JPH0316764B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an alloy for permanent magnets mainly containing Fe and rare earth elements, particularly to an Fe-BR alloy for permanent magnets. Permanent magnet materials have been known as one of the ferromagnetic alloys. Permanent magnet materials are extremely important electrical and electrical components used in a wide range of fields, from various household appliances to peripheral terminals for large computers.
It is one of the electronic materials. In recent years, with the demand for smaller size and higher efficiency of electrical and electronic equipment, permanent magnet materials are required to have even higher performance. Current typical permanent magnet materials are alnico, hard ferrite, and rare earth cobalt-based magnet materials. With the recent instability in the raw material situation for cobalt, the demand for alnico magnet materials containing 20 to 30% by weight of cobalt has decreased, and inexpensive hard ferrite, whose main component is iron oxide, has become the mainstream magnet material. It became. On the other hand, rare earth cobalt magnet materials contain 50 to 65% by weight of cobalt and use Sm, which is not contained in rare earth ores, so they are very expensive, but they have better magnetic properties than other magnet materials. Because it is much more expensive, it has come to be used primarily in small, high-value-added magnetic circuits. In order for magnetic materials using rare earth elements to be used in large quantities and at low cost in a wide range of fields, it is necessary to
It is necessary that it does not contain expensive cobalt and that the main component is a light rare earth metal, which is contained in large amounts in ores. As one attempt at such a permanent magnet material, an RFe ₂ compound (where R is a symbol representing a rare earth element) was investigated. JJCroat has reported that an ultra-quenched ribbon of Pr _0.4 Fe _0.6 exhibits _a coercive force of Hc ₌ 2.8 kOe at 295K (JJCroat Appl.Phys.Lett.37(12)
15 December 1980, pp. 1096-1098). after that
Even in _the ultra-quenched ribbon _{of Nd 0.4 Fe 0.6} at 295K
It is reported that the coercive force is Hc = 7.45 kOe (JJCroat Appl. Phmys. Lett. 39 (4) 15
August 1981, pp. 357-358). However, all of these ultra-quenched ribbons have low (BH)max (less than 4 MGOe). Furthermore, _N.C. Kuhn et al.
We found that when _an ultra-quenched _amorphous amorphous ribbon _{of 82La0.18)0.9Tb0.05La0.05 is annealed at} 627 _℃ , Hc reaches as _high as _9kOe (Br=5kG). However, in this case, the (BH)max is low due to the poor squareness of the magnetization curve (NCKoon et al., Appl. Phys. Lett. 39 (10),
1981, pp. 840-842). Also, L. Kabacoff et al. (Fe ₀ . ₈ B ₀ .
₂ ) An ultra-quenched amorphous ribbon with a composition of _1-x Pr _x (x = 0 to 0.3 atomic ratio) was prepared, and the amorphous alloy was
It has been reported that it has an Hc of about 50e. (L.
Kabakoff et al.: J.Appl.Phys.53(3) March 1982,
(pp. 2255-2257). Most of the ultra-quenched ribbons listed above have light rare earths as their main components, but all of them have lower (BH)max than conventionally used permanent magnet materials, so they cannot be used as practical permanent magnet materials. It was difficult to do so. In addition, these ultra-quenched ribbons are not practical permanent magnets (body) that can be used in general speakers, motors, etc.
It has not been possible to obtain practical permanent magnets having arbitrary shapes and dimensions from these ribbons. The present invention provides a novel alloy for practical permanent magnets that has sufficiently high magnetic properties equivalent to or higher than hard ferrite to meet such demands, and is particularly useful as a magnetically anisotropic permanent magnet material. The basic purpose is to In particular, the purpose is to obtain a material mainly composed of Fe, which can effectively use resource-rich light rare earth elements as R. As such an alloy for permanent magnets, the present inventor first developed a ferromagnetic alloy that essentially requires specific rare earth elements, mainly Nd and Pr, and Fe and B in a specific ratio, particularly magnetic anisotropy. We have developed a completely new type of practical ferromagnetic alloy that has the ability to orient in a magnetic field, and filed an application by the same applicant as the present application (Japanese Patent Application No. 1983).
