CN1636074A - Method for controlling structure of rare earth element-containing alloy, powder material of the alloy and magnet using the same - Google Patents
Method for controlling structure of rare earth element-containing alloy, powder material of the alloy and magnet using the same Download PDFInfo
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- CN1636074A CN1636074A CN 02800585 CN02800585A CN1636074A CN 1636074 A CN1636074 A CN 1636074A CN 02800585 CN02800585 CN 02800585 CN 02800585 A CN02800585 A CN 02800585A CN 1636074 A CN1636074 A CN 1636074A
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- 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
- H01F1/0551—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 in the form of particles, e.g. rapid quenched powders or ribbon flakes
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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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
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- 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
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
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- 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
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
- B22F2009/048—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by pulverising a quenched ribbon
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Abstract
An object of the present invention is to provide a method for controlling an internal metallographic structure of an alloy, particularly the distribution of R-rich phase; in order to achieve the object, the present invention provide a method for controlling the metallographic structure of an alloy containing a rare earth element, which comprises the steps of: melting said alloy containing a rare earth element in vacuum or under an inert gas; pouring a molten metal obtained by melting said alloy onto a rotatable roll which is rotating and being cooled, to thereby cool the molten metal for solification, said pouring being performed in a vacuum chamber or a chamber purged by an inert gas; forming a strip of said metal through solidification; immediately after solidification, reducing said resultant solidified strip into flakes; collecting said resultant fragmented alloy flakes in a receptacle; and controlling the cooling rate of said fragmented alloy flakes by means of a cooling medium.
Description
Technical field
The present invention relates to the method for inside structure that a kind of control contains the alloy of rare earth element, more specifically relate to the method for inside structure that a kind of control is used to produce the alloy that contains rare earth element of magnet.The invention still further relates to a kind of powdered alloy that obtains by this method and by the magnet of this powder production.
Background technology
In recent years, the Nd-Fe-B alloy that is used as magnet alloy relies on its performance characteristics turnout sharp increase, and these alloys are used for HD (hard disk), MRI (nuclear magnetic resonance), various electric motor etc.Usually, a part of Nd atom is by another kind of rare earth element such as Pr or Dy replacement (in this article, Nd and substituted Nd are called R), and a part of Fe is by another kind of transition metal such as Co or Ni replacement (in this article, Fe and substituted Fe are called T).Alloy and Nd-Fe-B alloy after so replacing are referred to as the R-T-B alloy.
The R-T-B alloy contains by R
2T
14Crystal formation ferromagnetic as principal crystalline phase of B, it is the major cause that produces magnetic, at R
2T
14Contain non magnetic rich R phase in the B crystalline crystal boundary, the rare earth element that it has low melting point and contains high density.R-T-B is a kind of reactive metal material.So, melting and the model casting in a vacuum or under protection of inert gas usually of this alloy.
In the typical method of producing magnet, alloy pig is broken into the powder (measuring by FSSS (Brigit Fischer (Schmidt) undersize degree instrument (Fisser Sub-Sieve Sizer)) method) that particle size is about 3 microns; Powder is pressed in magnetic field; The gained briquetting in sintering oven up to about 1,000-1,100 ℃ of sintering; As required, to sintered product heat, mechanical workout and anticorrosion plating.
Rich R removes column weight and will act in alloy.
(1) because rich R phase fusing point is low, this liquefies in sintering process, thereby helps to make the gained magnet to reach high-density, causes the improvement of the specific magnetising moment.
(2) rich R has the slick effect of the crystal boundary of making mutually, thereby is reduced in the nucleation site quantity in the reverse magnetic domain, thereby improves coercive force.
(3) rich R mutual-assistance principal crystalline phase magnetic insulation, thus coercive force improved.
Therefore, obtaining homodisperse rich R is crucial mutually, because otherwise can the magnetic property and the erosion resistance of the magnet produced be had a negative impact.
The distribution of rich R phase depends primarily on the structure of raw alloy ingot in the final product magnet.Particularly, when alloy carried out the model casting, speed of cooling caused forming big crystal grain usually slowly.Under these circumstances, the particle size of breakdown products becomes and is significantly less than the crystalline grain-size.Because rich R has the lamellar structure that contains thick subgrade mutually, so bad dispersibility.If the particle size of breakdown products is less than the crystalline grain-size, then produce only by the principal crystalline phase that does not contain rich R phase particle that forms and the particle that only forms mutually by rich R, feasiblely be difficult to uniform mixing principal crystalline phase and rich R mutually.
Another problem that relates in the model casting is because speed of cooling is slow, often forms γ-Fe as primary crystal.Under about 910 ℃ or lower temperature, γ-Fe is transformed into α-Fe, and this reduces crushing efficiency in the magnet generation process.If α-Fe is still residual behind sintering, then reduce the magnetic property of sintered product.Therefore, in order to remove α-Fe, the ingot that obtains by the model casting must at high temperature carry out long homogenizing processing.
In order to address the above problem, propose and in the actual production step, adopted made-up belt teeming practice (SC method), it can guarantee that the speed of cooling in the casting cycle is faster than the model casting.
In the made-up belt casting, molten metal is poured on the copper roller of inner water-cooled, formation thickness is tens of millimeters band.In casting cycle, molten metal solidifies by quick cooling, thereby produces the alloy with microlitic structure, and wherein rich R disperses mutually imperceptibly.Because rich R is dispersed in the alloy mutually imperceptibly, so, in the product that is obtained by broken and this alloy of sintering, it is satisfactory that the dispersion of rich R phase also becomes, thereby successfully improved magnetic property (Japanese Patent Application Publication (putting down) 5-222488 and 5-295490.In addition, also suppressed the generation of α-Fe.
Usually, the alloy by the casting of SC method comes cracked by hydrogen explosion (hydrogen decrepitation).The SC method is based on following concrete phenomenon: when hydrogen infiltrate rich R mutually in the time, the volumetric expansion of alloy pig cause producing the crackle that originates from rich R phase, and ingot is fragmented into fritter.Owing to before micro mist is broken, carry out the hydrogen explosion, so the important factor of the particle size that the control of the spacing between the rich R phase is decision to be produced.
Therefore, when controlling the distribution of the rich R phase (or the spacing between the rich R phase) that obviously influences magnetic property, controlled chilling speed in casting cycle, particularly near the control of the temperature rich R solidifying temperature is important.
Japanese Patent Application Publication (putting down) 8-176755 discloses rich R phase (being called " eutectic magnetic domain " in the disclosure) and has been present in principal crystalline phase (R
2T
14B) in and in the crystal boundary; The control of the spacing between the rich R phase is important for the decision magnetic property; And the speed of cooling that remains the mutually completely crued temperature range of rich R (800-600 ℃) of liquid in a part preferably is controlled to be 5 ℃/second or bigger.
