CA1255926A - Method of preparing a hard magnet by addition of a quench rate range broadening additive and a hard magnet prepared thereby - Google Patents
Method of preparing a hard magnet by addition of a quench rate range broadening additive and a hard magnet prepared therebyInfo
- Publication number
- CA1255926A CA1255926A CA000490359A CA490359A CA1255926A CA 1255926 A CA1255926 A CA 1255926A CA 000490359 A CA000490359 A CA 000490359A CA 490359 A CA490359 A CA 490359A CA 1255926 A CA1255926 A CA 1255926A
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- Canada
- Prior art keywords
- aluminum
- boron
- hard magnetic
- iron
- atomic percent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- 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
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C45/00—Amorphous alloys
- C22C45/008—Amorphous alloys with Fe, Co or Ni as the major constituent
Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed is a method of forming a glassy, hard magnetic material by rapidly quenching a molten composition of (1) a transition metal, as iron, cobalt, nickel, manganese, or mixtures thereof, (2) a lanthanide, as praesodymium, neodymium, or mixtures thereof, (3) boron, and (4) a quench rate broadening amount of a glass forming additive chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium. Also disclosed are the hard, magnetic materials prepared thereby.
Disclosed is a method of forming a glassy, hard magnetic material by rapidly quenching a molten composition of (1) a transition metal, as iron, cobalt, nickel, manganese, or mixtures thereof, (2) a lanthanide, as praesodymium, neodymium, or mixtures thereof, (3) boron, and (4) a quench rate broadening amount of a glass forming additive chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium. Also disclosed are the hard, magnetic materials prepared thereby.
Description
~255~Z~;
FIELD OF THE_I~VENTIO~
The invention relates to permanent magnets, i.e. hard magnets, formed of transition metal, a rare earth metal, and boron, and to methods of preparing the permanent magnetic materials.
BACKGROUND OF THE I~VE~TIO~
Hard magnets, that i5, permanent magnets are characterized by a high coercive force and a high remanence.
They may be formed of a transition metal and a rare earth metal, as samarium-cobalt, or a transition metal, a rare earth metal, and boron, as iron-neodymium-boron. The transition metal-rare earth metal~boron hard magnets are characterized by low cost and a precise morphology with the grain size being on the order of Erom about 1 to about 10 magnetic domains ~n size. Transition metal-rare earth metal-boron hard magnets and methods of preparing them are described in U.S. Patent 4,402,770 to ~.C. Koon for Hard Magnetic Alloys of a Transition Metal And Lantanide, U.S. 4,409,043 to ~.C. Koon for Amorphous Transition Metal Lantanide Alloys, and Japanese PubIished Patent Application 59-64739 of J.J. Croat.
In order to prepare bulk quantities o transition metal rare earth metal-boron magnets alloys, the material must be quenched from the melt. However, in order to attain maximum performance, i.e. high coercivity, high remanence, and high energy product, the composition and quenching conditions must be very precisely controlled. That is, the stoichiometry and thermal quenching require control within very narrow limits. Moreover, even very slight deviations from optimum rn/jc , ~`, ~
~ 25~g~i compositions and/or quench condi-tions lead to weak hard magnets, or even to soft magnetic materials.
The apparent stochiometric composition of the material approaches a minimum melting point composition, for example, a eutectoid. However, the properties of the solidifying melt are not invariant, but are believed to be a strong function of local deviations of the liquid composition from the eutectoid composition. Thus, too slow a quench rate results in a soft magnet material requiring remelting and recasting. Too rapid a quench rate is reported, e.g., in U.S.
Patent 4,402,770 to Koon, et al and ~apanese Published Patent Application 59-64739 of Croat to resul-t in a weak magnet that requl~es sub~equent annealing to obtain a hard magnetic morphology.
Both ~oon and Croat demonstrate a preference for a two step process characterized by over-quench and subsequent back annealiny.
The two step process of quenching and back annealing, while avoiding the effects of the sensitivity of the magnetic parameters to process parameters, imposes the economic burden of an added series of manufacturing steps.
SUMMARY OF THE INVE~TIO~
The invention herein provides an as-quenched, unannealed, microcrystalline hard magnet prepared with relaxed process parameters. The invention herein further provides a method for preparing an as quenched, unannealed, microcrystalline, hard magnet, not requiring subsequent annealing, and produced with rn/jc ~,.. ~ , .. ,. ~
Case 804 ~255~26 relaxed process parameters.
