JPH0232761B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the improvement of permanent magnets, which are one of the extremely important electrical and electronic materials used in a wide range of fields, from various household electrical products to peripheral terminals of large computers, and in particular, the present invention relates to the improvement of permanent magnets, which are one of the extremely important electrical and electronic materials used in a wide range of fields, from various household electrical appliances to peripheral terminals of large computers. −
Regarding R-based permanent magnets. In recent years, with the demand for smaller size and higher efficiency of electrical and electronic equipment, permanent magnets are required to have even higher performance. Current typical permanent magnets are alnico, hard ferrite, and rare earth cobalt magnets. With the recent instability in the raw material situation for cobalt, the demand for alnico magnets containing 20 to 30% cobalt by weight has decreased, and cheap hard ferrite, whose main component is iron oxide, has become the mainstream magnet material. Summer.
On the other hand, rare earth cobalt magnets contain 50 to 65% cobalt by weight and are very expensive because they use Sm, which is not often found in rare earth ores, but they have much higher magnetic properties than other magnets. Therefore, it has come to be used mainly in small, high value-added magnetic circuits. Rare earth cobalt magnets are RCo ₅ , R ₂ Co ₁₇ (R is
It is a permanent magnet based on a binary compound represented by rare earth elements (mainly Sm and Ce).
A small amount of Cu, Fe, Zr, Ti, V, Hf
It has been attempted to improve the magnetic properties by substituting transition metal elements such as. On the other hand, recently, as a magnetic material that does not contain cobalt,
A magnetic material for a sputtered thin film or an ultra-quenched ribbon has been proposed which contains Fe and R (hereinafter in the present invention, R is used as a symbol indicating a rare earth element) as main components. For example, the magnetic properties of sputtered thin film amorphous TbFe ₂ , DyFe ₂ , and SmFe ₂ alloys have been reported by Clark (AEClark: Appl. Phys.
Lett.vol.23No.11 1 Decembr 1973 642〜644
page). In addition, as a magnetic material for ultra-quenched ribbons, PrFe-based alloys (JJCroat: Appl.Phys.
Lett.37(12), 15 December 1980 pp. 1096-1098)
Furthermore, according to Kuhn et al. (Fe _0.82 B _0.18 ) _0.9
Tb _0.05 La _0.05 alloy (NCKoon et al.: Appl.Phys.
Lett.39(10), 15 November 1981, pp. 840-842),
According to Kabakov et al. (Fe _0.8 B _0.2 ) _1-x Pr _x (x=0~0.3
Atomic ratio) alloy (L.Kabakoff et al.: J.Appl.Phy.53
(3), March 1982, pp. 2255-2257). Furthermore, Kloth reported that although light rare earth iron alloys have long been considered attractive candidates for low-cost permanent magnets, attempts to magnetically harden these alloys by powder metallurgy were unsuccessful. They also reported that they found that Pr-Fe and Nd-Fe alloys can be magnetically hardened by melt spinning (ultra-quenching) (JJCroat: J.
Appl.Phys.53(4), April 1982, p. 3161). In order for magnets using rare earth metals to be used inexpensively and in large quantities in a wide range of fields, it is necessary to use magnets that do not contain expensive cobalt and are rare earth metals.
It would be necessary to have light rare earth elements, which are contained in large amounts in ores, as the main component. On the other hand, as mentioned above, in order to make R-Fe or R-Fe-B alloy useful as a magnetic material, it is said that sputter thinning, ultra-quenching, or amorphous formation is essential. However, it has not been possible to obtain bulk practical permanent magnets having arbitrary shapes and dimensions from these sputtered thin films or ultra-quenched ribbons. The magnetization curves of the Fe-B-R ribbons reported so far have poor squareness and cannot be considered as practical permanent magnets that can compete with conventional magnets. Furthermore, both the sputtered thin film and the ultra-quenched ribbon are essentially isotropic, and it has been virtually impossible to obtain a practical permanent magnet with magnetic anisotropy from them. The basic purpose of the present invention is to provide a new practical permanent magnet that should meet such demands, and in particular does not necessarily require rare Sm etc. as R.
The purpose of the present invention is to provide a permanent magnet that does not require Co and has magnetic properties equivalent to or better than conventional ferrite magnets. In order to create such a permanent magnet, the present inventor first developed a method using specific rare earth elements, mainly Nd and Pr, and Fe.
