CN1722317A - Rare-earth anisotropic magnetic iron powder - Google Patents

Abstract

To provide a rare-earth anisotropic magnet powder having oxidation resistance and a superior magnetic property.The rare-earth anisotropic magnet powder having the oxidation resistance and the superior magnetic property is produced by a high-temperature hydrogenation step of holding an alloy having a composition ratio of (R<1-X>La<X>)<12-14>Fe<bal>.B<9-10>(wherein R is a rare-earth element including yttrium except lanthanum; X=0.05-0.08; and Fe<SB>bal</SB>represents Fe and unavoidable impurities except a specified composition) in a treatment atmosphere which has a hydrogen partial pressure P1 of 10 to 100 kPa and is kept at a temperature T1 of 953 to 1,133 K; a structure stabilization step of holding the RLaFeB-based alloy which has passed through the high-temperature hydrogenation step, in a treatment atmosphere which has a hydrogen partial pressure P2 of 10 kPa or higher, is kept at a temperature T2 of 1,033 to 1,213 K, and satisfies a condition of T2>T1 or P2>P1; a controlled gas-removing step of holding the RLaFeB-based alloy which has passed through the structure stabilization step, in a treatment atmosphere which has a hydrogen partial pressure P3 of 0.1 to 10 kPa and is kept at a temperature T3 of 1,033 to 1,213 K; and a forced gas-removing step of removing hydrogen (H) remaining in the RLaFeB-based alloy which has passed through the controlled gas-removing step.

Description

Rare-earth anisotropic magnetic iron powder

Technical field

The present invention proposes a kind of about having the rare-earth anisotropic magnetic iron powder of outstanding non-oxidizability and high coercive force.

Technical background

Magnet is widely used among the various machine goods around ours such as various motor.Recently, since more and more higher to the requirement of compactization of engineening goods and high efficiency etc., require the permanent magnet of its use to have stronger more stable magnetic characteristic.According to above-mentioned requirements, for a long time, carried out extensive studies for the exploitation of the RFeB based magnet of forming by rare earth element (R) and boron (B) and iron (Fe) (rare earth element magnet).

As the manufacture method of rare earth element magnet, the fusion centre spinning of a kind of quick-frozen freezing method of conduct of having put down in writing in the following patent documentation 1,2 is arranged.In addition, also have and put down in writing in the following patent documentation 3,4, be basic comprising, produce the hydrogenation not HDDR method (hydrogenation-disproportion-decomposition-recombination) of homogenizing reaction with the two-step of hydrogenation process and dehydrogenation operation.But manufacture method before above-mentioned these all can only obtain the lower ferromagnetic powder of magnetic characteristic.And the anisotropic magnet manufacturing method of power before above-mentioned these all is to be difficult to realize the stable anisotropic magnet manufacturing method of power of producing in batches in high quality.

Different with above-mentioned former each manufacture method, the present inventor has developed the anisotropic magnet manufacturing method of power that can obtain to have very outstanding magnetic characteristic.It is heterogeneous utilizing the characteristic of the ferromagnetic powder that this manufacture method manufacturing obtains, and is very different with operation content of above-mentioned HDDR method etc., is called the d-HDDR method at this in order to be different from above-mentioned HDDR method.The characteristics of above-mentioned d-HDDR method are, plural number being provided with has the operation of different disposal temperature and hydrogen pressure, the reaction speed that RFeB is alloy and hydrogen be can control lentamente, homogeneous and the very outstanding anisotropic magnetic iron powder of magnetic characteristic obtained thereby can make.

Specifically, above-mentioned d-HDDR method mainly by under room temperature state, make RFeB be the alloy low temperature hydrogenation process that fully absorbs hydrogen, make it under the low hydrogen pressure to produce hydrogenation not the high temperature hydrogenation process and under high as far as possible hydrogen pressure, making it of homogenizing reaction decompose lentamente the 1st deairing step of hydrogen and thus after 4 operations of from material, removing the 2nd deairing step of dehydrogenation formed.The detailed content of each operation, the record publicity is in documents and materials such as following patent documentation 5,6 and non-patent literature 1.

No. 4851058 communiques of [patent documentation 1] United States Patent (USP)

No. 5411608 communiques of [patent documentation 2] United States Patent (USP)

No. 4402770 communiques of [patent documentation 3] United States Patent (USP)

[patent documentation 4] special square 2-4901 communique

[patent documentation 5] special square 11-31610 communique

No. 3250551 communiques of [patent documentation 6] patent

[patent documentation 7] spy opens the 2002-93610 communique

[non-patent literature 1] Japanese applied magnetics meeting magazine, 24 (2000), p.407

On the other hand, very early since, various magnet be widely used in the automobile various motor, drive in portion's product such as exciter.From the purposes of automobile, because the influence of its hot environment etc. is very high to the requirement of non-oxidizability.And, in recent years,, require portion's product such as motor when improving constantly its performance from the light-weighted needs of vehicle, also to realize miniaturization and.Therefore, the magnet for being used for portion's product such as above-mentioned motor requires it to have higher non-oxidizability and more remarkable magnetic characteristic.

Corresponding to the demand, though rare-earth sintered magnet as high-performance magnet is arranged, because cost is too high, dimensional accuracy is low, can not bring into play its potential outstanding magnet performance fully.In order to improve above-mentioned shortcoming, the rare earth anisotropic bond magnet that the RFeB based rare earth anisotropic magnetic iron powder of using aforesaid d-HDDR manufactured of having come on stage is successively in recent years made.Rare earth anisotropic bond magnet has reduced production cost, and has 160KJm ^-3The above maximum magnetic flux energy is long-pending, has presented good magnetic characteristic and dimensional accuracy, and beginning is used among the product such as household electrical appliance gradually.

Except that above-mentioned, in order to improve the thermal endurance of the RFeB based rare earth anisotropic magnetic iron powder that obtains owing to the d-HDDR manufactured, adopted in methods such as combination S mFeN fine-powders, made the ferromagnetic powder that obtains by the d-HDDR manufactured have fragmentation that is produced in the time of preventing to be shaped and the peculiar function of breaking.On this basis, succeeded in developing the compound rare-earth class anisotropic bond magnet that the magnet thermal endurance obtains tremendous raising.This compound rare-earth class anisotropic bond magnet can obtain 184KJm ^-3The above maximum magnetic flux energy is long-pending, has presented outstanding magnetic characteristic and thermal endurance height and remarkable dimensional accuracy.Now carry out above-mentioned compound rare-earth class anisotropic bond magnet and be applied to the big quantity research of automotive field.

Yet, with regard to the environment for use of automobile, under rigor condition, require portion's product such as its motor to have more reliable and more stable performance, therefore, for use therein magnet, not only require to have outstanding non-oxidizability, but also require remarkable magnetic characteristic.Particularly, require 0.8MAm for the ferromagnetic powder that is used in thin-walled ring-type binding magnet ^-1Above coercive force.In addition, also long-pending with regard to its maximum magnetic flux energy, require to reach 240kJm ^-3More than.

Before this, in order to reach above-mentioned required performance, considered following method.Promptly being, is the element La that interpolation has the resistance to oxidation characteristic in the alloy at the RFeB as raw material, and again according to d-HDDR manufactured RFeB based rare earth anisotropic magnetic iron powder, its result is though increased the non-oxidizability of magnetic, its coercive force 0.8MAm that descended ^-1Below, there is not actual usability.

Except that above-mentioned, before this, also considered adopting the d-HDDR method to manufacture the method for using diffusion La technology in the process of RFeB based rare earth anisotropic magnetic iron powder.But,, increased production cost owing to increased process number.And, in the use of said method, be diffused into surface, crystal grain interface and grain circle mutually, and it is relatively few to be diffused into the La of the magnetic phase of bearing magnetic characteristic the La relative priority.If use such ferromagnetic powder processing binding magnet that is shaped, the possibility that produces a spot of crackle is arranged when being shaped, in other words, have cause that non-oxidizability descends possibility.Particularly concerning the magnet that in the environmental condition of the very severe that existence such as petrolift, water pump are arranged, uses, require it to have higher non-oxidizability.

Summary of the invention

Inventor of the present invention, made full use of the resistance to oxidation characteristic of above-mentioned La, grasped because on the basis of the reduction characteristic that causes coercive force that La brought in research, proposed behind the high temperature hydrogenation process of d-HDDR method, have a mind to improve treatment temperature or pressure, thereby promote thoroughly carrying out fully of hydrogenation; By implement control deairing step, forced exhaust operation, when the antioxygenic property of La element to greatest extent brought into play, effectively suppress because the neodoxy that cause coercive force descend that La brought thereafter.The new invention that the present invention obtains with regard to being based on above-mentioned neodoxy.