−145072). In this Fe-B-R ternary alloy, boron (B) is not added in the conventional way, for example, as an amorphous promoting element when creating an amorphous alloy or as a sintering promoting element in powder metallurgy. Without,
RFe-, which is magnetically stable above room temperature and has high magnetic anisotropy, is the base of the Fe-BR-R ternary alloy.
It is an essential constituent element of B ternary compound. This alloy has a sufficiently high Curie temperature (approximately 300℃ or higher) for practical use.
has. The above-mentioned Fe-B-R ternary ferromagnetic alloy does not necessarily need to contain Co, and as R, light rare earths mainly consisting of Nd and Pr, which are abundant in resources, can be used, and Sm is not necessarily required. Without or Sm
The raw materials are cheap because there is no need to use
Extremely useful. Moreover, the magnetic properties of the Fe-BR-based magnetically anisotropic sintered permanent magnet obtained using this ferromagnetic alloy are superior to those of hard ferrite magnets (coercive force iHc≧1kOe, residual magnetic flux density
Br≧4kG, maximum energy product (BH) max≧
4MGOe) In a particularly preferred composition range, it can exhibit an extremely high energy product equal to or higher than that of rare earth cobalt magnets. The coercive force iHc of magnetically anisotropic sintered permanent magnets made using this Fe-B-R alloy ranges from 1 kOe to a maximum of approximately
It reaches 13kOe, which is so large that it rivals the iHc of rare earth cobalt magnets, which are currently known as the magnets with the highest characteristics. However, in recent years, permanent magnets have been exposed to increasingly harsh environments - for example, strong demagnetizing fields due to thinner magnets, strong reverse magnetic fields applied by coils and other magnets, and in addition to the increasing speeds and high loads of equipment. In many applications, even higher coercive force is required to stabilize the characteristics (in general, the iHc of permanent magnets decreases as the temperature rises). Therefore, if iHc at room temperature is small, demagnetization will occur when a permanent magnet is exposed to high temperatures.However, if iHc at room temperature is sufficiently high, such demagnetization will not occur in practice). From this point of view, the same applicant as the present application is Fe-B-
We have developed an Fe-BRM-based alloy that can further improve the coercive force of permanent magnets using R-based alloys, and have filed a patent application (Japanese Patent Application No. 57-200204). Here, the additive elements M are Ti, Ni, Bi, V, Nb, Ta, Cr,
One or more of Mo, W, Mn, Al, Sb, Ge, Sn, Zr, and Hf. Under such circumstances, the present invention has made further experimental efforts to achieve the above-mentioned purpose with respect to these new alloys for permanent magnets developed by the present inventors. In addition, other minor elements X (one or more of Cu, P, C, and S)
A new alloy for permanent magnets that can achieve magnetic properties equivalent to or better than hard ferrite by limiting its content to a predetermined amount or less, and that can be manufactured using practical raw materials and manufacturing processes. The present invention has been completed based on the discovery that the following can be obtained. That is, the alloy for permanent magnets of the present invention is as follows. First invention of the present application: R in atomic percentage (R is Nd and
One or two kinds of Pr) 8 to 30%, B2 to 28%, one or two or more kinds of additive elements M below a predetermined percentage (excluding 0%) (additional elements M and their predetermined percentages are: Ti 4.5%, Ni 8%, Bi 5%, V 9.5%, Nb 12.5%, Ta 10.5%, Cr 8.5%, Mo 9.5%, W 9.5%, Mn 8%, Al 9.5%, Sb 2.5%, Ge 7%, Sn 3.5 %, Zr 5.5%, and Hf 5.5%), one or more types of minor elements 4.0%, and P 3.5%, and when the additive element M and the minor element X are two or more types, the total amount of M and X is the maximum predetermined percentage of M and An alloy for a permanent magnet, characterized in that the remainder essentially consists of Fe. Second invention of the present application: R (R is Nd,