We have developed a completely new type of practical, high-performance permanent magnet that is a magnetically anisotropic sintered body, in which B and B are essential in a specific ratio, and have been filed by the same applicant as the present application (Japanese Patent Application No. 57- 145072). This Fe-B-R ternary permanent magnet is based on a new compound different from the conventionally known RCo ₅ and R ₂ Co ₁₇ compounds, and is made by forming an appropriate microstructure using powder metallurgy. It is a sintered permanent magnet obtained by
is not added as a conventional amorphous promoting element when creating an amorphous alloy or a sintering promoting element in powder metallurgy, but constitutes the substantial content of this Fe-B-R permanent magnet. R-Fe, which is magnetically stable above room temperature and has a high magnetic anisotropy constant.
-B is an essential constituent element of the compound. This compound has a sufficiently high Curie point (approximately 300°C or higher) for practical use. This Fe-B-R ternary permanent magnet has Fe as its main component and exhibits an extremely high energy product of more than 30 MGOe, and has high characteristics at a lower cost than conventional alconi magnets and rare earth cobalt magnets. . That is, it provides higher cost performance, has arbitrary moldability, and can use resource-rich materials, and has great industrial utility. Holding force iHc ranges from 1kOe to a maximum of approximately 13kOe
It is so large that it rivals the iHc of rare earth cobalt magnets, which are currently known as the magnets with the highest characteristics. The present invention provides such Fe-B-R ternary permanent magnets including Ti, Ni, Bi, V, Nb, Ta, Cr,
By adding a predetermined percentage of one or more specific additive elements M selected from the group consisting of Mo, W, Mn, Al, Sb, Ge, Sn, Zr, and Hf, Similar to the Fe-B-R ternary permanent magnet according to No. 57-145072), the above object is achieved. That is, the permanent magnet of the present invention is as follows. First invention of the present application: In terms of atomic percentage, at least one of Nd, Pr, Dy, Ho, and Tb as a rare earth element (R) is 8 to 30%, B2 to 28%, and not more than the following specified % (excluding 0%). One or more types of additive elements M (however, when there are two or more types of additive elements M, the total amount of M is not more than the specified percentage of the maximum specified percentage of the added elements), and the remainder is substantially made of Fe. A permanent magnet characterized by being a magnetically anisotropic sintered body consisting of Ti4.5%, Ni8%, Bi5%, V9.5%, Nb12.5%, Ta10.5%, Cr8.5%, Mo9 .5%, W9.5%, Mn8%, Al9.5%, Sb2.5%, Ge7%, Sn3.5%, Zr5.5%, and Hf5.5%. Second invention of the present application: At least one of Nd, Pr, Dy, Ho, and Tb as a rare earth element (R) and La, Ce, Pm, Sm, Eu, Gd, Er,
A total of 8-30% of at least one of Tm, Yb, Lu, and Y, B2-28%, and a specified percentage or less (excluding 0%)
One or more types of additive elements M (however, when there are two or more types of additive elements M, the total amount of M is not more than the predetermined percentage of the maximum predetermined percentage of the additive elements),
and the remainder being a magnetically anisotropic sintered body consisting essentially of Fe (the predetermined percentage of the additive element M is the same as that in the first invention). The present inventor has developed an Fe-B-R ternary alloy, especially 8
Fe consisting of ~30% R, 2-28% B, balance Fe
-Based on the B-R ternary alloy, in order to achieve the above-mentioned purpose, most elements except radioactive elements are contained in trace amounts (0.005 atomic%, below %).
Changes in coercive force and other magnetic properties due to the addition of the additives were investigated in detail in the range from 10% to 10% (unless otherwise specified, atomic % is indicated). As a result, even with the addition of the additive element M, a high-performance permanent magnet that has excellent magnetic properties equivalent to or better than a hard ferrite magnet, similar to a Fe-B-R ternary permanent magnet, can be produced without the need for Sm, Co, etc. We have discovered that it is possible to provide this without Moreover, in a preferred embodiment, Fe-
It has been found that it has the effect of imparting a higher coercive force than a BR ternary permanent magnet. However, it has also become clear that the addition of these additive elements M causes a gradual decrease in the residual magnetization Br in each aspect compared to the Fe-BR ternary permanent magnet.