Rare-earth anisotropic magnetic iron powder of the present invention has the characteristics of outstanding non-oxidizability and remarkable magnetic characteristic, is to make resulting by following operation.Promptly be,

To have (R _1-XLa _X) _12-14Fe _Bal.B _9-10(R does not contain lanthanum (La) and the rare earth element that contains yttrium (Y), X=0.05-0.08, Fe _BalBy specified form Fe and inevitably impurity formed) alloy (being designated hereinafter simply as RLaFeB) of ratio of components remain on the 1st processing pressure that the hydrogen dividing potential drop is 10～100kPa (below, abbreviate " P1 " as) and temperature be to implement the high temperature hydrogenation process handled in the ambient condition of 953～1133K the 1st treatment temperature (below, abbreviate " T1 " as);

RLaFeB after will handling through the high temperature hydrogenation process is an alloy, place the hydrogen dividing potential drop be 10kPa the 2nd processing pressure (below, abbreviate " P2 " as) and temperature be 1033～1213K the 2nd treatment temperature (below, abbreviate " T2 " as) ambient condition in, and under the condition that satisfies T2＞T1 or P2＞P1, handle organize the stabilisation operation;

To be alloy through organizing the RLaFeB after the stabilisation operation is handled, remain on the hydrogen dividing potential drop and be 0.1～10kPa the 3rd processing pressure (below, abbreviate " P3 " as) and temperature be the control deairing step of handling in the ambient condition of the 3rd treatment temperature (below, abbreviate " T3 " as) of 1033～1213K;

RLaFeB after handling through the control deairing step is the forced exhaust operation that hydrogen (H) removed surplus residual by alloy.

The rare-earth anisotropic magnetic iron powder that obtains by above-mentioned manufacture method manufacturing of the present invention, with the difference of the rare-earth anisotropic magnetic iron powder that contained La in the past be, though its form structure and the patent documentation 3 of passing by in the content clearly put down in writing the same, but because the complete difference of manufacturing process, the magnetic characteristic that obtains obviously is better than former anisotropic magnetic iron powder.The magnetic characteristic of the rare-earth anisotropic magnetic iron powder with same composition that patent documentation 3 is put down in writing, its maximum coercive force is 0.72MAm ^-1, the maximum magnetic flux energy is long-pending is 24KJm ^-3And rare-earth anisotropic magnetic iron powder of the present invention, its coercive force is at 0.8MAm ^-1More than, the maximum magnetic flux energy amasss at 240KJm ^-3More than, be diverse material obviously with aforesaid rare-earth anisotropic magnetic iron powder, presented unsurpassed magnet characteristic.And the manufacture method with regard to rare-earth anisotropic magnetic iron powder of the present invention is characterized in, compares with well-known d-HDDR method, newly is provided with between the two-step of high temperature hydrogenation process and control deairing step and organizes the stabilisation operation.Compare with high temperature hydrogenation treatment process, the maximum characteristics of this tissue stabilisation operation are to have increased to organize at least one side in the treatment temperature and hydrogen dividing potential drop in the stabilization processes operation.

Like this, behind the high temperature hydrogenation process, implemented at least one side in its treatment temperature and the hydrogen dividing potential drop and be higher than the high temperature hydrogenation process and organize the stabilisation operation, and controlled deairing step again and handle, just can obtain its non-oxidizability and magnetic characteristic all than outstanding in the past ferromagnetic powder.

Why can make with manufacture method of the present invention and to obtain having the above-mentioned anisotropic magnetic iron powder that goes out chromatic effect, its principle can be considered from following several aspects.

D-HDDR method is in the past said basically, and 4 following steps are arranged:

(a) in the low temperature hydrogenation process,, do not apply hydrogen pressure and make hydrogen produce solid solution fully in the temperature field below the homogenizing reaction in hydrogenation for the hydrogenation that makes following back to back operation (high temperature hydrogenation process) is not carried out to the homogenizing sluggish.

(b) secondly, in the high temperature hydrogenation process, in order to produce not homogenizing reaction of hydrogenation, on one side in the temperature that sets and set absorb under the pressure hydrogen carry out hydrogenation not homogenizing react.

(c) after this, in the control deairing step,, use the temperature same, under than the environment of higher setting pressure, carrying out not homogenizing reaction of above-mentioned hydrogenation lentamente in the dehydrogenation lentamente with the high temperature hydrogenation process in order to produce association reaction again.

(c) and, in the forced exhaust operation, finish processing in order to remove residual hydrogen, carry out three phase decompositions as far as possible lentamente, promptly make it combination more as far as possible lentamente.

The present inventor surpasses so far the manufacture method of the ferromagnetic powder of the outstanding magnetic characteristic of all ferromagnetic powders for this reason in order to develop its magnetic characteristic, the relation of above-mentioned various processing and tissue has been carried out research with keen determination, the d-HDDR method before having investigated again.

High temperature hydrogenation process in the past, since slowed down as much as possible hydrogenation not the homogenizing reaction carry out speed, make hydrogenation not homogenizing reaction can not get finishing fully, sediment is decomposed in 2-14-1 phase of remaining trace (R2Fe14B phase) and hydrogenation, thereby the characteristic that causes giving full play to magnetic characteristic can not get bringing into play fully.Hydrogenation not homogenizing reaction can not get fully thoroughly finishing, will cause again association reaction after, be difficult to obtain the crystal grain of homogeneous.Its result, ferromagnetic powder becomes mixed grain tissue, and its iHc is low, causes the reduction of the square property of magnetic bending, thereby has reduced (BH) max.

In general, chemical reaction is fast in the reaction speed of its initial reaction stage, and its speed will descend gradually afterwards.So if will not react the time that keeps long, its reaction will can not get finishing up hill and dale.Promptly be that when the approaching more end of reaction, its reaction speed is very slow.The simple retention time that increases the high temperature hydrogenation process, though make hydrogenation not the homogenizing reaction finished completely, heat treatment time is oversize, will produce tissue deterioration (for example, thickization of tissue etc.), its result has caused the decline of magnetic characteristic equally.

And, inventor of the present invention thinks, particularly having used the RFeB that contains La is that alloy is when carrying out the high temperature hydrogenation treatment, reaction progress between Nd and the H and the progress of the reaction between La and the H are different, with the alloy phase ratio that does not contain La, the passivation significantly of its reaction speed, thus make the magnetic characteristic be subjected to influencing significantly, produce deterioration.

Owing to contain the phenomenon of the reaction speed passivation that La brings, the present inventor has proposed increasing reaction speed in order to improve, can make hydrogenation not the homogenizing reaction can obtain thoroughly carrying out completely, be unlikely to cause the conception of thickization organized simultaneously again.Promptly be, in the ratio of reaction speed initial stage faster, make as far as possible hydrogenation not the homogenizing sluggish carry out, if continue like this, because reaction speed passivation (it is very slow that reaction speed becomes), finish reaction will need long time.For this reason, the present inventor has proposed the ending phase in reaction, tries every possible means to improve the not reaction speed conception of homogenizing reaction of hydrogenation.The present invention conception of having fact proved by after this is very effective to addressing the above problem.

Hydrogenation not homogenizing reaction is to react by control temperature and hydrogen dividing potential drop both sides' uniqueness.The present inventor makes full use of These characteristics, has studied by control temperature and hydrogen dividing potential drop, reaches the method that improves above-mentioned reaction speed.Promptly be, increase treatment temperature, can increase the not actuating force of homogenizing reaction of hydrogenation, thereby reaction is finished soon.On the other hand, increase the hydrogen dividing potential drop, also can obtain the effect the same, reaction is finished soon with increasing treatment temperature.

If conception according to the present invention as described hereinbefore in hydrogenation latter stage of homogenizing reaction not, increases in hydrogen pressure and the treatment temperature either party, quicken hydrogenation not finishing of homogenizing reaction be fully feasible.The present invention between high temperature hydrogenation process and control deairing step, organizes the stabilisation operation by newly appending to be provided with, and just can realize above-mentioned conception, thereby solve above-mentioned problem.

The simple declaration of drawing

Fig. 1 is the 1st process chart that each operation contents processing has been represented on simulation ground.

Fig. 2 is the 2nd process chart that each operation contents processing has been represented on simulation ground.

Fig. 3 is the 3rd process chart that each operation contents processing has been represented on simulation ground.

Fig. 4 is the 4th process chart that each operation contents processing has been represented on simulation ground.

Fig. 5 is the 5th process chart that each operation contents processing has been represented on simulation ground.

Fig. 6 is the 6th process chart that each operation contents processing has been represented on simulation ground.

Fig. 7 is the 7th process chart that each operation contents processing has been represented on simulation ground.

Best example of the present invention

(example)

Below, by example the present invention is specifically described.

(1) RLaFeB is an alloy

RLaFeB of the present invention is an alloy, is with (R _1-XLa _X) _12-14Fe _Bal.B _9-10Being ratio of components, is the alloy of main component with La (lanthanum) and the rare earth element (R) and B, the Fe that contain Y.At this, though R has removed La and the rare earth element that contains Y, but, R can be not limited only to a kind of element, can be the combination of plural kind rare earth element, also can be the material that its a part of element substitution is constituted for other elements.

