JPH02259039A - Rare earth magnetic alloy - Google Patents

Abstract

PURPOSE:To obtain the rare earth magnetic alloy having excellent coercive force and maximum energy product at a low cost by specifying the compsn. constituted of Sm, Pr, Y, Fe, Cu, Zr, Hf, Mn, Ti, B and Co. CONSTITUTION:The rare earth magnetic alloy contains, by weight, 8 to 20% Sm, 6 to 20% Pr and/or Y, 10 to 25% Fe, 5 to 10% Cu, 1 to 4% Zr and/or Rf, 0.1 to 1% Mn, 0.1 to 1% Ti and 0.003 to 0.015% B, furthermore contains, at need, <=5% of one or more kinds among rare earth metals R excluding Sm, Pr and Y and the balance Co and in which 22 to 28% Sm+Pr+Y or Sm+ Pr+Y+R is regulated. The alloy can be obtd. by executing refining, solidifying and pulverizing and subjecting the obtd. powder to magnetic press forming and sintering. In the above magnetic alloy, expensive Sm is substituted by other inexpensive rare earth metals to reduce its cost and it furthermore has excellent magnetic characteristics of about >=10KOe coercive force, about >=10.5KG residual magnetic flux density and about 28MGOe maximum energy product.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to permanent magnet alloy materials, particularly Sm-Co-Fe-Cu-Z, which belongs to the 2-17 type magnet among rare earth magnet alloys.
This invention relates to an r-based multi-component rare earth magnet alloy.

[Prior Art] Permanent magnets are widely used in various devices such as rotating equipment, communication, measurement, and audio equipment.
) max is large, and the magnetism is preferably maintained stably. In particular, the maximum magnetic energy product (B
H) Since a predetermined magnetic field can be obtained in a small volume by using a magnet with a large wax content, it is possible to reduce the size and weight of applied equipment.

Permanent magnet materials began with KS steel. Alnico magnets and ferrite magnets were used for a long time, but later research on rare earth magnets was carried out, and with the development of SmCo5 sintered magnets,
The maximum energy product of the magnet has been dramatically improved. 5LII
C05 is called a 1-5 type magnet, and is an intermetallic compound that appears in the Sm-Co binary system, with a BS value of 9.5 KG and a maximum energy product of ~20 MGOe.

After that, efforts were made to develop magnets with better magnetic properties than S+aCos, and a rare earth magnet using a compound of 5L112Co17, which is richer in Co than SmCo5 and has a high Bs value of 1.28 KG, appeared. This type of thing is 2-
Collectively called 17 type magnets, Sm(Co, Fe, Cu)s,
s and S m(Co, Fe, Cu, Z r)t
, < two types of rare earth magnets, 30 M G Oe
High degree maximum energy product (B H) max, 10K
It has a coercive force iHc of Oe or more.

[Problems to be Solved by the Invention] However, the rare earth metal Sm is expensive and is in short supply as a resource, making it difficult to procure it.

Therefore, in order to obtain an inexpensive magnet, a rare earth magnet has been proposed in which part of the conventional 5L11 is replaced with resource-rich Nd, Ce, and Pr. This product has a maximum energy product of about 24 M G Oe and a coercive force bHc of 7°6 KOe.
(about iHc9KOe) (Unexamined Japanese Patent Publication No. 62-24
3731), the 5in-Co-FeCu-Z
Both the maximum energy product and coercive force are lower than R alloy.

Furthermore, for the same reason, a rare earth magnet in which part of 5Lll is replaced with Ce and Zr and B are added has also been proposed. This material has a maximum energy product of about 24 MGOe and a coercive force iHc of about 13 KOe (Japanese Unexamined Patent Publication No. 63-28844), but has not yet been produced and sold. and,
The only commercially available 5LII-Ce-based magnets are those with a maximum energy product of about 22 M G Oe and a coercive force of about 1 Hc9KOe.
- Maximum energy product compared to Fe-Cu-Zr alloys,
Both coercive force is low.

This is expected to be due to manufacturing difficulties such as sintering characteristics. Therefore, it has been desired that rare earth magnet alloys be inexpensive and have both a large coercive force and a large maximum energy product.

However, expensive Sm can be replaced by resource-rich Nd and Pr.
, Y, Ce, etc., in order to obtain an inexpensive rare earth magnet alloy, as shown in the above publication, it is necessary to manufacture only one with a maximum energy product of about 24 M G Oe and a coercive force iHc of about 9 KOe. I can't.

The present invention was made in view of the above-mentioned problems with conventional rare earth magnet alloys, and by replacing expensive 5L11 with other inexpensive rare earth metals, it is possible to achieve an inexpensive magnet with excellent coercive force and maximum energy product. The purpose is to provide rare earth magnet alloys.

[Means for Solving the Problems] The present invention not only replaces a part of 5L11 with Pr and Y, but also combines the addition of other additives, and furthermore replaces a part of 5L11 with Pr and Y.
This was the result of intensive research into the structure of o-Fe-Cu-Zr rare earth magnet alloys.

That is, the theoretical upper limit value of the maximum energy product in a magnetic alloy is expressed as (4πl5)2/4.