Therefore, the content of the additive element M is such that at least the residual magnetization Br is higher than the residual magnetization Br of conventional hard ferrite.
The objects of the present invention are those exhibiting a high coercive force in a range equal to or higher than that of . Thus, the present invention
By further containing a specific additive element M in the Fe-B-R ternary permanent magnet, Fe-B-R
The present invention provides a novel Fe-BRM permanent magnet based on a compound. According to the present invention, it is possible to provide a new practical permanent magnet that is extremely useful industrially and includes a high-performance magnet that has magnetic properties equivalent to or better than conventional hard ferrite magnets and can be substituted for Sm-Co magnets. The permanent magnet of the present invention is Fe-BRM-based,
It does not necessarily need to contain Co, and as a preferred embodiment, light rare earths mainly composed of Nd and Pr, which are abundant in resources, can be used as R, and Sm is not necessarily required or it is not necessary to mainly contain Sm. Since there are no carbonaceous substances, the raw materials are cheap and extremely useful. In recent years, permanent magnets have been exposed to increasingly harsh environments, such as strong demagnetizing fields due to thinner magnets, strong reverse magnetic fields applied by coils and other magnets, and increased speeds and higher loads of equipment. They are often exposed to high temperature environments, and in order to stabilize their characteristics in many applications, even higher coercive force is required (in general, the iHc of permanent magnets decreases as the temperature increases. iHc at room temperature
If is small, demagnetization will occur when the permanent magnet is exposed to high temperatures. However, if iHc at room temperature is high enough, such demagnetization will not occur substantially).
Therefore, the magnets of the present invention, including those having higher iHc than Fe-B-R ternary permanent magnets, are also suitable as permanent magnets used under such harsh environments. The rare earth element R used in the permanent magnet of the present invention includes Y, and is a rare earth element including light rare earths and heavy rare earths, among which one or more predetermined types are used.
That is, this R includes Nd, Pr, La, Ce, Tb,
Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb,
Lu and Y are included. As R, light rare earths mainly composed of Nd and Pr are preferable. Also, it is usually sufficient to have a specific type of R (Nd, Pr, Dy,
Ho, Tb), La, Ce, Pm, Sm, Eu, Gd,
Er, Tm, Yb, Lu, Y etc. are other R, especially Nd,
It can be used as a mixture with Pr, Dy, Ho, and Tb (one or more types). In practice, a mixture of two or more types (mitsumetal, dishim, etc.) can be used for reasons such as availability. Sm, La,
Er, Tm, Ce, Gd, and Y alone are not preferable because they have low iHc, and Eu, Pm, Yb, and Lu exist only in trace amounts and are expensive. Therefore, as described above, these rare earth elements can be used as a mixture with other R such as Nd and Pr. Note that this R does not have to be a pure rare earth element, and may contain impurities (other rare earth elements, other rare earth elements,
Any material containing Ca, Mg, Fe, Ti, C, O, etc.) may be used. As B (boron), pure boron or ferroboron can be used, and as impurities Al, Si,
Those containing C or the like can also be used. In the Fe-BRM permanent magnet of the present invention,
The composition range of R and B is basically the same as that of the Fe--B--R ternary permanent magnet (8 to 30% R, 2 to 28% B). That is, in order to satisfy the coercive force iHc≧1kOe, B
is 2% or more, and B is 28% or less in order to maintain the residual magnetic flux density Br of the hard ferrite to be approximately 4 kG or more. R is required to be 8% or more in order to have a coercive force of 1 kOe or more, and is set to 30% or less because it is easily flammable and difficult to handle and manufacture industrially (and is expensive). In this B and R range, the maximum energy product (BH) max is hard ferrite (~4MGOe
degree) will be the same or higher. Nd and Pr are the main components of R (i.e. at least 50% of Nd and Pr in all R), 11 to 24% R, 3 to 27