La is the element that can embody feature of the present invention, has the chromatic effect that goes out that improves non-oxidizability.But, the anisotropic magnetic iron powder that the manufacture method manufacturing of above-mentioned fusion centre spinning, HDDR method and d-HDDR method etc. in the past obtains, because the existence of La, its magnetic characteristic has all presented the tendency that descends significantly.The present invention even wherein have La, also can guarantee the magnetic characteristic that it is high owing to proposed the anisotropic magnetic iron powder that the manufacture method manufacturing of combination hydrogen processing obtains, and also can give full play of outstanding non-oxidizability simultaneously.

Above-mentioned R can be made up of (Sc), yttrium (Y), a lanthanum bunch element.But, as the outstanding element of magnetic characteristic, above-mentioned R preferably contains the element more than at least a kind in Y, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) and the lutetium (Lu).Particularly from the viewpoint of cost and magnetic characteristic, above-mentioned R is preferably by Pr, and a kind of element among Nd and the Dy is above to be formed.

If (R _1-XLa _X) less than 12, will cause coercive force to descend; On the other hand, if (R _1-XLa _X) surpass 14, will make non magnetic increasing mutually and cause the decline of (BH) max.The ratio of components X of rare earth element R and La is preferably 0.05-0.08.If X is lower than 0.05, its non-oxidizability DeGrain; On the other hand, if surpassing 0.08, X will cause coercive force to descend.In addition, concerning B, if less than 9% will cause coercive force to descend; If surpass 10%, will make non magnetic increasing mutually and cause the decline of (BH) max.

Fe _BalExpression be to remove the above-mentioned special R that sets ratio of components, La, the Fe outside the B and by inevitable impurity institute component.

(2) RLaFeCoMnBT is an alloy

RLaFeCoMnBT of the present invention is that the ratio of components of alloy is (R _1-XLa _X) _12-14Fe _Bal.Co _0-3Mn _0-2(B _1-YT _Y) _9-10This alloy phase is an alloy for RLaFeB, has added Co, Mn, Al, Si, has obtained various additional effect.Co can improve stable on heating element, and addition is more favourable to improving thermal endurance, and but, Co is very expensive, from the reason of Financial cost, though good above 3%.

In addition, if (B _1-YT _Y) less than 9%, its coercive force will be very low; But,, will make non magnetic increasing mutually and cause the decline of (BH) max if surpass 10%.Said here T is made of Al and Si, and Y is the ratio of components of B and T, is recommended as Y=0-0.2 at this.From magnetic characteristic, Al, Si add by above-mentioned set amount, can obtain the action effect same with B.And Al, Si are the elements that can improve the d-HDDR Treatment Stability, can increase coercive force, still, if surpassed the above-mentioned amount that sets, will cause (BH) max to descend.Moreover the interpolation of Mn can improve Br, if but its addition surpasses 2%, and its effect will produce saturated phenomenon.

In this alloy, RLaFeCoBT is that alloy also contains inevitable impurity, and its composition keeps balance with Fe.

Because RLaFeB is alloy and RLaFeCoMnBT is that the main component of alloy is made of R, Fe and B, and in the following description, they are commonly referred to as RFeB is alloy.

As RFeB is alloy, can use the raw material of smelting piece and the manufacturing of cold-rolled steel modulus method that obtains with casting by various dissolution method (high frequency dissolution method, electric arc dissolution method etc.) dissolving.RFeB is that alloy is to have pulverized the powder of smelting piece and cold rolling etc., and the most handy d-HDDR carries out homogeneous to be handled.Above-mentioned said must the pulverizing can be carried out with methods such as general hydrogen pulverizing and mechanical crushing.

(3) d-HDDR handles

In the manufacture method of the present invention, the high temperature hydrogenation process, to organize 4 operations of stabilisation operation, control deairing step and forced exhaust operation be essential operation.But, these operation there is no need to carry out continuously.And,, be best for improving the productivity of producing in batches if having refrigerating work procedure behind low temperature hydrogenation process before the high temperature hydrogenation process and the control deairing step.Simultaneously, from the magnetic characteristic that improves the anisotropic magnetic iron powder and improve the hard magnet (binding magnet etc.) made with the anisotropic magnetic iron powder thus the viewpoint of purposes of expansion hard magnet such as thermal endurance, corrosion resistance, preferably implement heat diffusion treatment operation etc.Below, each operation is described.

(a) low temperature hydrogenation process

The low temperature hydrogenation process is before the high temperature hydrogenation process, is that alloy remains on the operation of handling in the hydrogen environment of (preferably 723K is following) below the temperature 873K with RFeB.By this operation, do not producing the not low temperature field of homogenizing reaction of hydrogenation, making RFeB is that alloy absorbs sufficient hydrogen, like this, in the high temperature hydrogenation process, can control the not reaction speed of homogenizing reaction of hydrogenation easily.But, be the hydrogen that alloy absorbs in advance for making RFeB, in a small amount of the processing, the high temperature hydrogenation process also can be taken into account enforcement.Therefore, manufacture method of the present invention, not the low temperature hydrogenation process as essential operation.Certainly,, improve the stability of the anisotropic magnetic iron powder of producing high magnetic characteristic in batches, the low temperature hydrogenation process preferably is set if consider that handling a large amount of RFeB is alloy.

Above-mentioned low temperature hydrogenation process, though under its temperature environment, do not produce not homogenizing reaction of hydrogenation,, can consider that following chemical reaction is the main generation that is reflected at this moment.

[chemical reaction 1]

R ₂Fe ₁₄B ₁→R ₂Fe ₁₄B ₁Hx

Promptly be, hydrogen only invades between the grid that RFeB is an alloy or the crystal grain interface, does not produce abnormal mutually in this operation basically.

Though the composition according to raw alloy has certain difference, in the ordinary course of things, in the temperature range of 873～1033K, will begin to produce not homogenizing reaction of hydrogenation.In this operation, surpass 873K, thereby cause the inhomogeneous of tissue making a raw alloy part produce tissue metamorphosis if temperature is set.This is the remarkable main reasons for decrease of magnetic characteristic that causes the anisotropic magnetic iron powder.Therefore, this operation with temperature be set in below the 873K, preferably below 723K.Say that further the optimum treatmenting temperature scope of this operation is room temperature～573K.Hydrogen pressure in the low temperature hydrogenation process (dividing potential drop) though do not have special requirement, in the scope of best 30～100kPa.Under the environment of the hydrogen pressure that 30kPa is above, will help to shorten RFeB is that alloy sucks the needed time of hydrogen, under the environment of 100kPa with interior hydrogen pressure, can obtain both economical suction hydrogen effect.In addition, processing environment is not limited to the environment of hydrogen, also can be hydrogen and inert gas mixed environment.At this, hydrogen dividing potential drop importantly, each following operation is too.

(b) high temperature hydrogenation process

The high temperature hydrogenation process is to be that to remain on hydrogen component be that 10～100kPa, temperature are the operation of handling under the environmental condition of the 1st treatment temperature (T1) of 953～1133K to alloy with RFeB.In this operation, the RFeB that has sucked hydrogen is that alloy structure will be carried out three phase decompositions (Fe phase, RH2 phase, Fe2B phase).At this moment, can consider mainly to have produced not homogenizing reaction of following hydrogenation.

[chemical reaction 2]

R ₂Fe ₁₄B ₁Hx→RH ₂+Fe(B)→RH ₂+Fe+Fe ₂B

Promptly be, at first, the RFeB that has sucked hydrogen is an alloy, is broken down into the hydride (RH of Fe and R ₂) become the tissue of thin slice stratiform.The Fe of this moment can think to be in the solid solution of the supersaturation ground state of B.And, make it only be partial to a direction to above-mentioned thin slice lamellar tissue, along the deflection of this thin slice lamellar tissue, oversaturated B will be with the Fe of regular crystal among the Fe ₂The form of B is separated out.

At this,, can not form the thin slice lamellar tissue that is partial to a direction, the Fe that separates out if above-mentioned reaction speed is too big ₂The orientation of B will be at random.Like this, thus will cause the anisotropy rate descend and cause the reduction of Br.Therefore, in order to obtain the anisotropic magnetic iron powder of high magnetic characteristic, should reduce above-mentioned reaction speed as far as possible.In order to carry out above-mentioned reaction lentamente, the upper limit of the hydrogen dividing potential drop in this operation is suppressed in the 100kPa.But the hydrogen dividing potential drop is too small, will cause above-mentioned reaction to carry out difficulty, and the result will cause the remaining of a large amount of not abnormal tissues, thereby causes the decline of coercive force.So, be defined as 10kPa under the hydrogen dividing potential drop.