Japanese Patent Application Publication (putting down) 10-36949 discloses the average cooling rate in 800-600 ℃ of scope has been controlled to be 1.0 ℃/second or littler, thereby makes the spacing between the rich R phase increase to the 3-15 micron.
As mentioned above because the distribution of the rich R phase of control in the alloy pig is important for the decision magnetic property, so, must control speed of cooling in from the liquidus temperature of the rich R phase of liquid to the temperature range of solidification value.In above-mentioned SC method, the liquidus temperature of this temperature range be equivalent to alloy fall from roller before the temperature of moment, even after falling from roller, the curing of alloy also is incomplete.At present, there is not the open method of determining to control associated temperature.Up to now, the perhaps circumferential speed by dancer rools or reach adjusting to change metal layer thickness to the speed of cooling that is present in the metallic substance on the roller by regulating metal flow.These methods relate to some insoluble problems.Particularly, when the completion of cure of principal crystalline phase, metal contacts from face-face with the way of contact between the roller and becomes a little-the face contact, thereby has reduced speed of cooling suddenly.If steadily production does not contain the alloy pig with suitable structure of α-Fe, then molten metal and wherein the alloy pig that has cured of principal crystalline phase only with roller contact number second.In the so short time, the rich R on can not control roller reaches completely crued temperature range mutually.When prolonging alloy pig by the circumferential speed that reduces roller with time that roller contact, the thickness increase of alloy pig, generation α-Fe.When reducing the molten alloy amount that is provided on the roller by the pitch velocity that reduces crucible, the temperature of molten alloy just reduced before it arrives on the roller, caused being easy to generate γ-Fe primary crystal.The further minimizing of the molten alloy amount that is provided in addition, causes molten alloy to solidify before it arrives roller.
Therefore, when adopting the SC method, under temperature, there is not effective means to control the speed of cooling of rich R on roller, to reach the effect of the structure that control satisfactorily cast near solidification value.In addition, the method for the structure of the cast alloys that fallen from roller of in fact open up to now control.
Therefore, the purpose of this invention is to provide a kind ofly in the conventional roll teeming practice that uses the rotation roller to carry out, the speed of cooling of the alloy slice that has fallen from roller by control is controlled the inner structure of alloy, the method for the distribution of particularly rich R phase.
Summary of the invention
Finished the present invention in order to achieve the above object, and the invention provides the method for structure that a kind of control contains the alloy of rare earth element, comprising following steps: fusing contains the alloy of rare earth element in vacuum or rare gas element; On the rotatable roller that the molten metal that obtains by molten alloy is poured over rotation and is cooled, thereby make the molten metal cooling curing, describedly be poured over vacuum chamber or with carrying out in the chamber of inert gas purge; By solidifying to form metal strip; After curing, make gained solidify band immediately and become sheet; In collector, collect the broken alloy slice of gained; And control the speed of cooling of broken alloy slice by heat-eliminating medium.
In the method, preferably described collector has cooled partition and can pass through described cooled partition as the gas or the liquid of heat-eliminating medium, thereby controls the speed of cooling of broken alloy slice.
In the method, further preferably when the rare gas element as heat-eliminating medium passed through described collector inside, described collector can be controlled the speed of cooling of broken alloy slice.
In the method, further preferably make the cooled partition that described rare gas element flows through to be provided and have venting port in described collector.
In the method, further preferably described collector has the separation dividing plate of the speed of cooling of the broken alloy slice of control.
In the method, further preferably also comprise a step, promptly after the broken alloy slice speed of cooling of control, broken alloy slice is indoorly transferred to the chamber that another is used for cooling off broken alloy slice from this.
In the method, further preferably adopt a molten alloy that contains rare earth element is poured over made-up belt teeming practice on the rotation roller, thereby cool off described molten metal and by solidifying to form made-up belt.
In the method, further preferably control the speed of cooling of broken alloy slice, thereby the average headway between the rich R phase is controlled to be the 3-15 micron.
In the method, further preferably the average cooling rate of broken alloy slice is 10-300 ℃/minute in 800-600 ℃ of scope.
And in the method, the alloy that also preferably contains rare earth element is R-T-B, and wherein, R represents at least a element that is selected from the rare earth element that comprises Y; Be at least a Y of being selected from, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; T represents mainly to comprise the material of Fe, and wherein a part of Fe atom is optional with replacements such as Co, Ni.
In addition, finished the present invention in order to achieve the above object, and the invention provides the powder of the alloy that contains rare earth element, this powder produces by pulverizing the broken alloy slice that obtains with described method, its thickness is the 0.1-0.6 millimeter, and the spacing between the rich R phase is the 3-15 micron.
In addition, finished the present invention to achieve these goals, and the invention provides a kind of magnet by contour alloy powder and sinter molding production of articles.
The accompanying drawing summary
Fig. 1 is a kind of melting of expression and casts the synoptic diagram of the method for the alloy that contains rare earth element.
Fig. 2 is a kind of sketch that is used for cooling off the method for the foundry goods fragment that comprises at collector and broken alloy slice of expression.
Fig. 3 is the sketch of the another kind of method of cooling of expression.
Fig. 4 is the sketch of the another kind of method of cooling of expression.
Fig. 5 is the sketch of the another kind of method of cooling of expression.
Fig. 6 is the sketch of the another kind of method of cooling of expression.
Embodiment
Usually, when casting contained the alloy of rare earth element, because its active character, described alloy is melting and casting in airtight working chamber.Working chamber's internal control is vacuum or inert atmosphere (for example argon or helium).Fig. 1 is the synoptic diagram of expression based on a kind of casting process of the SC method that adopts according to the present invention.Raw metal melting in crucible 2, crucible 2 are placed in the working chamber 1 by induction heating, thereby produce the alloy that remains on then in the crucible.The molten alloy of Sheng Chaning is transferred in the groove 4 by dumping crucible 2 like this, then in tundish 5.That molten alloy is poured over rotation and be placed on the vacuum or the rotatable rollers 3 in the inert atmosphere casting chamber 10 near melter.Roller is inner uses water cooling, and described alloy cools off on roller 3 and solidifies.
When roller rotated, so the solidified alloy came off from roller 3.Fall by the alloy that uses suitable guide plate to force to come off, so that prevent contacting again of alloy and roller 3.