The composition of %B and the balance (Fe+M) is in a preferable range in order to make the maximum energy product (BH) max≧7MGOe. More preferably, Nd and Pr are the main components of R (same as above), 12 to 20% R, 4 to 24% B, and the balance (Fe
+M), and the maximum energy product (BH)
max≧10MGOe is possible, and (BH)max reaches a maximum of 35MGOe or more. The desired range of M for Br in order to obtain a predetermined maximum energy product is basically the range shown in Figures 1 to 3, where Br is approximately 4 kG or more in order to have a residual magnetic flux density equal to or higher than that of hard ferrite. It can be found by referring to Furthermore, by replacing a portion of Fe with Co, the Curie temperature Tc can be increased. Further, it is also possible to replace a part of B with C, P, Si, etc., and it is possible to improve manufacturability and reduce costs. In addition,
In addition to the above-mentioned Fe, B, R, and M, the permanent magnet of the present invention includes
The presence of industrially unavoidable impurities such as C, S, P, Ca, Mg, O, and Si can be tolerated. These impurities are often mixed in from raw materials or manufacturing processes, and the total amount is preferably 5% or less. The Fe-BRM permanent magnet of the present invention is Fe-
Like the BR permanent magnet, it is obtained as a magnetically anisotropic sintered body. For example, a permanent magnet can be obtained by melting an alloy, cooling it, for example casting it, pulverizing the resulting alloy, and then shaping and sintering it in a magnetic field. EXAMPLES The present invention will be described in detail below with reference to experimental examples and examples. Permanent magnet samples of Fe-BRM alloys containing various additive elements M ranging from trace amounts to over 10% were prepared by the following method. (1) The alloy is high-frequency melted and cast in a water-cooled copper mold The starting materials are electrolytic iron with a purity of 99.9% as Fe, B
Ferroboron alloy and boron with a purity of 99% are used as R, with a purity of 99.7% or more (impurities are mainly other rare earth elements), and as additive elements M, Ti, Mo, Bi, Mn with a purity of 99%,
Sb, Ni, Ta, 98% W, 99.9% Al, 95%
Hf, 99.9% Ge, Sn and also ferrovanadium with 81.2% V as V, 67.6% as Nb
Ferronniobium containing Nb, 61.9% as Cr
Ferrochrome containing Cr, and 75.5% as Zr
Ferrozirconium containing Zr was used (purity is shown in weight%); (2) Grinding Coarsely ground to 35 mesh through using a stamp mill, then finely ground to crystal particles that can be oriented in a magnetic field for 3 hours using a ball mill (3 ~10μ
m); (3) Orientation and forming in a magnetic field (10 kOe) (pressurized at 1.5 ton/cm ² ); (4) Sintering 1000-1200°C in Ar for 1 hour, then allowed to cool. The iHc, Br, and (BH)max of the above samples were measured, and the results for representative samples are shown in Table 1 ((1) to (4)). Comparative examples with samples of the present invention prepared in the same manner as above are shown in Table 2. Note that the code C in Table 2 indicates a comparative example. Further, although Fe in Tables 1 and 2 does not have a numerical value, it shows the remainder. From the above results, the following became clear.
Samples 1 to 36 and samples 48 to 50 in Table 1 mainly contain Nd, which is a typical light rare earth, as a rare earth element, Fe-8B-15Nd system (samples 1 to 26), Fe-
17B−15Nd system (samples 27 to 36) and Fe−12B−
The effect of the additive element M in the 20Nd system (samples 48 to 50) was investigated. As a result, the samples in Table 2
Compared to iHc7.3kOe of C1, all the above samples (No.
Nos. 1 to 36 and Nos. 48 to 50) showed higher coercive force, reaching a maximum of 15 kOe or more (Nos. 31 and 36).
On the other hand, the residual magnetization Br generally shows a gradual decrease as the additive element M increases from the same level (No. 1, 4, etc.) as compared to 12.1 kG of C1. However, the residual magnetization of any of the above-mentioned samples of the present invention is sufficiently higher than the level of conventional hard ferrite, which is about 4 kG. Samples 37 to 39, 41, 51, and 52 in Table 1 were used to investigate the effect of the additive element M in the Fe-B-Pr system using Pr, which is a light rare earth element, as the rare earth element. Samples 43, 44, 53 to 58, 63, and 64 in Table 1 use Nd as the rare earth element and two or more types of additive elements M.