In addition, the treatment temperature in this operation below 953K in, above-mentioned reaction can not be carried out; On the other hand, if treatment temperature surpasses 1133K, will be difficult to from supersaturation Fe, separate out Fe ₂B, simultaneously, reaction speed is too fast, is difficult to the above-mentioned thin slice of formation lamellar tissue, and its result causes the Br of ferromagnetic powder to reduce.Therefore, the 1st design temperature (T1) that this operation is set is 953～1133K, has guaranteed slowly carrying out unceasingly of above-mentioned reaction.About the detailed content of optimum response speed, patent documentation 5 that sees also aforementioned and the record content in the non-patent literature 1.

(c) tissue stabilisation operation

Organizing the stabilisation operation is to obtain finishing fully completely for accelerated reaction speed makes above-mentioned reaction latter stage at the high temperature hydrogenation process, guarantees the operation that three above-mentioned phase decompositions are achieved.For this reason, in organizing the stabilisation operation, selected treatment temperature (T2) and hydrogen dividing potential drop (P2) aptly, formed processing environment in high temperature hydrogenation process accelerated reaction in latter stage speed.Specifically, compare, as long as satisfy one of them the condition of T2＞T1 or P2＞P1 with treatment temperature (T1) and hydrogen dividing potential drop (P1) in the high temperature hydrogenation process.The purpose of organizing the stabilisation operation is not to make its P2 and T2 be higher than the P1 and the T1 of high temperature hydrogenation process, and real purpose is to improve the high temperature hydrogenation process reaction speed in latter stage.Therefore, as long as can improve reaction speed, can set T2＞T1 and P2＜P1; Also can set T2＜T1 and P2＞P1.For example, when P1 is 30kPa, can be set at 20kPa to P2, offset greater than T1, under the situation of fully big T2, also can fully reach the purpose of organizing the stabilisation operation because the influence of P2＜P1 can only make by rising T2.On the other hand, for example, when T1 is 1073K, can be set at 1048K to T2, offset greater than P1, under the situation of fully big P2, also can fully reach the purpose of organizing the stabilisation operation because the influence of T2＜T1 can only make by rising P2.

Certainly, in order successfully to realize from the high temperature hydrogenation process to the transition of organizing the stabilisation operation, thereby obtain the ferromagnetic powder of stay-in-grade high magnetic characteristic, the processing environment of organizing the stabilisation operation is T2＞T1 and P2 〉=P1, perhaps P2＞P1 and T2 〉=T1 preferably.Promptly being, is benchmark with the high temperature hydrogenation process, organizes at least one side of the treatment temperature and the hydrogen dividing potential drop of stabilisation operation, is higher than the high temperature hydrogenation process.Under this condition, can strengthen the not speed of homogenizing reaction of the hydrogenation that in the high temperature hydrogenation process, reduced gradually, promote not finishing of homogenizing reaction of hydrogenation.And remaining 2-14-1 is mutually and the hydrogenation hydrogenation decomposition of decomposing precipitate after also can acceleration high temperature hydrogenation process to organize processing in the stabilisation operation.

At this, though the passing in elapsed time, the hydrogenation decomposition also might be accomplished in the temperature-rise period and the process of boosting.But, in any case, organize the stabilisation operation preferably will remain to the hydrogenation decomposition and finished basically.

As mentioned above, organize the stabilisation operation, high temperature hydrogenation process with the previous processed operation in the remaining 2-14-1 that gets off mutually and the hydrogenation hydrogenation decomposition of decomposing precipitate proceed.From then on viewpoint is considered, P2 is set in more than the 10kPa with the hydrogen dividing potential drop, and treatment temperature T2 is set in the scope of 1033～1213K.

If the not enough 10kPa of hydrogen dividing potential drop, combination will begin again, and its result will cause magnetic characteristic to descend.On the other hand, be not particularly limited its upper limit for the hydrogen dividing potential drop.Should, higher P2, the easier effect that obtains organizing the stabilisation operation.But, consider the cost of handling stove and durability etc., from the situation of actual production, the P2 upper limit preferably is set at 200kPa.

Concerning treatment temperature, be set at 1033～1213K.Below 1033K, remaining 2-14-1 mutually and the hydrogenation hydrogenation decomposition of decomposing precipitate can not proceed, thereby cause the decline of magnetic characteristic.On the other hand, will being defined as 1213K on the treatment temperature, is that the phenomenon of the reduction of the magnetic characteristic that causes for the generation that prevents owing to tissue deterioration produces.

(d) control deairing step

The control deairing step is to be that alloy remains on the 3rd processing pressure (P3) that the hydrogen dividing potential drop is 0.1～10kPa through organizing the RFeB after the stabilisation operation, and temperature is the operation of handling in the environment of the 3rd treatment temperature (T3) in 1033～1213K scope.

This operation, the RH in three phase decompositions that in the past have been generated in the high temperature hydrogenation process of operation ₂In remove dehydrogenation, with Fe ₂B is nucleus, is combined into the R that crystal orientation has been unified again ₂Fe ₁₄B ₁At this moment, can consider mainly to have produced following association reaction again.

[chemical reaction 3]

RH ₂+Fe+Fe ₂B→R ₂Fe ₁₄B ₁Hx+H ₂

The same with reaction recited above, above-mentioned association reaction more preferably also is to carry out lentamente as much as possible.If reaction speed is too fast, as the Fe of nucleus ₂B produces on crystal orientation and rocks, and causes the R that combines again ₂Fe ₁₄B ₁The anisotropy rate step-down of phase, thus cause magnetic characteristic to descend.

For this reason, the 3rd processing pressure (P3) in this operation is set at 0.1～10kPa.If implemented the rapid exhaust of the not enough 0.1kPa of hydrogen dividing potential drop, owing to, be easy to generate the uneven phenomenon of reaction of recombination speed near the alloy material of exhaust outlet and different away from the exhaust velocity of the alloy material of exhaust outlet.Simultaneously, association reaction is the endothermic reaction again, and above-mentioned rapid exhaust can cause the non-uniform temperature of the each place of alloy material.These above-mentioned phenomenons all cause the magnetic characteristic of anisotropic magnetic iron powder to reduce.On the other hand, if the hydrogen dividing potential drop surpasses 10kPa, association reaction will can not get carrying out again, and the generation of contrary tissue metamorphosis is insufficient, can not get the anisotropic magnetic iron powder of high iHc.

In the time of treatment temperature in this operation is not enough 1033K, above-mentioned reaction will not carried out; On the other hand, if treatment temperature surpasses 1213K, also will can not get desired association reaction again, crystal grain can not get the anisotropic magnetic iron powder of high iHc with thickization at this moment.For this reason, this operation is carried out in order to make above-mentioned sluggish ground, and the 3rd treatment temperature (T3) that sets is in the temperature range of 1033～1213K.About the detailed content of optimum response speed, the relevant record content in the patent documentation 5 that sees also aforementioned and the non-patent literature 1.

(e) forced exhaust operation

The forced exhaust operation is to remove the operation that RFeB after the control deairing step is handled is hydrogen (remaining hydrogen) residual in the alloy (RFeBHx).At this moment, can consider it mainly is to have produced following reaction.

[chemical reaction 4]

R ₂Fe ₁₄B ₁Hx→R ₂Fe ₁₄B ₁+xH ₂

Though in this operation, do not specify its treatment temperature and vacuum degree etc., but, roughly the same or be lower than T3 slightly with above-mentioned T3.In addition, with regard to vacuum degree, preferably can accomplish the vacuum that 1Pa is following.Vacuum degree is bad, might remaining hydrogen, thus cause magnetic characteristic to descend.In addition, treatment temperature is too low, and exhaust will need long time; And on the other hand, treatment temperature is too high, will cause thickization of crystal grain.

Above-mentioned system deairing step there is no need to carry out continuously with above-mentioned control deairing step.Behind the above-mentioned control deairing step and before this operation carries out, can insert the refrigerating work procedure of cooled alloy material.By the refrigerating work procedure that is provided with, can the RFeB that behind the control deairing step, obtains be alloy migration in other equipment such as processing stove, very effective when carrying out like this that forced exhaust operation etc. is handled when producing in batches.In addition, according to fixed granularity when to pulverize RFeB be alloy etc., it is also very convenient that refrigerating work procedure is set.And if carry out heat diffusion treatment described later, if be provided with refrigerating work procedure, can make RFeB is alloy (R ₂Fe ₁₄B ₁Hx) and the mixing of diffusion material become very easy.Moreover heat diffusion treatment operation at this moment can be considered the forced exhaust operation that dual-purpose the present invention sets forth.That is, can think that the heat diffusion treatment operation is a kind of form of forced exhaust operation.