The alloy that comes off from roller is owing to its high temperature is fragility, by using shredder assembly such as simple deflector roll 6 or making the fragmentation easily of its plain mode that contacts with obstacle such as baffle plate.Therefore, this alloy is fractured into thin slice, and these thin slices fall.Selectively, described alloy can be by in the impact that falls into collector 8 and fragmentation.
For the alloy size that reduces to come off from roller, the time that molten metal contacts with roller should be as short as the several seconds.As mentioned above, the solidified alloy in this stage still is in red-hot state, and the rich R with minimum solidification value does not also have completely solidified mutually.
Usually, force broken alloy slice 7 to fall into the box shape collector 8 of close described roller, and be collected in wherein.Because alloy is oxidation easily at high temperature, described collector is placed in the casting chamber 10 that casting equipment also is housed usually, and described alloy is cooled to the temperature that oxidation no longer takes place collected alloy.Japanese Patent Application Publication (putting down) 9-155507 discloses and the collector of wherein placing broken alloy slice has been transferred near in another chamber of this collector thin slice as described in working medium cools off as rare gas element.Yet this cooling step does not desire to be used for controlling the structure of alloy.
At first, the present invention relates to a kind of method of controlling the cooling temperature of alloy sheet, this method comprises places a collector that holds cast alloys fragment (alloy sheet hereinafter referred to as), so that be controlled at the structure under the solidification value, particularly controls low-melting rich R phase; And when alloy sheet is in collector, control the cooling temperature of the alloy sheet in the collector by heat-eliminating medium.This method can make alloy sheet be cooled when falling into collector.Therefore, with after casting, collector is transferred in another above-mentioned patent gazette that is used for the refrigerative chamber disclosed method and compares, method of the present invention has realized uniform cooling, and can be before controlled chilling speed begins by the less reduction of temperature in relative broad range inner control speed of cooling.In addition, if necessary, when described collector is not cooled, only because the heat of alloy itself just can keep the temperature of alloy.According to present method, can easily be controlled at the speed of cooling in the 800-600 ℃ of temperature range; Should notice that the speed of cooling in this scope obviously influences the structure of alloy.
Secondly, owing to finish and inner structure has become solid postcooling speed and no longer influences inner structure at rich R solidifying, so, must discharge alloy sheet as quickly as possible, so that satisfy processing requirement.Therefore, preferably be cooled to 100-200 ℃ as early as possible in such as inert gas atmosphere, oxidation this moment no longer carries out and alloy sheet can be rejected in the air.
In order to satisfy above-mentioned two requirements, for example, adopt collector shown in Figure 2.Particularly, provide a kind of stainless (steel) wire 233 in the collector bottom, inertia cooling gas 23 can pass through this net as helium.After having collected the alloy sheet that falls, gas is passed through.Can change the speed of cooling of alloy sheet by the flow that changes gas.When the temperature of alloy sheet reaches when being lower than above-mentioned rich R solidifying temperature range and being 800-600 ℃, can cool off with maximum gas flow, reach alloy sheet until temperature and can be rejected to airborne temperature.
In the above-described embodiment, contact with the gas that can between settling, pass through by sedimentary alloy sheet and cool off.Therefore, when depositing a large amount of alloy sheets and adopting the collector of large volume, the control of speed of cooling often is restricted, and perhaps is easy to generate the difference of cooling performance in the alloy sheet in collector.
In this case, as shown in Figure 3, collector inside is separated by hollow shelf 211 is provided, and heat-eliminating medium 22 is introduced each dividing plate, thereby by the speed of cooling that has improved alloy sheet that contacts between dividing plate and the thin slice.In this way, because heat-eliminating medium does not contact with alloy sheet, so except rare gas element, can be used as heat-eliminating medium such as the gas of air or such as the liquid of water.
Selectively, it also may be practical adopting the method for cooling of collector shown in Figure 4.Fig. 4 has represented a kind of method of cooling, and the ventage 212A that wherein being used for the rare gas element 23 of cooled alloy thin slice provides from cooled partition 212 bottoms introduces and a part of gas can flow through collector, thus the cooled alloy thin slice.
After the structure of alloy inside has cured, carry out cooling subsequently as early as possible, to obtain high cooling efficiency.Particularly when casting continuously, so quick cooling is preferred.Fast cooling can be carried out in that aforesaid casting is indoor.Selectively, cooling can be carried out in another chamber fast, wherein collector is transferred in this chamber.
When described collector took out from the casting chamber and transfers in another chamber that rare gas element is housed, cap covers can be used in the collector top, and this collector can cooling once more in described chamber.Do not need to seal this collector fully in transfer process, can provide rare gas element to this collector continuously in transfer process, the amount of rare gas element makes gas overflow from collector.If shift used time weak point, after having adorned gas, can stop gas and supply with, and the collector top keeps covering.In this case, from collector, remove the flexible pipe of supply gas etc., block the connection portion.Because rare gas element such as argon are heavier than air, so even this collector does not cover fully, rare gas element can not leak from collector.
In making the another kind of method of inert gas flows, can provide gas from the ventage 213A that provides in hollow shelf 213 sides, as shown in Figure 5.
Provide at the center of each collector shown in Fig. 5 and 6 and to be used to separate its inner dividing plate 24.In these collectors, alloy sheet is divided into less part, so cooling easily.If do not provide these to separate dividing plate, alloy sheet is confined to the local location of collector, thereby forms its aggregate, thereby may hinder cooling or fusing and bond with state of aggregation easily.Supplying with rare gas element by ventage 213A that provides from each cooled partition 213 or the stainless (steel) wire 233 that provides in the collector bottom in collector cools off.Also can use the method for cooling that adopts the collector shown in Fig. 3 or 4.After cooling is finished, but by for example door taking-up collector in the casting lateral folding in chamber.
According to the above-mentioned two-step approach that is used to control collector internal cooling speed, by control particularly the temperature in first high temperature range can control the distribution of rich R phase.No matter the speed of cooling in first high temperature range how, the cooling in second temperature range that inner structure is not influenced can be carried out fast, thereby realizes smoothly carrying out of described step.
When by described method being SC method casting when producing thickness and being the alloy sheet of 0.1-0.6 millimeter, these come off and the temperature that falls into the thin slice of collector is about 800 ℃ from roller.Be selected from any mode in the above-mentioned method of cooling of carrying out by employing in collector, the speed of cooling in first temperature range is controlled slowlyer, improves the spacing of rich R between mutually, and controlled chilling is very fast, then reduces the spacing of rich R between mutually.In the present invention, casting process is not limited to SC method shown in Figure 1, also can adopt other method, for example by casting in the space between the rotatable roller that molten alloy is poured over two rotations.