Nos. 42 and 65 show cases in which Pr was used as the rare earth element and two or more types were used as the additive element M, and good results were obtained in both cases. Furthermore, samples 45 to 47 and 59 to 62 in Table 1 were used to investigate the effect of the additive element M when two or more rare earth elements were used. These Table 1 Samples 37 to 47 and Samples 51 to 65 are also Samples 1 to 1 in Table 1.
Similar to Sample No. 36 and Samples 48 to 50, it is possible to obtain good results using the additive element M. In addition, the iHc value of Comparative Examples C5 and C6 is 12.4,
The high 13.9kOe is due to the high content of Nd, and for these samples 48-50, 53-55
The effect of M addition is clear in Samples 63 and 64, respectively. Sample No. 56 has iHc4.3kOe, but comparative example C16
(iHc2.8kOe) and iHc7.30kOe of sample No. 59
When compared with C7 (iHc5.1kOe), the effect of M addition is recognized. Furthermore, as in Samples 1, 4, and 20, it is also possible to achieve a high coercive force while maintaining a high (BH) max.

【table】

【table】

【table】

【table】

[Table] The permanent magnet of the present invention is based on Fe-
In the B-R ternary system, the already mentioned 8 to 30% R, 2 to
The effectiveness of the additive element M has been recognized over the entire range of 28% B and the balance Fe (atomic percentage).
It is not effective outside each composition range of Fe-BR (see Comparative Examples C12, C13, and C17 have too little R; C14 has too much B; C15 has too much R; C8 to C11 do not contain B, etc.). Next, in order to clarify the effect of each addition of the additive element M, we conducted an experiment by changing the amount of addition of Br.
The results are shown in Figures 1 to 3 (corresponding to the Br data in Table 1). Bi, Mn,
Additive elements M excluding Ni (Ti, V, Nb, Ta, Cr,
As shown in FIGS. 1 to 3, the upper limit of the amount of Mo, W, Al, Sb, Ge, Sn, Zr, Hf) is determined to be equal to or higher than approximately 4 kG of Br of hard ferrite. That is, the upper limits of these additive elements are as follows. Ti4.5%, V9.5%, Nb12.5%, Ta10.5%, Cr8.5%, Mo9.5%, W9.5, Al9.5%, Sb2.5%, Ge7%, Sn3.5 %, Zr5.5%, and Hf5.5%. Maximum energy product (BH) in this range of M
The max is equal to or higher than that of hard ferrite (~4MGOe). Furthermore, the preferable range is 6 for Br,
It can be clearly read from FIGS. 1 to 3 by dividing it into stages such as 8 and 10 kG. Mn and Ni do not significantly reduce Br up to 10% or more (see Figure 2), but when added in large amounts,
Since iHc decreases, the upper limits of Mn and Ni are set at 8.8% each, taking into consideration the need to maintain Br as high as possible in order to obtain magnetic properties equivalent to or better than hard ferrite.
%. Also, the addition of small amounts of Mn and Ni has the effect of increasing coercive force like other M (first
(See Tables No. 16 to 19 and Comparative Example Table 2 No. C1),
If Mn exceeds 3.5% and Ni exceeds 4.5%, iHc becomes lower than that without additives, so the preferred range is below these. Regarding Bi, its vapor pressure is extremely high and Bi5%
It is virtually impossible to manufacture alloys exceeding 5%.