In a preferred exemplification, the magnetic material is prepared by rapidly quenching a molten c ompo s i tion of:
(1) a transition metal SUCh as iron9 cobalt, nickel, manganese, and mixtures thereof;
FIELD OF THE_I~VENTIO~
The invention relates to permanent magnets, i.e. hard magnets, formed of transition metal, a rare earth metal, and boron, and to methods of preparing the permanent magnetic materials.
BACKGROUND OF THE I~VE~TIO~
Hard magnets, that i5, permanent magnets are characterized by a high coercive force and a high remanence.
They may be formed of a transition metal and a rare earth metal, as samarium-cobalt, or a transition metal, a rare earth metal, and boron, as iron-neodymium-boron. The transition metal-rare earth metal~boron hard magnets are characterized by low cost and a precise morphology with the grain size being on the order of Erom about 1 to about 10 magnetic domains ~n size. Transition metal-rare earth metal-boron hard magnets and methods of preparing them are described in U.S. Patent 4,402,770 to ~.C. Koon for Hard Magnetic Alloys of a Transition Metal And Lantanide, U.S. 4,409,043 to ~.C. Koon for Amorphous Transition Metal Lantanide Alloys, and Japanese PubIished Patent Application 59-64739 of J.J. Croat.
In order to prepare bulk quantities o transition metal rare earth metal-boron magnets alloys, the material must be quenched from the melt. However, in order to attain maximum performance, i.e. high coercivity, high remanence, and high energy product, the composition and quenching conditions must be very precisely controlled. That is, the stoichiometry and thermal quenching require control within very narrow limits. Moreover, even very slight deviations from optimum rn/jc , ~`, ~
~ 25~g~i compositions and/or quench condi-tions lead to weak hard magnets, or even to soft magnetic materials.
The apparent stochiometric composition of the material approaches a minimum melting point composition, for example, a eutectoid. However, the properties of the solidifying melt are not invariant, but are believed to be a strong function of local deviations of the liquid composition from the eutectoid composition. Thus, too slow a quench rate results in a soft magnet material requiring remelting and recasting. Too rapid a quench rate is reported, e.g., in U.S.
Patent 4,402,770 to Koon, et al and ~apanese Published Patent Application 59-64739 of Croat to resul-t in a weak magnet that requl~es sub~equent annealing to obtain a hard magnetic morphology.
Both ~oon and Croat demonstrate a preference for a two step process characterized by over-quench and subsequent back annealiny.
The two step process of quenching and back annealing, while avoiding the effects of the sensitivity of the magnetic parameters to process parameters, imposes the economic burden of an added series of manufacturing steps.
SUMMARY OF THE INVE~TIO~
The invention herein provides an as-quenched, unannealed, microcrystalline hard magnet prepared with relaxed process parameters. The invention herein further provides a method for preparing an as quenched, unannealed, microcrystalline, hard magnet, not requiring subsequent annealing, and produced with rn/jc ~,.. ~ , .. ,. ~
Case 804 ~255~26 relaxed process parameters.
In a preferred exemplification, the magnetic material is prepared by rapidly quenching a molten c ompo s i tion of:
(1) a transition metal SUCh as iron9 cobalt, nickel, manganese, and mixtures thereof;
(2) a rare earth metal, i.e. a lanthanide, ascerium~ neodymium, praesodymium, and mixtures thereof;
lQ (3) boron; and (4) a quench rate range broadening amount of a glass forming additive, for example, chosen from the group consisting of aluminum, aluminium-vanadium, zirconlum, and zlrconium-niobium.
In a particularly preferred exempl~fication, the magnetic mater~al Is prepared by rapidly quenching a molten composition of iron, neodymium or praesodymium, boron, and aluminum, whereby to ~orm the as-quenched, unannealed~ microcrystalline hard magnet, and the as-quenched, unannealed, microcrystalline hard magnet prepared thereby.
THE FIGURES
The invention may be understood by reference to the Figures.
Figure 1 shows the as-quenched energy products of neodymium-iron-boron and praesodymium-iron-boron-aluminùm alloys.
Figure 2 shows the as quenched energy products of a praesodymium-iron-boron and ; neodymium-iron-boron-aluminum alloys.
Case 804 ~2 ~ ~2 ~
DETAILED DESCRIPTInN OF THE_INVENTION
The as-quenched hard magnetic alloys herein contemplated are characterized by morphologies associated with high magnetic remanences, high energy products, high coercivities, and high Curie temperatures and are further characterized in that they do not require annealing to obtain these properties.
The preferred composition has the formula TMWRExByGz. TM represents a transition metal or metals chosen from the group consisting of iron, cobalt, nickel, manganese, and mixtures thereof.