Refrigerating work procedure be not RFeB be the state of cooling of alloy as purpose, but only be for use handle convenient.So, there is no need to discuss chilling temperature, cooling means, cooler environment etc.Simultaneously, hydride has non-oxidizability, and can make RFeB under the state of room temperature is that alloy is in the atmospheric environment.Certainly, be alloy (R for the RFeB behind the refrigerating work procedure ₂Fe ₁₄B ₁Hx), preferably heat up to implement forced exhaust operation such as vacuum traction once more.

Moreover, if the RFeB behind the control deairing step is alloy (R ₂Fe ₁₄B ₁Hx) mix after the diffusion material in, when implementing the heat diffusion treatment operation again, the forced exhaust operation is included in the subsequent handling in the lump, can improve treatment effeciency.

(4) heat diffusion treatment

Though only implement the processing of above-mentioned d-HDDR, also can obtain having the anisotropic magnetic iron powder of fully high magnetic characteristic.But,, can also further improve the coercive force and the corrosion resistance of anisotropic magnetic iron powder if implement following heat diffusion treatment again.

Specifically, above-mentioned heat diffusion treatment comprises that the RFeB after handling through the control deairing step is alloy (R ₂Fe ₁₄B ₁Hx) RFeB after handling or through the forced exhaust operation be mix the diffusion material that is constituted by Dy etc. in the alloy (anisotropic magnetic iron powder) and make mixed-powder mixed processes and, heat this mixed-powder, making the mixed-powder RFeB that is diffused into of Dy etc. is the heat diffusion treatment operation of going in alloy surface and the inside.

(a) diffusion material

Diffusion material is made up of at least a above element in dysprosium (Dy), terbium (Tb), neodymium (Nd), praseodymium (Pr) and lanthanum (La) bunch element (below, abbreviate " R1 " as).That is, diffusion material contains monomer, alloy, the compound of Dy, Tb, Nd, Pr and La bunch element (R1) even comprises more than a kind of hydride (R1 material).Above-mentioned hydride can be the R1 monomer, also can be alloy even can be the hydride that compound constitutes.Furtherly, can use the mixture of above-mentioned each element.Though, can be regardless of the form of the diffusion material before the mixed processes,, from mixed processes, become the most at last Powdered, so that diffusion material is preferably is Powdered.Therefore, use pulverous diffusion material (diffusion powder) best as required, also can make it to be easy to evenly be diffused into R1RFeB is in the alloy.

The R1 material has comprised the transition elements more than a kind in 3d transition elements and the 4d transition elements (below, be called " TM ").In the heat diffusion treatment operation, with R1, it is alloy surface and inside that TM is diffused into RFeB equably.For this reason, can further improve the permanent magnetic ratio that reduces of coercive force and reduction.So-called 3d transition elements is meant the element of atom number 21 (Sc)～atom number 29 (Cu), and so-called 4d transition elements is meant the element of atom number 39 (Y)～atom number 47 (Ag).Particularly, the Fe of 8 families, Co, the Ni element is very effective for improving magnetic characteristic.In addition, the powder of the powder of diffusion material and R1 material, the monomer of TM, alloy, compound mixes them afterwards for preferably being ready to respectively in advance again.Moreover, in the compound described in this specification, comprised intermetallic compound.Simultaneously, in the hydride, also comprised the hydrogen that exists with solid solution condition.

Above-mentioned diffusion material has comprised dysprosium powder, dysprosium cobalt dust, dysprosium iron powder, dysprosium hydride powder, dysprosium cobalt hydride powder, dysprosium iron hydride powder or the like.Particularly, when R1 is Dy, can improve the coercive force of anisotropic magnetic iron powder.When TM is Co, can improve the Curie point of anisotropic magnetic iron powder.And,, can realize cost degradation if comprised Fe among the TM.

Particularly, when the average particle diameter of diffusion material is the diffusion powder of 0.1～500 μ m, be beneficial to very much the R1 diffusion.The average particle diameter is that the following diffusion powder of 0.1 μ m is made very difficult; On the other hand, if the average particle diameter greater than 500 μ m, diffusion powder and RFeB be the homogeneous of alloy mix will become very difficult.Generally speaking, spread preferably 1～50 μ m of powder average particle diameter.

Above-mentioned diffusion powder obtains methods such as the mechanical crushing of R1 material by hydrogen pulverizing or dry type, wet type (fine motion pulverizing, disk are pulverized, ball is pulverized, vibration is pulverized and injecting type pulverizing etc.).Concerning the R1 material, the efficient height that hydrogen is pulverized.From this viewpoint, use the hydride powder best as the diffusion powder.Say that further hydrogen carries out the mechanical crushing of dry type or wet type etc. after pulverizing again, its effect is better.

(b) RFeB before the heat diffusion treatment is an alloy

Concerning the RFeB that will mix diffusion material is alloy, use through the control deairing step handle the back or handle through the forced exhaust operation after the RFeB that obtains be that the efficient of alloy is higher, also be more satisfactory from the viewpoint of the magnetic characteristic that improves the anisotropy ferromagnetic powder.Using through the RFeB after the processing of control deairing step is alloy (R ₂Fe ₁₄B ₁Hx) time, can before the heat diffusion treatment operation, carry out the dehydrogenation treatment process, also can take into account the forced exhaust operation and implement the heat diffusion treatment operation.Promptly, above-mentioned mixed processes is that the RFeB that will obtain behind the above-mentioned control deairing step is the hydride powder of alloy and has comprised the diffusion powder that the hydride powder by R1 constitutes and mix the operation that obtains mixed-powder, and above-mentioned heat diffusion treatment operation also can be described as the operation of having taken into account the above-mentioned forced exhaust operation of removing remaining hydrogen from this mixed-powder.

For RFeB is the form of alloy, though there is not special requirement,, consider the factor such as Combination, diffusivity of diffusion material, its particle mean size is preferably in below the 200 μ m.

(c) mixed processes

Mixed processes is to be that alloy and diffusion material mix the operation that obtains mixed-powder with above-mentioned RFeB.In the mixed processes, can use flow-type mixer, rocking arm mixer, ball mill etc.For the processing stove that uses in the heat diffusion treatment operation, preferably subsidiary have the revolution that mixes function to handle stove, and perhaps stove is handled in the revolution distillation.In order to make RFeB is the even mixing of alloy and diffusion material, preferably each raw material is carried out suitable pulverizing and classification.Owing to carried out classification, than being easier to form binding magnet etc.Simultaneously, mixed processes is preferably in environment (for example, inert gas or the vacuum) state of preventing oxidation and carries out, and can suppress the oxidation of anisotropic magnetic iron powder like this.

For what of the diffusion material amount of mixing, all as 100 quality % the time, comparatively suitable with the ratio preparation diffusion material of 0.1～3.0 quality % mixed-powder.Suitably adjust the mixed proportion of diffusion material, can obtain to have given play to the high magnetic characteristic of characteristics such as good coercive force, residual magnetic flux density and square property, have the high-performance anisotropic ferromagnetic powder of outstanding permanent minimizing magnetic ratio again.

(d) dehydrogenation operation

The dehydrogenation operation is to remove the operation that remains in the hydrogen in the mixed-powder.At this,,, before the heat diffusion treatment operation, need to implement the dehydrogenation operation, or need take into account the dehydrogenation operation of heat diffusion treatment operation owing to contain hydrogen as long as RFeB is when having one to be hydride in alloy and the diffusion material.

If the RFeB before the forced exhaust operation handled is alloy a mixings diffusion material when having carried out heat diffusion treatment, this operation dual-purpose the forced exhaust operation content in the d-HDDR processing.If the RFeB after the forced exhaust operation handled is when mixing the diffusion material of being made up of hydride in the alloy and carry out heat diffusion treatment, before enforcement heat diffusion treatment operation, must implement the dehydrogenation operation of carrying out dehydrogenation.Dehydrogenation operation in this case is preferably in that 1Pa is following, carries out in the vacuum environment of 1023～1123K.At this pressure below desired 1Pa, be that hydrogen will be left behind because surpass 1Pa, thereby cause the coercive force of anisotropic magnetic iron powder to reduce.Temperature for 1023～1123K is set, if the not enough 1023K of temperature, the speed of removing of remaining hydrogen is very slow; If temperature surpasses 1123K, will cause thickization of crystal grain.

(e) heat diffusion treatment operation

The heat diffusion treatment operation is that the mixed-powder that will obtain behind the mixed processes heats, and making R1 as diffusion material be diffused into RFeB is operation in alloy surface and the inside.

R1 has the function that absorbs oxygen, can suppress the anisotropic magnetic iron powder and the oxidation of the hard magnet made with this anisotropic magnetic iron powder.For this reason, even under hot environment, use this magnet, can suppress effectively and prevent because the performance degradation that oxidation brings.Therefore, owing to improved the thermal endurance of ferromagnetic powder, enlarged its scope of application.