At least one of Pr, Dy, Ho, Tb, La, Ce, Gd, Y, and 50% or more of R is one or two of Nd and Pr) 8 to 30%, B2 to 28%, below a specified % One or more of the additive elements M (excluding 0%) (the additive elements M and their specified percentages are Ti 4.5%, Ni 8%, Bi 5%, V 9.5%, Nb 12.5%, Ta 10.5%, Cr 8.5%, Mo 9.5%, W 9.5%, Mn 8%, Al 9.5%, Sb 2.5%, Ge 7%, Sn 3.5%, Zr 5.5%, and Hf 5.5%), below the specified percentage (excluding 0%) ) of one or more minor elements X (minor element An alloy for permanent magnets, characterized in that the total amount of M and X is at most a predetermined percentage of M and X, but not more than the predetermined percentage), and the remainder substantially consists of Fe. According to the present invention, there is provided a novel high-performance permanent magnet material that is extremely useful industrially and has magnetic properties equivalent to or better than conventional hard ferrite, and can be substituted for Sm-Co magnet materials. The alloy for permanent magnets of the present invention is Fe-B-R-M-
It is X-based and does not necessarily need to contain Co, and as R, light rare earths mainly consisting of Nd and Pr, which are abundant in resources, can be used, 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. or,
The above-mentioned predetermined content of X allows the use of raw materials with low purity and enables easy and inexpensive production, which is extremely advantageous industrially. As is clear from the examples, the alloy of the present invention has the ability to align in a magnetic field. The reasons for limiting the composition range of the alloy for permanent magnets of the present invention will be explained in detail with reference to examples below, but in particular, when the present invention is used most effectively, that is,
We selected a composition range that would provide magnetic properties equivalent to or better than hard ferrite when used as a magnetically anisotropic sintered permanent magnet. That is, the Fe of the present invention
-B-R-M-X permanent magnet alloy, R,
The composition range of B is basically the same as that of the Fe-B-R ternary alloy (8 to 30% R, 2 to 28% B). That is, as an anisotropic sintered magnet, B should be 2% or more to satisfy a coercive force iHc of 1 kOe or more, and 28 to make the residual magnetic flux density of hard ferrite Br about 4 kG or more
% or less. 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, it exhibits magnetic properties of coercive force iHc≧1kOe and residual magnetic flux density Br≧4kG, and the maximum energy product (BH) max is equivalent to or higher than that of hard ferrite (~4MGOe) and an anisotropic sintered magnet. can do. Nd and Pr are the main components of R (i.e. at least 50 at% of one or more of Nd and Pr in all R), and 11 to 24% R, 3
The composition of ~27% B and the balance (Fe+M+X) is in a preferable range in order to make the maximum energy product (BH) max≧7MGOe. Most 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 + A permanent magnet made using the alloy of the present invention exhibits good squareness, and as described above, within the preferred range, exhibits high magnetic properties comparable to rare earth cobalt magnets. The alloy for permanent magnets of the present invention is the base thereof.
In the Fe-B-R ternary system, the already mentioned 8 to 30% R,
The effectiveness of the additive element M and the small amount of the element X has been confirmed in the entire range of 2 to 28% B and the balance Fe (atomic percentage), and is not effective outside this Fe-B-R range. Moreover, the permanent magnet of the present invention is Fe-B-
Like the R ternary system, it generally exhibits a Curie point of around 300°C to 370°C, and is an alloy system with a novel crystal structure. The additive element M has the effect of increasing the iHc of the Fe-B-R ternary system. This trend is
As shown in Figures 1 to 3, it can be discussed separately from the effect of containing a small amount of element It is valid as is. Due to the inclusion of M, the Fe-B-R-M-X alloy of the present invention has
A magnetically anisotropic sintered permanent magnet having an even higher coercive force can be provided. Therefore, when exposed to extremely strong reverse magnetic fields and harsh environments with high temperatures,
It is extremely effective in stabilizing the magnetic properties of permanent magnets. The present inventor has developed an Fe-B-R ternary alloy, especially 8
Fe-B consisting of ~30% R, 2~28% B, and the balance Fe
- Based on the R ternary alloy, with the goal of improving its coercive force, most elements except radioactive elements are present in trace amounts (0.005 atomic%, below %).