Preferably iron is the predominant or even sole transition metal. Where iron is not the sole transition mekal, it const1tutes the major part of the total translt~on metal content of the alloy, generally being above about 70 atomic percent of the total transition metals present in the magnetic material.
That is, the transition metal content is preferably substantially all iron with inconsequential impurities. Optionally up to 30 atomic percent of cobal~, nickel and/or manganese, basis total transition metal content of the composition, may be present without deleterious effect, and may even provide an additive effect.
RE represents a rare earth metal or metals.
The rare earth metal or metals are light rare earth metals chosen from the group consisting of cerium, 3Q neodymium, praesodymium, and mixtures thereof.
B represents boron.
G represents a quench ra~e range broadening glass forming additive or combinations thereof chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium.
We have found tha~ certain combinations of glass ., Case 804 ~2~5~6 formers appear to synergistically interact as aluminum-vanadium and zirconium-niob1um, which are preferred combinations, while others appear to counteract each other as aluminum-zirconium, aluminum-niobium, vanadium-zirconium and vanadium-niobium.
w, the atomic percent of transition metal is about 60 to about 92. x, the atomic percent of total rare earth metals is from about 8 to about 40. y, the atomic percent of boron is from abou~ traces to about 20. z, the atomic percent of the ~uench rate range broadening material, is a quench rate range broadening amount of the glass forming material. The content of glass form~ng material is generally above about one atomic percent and preferably above about two atomic percent, b~t also generally less than about ten atomic percent.
Hard magnetic properties arise from the interaction of boron, the transition metal, and the 2a rare earth metal, With partial substitution of boron, the transition metal, or the rare earth metal, or any or all of the alloy constituents by the glass former, it is possible to provide processing advantages according to the method of this invention.
Notwithstanding the presence of the glass formers, the amount of boron must be high enough to interact w~th the transition metal and rare earth metal, but not so high as to form non-magnetic phases or to render the alloy soft or even non-magnetic. Moreover, the amount 3Q of boron should not be so low as to fail to provide an operative, hard magnet. Within this range of boron composition, the glass former is added to enhance the quench rate range at which a high coercivity, high remanence, high energy product magnetic alloy is formed.
_5_ Case 804 The invention further contemplates the method of forming the alloy. The alloy is formed by a rapid solidification process, i.e. a quench process, to form a hard magnet. In the melt spinning method of quenching molten metals, quench rate is expressed as the product of the rotational velocity of the chill wheel the radius of the chill wheel, and pi. This gives a linear velocity with respect to the molten metal effluent. At constant effluenl; geometry, I0 effluent spacing, hydrostatic head, and melt temperature, quench rate is monotonic and approximately linear with chill surface linear velocity. For a melt spinner utilizing a 20 inch diameter copper clad chill wheel spaced 1 to 30 millimeters from a 0.2 to 2.0 millimeter diameter aperture with a 0.5 to 10 pounds per square inch head, a Chill wheel velocity of 1000 revolt~ons per minuke, l.e., a l~near velocity of 1.32 x 103 cm/sec. The quench rate is above 0.5 x 105C per second, 2Q preferably above about 1 x lO5C per second, and in a particularly preferred embodiment above about 10 x 105C per second. Molten compositions of transition metal-rare earth metal-boron exhibit a relatively sharp local maximum of e.g., coercivity, as a function of chill wheel velocity, with coercivity dropping off to 30 percent of peak value at chill wheel velocities of plus or minus 10 percent of the chill wheel velocity corresponding to peak coercivity. By way of contrast molten compositions of transition metal-rare 3a earth metal-boron-aluminum exhibit a flat local maximum of, e.g., coercivity as a function of chill wheel velocity, with coercivity being 85 to 90 percent of peak value at chill wheel velocities of plus or minus 10 percent of the chill wheel velocity corresponding to peak coercivity, and 60 percent of ; peak value of at chill wheel velocities of plus or Case 804 minus 20 percent of the chill wheel velocity corresponding to peak coercivity. As herein contemplated, a molten composition of ~ransition metal, rare earth metal, boron, and glass former is quenched within a quench rate range to form a glassy, hard, magnetic material having optimal grain sizesO
The method may optionally include post-quench annealing if a grain size above that obtained by the quenching is required.
The components of the magnetic alloy preferably obtained to 99.9 percent purity and particularly a preferred exemplification to ~9.99 percent pur~ty.
The precursor materials, that is, the transit~on metal, the rare earth metal, boron, and the quench rate range enhancing glass forming mater~al are melted together in an 1nert atmosphere, for examp1e, an argon helium atmosphere. Melting and remelting may be carried out several times in order to obtain 2Q substantially homogeneous alloy.
