenigstens eines magnetischen Materials, das aus der Gruppe gewählt ist, die besteht aus einem magnetischen Material, das durch die Formel



            RαFe(100-α-β-γ)NβHγ   (I)



    wiedergegeben wird, worin
       R für wenigstens ein Seltenerd-Element einschließlich Y steht;
       α 5 bis 20 Atomprozent bedeutet;
       β 5 bis 30 Atomprozent bedeutet; und
       γ 0,01 bis 10 Atomprozent bedeutet und Kleiner ist als β,
    und einem magnetischen Material, das durch die Formel



            RαFe(100-α-β-γ-δ)NβHγMδ   (II)



    wiedergegeben wird, worin
       R, α, β, und γ dieselbe Bedeutung haben, wie sie für Formel (I) definiert wurde;
       M wenigstens ein Zusatzstoff ist, der gewählt ist aus der aus Sn, Ga, In, Bi, Pb, Zn, Al, Zr, Cu, Mo, Ti, Si, MgO, Al₂O₃, Sm₂O₃, AlF₃, ZnF₂, SiC, TiC, AlN und Si₃N₄ bestehenden Gruppe;
       δ 0,1 bis 40 Atomprozent bedeutet; und
       (100-α-β-γ-δ) nicht weniger als 40 Atomprozent ist,
    wobei die Teilchen in einer gewünschten Magnetform durch ein Bindemittel gehalten werden, das zwischen ihnen verteilt ist.
  28. Gebondeter Magnet nach Anspruch 27, worin Fe in dem wenigstens einen magnetischen Material durch Co in einer Menge nicht über 50 Atom-% Fe substituiert ist.
  29. Gebondeter Magnet nach Anspruch 27, worin das wenigstens eine magnetische Material eine Kristallstruktur des rhomboedrischen Systems oder des hexagonalen Systems aufweist.
EP89104753A 1988-11-14 1989-03-16 Magnetische Stoffe, enthaltend Seltenerdelemente, Eisen, Stickstoff und Wasserstoff Expired - Lifetime EP0369097B1 (de)

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