Changes in coercive force and other magnetic properties caused by the addition of the compound were investigated in detail in a range from 10% to 10% (indicates atomic percent). As a result, it was found that the addition of the additive element M has the effect of imparting a higher coercive force than the Fe-B-R ternary alloy.
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. Therefore, the content of the additive element M is such that the residual magnetization Br is at least equal to or higher than the residual magnetization Br of conventional hard ferrite, and the content exhibits the effect of increasing the coercive force. Ru. Other elements other than Bi, Mn, and Ni among the additive elements M
Ti, Zr, Hf, V, Ta, Nb, Cr, W, Mo, Sb,
The upper limit of the amount of Sn, Ge, and Al added is set as a range equivalent to or higher than approximately 4kG of Br in hard ferrite.
Ti4.5% or less, Ni8.0% or less, Bi5% or less, V9.5%
Below, Nb 12.5% or less, Ta 10.5% or less, Cr 8.5% or less, Mo 9.5% or less, W 9.5% or less, Mn 6.0% or less,
Al9.5% or less, Sb2.5% or less, Ge7% or less, Sn3.5
% or less, Zr5.5% or less, and Hf5.5% or less. Incidentally, FIGS. 1 to 3 are graphs showing the influence of the additive element M on the residual magnetization Br for the Fe-BR basic system. The trends due to M addition shown in Figs. 1 to 3 are basically Fe-B-R-X
It is also valid for systems. As is clear from the Br characteristic curve, a preferable range can be set in stages such as Br6.5kG, 8kG, 10kG, etc. When Mn and Ni are added in large amounts, iHc decreases.
That is, in order to make iHc 1 kOe or more, the upper limits of Mn and Ni are each 8%. Mn of 3.5% or less and Ni of 4.5% or less do not lower iHc more than when no additive is added, so these are the upper limits of the preferable range. As for Bi, its vapor pressure is extremely high and it is virtually impossible to produce an alloy exceeding Bi5, so it should be kept at 5% or less. In the case of alloys containing two or more types of additive elements M, Br
In order to satisfy the condition of 4 kG or more, it is necessary that the amount of addition of each of the above-mentioned elements be equal to or less than the maximum value (%). Note that the Br characteristics in this case are obtained as a curve obtained by synthesizing the characteristic curves of each M shown in FIGS. 1 to 3 according to the component ratio of each component,
Its current value takes an intermediate value that is less than or equal to the maximum value of each of the contained components. This relationship is the relationship between the additive element M and the minor element X, M and/or
The same applies to relationships in which two or more types of each are included. As is clear from Figures 1 to 3, the additive metal M
As the amount of addition increases, Br decreases in most cases, and (BH)max also decreases as shown in Table 1. However, an increase in coercive force iHc is an important property for permanent magnet materials when subjected to extremely strong reverse magnetic fields or harsh environments at high temperatures, and is similar to high (BH) max type permanent magnet materials. It has great industrial utility. Minor elements X such as Cu, S, C, and P are industrially treated as Fe.