The substantially homogeneous alloy is discharged to a quenched surface to rapidly quench ~he material. The quencll surface may be a rapidly moving inert surface, that is, a surface moving at a quench speed of about at least 300 centimeters per minute w1th respect to the molten alloy affluent.
Preferably, the rapidly moving surface is a rapidly rotating inert surface such as a polished copper wheel rotating at an angular velocity so as to provide a 3Q linear velocity of above about 300 centimeters per second, preferably above about lO00 centimeters per second but less than about 5000 centimeters per second.
The following examples are illustrative of the method of ~his invention.
Case 804 z ~
EXA~PLES
I. Preparation of the Alloys Alloys of the examples were prepared by weighing out the appropriate constituents. The praesodymium was Morton Thiokol Alfa praesodymium, having a nominal purity of 99.99 percent. The neodymium was Research Chemicals Inc., neodymium, having a nominal purity of 99.9 percent. The boron was Morton Thiokol Alfa boron, having a nominal purity of 99.9 percent. The aluminu~ was Atlantic Equipment aluminum, having a nominal purity of 99.99 percent.
The iron was Atlantic Equipment electrolytic iron, having a nom~nal purlty of 99.999 percent.
The const~tuents were placed in a l9 mm o~d., 17 mm ~.d~ quartz cruclble, and heated 1n an elec~r~c induction furnace under a purified argon atmosphere, whereby to form an ingot. The ingots were homogenized by repeated remelting.
20 II. Quenchin~
Quenching was carried out using an argon pressurized quartz crucible having an orifice on the bottom. The oriflce was vertically spaced from a moving chill surface, i.e., a 20 inch diameter rotating, copper wheel. The molten metal was ejected through the orifice onto the copper chill wheel.
The crucible was purged with argon.
Thereafter9 a portion of the homogenized ingo~ was placed in the crucible~ and ~he crucible was heated in ~ an induction furnace. When the ingot was molten, the ; molten composition was ejected onto the rapicly rotating copper chill wheel. A thin ribbon was recovered.
Case 804 ~ 6 III. Ma~netization Magnetization measurements were made using a v;brating sample magnetometer. The magnetome~er was calibrated using a standard N.B.S. nickelsphere sample.
EXAMPLE I
10 S~mples of Fe82B6Prl2 and Fe79B~Prll 5A13 5 were prepared, quenched, and tested as described above. The following results were obtained:
Compositin Fe~2B6Prl2 Fe79B6Prll-5A 3,5 Quench surface velocity = 1596cm/sec (600 rpm) Energy product .3 x 106 6-Oe Remanence 2.95 x 103G
Coercive force .87 x 1030e Quench surface velocity = 1728cm/sec (650 rpm) Energy product 2.23 x 106G-Oe Remanence 3.85 x 103G
Coercive force 2.40 x 1030e ~ Case 804 ~2~ 6 Quench surface velocity = 1862cm/sec (790 rpm) Energy product 3.8 x 106 G-Oe, 3.8 x 106G-Oe 1.8 x 106G-Oe Remanence 7.98 x 103G, 5.73 x 103G
6.97 x 103G
Coerci~e force 7.75 x 1030e~ 4.3 x 1030e .55 x 1030e lQ _ _ _ _ _ Quench sur~ace veloclty ~ 1994cm/sec (750 rpm) Energy product 2~6 x 106G Oe Remanen~,e 4.46 x 103G
Coercive force 3.97 x 10 Oe EXAMPLE II
Samples of Fe79B6Ndl5 and Fe77B6Ndl5A12 were prepared, quenched, and tested as described above. The following results, shown graphically in Figure 2, were obtained:
Composition Fe79B6Ndl5 Fe77B5Ndl5A12 3Q Quench surface velocity = 2394cm/sec (900 rpm) Energy product 1.9 x 106G-Oe 4.9 x 106G-Oe 9. 9 x 1 05G-Oe Remanence 5.69 x 103G 5.57 x 103G
~: -10 Case 804 ~S~
7.44 x 103G
Coercive force 1.04 x 1040e 1~21 x 1040e 1.32 x 1040e _ Quench surface velocity = 2660cm/sec (1000 rpm) Energy product 2.59 x 106G-Oe 9.08 x 106G-Oe lQ 9.0 x 106G-Oe Remanence 6.79 x 103G3.87 x 103G
7.09 x 13G6.7 x 103G
Coercive force 0.48 x 1040e 1.17 x 1040e 1.32 x 1040e1.21 x 1040e Quench surface velocity = 2926cm/sec (1100 rpm) Energy product 5.1 x 1066-Oe S.l x 106G-Oe 14.8 x 105G-Oe Remanence 4.71 x 103G5.81 x 103G
8.8 x 103G
Coercive force 4.17 x 1030e 1.13 x 1040e 1.24 x 1040e - Case 804 ~ 2 6 While the invention has been ~escribed with respect to certain preferred exemplifications and embodiments thereof, it is not intended to limit the scope of protection thereby, but solely by the claims appended hereto.