The method according to this invention, (R represents at least a element that is selected from the rare earth element that comprises Y, promptly at least a Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and the Lu of being selected to contain the alloy of rare earth element such as R-T-B alloy; T represents mainly to comprise the material of Fe, and wherein a part of Fe atom is optional with replacements such as Co, Ni.) the rich R spacing between mutually may be controlled to about 3-15 micron.For controlling the rich R spacing between mutually in above-mentioned scope, suitable average cooling rate is 10-300 ℃/minute in 800-600 ℃ the scope, preferred 10-200 ℃/minute, and more preferably 10-50 ℃/minute.
Obtain the rich R spacing between mutually by following process.Particularly, use the carborundum disc polishing and the cross section of the alloy sheet that on thickness direction, cuts with polishings such as aluminum oxide, diamonds, descend observation post's polished surface in scanning electronic microscope (SEM), thus the acquisition reflected electron image.In this image, rich R is viewed as light field mutually, because the average atom number of the atom that exists in mutually at rich R is greater than the R as principal crystalline phase
2Fe
14The atom that exists among the B.Measure the spacing of rich R between mutually by observing cross section on the thickness direction.More specifically, in the middle of the thickness direction cross section, draw one and be parallel to the roller surface line segment of (being parallel on the direction of roll shaft).The length of line segment is removed with the number of times that rich R passes this line segment mutually.For different viewing area repeated observation five times.Mean value is as the spacing between the rich R phase.
According to the present invention, the spacing between the rich R phase may be controlled to the 3-15 micron, preferred 3-12 micron, more preferably 4-10 micron.Surpassing under 15 microns the situation, can not obtain the dispersion of rich R phase satisfactorily, and when being the powder particle of 3-5 micron, comprise that the ratio of the powder particle of rich R phase reduces by the broken particle size that is formed for moulding in magnetic field of micro mist.Therefore, the dispersiveness of the rich R phase of the product of moulding is lowered in magnetic field, causes coking property to reduce and reduce the specific magnetising moment and the coercive force of the magnet of being produced.In addition, the Local enrichment of rich R phase causes coercitive local the reduction, causes the squareness ratio of the magnet of producing to reduce.On the contrary, when the rich R spacing between mutually during less than 3 microns, crystal grain is caused the deterioration of magnetic property unfriendly by excessively micro mist is broken.
Subsequently, above-mentioned alloy sheet is pulverized, moulding and sintering, thus the anisotropy magnet of production performance excellence.
Usually, pulverize successively by hydrogen explosion, middle pulverizing and fine order, thereby the production size generally is about the powder of 3-5 micron (FSSS).
In the present invention, the hydrogen explosion comprise the hydrogen adsorption step as first step and hydrogen desorption step as second step.In the hydrogen adsorption step, 2.7 * 10
4Pa-4.9 * 10
6Make under the nitrogen atmosphere of Pa rich R that hydrogen mainly is adsorbed on alloy sheet mutually in.Because in this step, produce the hydride of R, thus the expansion of rich R phase volume, thus reduce alloy sheet itself imperceptibly or produce a large amount of tiny cracks.Under the situation of alloy sheet of the present invention, crackle can produce along the almost whole portion of rich R phase.Especially, because the crystal boundary of principal crystalline phase contains rich R phase, being adsorbed in the almost whole grain boundary portion of hydrogen cracks.Therefore, form by single crystal particle through the powder of middle pulverizing and the broken generation of micro mist, thereby improved magnetic property.Hydrogen adsorption is carried out in about 600 ℃ temperature range in room temperature.But,,, preferably in about 100 ℃ temperature range, carry out hydrogen adsorption in room temperature so that reduce lamina dimensions effectively in order to increase the volumetric expansion of rich R phase.Preferred 1 hour of the time of hydrogen adsorption or longer.The R hydride that forms by the hydrogen adsorption step is unsettled and oxidized easily in atmosphere.Therefore, the product of absorption hydrogen preferably remains on and carries out hydrogen desorption in 200-600 ℃, 130Pa or the littler vacuum and handle.By this processing, R hydride can be transformed into stable product in atmosphere.Preferred 30 minutes of the time that hydrogen desorption is handled or longer.If oxidation is prevented in controlled atmosphere in the step that sintering carries out after hydrogen adsorption, also can omit the hydrogen desorption step.
Selectively, can pulverize and micro mist is broken pulverizes by the centre, and not carry out the hydrogen explosion.
The middle pulverizing is a pulverising step, and wherein, particle size is 500 microns or littler to alloy sheet as for example being crushed in argon gas or the nitrogen in inert atmosphere.The example that is used to carry out the pulverizer of this pulverizing comprises the Brawn mill.In the present invention, if alloy sheet has passed through the hydrogen explosion, alloy sheet has been reduced or has wherein been comprised the tiny crack of a large amount of generations imperceptibly.Therefore, can omit middle the pulverizing.
Micro mist is broken to be a kind of pulverising step that is used to obtain the particle size of about 3-5 micron (FSSS).The example that is used to carry out the pulverizer of this pulverizing comprises jet mill.When micro mist was broken, controlled atmosphere was for example argon atmospher or nitrogen atmosphere of inert atmosphere.Rare gas element can contain 2% (quality) or oxygen still less, preferred 1% (quality) or still less.The existence of oxygen improves crush efficiency and acquisition is 1 by the oxygen concn of pulverizing the powder that produces, 000-10, and 000ppm, thus improve oxidation-resistance.In addition, can prevent that the abnormal grain in the sintering process from growing up.
In magnetic field, carry out moulding.For the friction that reduces the friction between powder and the model inwall and reduce to produce between the powder particle to strengthen orientation, preferably in the pressing under magnetic field process, in powder, add lubricant such as Zinic stearas.The add-on of lubricant is 0.01-1% (quality).Though lubricant can add before or after micro mist is broken,, preferably in magnetic field, before the moulding, utilize suitable mixing equipment such as V-Mixer thorough mixing in inert atmosphere such as argon gas or nitrogen.
Powder by the broken acquisition of micro mist utilizes molding device compression moulding in magnetic field.Consider the orientation of magnetic field in die cavity, used model is made with magneticsubstance and nonmagnetic substance combination.The preferred 0.5-2t/cm of forming pressure
2, the preferred 5-20kOe in magnetic field in the moulding process in the die cavity.The preferred inert atmosphere of atmosphere in the moulding process is argon gas or nitrogen for example.But,, then can in air, carry out moulding if powder has passed through above-mentioned antioxidation treatment.