When manufacturing a -BRM alloy, it is often contained due to raw materials, manufacturing processes, etc. For example, when Fe-B is used as a raw material, S and P are often contained, and C is often contained as a residue of an organic binder (molding aid) in a powder metallurgy process. Further, as X, Cu is an inexpensive raw material iron with low purity, and some irons contain a large amount of Cu. As a result of the present invention, it has been found that the residual magnetic flux density Br tends to decrease as the content of the element X increases, as is clear from FIGS. 4 to 8. As a result, Cu3.5% or less in atomic percentage (the same applies hereafter unless otherwise specified), S2.0
% or less, C4.0% or less, P3.0% or less (and the total X is less than the value of the maximum value of each contained element), properties equivalent to or better than hard ferrite (Br about 4kG) can be obtained. Since both M and X show a decreasing tendency of Br, the total amount of M and X is determined in almost the same way as when two or more types of M or or less. The Br properties when two or more components, M and X, are contained generally appear as properties obtained by synthesizing the Br properties of the contained elements according to the component ratio of each element. Of the above-mentioned minor elements It is advantageous because the characteristics are secured. Although the inclusion of C slightly increases the sintering temperature, as mentioned above, it is advantageous in the manufacturing process because carbon from the organic binder commonly used in powder metallurgy does not have to completely disappear. . In this way, the predetermined content of the minor element X is
It is extremely advantageous industrially because it allows the use of low-purity raw materials and can be manufactured at low cost, and by controlling the small amount of element , a magnetically anisotropic sintered permanent magnet having a high energy product is provided with stable quality. In a preferred embodiment of the present invention,
The range of Br6.5kG or more is S1.3% or less, C3.3% or less, P2.3% or less, Cu2.7% or less, and S, C, P,
When the total amount of Cu is 3.3% or less (when X is two or more of S, C, P, and Cu), each of these can be obtained. Thus, the present invention provides a novel Fe-B-R-M based on the Fe-B-R compound by further containing a specific additive element M and a small amount of element X in the Fe-B-R ternary alloy. -X alloy for permanent magnets is provided. Like the Fe-B-R ternary alloy, the Fe-B-R-M-X alloy of the present invention exhibits a high anisotropic magnetic field and has the ability to orient in a magnetic field, so it is particularly suitable as a material for anisotropic magnets. Useful. That is, in particular, the present invention provides the aforementioned Fe-B-R ternary alloy with a sufficiently high coercive force for practical use due to the inclusion of the additive element M, and the inclusion of a small amount of the element X expands the range of raw material selection and facilitates manufacturing. The above limitations are relaxed, and the energy product (BH) is sufficiently high for practical use.
max, it is possible to realize a magnetically anisotropic sintered permanent magnet. In order to improve the temperature characteristics of the Fe-BRM-X permanent magnet alloy of the present invention, a part of Fe may be replaced with Co. The inclusion of Co has the effect of increasing the Kyrie point of the alloy. Using the Fe-B-R-M-X alloy of the present invention,
Practical permanent magnets can be manufactured in the same manner as the previously applied Fe-BR alloy. For example, by melting the alloy, cooling it, for example casting it, pulverizing the resulting alloy, and then shaping and sintering it to form an appropriate microstructure, it is possible to most effectively obtain a practical high-performance permanent magnet. Can be done. As for R, Nd and Pr are abundant resources compared to Sm, etc., and they are generally not used very often, so they are in surplus. It is extremely advantageous to use elements. R is Nd, Pr, La, Ce, Tb, Dy,
Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y are included, and among these, one or two of Nd and Pr are usually sufficient, but these Nd and Pr are
Other Dy, Ho, Tb, La, Ce,
At least one of Gd and Y can be used as a mixture. Note that heavy rare earths are rare and expensive resources, but as mentioned above, they can be used in combination with Nd and Pr. In practice, a mixture of two or more types (Mitsushimetal, didymium, etc.) can be used for reasons such as convenience of availability. Furthermore, this R