Moreover, the scope of protection is not intended to be limited by the above described embodiment and exemplifications, but solely by the lQ claims appended hereto.
lQ (3) boron; and (4) a quench rate range broadening amount of a glass forming additive, for example, chosen from the group consisting of aluminum, aluminium-vanadium, zirconlum, and zlrconium-niobium.
In a particularly preferred exempl~fication, the magnetic mater~al Is prepared by rapidly quenching a molten composition of iron, neodymium or praesodymium, boron, and aluminum, whereby to ~orm the as-quenched, unannealed~ microcrystalline hard magnet, and the as-quenched, unannealed, microcrystalline hard magnet prepared thereby.
THE FIGURES
The invention may be understood by reference to the Figures.
Figure 1 shows the as-quenched energy products of neodymium-iron-boron and praesodymium-iron-boron-aluminùm alloys.
Figure 2 shows the as quenched energy products of a praesodymium-iron-boron and ; neodymium-iron-boron-aluminum alloys.
Case 804 ~2 ~ ~2 ~
DETAILED DESCRIPTInN OF THE_INVENTION
The as-quenched hard magnetic alloys herein contemplated are characterized by morphologies associated with high magnetic remanences, high energy products, high coercivities, and high Curie temperatures and are further characterized in that they do not require annealing to obtain these properties.
The preferred composition has the formula TMWRExByGz. TM represents a transition metal or metals chosen from the group consisting of iron, cobalt, nickel, manganese, and mixtures thereof.
Preferably iron is the predominant or even sole transition metal. Where iron is not the sole transition mekal, it const1tutes the major part of the total translt~on metal content of the alloy, generally being above about 70 atomic percent of the total transition metals present in the magnetic material.
That is, the transition metal content is preferably substantially all iron with inconsequential impurities. Optionally up to 30 atomic percent of cobal~, nickel and/or manganese, basis total transition metal content of the composition, may be present without deleterious effect, and may even provide an additive effect.
RE represents a rare earth metal or metals.
The rare earth metal or metals are light rare earth metals chosen from the group consisting of cerium, 3Q neodymium, praesodymium, and mixtures thereof.
B represents boron.
G represents a quench ra~e range broadening glass forming additive or combinations thereof chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium.
We have found tha~ certain combinations of glass ., Case 804 ~2~5~6 formers appear to synergistically interact as aluminum-vanadium and zirconium-niob1um, which are preferred combinations, while others appear to counteract each other as aluminum-zirconium, aluminum-niobium, vanadium-zirconium and vanadium-niobium.
w, the atomic percent of transition metal is about 60 to about 92. x, the atomic percent of total rare earth metals is from about 8 to about 40. y, the atomic percent of boron is from abou~ traces to about 20. z, the atomic percent of the ~uench rate range broadening material, is a quench rate range broadening amount of the glass forming material. The content of glass form~ng material is generally above about one atomic percent and preferably above about two atomic percent, b~t also generally less than about ten atomic percent.
Hard magnetic properties arise from the interaction of boron, the transition metal, and the 2a rare earth metal, With partial substitution of boron, the transition metal, or the rare earth metal, or any or all of the alloy constituents by the glass former, it is possible to provide processing advantages according to the method of this invention.
Notwithstanding the presence of the glass formers, the amount of boron must be high enough to interact w~th the transition metal and rare earth metal, but not so high as to form non-magnetic phases or to render the alloy soft or even non-magnetic. Moreover, the amount 3Q of boron should not be so low as to fail to provide an operative, hard magnet. Within this range of boron composition, the glass former is added to enhance the quench rate range at which a high coercivity, high remanence, high energy product magnetic alloy is formed.