The following shall apply. In the case of an alloy containing two or more types of additive elements M, in order to satisfy the same or higher conditions as hard ferrite, the total amount must be below the maximum predetermined value (%) of the upper limits of the amounts of each element added above. It is necessary that there be. As is clear from Figures 1 to 3, the additive element M
As the amount of addition increases, Br decreases in most cases, and as shown in Table 1, (BH)max basically shows a tendency to decrease except in a certain range. However, an increase in coercive force iHc is an important characteristic for permanent magnets when exposed to extremely strong reverse magnetic fields or harsh high-temperature environments, and as with high (BH) max type permanent magnets, it is an important characteristic for permanent magnets. It is very useful. If two or more types of M are included,
It shows a Br curve that is almost the same as the one obtained by synthesizing the characteristic curves of each additive element. Note that the amount of M added is most preferably 0.1 to 3%, considering the effect of increasing iHc, the tendency to decrease Br, and the influence on (BH)max. Also, as for M, as is clear from Figures 1 to 3, V, Ta,
Nb, Cr, W, Mo, Mn, Ni, and Al do not significantly reduce Br even when added in relatively large amounts (for example, Br is 4kG or more even when added at 8%), and especially
V, Ta, Nb, Cr, W, Mo, Al except Mn and Ni
contributes to iHc improvement in a wide range of areas. Figure 4 shows typical examples (1) 77Fe−8B−15Nd, (2)
76Fe−8B−15Nd−1Nb, (3)75Fe−8B−15Nd−
Three types of initial magnetization curves and demagnetization curves 1 to 3 of 2Al are shown. Sample (1) (curve 1) is the same as Comparative Example C1 (Table 2), Sample (2) (curve 2) is the same as Example Sample No. 5, and Sample (3) (curve 3) is the same as Comparative Example C1 (Table 2). This was measured on the same sample as Example Sample No. 21. Both curves 2 and 3 show high squareness useful as a permanent magnet. As detailed above, the present invention provides novel Fe-B-
The present invention provides a practical permanent magnet made of an RM-based magnetic anisotropic sintered body, and achieves magnetic properties higher than conventional levels without necessarily using Sm as R or without necessarily requiring Co. In its embodiment, the present invention further provides a practical high-performance permanent magnet that has a high coercive force and a high energy product superior to conventional magnets, and as a preferred embodiment, it also realizes the highest energy product ever seen. be. In addition, since light rare earth elements such as Nd and Pr can be used as the core of R, it is a permanent magnet that is excellent in terms of resources, price, and magnetic properties, and has extremely high industrial applicability. . Also
When compared with Fe-BR-based magnets, the inclusion of the additive element M makes it possible to increase the coercive force, expanding the range of applications and increasing practical value.

[Brief explanation of drawings]

Figures 1 to 3 are (77-x)Fe-8B-15Nd
Figure 4 is a graph showing the relationship between the amount of added metal M (x%) and residual magnetization Br (kG) at −xM.
1Nb), No. 21 (75Fe-8B-15Nd-2Al), and sample No. C1 (77Fe-
8B−15Nd) (vertical axis is magnetization 4πI
(kG), and the horizontal axis represents the magnetic field H (kOe).

Claims (1)

[Claims] 1 Nd as a rare earth element (R) in atomic percentage;
At least one of Pr, Dy, Ho, Tb 8-30
%, B2~28%, below specified % (excluding 0%)
One or more types of additive elements M (however, when there are two or more types of additive elements M, the total amount of M is not more than the predetermined percentage of the maximum predetermined percentage of the additive elements),
A permanent magnet characterized by being a magnetically anisotropic sintered body consisting essentially of Fe and the remainder; Ti4.5%, Ni8%, Bi5%, V9.5%, Nb12.5%, Ta10.5% , Cr8.5%, Mo9.5%, W9.5%, Mn8%, Al9.5%, Sb2.5%, Ge7%, Sn3.5%, Zr5.5%, and Hf5.5%. 2 The rare earth element (R) 12 to 20 in atomic percentage
% (However, more than 50% of the rare earth elements (R) are Nd
2. The permanent magnet according to claim 1, wherein the permanent magnet comprises B4 to 24%, the additive element M at the predetermined percentage or less, and the remainder substantially Fe. 3 Nd as a rare earth element (R) in atomic percentage,
At least one of Pr, Dy, Ho, Tb and La,
Ce, Pm, Sm, Eu, Gd, Er, Tm, Yb, Lu,
A total of 8-30% of at least one type of Y, B2-
28%, below the specified percentage below (excluding 0%) of one or more types of additive elements M (however, when there are two or more types of additive elements M, the total amount of M is the maximum specified percentage of the added elements) A permanent magnet characterized by being a magnetically anisotropic sintered body consisting essentially of 4.5% Ti, 8% Ni, 5% Bi, 9.5% V, and 12% Nb. 5%, Ta10.5%, Cr8.5%, Mo9.5%, W9.5%, Mn8%, Al9.5%, Sb2.5%, Ge7%, Sn3.5%, Zr5.5%, and Hf5.5%. 4 The rare earth element (R) 12 to 20 in atomic percentage
% (However, more than 50% of the rare earth elements (R) are Nd
and Pr), 4 to 24% of B, the predetermined percentage or less of the additive element M, and the remainder substantially of Fe.