It does not have to be a pure rare earth element, and may contain impurities (other rare earth elements, Ca, Mg, Fe, Ti, C, O, etc.) that are unavoidable in production within an industrially available range. As described above, the present invention is extremely advantageous in that R that is industrially easily available can be mainly used. As B (boron), pure boron or ferroboron can be used, and as impurities Al, Si
It is also possible to use those containing the following. The above-mentioned Fe-BRM-X permanent magnet material can tolerate the presence of impurities that are unavoidable in industrial production in addition to the above-mentioned Fe, B, R, M, and X. Furthermore, it is also possible to partially replace B with N, Si, etc., thereby making it possible to improve manufacturability and reduce costs. EXAMPLES Experimental examples and examples of the present invention will be shown below, but the present invention is not limited thereto. Permanent magnet samples made of Fe-B-R-M-X alloys containing various additive elements were prepared in the following manner. (1) The alloy is melted by high frequency and cast in a water-cooled copper mold: The starting materials are Fe with a purity of 99.9% electrolytic iron, B with a ferroboron alloy and boron with a purity of 99%, R with a purity of 99.7% or more (no impurities Mainly using other rare earth metals), the additive elements M include Ti, Mo, Bi, Mn, Sb, and 99% pure Ti, Mo, Bi, Mn, Sb,
Ni, Ta, 98% W, 99.9% Al, 95% Hf,
99.9% Ge, Sn, ferrovanadium containing 81.2% V as V, ferronniobium containing 67.6% Nb as Nb, ferrochrome containing 61.9% Cr as Cr, and ferro containing 75.5% Zr as Zr. Zirconium was used. S with a purity of 99% or more as minor element X, 26.7%
Ferrorin containing P, C with a purity of 99% or more, and electrolytic Cu with a purity of 99.9% or more were used. (2) Coarsely pulverize to 35 mesh through using a crushing stamp mill, then finely pulverize into crystal particles that can be oriented in a magnetic field for 3 hours using a ball mill (3~
(10μm), (3) Orientation and forming in a magnetic field (10kOe) (pressure at 1.5t/cm ² ), (4) Sintering at 1000-1200℃ for 1 hour in Ar, 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 Tables 1 and 2. Also in Tables 1 and 2
Although the numerical value of Fe is not listed, it is the remainder, and * indicates a reference example. In addition, when the properties of the alloy (powder state) after pulverization were investigated in the process of creating this permanent magnet sample, it showed a high value of iHc1kOe or more.

【table】

[Table] From Tables 1 and 2, magnetically anisotropic sintered magnets made of Fe-B-R-M-X alloys have 4MGOe or more, which is equivalent to hard ferrite, over a wide composition range, and even
It can be seen that it has a high energy product of more than 10MGOe. This table mainly lists examples of alloys containing Nd and Pr, but the alloys of the present invention also exhibit good permanent magnet properties when used in combination with other predetermined R.
However, as mentioned above, rare earth ores contain relatively large amounts of Nd and Pr, and in particular, there are no known uses for Nd in large quantities, so it is unlikely that they can be used primarily. This is far more advantageous than permanent magnet materials that must be made mainly from other rare earth elements (Sm, Y, etc.). In addition, Fe−8B−15Nd−aM (X=
As a quaternary system of 0%), an experiment was conducted to examine the influence of the additive element M on the residual magnetic flux density Br with respect to the Fe-B-R ternary system base in the range of a=0 to 14% or less. The results are shown in Figures 1-3. Even if a predetermined amount of a small amount of element X is contained, there is no substantial effect, and this tendency remains valid. Additive elements M excluding Bi, Mn, and Ni (Ti, Zr, Hf,
V, Ta, Nb, Cr, W, Mo, Sb, Sn, Ge, Al)
The upper limit of the amount of addition is as shown in Figures 1 to 3,
Br of hard ferrite when made into an anisotropic sintered body
It is defined as a range equal to or greater than approximately 4kG. Furthermore, the preferable range is determined by dividing Br into stages of 6, 8, 10 kG, etc., as shown in Figures 1 to 3, respectively.
It can be clearly read from the figure. The amount of M added should be 0.1 to 3, considering the effect of increasing iHc, decreasing tendency of Br, and influence on (BH)max.
% is most desirable, and M is V, Nb, Ta, Mo, W, Cr,
Even if Al, Mn, and Ni are added in relatively large amounts, they do not significantly reduce Br (for example, even when added at 8%).