Sintering is 1,000-1, and 100 ℃ are carried out.Before sintering, must from briquetting to be sintered, get rid of lubricant and hydrogen fully.Preferably by keeping briquetting under following condition, to get rid of in lubricant: 1.3Pa or the lower vacuum or in the argon gas stream atmosphere under reduced pressure; At 300-500 ℃; 30 minutes or longer.Preferably by keeping briquetting under following condition, to get rid of in hydrogen: 1.3Pa or the lower vacuum; At 700-900 ℃; 30 minutes or longer time.Preferred argon atmospher of atmosphere in the sintering process or 1.3Pa or lower vacuum.Preferred 1 hour of soaking time or longer.
After sintering was finished, in order to improve coercive force, sintered product can be 500-650 ℃ of processing as required.Preferred argon atmospher or vacuum atmosphere, preferred 30 minutes of soaking time or longer.
Describe the result who controls structure (rich R phase) according to the present invention in detail below by embodiment.
Embodiment 1
Element neodymium, ferroboron, cobalt, aluminium, copper and iron are mixed, thereby obtain following alloy composition: Nd:30.0% (quality), B:1.00% (quality), Co:2.0% (quality), Al:0.30% (quality), Cu:0.10% (quality), surplus is an iron.The mixture of gained utilizes high-frequency induction smelting furnace (crucible) to carry out melting under argon atmospher (1 normal atmosphere) in alumina crucible.The molten alloy of gained is poured on diameter 40cm and the circumferential speed copper roller rotating with 0.97 meter per second by tundish.The total mass of molten metal is 15kg, and the temperature of molten metal when beginning to cast is controlled to be 1,450 ℃.In casting cycle, the inside water cooling of copper roller.
The alloy utilization of solidifying on the copper roller is in the locational deflector roll fragmentation that alloy comes off from the copper roller.Cracked alloy is collected in the box-shaped collector below the deflector roll.The long 31cm of collector, wide 21cm, high 40cm (outside dimension) make with the iron plate of thick 5mm.In addition, as shown in Figure 2, stainless (steel) wire (the scale spacing: 5mm) be placed on collector bottom, exceed the position of collector base plate 1cm, broken alloy slice is collected in that this is online.
The last finishing to casting in the moment before begin to cast 10 minutes, make argon gas continuously upwards by described stainless (steel) wire, flow is 30 liters/minute.
Suppose that the temperature that falls the process interalloy is approximately equal to the temperature of the alloy slice that gathers in collector, then utilize the temperature of the thermocouple measurement alloy slice that provides in collector to determine the temperature of alloy in falling process, thermopair stretches out from the aperture of collector side.So the temperature of alloy sheet in falling process of measuring is 780 ℃.Alloy sheet is cooled off gradually, and reaching 600 ℃ of required times up to temperature is 5 minutes.
After casting is finished 10 minutes, make upwards the flow of the argon gas by stainless (steel) wire increase to 100 liters/minute, thereby make the alloy sheet cooling.After 2 hours, the temperature of alloy sheet is reduced to 98 ℃.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Embodiment 2
Mix with embodiment 1 in used same materials, thereby obtain the composition identical with embodiment 1, the mixture utilization of gained and embodiment 1 identical equipment is made alloy sheet.Use collector shown in Figure 2.From beginning the moment before of casting, introduce helium and make gas to the collector bottom continuously by described net with 100 liters/minute flows.Alloy sheet the temperature during falling process measured by aforesaid method is 750 ℃.Cooled alloy thin slice to the 600 ℃ required time is 40 seconds.
Even after casting is finished, still make helium continuously by so that the cooled alloy thin slice, its temperature was reduced to 96 ℃ in 30 minutes after casting is finished.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Embodiment 3
Mix with embodiment 1 in used same metal raw material, thereby obtain the composition identical, the melting under the condition identical of the mixture of gained with embodiment 1 with embodiment 1.The molten alloy utilization of gained and embodiment 1 used identical copper roller casting.
Utilize with embodiment 1 in the alloy that on the copper roller, solidifies of used identical deflector roll fragmentation.Alloy after the fragmentation is collected in the box shape collector below the deflector roll.The long 31cm of collector, wide 21cm, high 40cm (outside dimension) make with the iron plate of thick 5mm.In addition, as shown in Figure 3, two iron dividing plates (thickness: 7cm) 211 with identical pitch arrangement on turning axle direction perpendicular to the copper roller.The structure of each dividing plate is that the gas that supplies in the dividing plate can not be leaked in the collector.From beginning the moment before of casting, make argon gas continuously by each dividing plate, flow is 100 liters/minute.
By the temperature of alloy sheet in falling process measured with the used same procedure of embodiment 1 is 790 ℃.Cooled alloy thin slice gradually, making alloy sheet be cooled to 600 ℃ of required times is 7 minutes.
Even after casting is finished, still make helium continuously by so that the cooled alloy thin slice, its temperature was reduced to 106 ℃ in 2 hours after casting is finished.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Embodiment 4
Mix with embodiment 1 in used same metal raw material, thereby obtain the composition identical with embodiment 1, the mixture use of gained and embodiment 3 identical equipment are made alloy sheet.Adopt collector shown in Figure 3.From beginning the moment before of casting, make water continuously by each dividing plate, flow is 30 liters/minute.
By the temperature of alloy sheet in falling process measured with the used same procedure of embodiment 1 is 790 ℃.Cooled alloy thin slice gradually, making alloy sheet be cooled to 600 ℃ of required times is 6 minutes.
Even after casting is finished, still make water continuously by so that the cooled alloy thin slice, its temperature was reduced to 98 ℃ in 2 hours after casting is finished.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Embodiment 5
Mix with embodiment 1 in used same metal raw material, thereby obtain the composition identical, the melting under the condition identical of the mixture of gained with embodiment 1 with embodiment 1.The molten alloy utilization of gained and embodiment 1 used identical copper roller casting.
Utilize with embodiment 1 in the alloy that on the copper roller, solidifies of used identical deflector roll fragmentation.Alloy after the fragmentation is collected in the box shape collector below the deflector roll.The long 31cm of collector, wide 21cm, high 40cm (outside dimension) make with the iron plate of thick 5mm.In addition, as shown in Figure 4, collector inner place two iron dividing plates (thickness: 7cm) 212, make two dividing plates with identical pitch arrangement on turning axle direction perpendicular to the copper roller, wherein, the structure of dividing plate makes gas flow into the collector from the bottom.From beginning the moment before of casting, argon gas is passed through continuously from the ventage 212A of each dividing plate, flow is 30 liters/minute.
By the temperature of alloy sheet in falling process measured with the used same procedure of embodiment 1 is 780 ℃.Cooled alloy thin slice gradually, making alloy sheet be cooled to 600 ℃ of required times is 5 minutes.