_5_ Case 804 The invention further contemplates the method of forming the alloy. The alloy is formed by a rapid solidification process, i.e. a quench process, to form a hard magnet. In the melt spinning method of quenching molten metals, quench rate is expressed as the product of the rotational velocity of the chill wheel the radius of the chill wheel, and pi. This gives a linear velocity with respect to the molten metal effluent. At constant effluenl; geometry, I0 effluent spacing, hydrostatic head, and melt temperature, quench rate is monotonic and approximately linear with chill surface linear velocity. For a melt spinner utilizing a 20 inch diameter copper clad chill wheel spaced 1 to 30 millimeters from a 0.2 to 2.0 millimeter diameter aperture with a 0.5 to 10 pounds per square inch head, a Chill wheel velocity of 1000 revolt~ons per minuke, l.e., a l~near velocity of 1.32 x 103 cm/sec. The quench rate is above 0.5 x 105C per second, 2Q preferably above about 1 x lO5C per second, and in a particularly preferred embodiment above about 10 x 105C per second. Molten compositions of transition metal-rare earth metal-boron exhibit a relatively sharp local maximum of e.g., coercivity, as a function of chill wheel velocity, with coercivity dropping off to 30 percent of peak value at chill wheel velocities of plus or minus 10 percent of the chill wheel velocity corresponding to peak coercivity. By way of contrast molten compositions of transition metal-rare 3a earth metal-boron-aluminum exhibit a flat local maximum of, e.g., coercivity as a function of chill wheel velocity, with coercivity being 85 to 90 percent of peak value at chill wheel velocities of plus or minus 10 percent of the chill wheel velocity corresponding to peak coercivity, and 60 percent of ; peak value of at chill wheel velocities of plus or Case 804 minus 20 percent of the chill wheel velocity corresponding to peak coercivity. As herein contemplated, a molten composition of ~ransition metal, rare earth metal, boron, and glass former is quenched within a quench rate range to form a glassy, hard, magnetic material having optimal grain sizesO
The method may optionally include post-quench annealing if a grain size above that obtained by the quenching is required.
The components of the magnetic alloy preferably obtained to 99.9 percent purity and particularly a preferred exemplification to ~9.99 percent pur~ty.
The precursor materials, that is, the transit~on metal, the rare earth metal, boron, and the quench rate range enhancing glass forming mater~al are melted together in an 1nert atmosphere, for examp1e, an argon helium atmosphere. Melting and remelting may be carried out several times in order to obtain 2Q substantially homogeneous alloy.
The substantially homogeneous alloy is discharged to a quenched surface to rapidly quench ~he material. The quencll surface may be a rapidly moving inert surface, that is, a surface moving at a quench speed of about at least 300 centimeters per minute w1th respect to the molten alloy affluent.
Preferably, the rapidly moving surface is a rapidly rotating inert surface such as a polished copper wheel rotating at an angular velocity so as to provide a 3Q linear velocity of above about 300 centimeters per second, preferably above about lO00 centimeters per second but less than about 5000 centimeters per second.
The following examples are illustrative of the method of ~his invention.
Case 804 z ~
EXA~PLES
I. Preparation of the Alloys Alloys of the examples were prepared by weighing out the appropriate constituents. The praesodymium was Morton Thiokol Alfa praesodymium, having a nominal purity of 99.99 percent. The neodymium was Research Chemicals Inc., neodymium, having a nominal purity of 99.9 percent. The boron was Morton Thiokol Alfa boron, having a nominal purity of 99.9 percent. The aluminu~ was Atlantic Equipment aluminum, having a nominal purity of 99.99 percent.
The iron was Atlantic Equipment electrolytic iron, having a nom~nal purlty of 99.999 percent.
The const~tuents were placed in a l9 mm o~d., 17 mm ~.d~ quartz cruclble, and heated 1n an elec~r~c induction furnace under a purified argon atmosphere, whereby to form an ingot. The ingots were homogenized by repeated remelting.
20 II. Quenchin~
Quenching was carried out using an argon pressurized quartz crucible having an orifice on the bottom. The oriflce was vertically spaced from a moving chill surface, i.e., a 20 inch diameter rotating, copper wheel. The molten metal was ejected through the orifice onto the copper chill wheel.
The crucible was purged with argon.
Thereafter9 a portion of the homogenized ingo~ was placed in the crucible~ and ~he crucible was heated in ~ an induction furnace. When the ingot was molten, the ; molten composition was ejected onto the rapicly rotating copper chill wheel. A thin ribbon was recovered.
Case 804 ~ 6 III. Ma~netization Magnetization measurements were made using a v;brating sample magnetometer. The magnetome~er was calibrated using a standard N.B.S. nickelsphere sample.