Br is 4kG or more), especially V, Ta, excluding Mn and Ni
Nb, Cr, W, Mo, and Al contribute to iHc improvement in a wide range. Furthermore, in the same way, we investigated the influence of the minor element ~ Shown in Figure 8. If the type and amount of M changes, it will differ slightly depending on the influence of each M shown in Figures 1 to 3, but basically the 4th
A similar tendency is shown in FIGS. (In addition, when two or more types of M are included, a Br curve that is almost the same as the one obtained by synthesizing the characteristic curves of each element is shown.) As is clear from Figures 4 to 8, Br increases as M increases. Although it decreases over time, C4%, P3.5%, S2.5%,
It can be seen that if Cu is 3.5% or less, properties greater than 4kG (corresponding to Br of hard ferrite) can be maintained. Further preferred ranges can be clearly read from Tables 1 and 2 and FIG. 1 by partitioning Br in steps of 7 kG. The alloy for permanent magnets of the present invention is the base thereof.
In the Fe-B-R ternary system, 8-30% R, 2-
It is recognized that in the entire range of 28% B and the balance Fe (atomic percentage), the additive element M in a predetermined percentage or less can contribute to increasing the coercive force, and the presence of a small amount of the element X in a predetermined percentage or less is allowed. As detailed above, the present invention provides novel Fe-B-
R-M-X ferromagnetic alloy, i.e. Fe-based and Co
It is an alloy for permanent magnets based on a Fe-B-R compound mainly composed of rare earth elements (Nd, Pr), which are abundant in resources and easy to obtain industrially. It is useful as an anisotropic permanent magnet material. By using this, it has become possible to provide Fe-B-R-M-X-based magnetically anisotropic sintered permanent magnets that have magnetic properties superior to hard ferrite and can be substituted for Sm-Co-based materials. in,
It is extremely valuable industrially. In particular, its advantages as a permanent magnet material are extremely significant when compared with conventional Sm-Co based materials in terms of its main constituent elements. In addition, even when compared with the Fe-B-R ternary alloy, the coercive force of the sintered magnet can be increased by including a specific additive element M, and the range of applications can be expanded. Furthermore, since it allows the use of raw materials with low purity and can be produced at low cost, it is extremely advantageous industrially and can also contribute to increasing practical value.

[Brief explanation of drawings]

Figures 1 to 3 are graphs showing the relationship between the content of the additive element M and the residual magnetic flux density Br, and Figures 4 to 8 are graphs showing the relationship between the content of the additive element M and the residual magnetic flux density Br.
Graphs showing the relationship between the content of the minor element X and the residual magnetic flux density Br are shown.

Claims (1)

[Claims] 1. R (R is one or two of Nd and Pr) 8 to 30%, B2 to 28%, and one or two of the additive elements M at a predetermined % or less (excluding 0%) in atomic percentage. (Additional elements M and their specified percentages are Ti 4.5%, Ni 8%, Bi 5%, V 9.5%, Nb 12.5%, Ta 10.5%, Cr 8.5%, Mo 9.5%, W 9.5%, Mn 8 %, Al 9.5%, Sb 2.5%, Ge 7%, Sn 3.5%, Zr 5.5%, and Hf 5.5%), one or more minor elements X (minor element X and its predetermined percentage are Cu 3.5%, S 2.5%, C 4.0%, and P 3.5%, and when the additive element M and the minor element X are two or more types, the total amount of M and . 2 R in atomic percentage (R is Nd, Pr, Dy, Ho,
At least one of Tb, La, Ce, Gd, Y,
and 50% or more of R is one or both of Nd and Pr)8
~30%, B2~28%, below the specified percentage (excluding 0%)
One or more of the additive elements M (the additive elements M and their specified percentages are Ti 4.5%, Ni 8%, Bi 5%, V 9.5%, Nb 12.5%, Ta 10.5%, Cr 8.5%, Mo 9.5 %, W 9.5%, Mn 8%, Al 9.5%, Sb 2.5%, Ge 7%, Sn 3.5%, Zr 5.5%, and Hf 5.5%), with minor amounts of element X below a specified percentage (excluding 0%). One or more types (minor element and X (the total amount of M and X is at most a predetermined percentage but not more than the predetermined percentage), and the remainder substantially consists of Fe.