After casting is finished 10 minutes, make argon flow amount increase to 100 liters/minute, and cover the collector top by each dividing plate.Subsequently, this collector is moved on to the air from vacuum apparatus, transfer to immediately with in another chamber of purification for argon.Because oxygen concn and cooled alloy thin slice in this chamber atmosphere that jump operation increases even after described collector has been transferred in another chamber, still make argon gas continuously by each dividing plate, flow is 100 liters/minute in order to reduce.
After casting is finished 2 hours, the temperature of alloy sheet was 94 ℃.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
In addition, the oxygen concn of alloy sheet is measured as 140ppm, and the oxygen concn (130ppm) of the alloy sheet of this and embodiment 1 is suitable.This shows that the described collector of transfer does not cause the oxidation of alloy sheet.
Embodiment 6
Element neodymium, element dysprosium, ferroboron, cobalt, aluminium, copper and iron are mixed, thereby obtain following alloy composition: Nd:29.0% (quality), Dy:3.5% (quality), B:1.05% (quality), Co:1.0% (quality), Al:0.30% (quality), Cu:0.10% (quality), surplus is an iron.The mixture of gained utilizes the high-frequency induction smelting furnace to carry out melting under argon atmospher (1 normal atmosphere) in alumina crucible.The molten alloy of gained is by being poured among the embodiment 1 on the circumferential speed copper roller rotating used and with 0.97 meter per second with embodiment 1 used identical tundish.The total mass of molten metal is 15kg, and the temperature of molten alloy when beginning to cast is controlled to be 1,450 ℃.
The alloy that utilizes embodiment 1 used deflector roll fragmentation on the copper roller, to solidify.Cracked alloy is collected in the box-shaped collector below the deflector roll.The long 31cm of collector, wide 21cm, high 40cm (outside dimension) make with the iron plate of thick 5mm.In addition, as shown in Figure 5, separate dividing plates (thickness: 2cm) 24 be placed on collector inside, make that separating dividing plates for these two is arranged on the direction perpendicular to the turning axle of copper roller with identical distance to two.Separating dividing plate and make with the refractory materials that mainly contains aluminum oxide, is 0.2kcal/ (mh ℃) (0.23W/m ℃) 1,000 ℃ thermal conductivity.In addition, separate a middle cooled partition made of iron (thickness: 3cm) 213 that provides of dividing plate at two.This cooled partition is hollow, and (the diameter: 1mm) 213A that provides some holes on each side.The structure of this cooled partition makes the rare gas element that is provided enter in the collector by these holes, thus the cooled alloy thin slice.To casting is finished after 10 minutes moment before begin to cast, make argon gas with 10 liters/minute flow by each dividing plate, alloy sheet is cooled off by the argon gas that the hole on each bulkhead sides provides.
With with embodiment 1 in used identical method to measure the temperature of alloy in falling process be 690 ℃.Cooled alloy thin slice gradually, making alloy sheet be cooled to 600 ℃ of required times is 6 minutes.
After casting is finished 10 minutes, make the flow of the argon gas by each dividing plate increase to 50 liters/minute, by make the alloy sheet cooling at the effusive argon gas in the hole of each bulkhead sides.After casting is finished 2 hours, the temperature of alloy sheet was 101 ℃.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Embodiment 7
Mix with embodiment 6 in used same metal raw material, thereby obtain the composition identical, the melting under the condition identical of the mixture of gained with embodiment 1 with embodiment 6.The molten alloy utilization of gained and embodiment 1 used identical copper roller casting.
The alloy that utilizes embodiment 1 used deflector roll fragmentation on the copper roller, to solidify.Cracked alloy is collected in the box-shaped collector below the deflector roll.As shown in Figure 6, used collector is similar to the collector of embodiment 1, also comprise be placed on this collector inside three separate dividing plates (thickness: 2cm), these three separate dividing plate with identical pitch arrangement on direction perpendicular to copper roller turning axle.The separation dividing plate is used with embodiment 6 used identical materials and is made.Moment before begin to cast finish to casting after 10 minutes, make argon gas with 10 liters/minute flow upwards by the stainless (steel) wire on the collector bottom.
By using the temperature of alloy sheet in falling process of measuring with the used same procedure of embodiment 1 is 690 ℃.Cooled alloy thin slice gradually, making alloy sheet be cooled to 600 ℃ of required times is 6 minutes.
The last finishing from casting 10 minutes, argon gas is become helium, and make helium with 100 liters/minute flow upwards by the stainless (steel) wire on the collector bottom, thereby the cooled alloy thin slice.After casting is finished 30 minutes, the temperature of alloy sheet was 103 ℃.Subsequently, alloy sheet is moved on in the air, use the miking mean thickness, measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
The comparative example 1
Mix with embodiment 1 in used same metal raw material, thereby obtain the composition identical, the melting under the condition identical of the mixture of gained with embodiment 1 with embodiment 1.The molten alloy utilization of gained and embodiment 1 used identical copper roller casting.
Utilize with embodiment 1 in the alloy that on the copper roller, solidifies of used identical deflector roll fragmentation.Alloy after the fragmentation is collected in the box shape collector below the deflector roll.The long 31cm of collector, wide 21cm, high 40cm (outside dimension) make with the iron plate of thick 5mm.In this collector, be not provided at net used among the embodiment 1-7, cooled partition, separation dividing plate etc., do not carry out the cooling of carrying out with rare gas element or similar mediums.Therefore, be not controlled at the speed of cooling of the alloy sheet that contains in the collector.
By using the temperature of alloy sheet in falling process of measuring with the used same procedure of embodiment 1 is 790 ℃.The speed of cooling of alloy sheet is obviously slow, and alloy sheet is cooled off gradually, and it is 1 hour that alloy sheet is cooled to 600 ℃ of required times.In addition, along with the alloy sheet temperature descends, speed of cooling reduces.Need the very long time, after promptly casting is finished 8 hours, alloy temperature just can reach 200 ℃, and at this moment, oxidation no longer takes place in air alloy.
Subsequently, when alloy sheet is moved on in the air, adhere strongly mutually between the alloy sheet can not be used the miking mean thickness.Can measure the spacing of rich R between mutually based on the electron reflection photo of the cross section that obtains by SEM.Table 1 expression measuring result.