Above-mentioned heat diffusion treatment operation is to carry out under environment (for example, the vacuum environment) condition of anti-oxidation.Its treatment temperature is 673～1173K, and particularly, its treatment temperature that ideal is is in the temperature T of control deairing step below 3.In the time of treatment temperature deficiency 673K, the diffusion velocity of R1 and TM is too slow, and efficient is too poor; On the other hand, treatment temperature surpasses 1173K and T3, will cause thickization of crystal grain.Further say, adopt chilling, can prevent thickization of crystal grain effectively.

(4) other

The anisotropic magnetic iron powder that adopts manufacture method of the present invention to obtain can be made the sintered magnet and the binding magnet of required form.Particularly, its anisotropic magnet powder shape degree of freedom is big, does not need heat also can make required binding magnet.Above-mentioned binding magnet can be by adding thermosetting resin, thermoplastic resin or bond in the anisotropic magnetic iron powder, through after mixing, methods such as extrusion molding, extrusion molding, injection molding are made production in magnetic field.

Embodiment

Below, list specific embodiment and describe the present invention in detail.

(manufacturing of sample)

(1) the 1st embodiment

For the effect of confirming to handle about d-HDDR among the present invention, sample No.1～8 and the sample No.C1～C20 that are shown in the table 1 have been made respectively.The raw material that use this moment are made of 13 kinds of different tissues, and the RFeB that must contain the La composition is an alloy.In the table 2, represented their organizational composition.Unit in the table 2 is at%, and alloy all as 100at%.After this, the symbol a～m in the employing table 2 distinguishes and represents that the above-mentioned RFeB with different formations of address are alloy.For example, alloy a, alloy b or the like.

[table 1]

Sample No.	Be suitable for example	The alloy number	The high temperature hydrogenation process		Organize the stabilisation operation		The control deairing step		(BH)max (kJ/m3)	iHc (MA/m)	The permanent magnetic ratio that reduces	Remarks
													Treatment temperature T1 (K)	Hydrogen dividing potential drop P1 (kPa)	Treatment temperature T2 (K)	Hydrogen dividing potential drop P2 (kPa)	Design temperature T3 (K)	Hydrogen dividing potential drop P3 (kPa)
			1	Embodiment	a	1053	30	1113											30	1113	1	248	0.84	-3.50	The stabilisation operation (the low temperature hydrogenation process is arranged) of organizing of the present invention
2	Embodiment	b							1053	35	1113	35	1113	1	282	0.97	-2.80
			3	Embodiment	c	1053	35	1103										80	1113	1	272	0.96	-2.50
4	Embodiment	d							1053	30	1113	30	1113	1	264	1.06	-2.20
			5	Embodiment	e	1053	30	1113										30	1113	1	266	1.08	-2.20
6	Embodiment	b							1053	35	1133	20	1113	1	276	0.94	-3.00
			7	Embodiment	b	1113	35	1103										200	T1＝T2＝T3	1	270	0.94	-3.10
8	Embodiment	b							1053	35	1113	35	1113	1	256	0.98	-3.10							The stabilisation operation (no low temperature hydrogenation process) of organizing of the present invention
			C1	Comparative example	f	1053	35	1113										35	1113	1	144	0.56	-5.50		The stabilisation operation (the low temperature hydrogenation process is arranged) of organizing of the present invention
C2	Comparative example	g							1053	30	1113	30	1113	1	208	0.81	-4.00
			C3	Comparative example	h	1053	35	1113										35	1113	1	224	0.64	-4.50
C4	Comparative example	i							1053	30	1113	30	1113	1	216	0.64	-4.40
			C5	Comparative example	j	1053	35	1113										35	1113	1	192	0.80	-4.10
C6	Comparative example	k							1053	35	1113	35	1113	1	232	0.92	-3.80
			C7	Comparative example	l	1053	35	1113										35	1113	1	236	0.98	-2.90
C8	Comparative example	m							1053	30	1113	30	1113	1	224	0.64	-4.10
			C9	Comparative example	b	1053	35	-										-	T1＝T2＝T3	1	184	0.40	-3.90	Do not organize stabilisation operation d-HDDR in the past to handle (identical) with T1
C10	Comparative example	b							1113	35	-	-	T1＝T2＝T3	1	240	1.00	-5.30								Do not organize stabilisation operation d-HDDR in the past to handle (identical) with T3
			C11	Comparative example	b	933	35	1113										30	1113	1	14	0.04	And do not measure	T1 is lower than best design temperature scope
C12	Comparative example	b							1153	35	1193	30	1193	1	30	0.13	And do not measure								T1 is higher than best design temperature scope
			C13	Comparative example	b	993	35	1013										30	1013	1	7	0.02	And do not measure	T2, T3 all are lower than best design temperature scope
C14	Comparative example	b							1053	35	1233	30	1233	1	204	0.86	-0.90								T2, T3 all are higher than best design temperature scope
			C15	Comparative example	b	1113	35	1053										30	1053	1	71	0.18	And do not measure	T1＞T2, T3: outside best design temperature scope
C16	Comparative example	b							1053	35	1053	5	1053	1	79	0.23	And do not measure								P2 is lower than the best hydrogen dividing potential drop scope of setting
			C17	Comparative example	B	1053	35	1053										300	1053	1	198	0.91	-10.20	P2 is higher than the best hydrogen dividing potential drop scope of setting
C18	Comparative example	B							1053	35	1233	300	1233	1	165	0.88	-11.50								T2, T3 all are higher than best design temperature scope P2 and are higher than the best hydrogen dividing potential drop scope of setting
			C19	Comparative example	B	1053	35	-										-	1053→ 1113	1	229	0.58	-7.20	The control deairing step rose to 1113K with temperature in 5 minutes through after 5 minutes
C20	Comparative example	B							1053	35	-	-	1053→ 1113	1	228	0.51	-8.10								The control deairing step rose to 1113K with temperature in 5 minutes through after 15 minutes

* the maximum energy amasss at 100kJm ^-3In the time of following, because coercive force is at 0.5MAm ^-1Below, be worth too little not measurement.

[table 2]

The alloy number	Alloy composition (at%)
														Nd	La	Pr	Dy	Tb	Fe	Co	Mn	Al	Si	Ga	Nb	B
	a	12.5	0.8				Surplus																				9.2
b														12.4	0.8	0.3			Surplus	2	0.2	0.8				8.5
	c	12	0.8	0.7			Surplus	3	0.2	0.5	0.2																8.7
d														11.8	1	0.9	0.2		Surplus		0.5	0.8				8.5
	e	12.7	0.7			0.1	Surplus		0.5	1																	9.5
f														10.4	0.6				Surplus	2	0.5	0.7				8.5
	g	14.2	0.8				Surplus	1	2	1.5																	9.5
h														12.4	1.5				Surplus	2	0.2	0.6				8.5
	i	12.4	0.8	0.3			Surplus	1	0.5	1																	6
j														11.8	1				Surplus	1.5	0.5	1				12
	k	12.4	0.8	0.3			Surplus	2	2.5	1																	8.5
l														12.4	0.8	0.3			Surplus	2	0.2	3				8.5
	m	12.4	0.8	0.3			Surplus	1	0.2	1	3																8.5
n														12.4		0.3			Surplus	2	0.2	0.8				8.5

Above-mentioned alloy a～m obtains with following method manufacturing.All the raw material of buying from common market by required formation metering dissolves them with high frequency dissolution process stove, and casting becomes the piece of smelting of 100kg weight.In the environment of Ar gas, these alloys are smelted piece be heated to 1413K, and keep temperature to make its tissue homogenize (promptly implementing to homogenize heat treatment) in 40 hours.Adopting the fine motion comminuting method, will smelting the piece pulverizing through the alloy after the heat treatment that homogenizes is the following particle of average particle diameter 10mm, obtains the alloy a～m of different tissues respectively.

As shown in table 1 and table 2, various samples are to change the alloy species of its use and operation content to make respectively and obtain.The treating capacity of various samples is 12.5g.The alloy that various samples are used is put into and is handled stove, and under the environmental condition of room temperature * 100kPa * 1 hour, the low temperature hydrogenation process has been carried out in common enforcement.Then, implement 30 minutes high temperature hydrogenation process.Treatment temperature (T1) in this high temperature hydrogenation process and hydrogen dividing potential drop (P1) are indicated in the table 1 with separately sample respectively.

In addition, only the sample No.8 shown in the table 1 does not implement above-mentioned low temperature hydrogenation process, in deciding hydrogen pressure, from room temperature be warmed up to fixed temperature, directly implement the high temperature hydrogenation process.

And, be under the condition of 1kPa in the hydrogen dividing potential drop, implemented 90 minutes control deairing step.The treatment temperature (T3) of control in the deairing step is illustrated in the table 1 with separately sample respectively.But, sample No.C9, C10, the treatment temperature of its high temperature hydrogenation process and control deairing step is equal, i.e. T3=T1.At last,

With control deairing step identical treatment temperature, and the hydrogen dividing potential drop that keeps handling in the stove is under the following condition of 1Pa, implements 30 minutes forced exhaust operation.