EXAMPLE I
10 S~mples of Fe82B6Prl2 and Fe79B~Prll 5A13 5 were prepared, quenched, and tested as described above. The following results were obtained:
Compositin Fe~2B6Prl2 Fe79B6Prll-5A 3,5 Quench surface velocity = 1596cm/sec (600 rpm) Energy product .3 x 106 6-Oe Remanence 2.95 x 103G
Coercive force .87 x 1030e Quench surface velocity = 1728cm/sec (650 rpm) Energy product 2.23 x 106G-Oe Remanence 3.85 x 103G
Coercive force 2.40 x 1030e ~ Case 804 ~2~ 6 Quench surface velocity = 1862cm/sec (790 rpm) Energy product 3.8 x 106 G-Oe, 3.8 x 106G-Oe 1.8 x 106G-Oe Remanence 7.98 x 103G, 5.73 x 103G
6.97 x 103G
Coerci~e force 7.75 x 1030e~ 4.3 x 1030e .55 x 1030e lQ _ _ _ _ _ Quench sur~ace veloclty ~ 1994cm/sec (750 rpm) Energy product 2~6 x 106G Oe Remanen~,e 4.46 x 103G
Coercive force 3.97 x 10 Oe EXAMPLE II
Samples of Fe79B6Ndl5 and Fe77B6Ndl5A12 were prepared, quenched, and tested as described above. The following results, shown graphically in Figure 2, were obtained:
Composition Fe79B6Ndl5 Fe77B5Ndl5A12 3Q Quench surface velocity = 2394cm/sec (900 rpm) Energy product 1.9 x 106G-Oe 4.9 x 106G-Oe 9. 9 x 1 05G-Oe Remanence 5.69 x 103G 5.57 x 103G
~: -10 Case 804 ~S~
7.44 x 103G
Coercive force 1.04 x 1040e 1~21 x 1040e 1.32 x 1040e _ Quench surface velocity = 2660cm/sec (1000 rpm) Energy product 2.59 x 106G-Oe 9.08 x 106G-Oe lQ 9.0 x 106G-Oe Remanence 6.79 x 103G3.87 x 103G
7.09 x 13G6.7 x 103G
Coercive force 0.48 x 1040e 1.17 x 1040e 1.32 x 1040e1.21 x 1040e Quench surface velocity = 2926cm/sec (1100 rpm) Energy product 5.1 x 1066-Oe S.l x 106G-Oe 14.8 x 105G-Oe Remanence 4.71 x 103G5.81 x 103G
8.8 x 103G
Coercive force 4.17 x 1030e 1.13 x 1040e 1.24 x 1040e - Case 804 ~ 2 6 While the invention has been ~escribed with respect to certain preferred exemplifications and embodiments thereof, it is not intended to limit the scope of protection thereby, but solely by the claims appended hereto.
Moreover, the scope of protection is not intended to be limited by the above described embodiment and exemplifications, but solely by the lQ claims appended hereto.
Claims (13)
- THE EMBODIMENTS OF THE INVENTION IN WHICH AN
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE
DEFINED AS FOLLOWS:
l. A hard magnetic material comprising:
(a) a transition metal chosen from the group consisting of iron, cobalt, nickel, manganese and mixtures thereof;
(b) a lanthanide chosen from the group consisting of praesodymium, neodymium, and mixtures thereof;
(c) boron; and (d) a quench rate range broadening amount of a glass forming additive chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium. - 2. The hard magnetic material of Claim 1, wherein the transition metal is iron.
- 3. The hard magnetic material of Claim l, wherein the glass forming additive is aluminum.
- 4. The hard magnetic material of Claim 3, wherein the aluminum content is from about 2 to about 10 atomic percent.
- 5. The hard magnetic alloy of Claim 4, wherein the alloy comprises about 8 to about 40 atomic percent lanthanide, about 2 to 10 atomic percent aluminum, up to about 20 percent boron, balance iron.
- 6. A method of forming a glassy, hard magnetic material by rapidly quenching a molten composition, comprising the steps of:
(l) forming a molten composition of:
(a) a transition metal chosen from the group consisting of iron, cobalt, nickel, manganese, and mixtures thereof;
(b) a lanthanide chosen from the group consisting of praesodymium, neodymium, and mixtures thereof;
(c) boron; and (d) a quench rate range broadening amount of a glass forming additive chosen from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium, and (2) quenching the molten composition within a quench rate range to form a glassy, hard magnetic material. - 7. The method of Claim 6, wherein the transition metal is iron.
- 8. The method of Claim 6, wherein the glass forming additive is aluminum.
- 9. The method of Claim 8, wherein aluminum content is from about 2 to about 10 atomic percent.
- 10. The method of Claim 9, wherein the hard magnetic alloy comprises about 8 to about 40 atomic percent lanthanide, up to about 20 atomic percent boron, about 2 to 10 atomic percent aluminum, balance iron.
- 11. The method of Claim 6 comprising quenching the molten composition on a chill surface.
- 12. The method of Claim 11 comprising discharging the molten composition onto the chill surface.