Spacing between table 1-1 casting condition and the rich R phase
| Component % (quality) | |||||||
| ????Nd | ????Dy | ????B | ????Co | ????Al | ????Cu | ????Fe | |
| Embodiment 1 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 2 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 3 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 4 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 5 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 6 | ????29.0 | ????3.5 | ????1.05 | ????1.0 | ????0.30 | ????0.10 | All the other |
| Embodiment 7 | ????29.0 | ????3.5 | ????1.05 | ????1.0 | ????0.30 | ????0.10 | All the other |
| The comparative example 1 | ????30.0 | ????0 | ????1.00 | ????2.0 | ????0.30 | ????0.10 | All the other |
Spacing between table 1-2 casting condition and the rich R phase
| The casting condition | Outward appearance | Cross-sectional structure | |||||
| The circumferential speed of roll (meter per second) | The temperature of molten alloy in the casting cycle (℃) | The temperature of dropping process interalloy thin slice (℃) | The gas that provides to container | Up to 600 ℃ speed of cooling (℃/minute) | The mean thickness of alloy sheet (millimeter) | Spacing (micron) between the rich R phase | |
| Embodiment 1 | ??0.97 | ??1,450 | ????780 | Argon | ????36 | ????0.332 | ?????6.8 |
| Embodiment 2 | ??0.97 | ??1,450 | ????750 | Helium | ????22.5 | ????0.325 | ?????3.4 |
| Embodiment 3 | ??0.97 | ??1,450 | ????790 | Hydrogen | ????27 | ????0.331 | ?????7.5 |
| Embodiment 4 | ??0.97 | ??1,450 | ????790 | (water) | ????32 | ????0.336 | ?????7.0 |
| Embodiment 5 | ??0.97 | ??1,450 | ????780 | Argon | ????36 | ????0.330 | ?????6.8 |
| Embodiment 6 | ??0.97 | ??1,450 | ????690 | Argon | ????15 | ????0.328 | ?????4.7 |
| Embodiment 7 | ??0.97 | ??1,450 | ????690 | Argon | ????15 | ????0.326 | ?????4.6 |
| The comparative example 1 | ??0.97 | ??1,450 | ????790 | Do not have | ????3 | Do not measure | ?????19.2 |
Magnet generation
Embodiment 8
Pulverize the alloy sheet of in embodiment 1, producing according to hydrogen explosion, middle pulverizing and fine order.Under following condition, carry out the hydrogen adsorption step, i.e. first step of hydrogen explosion: 100% hydrogen atmosphere, 1 normal atmosphere, 1 hour hold-time.The temperature of alloy sheet is 25 ℃ when hydrogen adsorption reaction beginning.Carry out the hydrogen desorption step under the following conditions, promptly the vacuum of step subsequently: 13Pa, 500 ℃, soaking time are 1 hour.Use the Brawn mill to carry out centre pulverizing, and in 100% nitrogen atmosphere the powder of hydrogen explosion to be crushed to particle size be 425 microns or littler.The Zinic stearas powder that in the powder of gained, adds 0.07% (quality).Utilize V-Mixer this mixture of thorough mixing in 100% nitrogen atmosphere, (4, little particle size that is crushed to is 3.2 microns (FSSS) in nitrogen atmosphere 000ppm) being mixed with oxygen to utilize the air-flow jet mill then.The powder of gained utilizes V-Mixer thorough mixing once more in 100% nitrogen atmosphere.The oxygen concn of finding the gained powder is 2,500ppm.By the carbon concentration of analysed for powder, the Zinic stearas content that calculates this powder is 0.05% (quality).
Subsequently, utilize molding device, in 100% nitrogen atmosphere the powder that is obtained compression moulding in transverse magnetic field.Forming pressure is 1.2t/cm
2, the magnetic field in the die cavity is controlled to be 15kOe.
Thus obtained briquetting is successively 1.3 * 10
-3Kept 1 hour in Pa, 500 ℃ the vacuum, 1.3 * 10
-3Pa, 800 ℃ kept 2 hours, thereby removed zinc stearate and hydrogen, again 1.3 * 10
-3Sintering was carried out in Pa, 1,060 ℃ of maintenance in 2 hours.The density of sintered product is enough high, is 7.52g/cm
3The thermal treatment 1 hour in 540 ℃, argon atmospher again of this sintered product.
The sintered product magnetic property that utilizes DC B H curve drafter to measure is as follows: Br=13.9kG, iHc=10.6kOe, (BH)
Maximum=45.4MGOe.The oxygen concn of sintered product is 3,100ppm.
The cross section of mirror polish sintered product is observed glazed surface under polarizing microscope.The average grain size of gained is the 15-20 micron, and size is even substantially.
The comparative example 2
Pulverizing the alloy sheet of producing with method similar to Example 8 in comparative example 1, is the powder of 3.3 microns (FSSS) thereby produce particle size.The oxygen concn of this powder is 2,600ppm.With method similar to Example 8, this powder of moulding and sintering in magnetic field, thus produce anisotropic magnet.When sintering temperature was 1,060 ℃, the density of sintered product was 7.38g/cm
3, show that sintering is insufficient.So sintering temperature is brought up to 1,090 ℃.
As follows with the sintered product magnetic property of measuring with the used identical DC B H curve drafter of embodiment 8: when sintering temperature is 1,060 ℃, Br=13.5kG, iHc=9.8kOe, (BH)
Maximum=42.8MGOe; When sintering temperature is 1,090 ℃, Br=13.8kG, iHc=7.4kOe, (BH)
Maximum=35.2MGOe.The oxygen concn of these sintered products is respectively 3,100ppm and 3,200ppm.
The cross section of every kind of sintered product of mirror polish is observed glazed surface under polarizing microscope.Average grain size at 1,060 ℃ of agglomerating product is the 15-20 micron, and size is even substantially.But, mainly to form at 1,090 ℃ of agglomerating product by approximately uniform grain-size, average grain size is the 20-25 micron.In addition, found in some positions to grow up to tens of crystal grain to hundreds of micron-scales.
In order to study the reason that in 1,060 ℃ of agglomerating product, can not obtain sufficient intensity, under scanning electronic microscope, observe the broken particulate cross section of micro mist with the electron reflection picture.Based on these images, contain some contain rich R phase at its edge crystal grain in the product of discovery embodiment 8, and the content of such crystal grain is obviously few in comparative example 2 the product, and obviously contains the crystal grain that has only rich R phase.Therefore, these results show, the rich R phase bad dispersibility of comparative example 2 powder, and when this powder with embodiment 8 under the used similar sintering temperature during sintering, the sintered product with sufficient density can not be provided.