Concerning sample No.1～8, between above-mentioned high temperature hydrogenation process and control deairing step, implemented the set stabilisation operation of organizing.In this tissue stabilisation operation, increased the side in treatment temperature and the hydrogen dividing potential drop at least.The operation simulation drawing of having represented above-mentioned each operation process among Fig. 1, Fig. 2 and Fig. 3 respectively.Moreover (T1 → T2) be 5 minutes, the retention time after this is 90 minutes to organize temperature-rise period in the stabilisation operation.

Concerning sample No.C9, C10, do not carry out the above-mentioned stabilisation operation of organizing, directly make it to have shifted the control deairing step from the high temperature hydrogenation process.Fig. 4 has represented the operation simulation drawing of this operation process.

To sample No.C11～C18, though, implemented the set above-mentioned stabilisation operation of organizing,, T1 in the high temperature hydrogenation process and organize T2, P2 in the stabilisation operation, and being set in outside the optimum range that the present invention recommends of the T3 in the control deairing step.

Concerning sample No.C19, do not implement the above-mentioned stabilisation operation of organizing, after the control deairing step began 5 minutes, the temperature that will handle in the stove with 5 minutes times was warmed up to T3 from T1.In addition, concerning sample No.C20, do not implement the above-mentioned stabilisation operation of organizing equally, after the control deairing step began 15 minutes, the temperature that will handle in the stove with 5 minutes times was warmed up to T3 from T1.Fig. 5 has represented the operation simulation drawing of above-mentioned each operation process.

(2) the 2nd embodiment

In order to confirm in above-mentioned d-HDDR handles, to append the effect of heat diffusion treatment, sample No.9～10 shown in the table 3 have been made.As the raw material of the diffusion material that uses this moment, prepared the rare earth alloy that the ratio of components by Dy-40at%Fe and Dy-40at%Co constitutes.

[table 3]

Sample No.	Be suitable for example	The alloy number	The high temperature hydrogenation process		Organize the stabilisation operation		The control deairing step		RFeB was the final operation of alloy before heat diffusion treatment was handled	Diffusion material			(BH)max (kJ/m3)	iHc (MA/m)	The permanent magnetic ratio that reduces
																Treatment temperature T1 (K)	Hydrogen dividing potential drop P1 (kPa)	Treatment temperature T2 (K)	Hydrogen dividing potential drop P2 (kPa)	Design temperature T3 (K)	Hydrogen dividing potential drop P3 (kPa)	The rare earth alloy name	Pulverulence	Powder weight (quality %)
			9	Embodiment	B	1053	35	1113		35	1113	1													The control deairing step	Dy-40％Fe	Hydride	1	264	1.12	-2.00
10	Embodiment	B							1083				35	1113	35	1113	1	The control deairing step	Dy-40％Co	Hydride	3	240	1.24	-1.80
			C21	Comparative example	B	1083	35	1113		35	1113	1													The control deairing step	Dy-30％La-4 0％Co	Hydride	4	168	1.12	-4.10

Making sample No.9～10 o'clock, at first, alloy b shown in the his-and-hers watches 2, use has been implemented aforesaid low temperature hydrogenation process, high temperature hydrogenation process, has been organized stabilisation operation and control deairing step, and the RFeB that obtains with the refrigerating work procedure cool to room temperature is the hydride powder (its average particle diameter is 100 μ m) of alloy.And, among the sample No.9, used the ferromagnetic powder that is implemented into the forced exhaust operation.Concrete treatment conditions are as shown in table 3.

As a comparative example, prepared not contain the alloy (alloy number n) of La.The composition of this alloy n is not except that containing the La, and other the alloy b with sample No.9,10 uses are the same.For alloy n, obtain sample No.C21 by the processing of the condition shown in the table 3.

Secondly, as diffusion material, used the hydride powder of rare earth alloy Dy-40%Fe and Dy-40%Co.

In sample No.C21 as a comparative example, used the hydride powder of Dy-30%La-40%Co.Though the average particle diameter of the hydride powder of above-mentioned these rare earth alloys is had nothing in common with each other, all in 5～30 μ m.

The mixed-powder (mixed-powder that obtains through mixed processes) that has mixed above-mentioned two powder is implemented the heat diffusion treatment operation, obtained through sample No.9～10 after the heat diffusion treatment, and the anisotropic magnetic iron powder of No.C21.This comparative example has been described, and for the alloy of the alloy that does not contain La, has implemented to have appended the d-HDDR of stabilization processes that organizes of the present invention and has handled, and adds the situation of La afterwards again according to heat diffusion treatment.

The final La amount of sample No.C21 is 1at%.Fig. 6,7 has represented the operation simulation drawing of operation process this moment.

Carry out above-mentioned each sample No.9～10 when making, under following condition, implemented d-HDDR and handled and heat diffusion treatment.The different condition of its each sample is illustrated in the table 4.Promptly be, RFeB is that the treating capacity of alloy is 12.5g, the low temperature hydrogenation process is room temperature * 100kPa * 1 hour, the high temperature hydrogen operation is 1053K * 35kPa * 30 minute, organizing the stabilisation operation is 1113K * 35kPa * intensification 5 minutes → kept 90 minutes, the control deairing step is 1113K * 1kPa * 90 minute, the forced exhaust operation be 1113K * 10Pa following * 30 minutes, dehydrogenation heat diffusion treatment operation be 1073K * 1Pa following * 1 hour.

(mensuration of sample)

At ambient temperature, the ferromagnetic powder of each sample that above-mentioned making is obtained has carried out the mensuration of magnetic characteristic ((BH) max, iHc and Br).Used VSM in the mensuration.Concerning as measuring with sample, at first, ferromagnetic powder is carried out classification in the particle size range of 75～106 μ m.Ferromagnetic powder after the classification, with paraffin be cured and shaping to make its demagnetization coefficient be 0.2.And, in the magnetic field of 1.5T, carry out orientation after, magnetize with 4.5T.At last, use VSM to measure its (BH) max, iHc and Br.

Among the present invention in order to obtain outstanding permanent minimizing magnetic ratio, to be fine-powder cooperate by weight 4: 1 ratio for the ferromagnetic powder of each sample and SmFeN, and add interfacial agent and mix after this in both, interpolation epoxy resin mixes under 100 ℃ of heating conditions and obtains mixture (mixed-powder).

Use said mixture, made and be used for the binding magnet that magnetic measurement is used.The shaping of binding magnet is to be under 150 ℃ of conditions at forming temperature, has implemented the orientation magnetic field (heating orientation operation) of 2.0MA/m, and, be to heat shaping (forming process) under the condition of 882MPa (9ton/cm2) in forming pressure.Like this, make the formed body of the cube shaped that has obtained 7 * 7 * 7mm.At this, the permanent definition that reduces the magnetic ratio is, the binding magnet that shaping is obtained remains in 120 ℃ and the atmospheric environment through the irreversible minimizing magnetic ratio at the initial stage after 1 hour and the ratio that remains in 120 ℃ and the atmospheric environment through the reduction amount of the irreversible minimizing magnetic ratio after 1000 hours.In addition, the MODEL FM-BIDSC that electronics magnetism Co., Ltd. makes has been used in the magnetic flux measurement of above-mentioned binding magnet.

(evaluation)

(1) handles about d-HDDR

Sample No.1～8 and sample No.C1～C10 are compared and can obviously find out, based on sample No.1 of the present invention～8, owing in as the rare earth alloy of raw material, added La by the amount that sets, and between high temperature hydrogenation process and control deairing step, implemented to organize the stabilisation operation, on the integral body of ferromagnetic powder, its coercive force reaches 0.8 (MAm ^-1) more than, the long-pending 240 (kJ/m that reach of the maximum magnetic flux energy ³) more than, embodied outstanding magnetic characteristic, simultaneously, because present embodiment is to have added SmFeN compoiste adhering magnet, it forever reduces the magnetic ratio is-2.2～-3.5%, has shown extraordinary non-oxidizability.

For example, by the anisotropic magnetic iron powder that alloy b forms, handle the sample No.2 that obtains owing to having implemented hydrogen of the present invention, its coercive force is 0.97 (MAm ^-1), the maximum energy long-pending ((BH) max) is 282 (kJ/m ³), forever to reduce the magnetic ratio be-2.8%, presented outstanding magnetic characteristic and non-oxidizability.