- 13. The method of Claim 12, wherein the chill surface moves with respect to the molten composition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65120384A | 1984-09-17 | 1984-09-17 | |
| US651,203 | 1984-09-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1255926A true CA1255926A (en) | 1989-06-20 |
Family
ID=24611980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000490359A Expired CA1255926A (en) | 1984-09-17 | 1985-09-10 | Method of preparing a hard magnet by addition of a quench rate range broadening additive and a hard magnet prepared thereby |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0175222A1 (en) |
| JP (1) | JPS6173861A (en) |
| KR (1) | KR860002841A (en) |
| AU (1) | AU573895B2 (en) |
| CA (1) | CA1255926A (en) |
| IL (1) | IL76395A (en) |
| PH (1) | PH21010A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1271394A (en) * | 1985-02-25 | 1990-07-10 | Karen S. Canavan | Enhanced remanence permanent magnetic alloy and bodies thereof and method of preparing same |
| ATE68626T1 (en) * | 1986-01-10 | 1991-11-15 | Ovonic Synthetic Materials | PERMANENT MAGNETIC ALLOY. |
| JPS62228582A (en) * | 1986-03-31 | 1987-10-07 | スガツネ工業株式会社 | Door rail for inset plane closing double sliding door device |
| JPS63157740A (en) * | 1986-07-11 | 1988-06-30 | Pilot Pen Co Ltd:The | Fine wire made of fine crystal of cobalt-base alloy and its production |
| JPH01103805A (en) * | 1987-07-30 | 1989-04-20 | Tdk Corp | Permanent magnet |
| JPH0257662A (en) * | 1988-08-23 | 1990-02-27 | M G:Kk | Rapidly cooled thin strip alloy for bond magnet |
| US20210062310A1 (en) * | 2018-07-27 | 2021-03-04 | Neo Performance Materials (Singapore) Pte. Ltd. | Alloys, magnetic materials, bonded magnets and methods for producing the same |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS587702B2 (en) * | 1977-12-27 | 1983-02-10 | 三菱製鋼株式会社 | Fe-Cr-Co magnet alloy |
| JPS5810454B2 (en) * | 1980-02-07 | 1983-02-25 | 住友特殊金属株式会社 | permanent magnet alloy |
| US4419148A (en) * | 1980-04-22 | 1983-12-06 | Bell Telephone Laboratories, Incorporated | High-remanence Fe-Ni and Fe-Ni-Mn alloys for magnetically actuated devices |
| EP0072893B1 (en) * | 1981-08-21 | 1986-12-03 | Allied Corporation | Metallic glasses having a combination of high permeability, low coercivity, low ac core loss, low exciting power and high thermal stability |
| US4402770A (en) * | 1981-10-23 | 1983-09-06 | The United States Of America As Represented By The Secretary Of The Navy | Hard magnetic alloys of a transition metal and lanthanide |
| US4374665A (en) * | 1981-10-23 | 1983-02-22 | The United States Of America As Represented By The Secretary Of The Navy | Magnetostrictive devices |
| US4409043A (en) * | 1981-10-23 | 1983-10-11 | The United States Of America As Represented By The Secretary Of The Navy | Amorphous transition metal-lanthanide alloys |
| DE3379131D1 (en) * | 1982-09-03 | 1989-03-09 | Gen Motors Corp | Re-tm-b alloys, method for their production and permanent magnets containing such alloys |
| AU572120B2 (en) * | 1983-06-24 | 1988-05-05 | General Motors Corporation | High energy product rare earth transition metal magnet alloys |
-
1985
- 1985-09-04 AU AU47077/85A patent/AU573895B2/en not_active Ceased
- 1985-09-05 EP EP85111219A patent/EP0175222A1/en not_active Withdrawn
- 1985-09-10 CA CA000490359A patent/CA1255926A/en not_active Expired
- 1985-09-13 IL IL76395A patent/IL76395A/en unknown
- 1985-09-17 KR KR1019850006795A patent/KR860002841A/en not_active Application Discontinuation
- 1985-09-17 PH PH32794A patent/PH21010A/en unknown
- 1985-09-17 JP JP60205136A patent/JPS6173861A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU573895B2 (en) | 1988-06-23 |
| AU4707785A (en) | 1986-03-27 |
| JPS6173861A (en) | 1986-04-16 |
| PH21010A (en) | 1987-06-23 |
| KR860002841A (en) | 1986-04-30 |
| EP0175222A1 (en) | 1986-03-26 |
| IL76395A0 (en) | 1986-01-31 |
| IL76395A (en) | 1988-11-30 |
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