Claims (12)
1. a control contains the method for structure of the alloy of rare earth element, comprising following steps:
The described alloy that contains rare earth element of melting in a vacuum or in inert atmosphere;
On the rotatable roller that the molten metal that obtains by the described alloy of melting is poured over rotation and is cooled, thereby make described molten metal cooled and solidified, describedly be poured in the vacuum chamber or with carrying out in the chamber of inert gas purge;
By solidifying the band that forms described metal;
After solidifying, make the described band that solidifies be broken into thin slice immediately;
In a collector, collect described broken alloy sheet; With
Control the speed of cooling of described broken alloy sheet by heat-eliminating medium.
2. the method for structure that contains the alloy of rare earth element according to the control of claim 1, wherein, described collector has cooled partition and can pass through described cooled partition as the gas or the liquid of heat-eliminating medium, thereby controls the speed of cooling of described broken alloy sheet.
3. the method for structure that contains the alloy of rare earth element according to the control of claim 1 wherein, makes rare gas element as heat-eliminating medium by described collector when inner, and described collector can be controlled the speed of cooling of described broken alloy sheet.
4. contain the method for structure of the alloy of rare earth element according to the control of claim 1, wherein, make described rare gas element flows through provided and had a ventilating pit in described collector cooled partition.
5. the method for structure that contains the alloy of rare earth element according to the control of claim 1, wherein, described collector has the separation dividing plate of the speed of cooling that is used to control described broken alloy sheet.
6. the method for structure that contains the alloy of rare earth element according to the control of claim 1 also is included in after the speed of cooling of the broken alloy sheet of control the step of described broken alloy sheet being transferred to another chamber that is used for cooling off described broken alloy sheet from described chamber.
7. the method for structure that contains the alloy of rare earth element according to the control of claim 1, wherein, adopt the made-up belt teeming practice that the described molten alloy that contains rare earth element is poured on the rotatable roller of described rotation, thereby make described molten alloy cooling and form band by solidifying.
8. contain the method for structure of the alloy of rare earth element according to the control of claim 1, wherein, control the speed of cooling of described broken alloy sheet, thereby the average headway of rich R between mutually is controlled to be the 3-15 micron.
9. contain the method for structure of the alloy of rare earth element according to the control of claim 1, wherein, the average cooling rate of described broken alloy sheet in 800-600 ℃ of scope is 10-300 ℃/minute.
10. the method for structure that contains the alloy of rare earth element according to the control of claim 1, wherein, the described alloy that contains rare earth element is the R-T-B alloy, and wherein, R represents the element of at least a Y of being selected from, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; T represents mainly to comprise the material of Fe, and a part of Fe atom is randomly by replacements such as Co, Ni.
11. a powder that contains the alloy of rare earth element, this powder produces by pulverizing the broken alloy sheet that is obtained by the method according to claim 1, and thickness is the 0.1-0.6 millimeter, and the spacing between the rich R phase is the 3-15 micron.
12. one kind by making the magnet of producing according to the powdered alloy moulding and the sinter molding product of claim 11.
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| JP2001068258A JP3561692B2 (en) | 2001-03-12 | 2001-03-12 | Structure control method for rare earth element-containing alloy, alloy powder and magnet using the same |
| JP068258/2001 | 2001-03-12 | ||
| JP068258/01 | 2001-03-12 | ||
| US28219801P | 2001-04-09 | 2001-04-09 | |
| US60/282,198 | 2001-04-09 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101356030B (en) * | 2006-04-07 | 2010-12-22 | 昭和电工株式会社 | Apparatus for manufacturing alloy and rare earth element alloy |
| CN101808769B (en) * | 2007-09-25 | 2013-07-10 | 昭和电工株式会社 | Production system of alloy |
| CN109161784A (en) * | 2018-09-17 | 2019-01-08 | 宁波科田磁业有限公司 | A kind of preparation method of R-T-B permanent-magnet alloy |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7722726B2 (en) * | 2004-03-31 | 2010-05-25 | Santoku Corporation | Process for producing alloy slab for rare-earth sintered magnet, alloy slab for rare-earth sintered magnet and rare-earth sintered magnet |
| EP1749599B1 (en) * | 2004-04-30 | 2015-09-09 | Hitachi Metals, Ltd. | Methods for producing raw material alloy for rare earth magnet, powder and sintered magnet |
| WO2007117037A1 (en) | 2006-04-07 | 2007-10-18 | Showa Denko K.K. | Apparatus for producing alloy and rare earth element alloy |
| JP5124586B2 (en) * | 2007-09-25 | 2013-01-23 | 株式会社アルバック | Cooling device, casting device |
| CN103996519B (en) * | 2014-05-11 | 2016-07-06 | 沈阳中北通磁科技股份有限公司 | A kind of manufacture method of high-performance Ne-Fe-B rare earth permanent magnet device |
| CN106887322B (en) * | 2017-03-03 | 2018-03-30 | 北京科技大学 | A kind of method of high-efficiency production of nano crystalline substance rare earth permanent magnet powder |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2788919B2 (en) * | 1988-02-10 | 1998-08-20 | ノルスク・ヒドロ・アーエスアー | Method and apparatus for producing metal powder |
| JPH04310A (en) * | 1990-04-16 | 1992-01-06 | Sumitomo Metal Ind Ltd | Method for cooling gas atomized metal powder |
| JP3932143B2 (en) * | 1992-02-21 | 2007-06-20 | Ｔｄｋ株式会社 | Magnet manufacturing method |
| JPH06279812A (en) * | 1993-03-29 | 1994-10-04 | Daido Steel Co Ltd | Apparatus for producing and classifying powder |
| JP3201944B2 (en) * | 1995-12-04 | 2001-08-27 | 株式会社三徳 | Rare earth metal containing alloy production system |
| CN1139082C (en) * | 1996-04-10 | 2004-02-18 | 昭和电工株式会社 | Cast alloy used for production of rare earth magnet and method for producing cast alloy and magnet |
| JP2000273506A (en) * | 1999-03-19 | 2000-10-03 | Asahi Chem Ind Co Ltd | New copper alloy powder, and its manufacture |
-
2002
- 2002-03-11 CN CNB028005856A patent/CN100345987C/en not_active Expired - Lifetime
- 2002-03-11 WO PCT/JP2002/002244 patent/WO2002072900A2/en active Application Filing
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101356030B (en) * | 2006-04-07 | 2010-12-22 | 昭和电工株式会社 | Apparatus for manufacturing alloy and rare earth element alloy |
| CN101808769B (en) * | 2007-09-25 | 2013-07-10 | 昭和电工株式会社 | Production system of alloy |
| CN109161784A (en) * | 2018-09-17 | 2019-01-08 | 宁波科田磁业有限公司 | A kind of preparation method of R-T-B permanent-magnet alloy |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100345987C (en) | 2007-10-31 |
| WO2002072900A2 (en) | 2002-09-19 |
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