Compare with above-mentioned performance, sample No.C9,10 as a comparative example contains the same alloy b that forms with sample No.2 in the alloy composition of former technology (No. 4402770 communiques of United States Patent (USP)), but has only used well-known d-HDDR facture.Particularly, sample No.C9 has used the design temperature T1 of the high temperature hydrogenation process of sample No.2 to handle; Sample No.C10 has then used the design temperature T2 that organizes the stabilisation operation of sample No.2 to handle.With regard to sample No.C9, its coercive force is 0.40 (MAm ^-1), the maximum magnetic flux energy long-pending ((BH) max) is 184 (kJ/m ³) and forever to reduce the magnetic ratio be-3.9%; And to sample No.C10, coercive force is 1.00 (MAm ^-1), the maximum magnetic flux energy long-pending ((BH) max) is 240 (kJ/m ³) and forever reduce magnetic ratio-5.1%.Compare with the embodiment of the invention described above, above-mentioned sample No.C9,10 has all expressed inferior non-oxidizability and magnetic characteristic.

According to above-mentioned discussion result, proved that the LaRFeB that contains that proposes among the present invention is combining of handling of hydrogen that alloy and the present invention propose, have very obvious effects to improving non-oxidizability and magnetic characteristic.

In addition, sample No.C1～C8 as a comparative example, the ratio of components of its alloy are the samples that does not satisfy institute's recommendation scope among the present invention.Because these comparative examples, its composition does not get in the ideal range in institute of the present invention recommendation, its coercive force is that 0.8 (MAm-1) is above, the maximum magnetic flux energy amasss is more than 240 (kJ/m3), forever reduce the magnetic ratio for more than-5.0%, always has the performance more than 1 not satisfy requirement.

Moreover, sample No.C10～C20 as a comparative example, though between high temperature hydrogenation process and control deairing step, also be provided with and organize the stabilisation operation, departed from optimum temperature range set forth in the present invention and hydrogen dividing potential drop scope, equally also can not get desired magnetic characteristic.

In addition, concerning treatment temperature, sample No.C19, No.C20 compared with sample No.2 can understand and know,, also can not get desired magnetic characteristic in the control deairing step if the intensification of carrying out is inappropriate.

From investigating the result of sample No.3, can know clearly, improve the hydrogen dividing potential drop of organizing in the stabilisation operation (P2), can improve the magnetic characteristic of anisotropic magnetic iron powder.But, can know that according to present inventor's result of study P2 increases after the degree that reaches certain, the raising effect of magnetic characteristic is not clearly, promptly the raising effect of magnetic characteristic has presented saturated tendency.Therefore, when producing in batches, wait from the cost of handling stove and durability and to consider, organize the upper limit of the P2 of stabilisation operation preferably to be decided to be 200kPa.

Sample No.6 is to have adopted the condition of T2＞T1 and P2＜P1 also can obtain the embodiment of comparatively desirable effect.In the present embodiment, when P1 is 30kPa, P2 is set at 20kPa, by the influence that P2＜P1 brought, can remedy by temperature T 2 is risen to 1133K from the 1053K of T1, obtained being provided with the effect of organizing the stabilisation operation desired, promptly reached the intended purposes of organizing the stabilisation operation is set.

On the other hand, sample No.7 is to have adopted the condition of T2＜T1 and P2＞P1 also can obtain the embodiment of comparatively desirable effect.In the present embodiment, when T1 is 1113K, T2 is set at 1103K, by the influence that T2＜T1 brought, can remedy by P2 is risen to 200kPa from the 30kPa of P1, same H has also obtained being provided with the effect of organizing the stabilisation operation desired, has promptly reached the intended purposes of organizing the stabilisation operation is set.

Above-mentioned presentation of results, sample No.6,7 all can present good magnet.

Concerning sample No.8 and sample No.C9, the condition of both alloy compositions and high temperature hydrogenation process is all the same, only is the difference that has or not the low temperature hydrogenation process and organize the stabilisation operation.Can see from both comparisons,,, also can improve magnetic characteristic (BH) max and iHc as long as implemented to organize the stabilisation operation even do not apply the low temperature hydrogenation process.

(2) about heat diffusion treatment

Compare according to sample No.9～10 and sample No.1～8, we can say that implementing heat diffusion treatment universally can increase iHc.This is from improving the thermal endurance of magnet, is unusual the important point.

Concerning the sample C21 of comparative example, except not containing the La, remaining was the same with sample No.9, the 10 alloy b that use, and is to use hydrogen treatment process of the present invention during it was formed, and the method manufacturing by heat diffusion treatment interpolation La obtains again afterwards.This situation with from beginning to add DyCo and the sample No.10 that obtains compares originally with regard to diffusion the alloy that contains La, its magnetic characteristic and non-oxidizability are all comparatively inferior.Therefore, add DyCo even spread, also will resemble the present invention like this, under the alloy materials state, add La, implement to have comprised the d-HDDR processing of organizing the stabilisation operation of hydrogen processing method of the present invention after this, very outstanding anisotropic magnetic iron powder such as the magnetic property that obtains.

Claims (4)

1. the rare-earth anisotropic magnetic iron powder that has outstanding non-oxidizability and remarkable magnetic characteristic, this rare-earth anisotropic magnetic iron powder are constituted the manufacture method manufacturing by following operation to obtain:

To have (R _1-XLa _X) _12-14Fe _Bal.B _9-10The RLaFeB of ratio of components is that alloy remains on and implements the high temperature hydrogenation process handled in the ambient condition of the 1st treatment temperature T1 that the 1st processing pressure P1 that the hydrogen dividing potential drop is 10～100kPa and temperature be 953～1133K, wherein R does not contain lanthanum La and the rare earth element that contains yttrium Y, X is the ratio of components of rare earth element R and La, X=0.05-0.08, Fe _BalBy specified form Fe and inevitably impurity formed;

RLaFeB after will handling through the high temperature hydrogenation process is an alloy, placing the hydrogen dividing potential drop is the 2nd processing pressure P2 of 10kPa and the ambient condition of the 2nd treatment temperature T2 that temperature is 1033～1213K, and under the condition that satisfies T2＞T1 or P2＞P1, handle organize the stabilisation operation;

To be alloy through organizing the RLaFeB after the stabilisation operation is handled, remaining on the hydrogen dividing potential drop be the control deairing step of handling in the ambient condition of the 3rd processing pressure P3 of 0.1～10kPa and the 3rd treatment temperature T3 that temperature is 1033～1213K;

RLaFeB after handling through the control deairing step is the forced exhaust operation that hydrogen H removed surplus residual by alloy.

2. the rare-earth anisotropic magnetic iron powder that has outstanding non-oxidizability and remarkable magnetic characteristic, this rare-earth anisotropic magnetic iron powder are constituted the manufacture method manufacturing by following operation to obtain:

To have (R _1-XLa _X) _12-14Fe _Bal.Co _0-3Mn _0-2(B _1-YT _Y) _9-10The RLaFeCoMnBT of ratio of components is that alloy remains on and implements the high temperature hydrogenation process handled in the ambient condition of the 1st treatment temperature T1 that the 1st processing pressure P1 that the hydrogen dividing potential drop is 10～100kPa and temperature be 953～1133K, wherein R is the rare earth element that does not contain lanthanum La, X=0.05-0.08, Fe _BalBy specified form Fe and inevitably impurity formed, in addition, T is made up of Al and Si, the ratio of components of B and T is Y, Y=0-0.2;

RLaFeCoMnBT after will handling through the high temperature hydrogenation process is an alloy, placing the hydrogen dividing potential drop is the 2nd processing pressure P2 of 10kPa and the ambient condition of the 2nd treatment temperature T2 that temperature is 1033～1213K, and under the condition that satisfies T2＞T1 or P2＞P1, handle organize the stabilisation operation;

To be alloy through organizing the RLaFeCoMnBT after the stabilisation operation is handled, remaining on the hydrogen dividing potential drop be the control deairing step of handling in the ambient condition of the 3rd processing pressure P3 of 0.1～10kPa and the 3rd treatment temperature T3 that temperature is 1033～1213K;

RLaFeCoMnBT after handling through the control deairing step is the forced exhaust operation that hydrogen H removed surplus residual by alloy.

3. rare-earth anisotropic magnetic iron powder as claimed in claim 1 or 2, it is characterized in that, before above-mentioned high temperature hydrogenation process, also comprise with above-mentioned RLaFeB being that alloy or above-mentioned RLaFeCoMnBT are that to remain on temperature be to implement the hydrotreated operation of low temperature in the nitrogen atmosphere below the 873k to alloy.

4. rare-earth anisotropic magnetic iron powder as claimed in claim 1 or 2 is characterized in that, above-mentioned manufacture method also comprises:

With behind the above-mentioned control deairing step or the above-mentioned RLaFeB that obtains after the above-mentioned forced exhaust operation be that alloy or above-mentioned RLaFeCoMnBT mix at least the diffusion material of being made up of more than one elements R1 among dysprosium Dy, terbium Tb, neodymium Nd, the praseodymium Pr and the mixed processes that obtains mixed-powder in the alloy; With

Heat above-mentioned mixed-powder, making above-mentioned R1 be diffused into above-mentioned RLaFeB is alloy surface and inner diffusion heat treatments operation.

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