(Here, 4πIs2 is the saturation magnetic flux density.) Figure 1 shows various rare earth cobalt compounds R2Co17, RCos,
S trnaL results showing the saturation magnetic flux density of R2Co7 (R is a rare earth element) at room temperature (Proel 9
72 I NTER, MAG Conf, Kyo
to, Japan (1972) April, P511). Moreover, FIG. 2 shows S mxc e+-x(CoO,
? 2SF e,,2. Cuo,ossZre,. 2)7
This shows the changes in Br (residual magnetic flux density), 1Hc (coercive force), and maximum energy product (B H) wax when the value of X is changed in the -5 rare earth magnet alloy (source;
Journal of the Japanese Society of Applied Magnetics, Vol. 9, N051.1985
> is. From these figures 1 and 2, Ce 2 C
ol? Since the compound has a lower saturation magnetic flux density than the 5I112Co17 compound, a rare earth magnet alloy in which 5LIl is replaced with Ce inevitably has a lower maximum energy product.

On the other hand, when S16 is replaced with Pr and Y, Pr2C.

Since the 7 compound and the Y2Co17 compound have higher saturation magnetization than the 2Co compound for S (see Figure 1), the saturation magnetic flux density of the alloy increases, and an improvement in the maximum energy product can be expected. However, in the above-mentioned prior art, a large maximum energy product cannot be obtained because the coercive force suddenly decreases (see FIG. 3) and the squareness of the demagnetization curve decreases.

The above figure 3 shows Sm, -xPrx(Coo, 672Cuo
, osF eo, 22Z ro-028) shows the change in coercive force when the X value is changed for a rare earth alloy of 8.35 (Journal of the Japan Society of Applied Magnetics, Vol.

11, No. 2.1987).

Based on this knowledge, the present invention focused on rare earth magnet alloys in which part of Sm was replaced with Pr and Y, and as a result,
The present invention was achieved by making a composite addition of M n -T i -B and by adjusting Pr and Y of each component in the alloy, namely Fe, Cu, Zr, and SI, to a specific range. be.

The rare earth magnet alloy of the first invention of the present application has a weight ratio of Sm;
~20%, one or two selected from Pr and Y;
6-20%, Fe; 10-25%, Cu; 5-. 10%
, one or two of Zr and Hf; 1 to 4%, Mn;
0.1-1%, Ti; 0.1-1%, B; o, o 0
3 to 0.015%, the balance being Co, and Sm+Pr
The gist is that 10Y is in the range of 22 to 28%.

Moreover, the rare earth magnet alloy of the second invention has a weight ratio of SIA;
8 to 20%, one or two selected from Pr and Y; 6 to 20%, Fe; 10 to 25%, Cu; 5 to 10%
, one or two of Zr and Hf; 1 to 4%, M n
; 0, 1-1%, Ti; 0.1-1%, B; o,
o O3 ~ 0.015%, the balance is Co, and a lot of Si
The gist is that it contains 5% or less of one or more rare earth metals R excluding n, Pr, and Y, and that Sm+PrfY+R is in the range of 22 to 28%.

Next, the reason for limiting the components in the rare earth magnet alloy of the above invention will be explained.

Sm; 8 to 20% S + o, together with Pr and Y, forms the main component of the rare earth magnet alloy of the present invention and is a component that influences the characteristics of maximum energy product and coercive force, but if it is less than 8%, there is insufficient maximum energy. Product and coercive force cannot be obtained. On the other hand, if it exceeds 20%, the cost will be high and there will be no resource advantage.

Pr, Y 6 to 20% Pr and Y are substituted with S m to reduce the cost of rare earth magnet alloys and have resource benefits, but if they are less than 6%, the above effects cannot be sufficiently obtained. on the other hand.

If these elements are added in excess of 20%, the maximum energy product and coercive force will drop sharply, so the upper limit should be set at 20%.
%.

Fe・10-25% If the Fe content is less than 10%, sufficient residual magnetic flux density and maximum energy product cannot be obtained, so the lower limit is set to 10%. Further, if the Fe content exceeds 25%, sufficient coercive force cannot be obtained, so the upper limit was set to 25%.

Cu; 5 to 10% If Cu is less than 5%, sufficient coercive force cannot be obtained, so the lower limit was set to 5%. On the other hand, if the amount of Cu added exceeds 10%, the residual magnetic flux density and the maximum energy product will decrease.
The upper limit was set at 10%.

Zr, Hf: 1 to 4% If the amount of Zr or Hf added is less than 1%, sufficient coercive force cannot be obtained, so 1% or more was added. However, if the content exceeds 4%, both the residual magnetic flux density and the maximum energy product decrease, so the upper limit was set at 4%.

Mn: 0.1 to 1% Mn exhibits the effect of improving the uniformity of the structure during solution treatment of rare earth magnet alloys. As a result, a sufficient amount of Zr,
Hf and Ti can be dissolved in solid solution in the base. Further, Mn exhibits its additive effect only when added in combination with Ti and B, and its contribution to the magnetic properties when added alone is extremely small. However, 0.1%
If less than 1% is added, the effect of improving the magnetic properties is not sufficient, so the lower limit is set to 0.1%, and if it exceeds 1%, the maximum energy product decreases, so the upper limit is set to 1%.

Ti; 0.1 to 1% Ti is thought to increase the precipitation of the (Sin, Pr, Y)2(Co, Fe, Cu) phase (hereinafter referred to as the 2-7 phase) and contribute to improving the coercive force. It will be done. However, when used alone, the squareness of the demagnetization curve is poor and the maximum energy product decreases. Therefore, if it is less than 0.1%, the effect of improving magnetic properties will be small, while if it exceeds 1%, the maximum energy product will decrease.

B, 0.003-0.015% These elements prevent the coarse 27 phases from precipitating unevenly at grain boundaries and sub-grain boundaries, and uniformly precipitate the fine 2-7 phases throughout the structure. let Therefore, the squareness of the demagnetization curve is improved and the maximum energy product is improved. However, when added alone, the maximum energy product and coercive force decrease. However, if it is less than 0.003%, the effect of improving magnetic properties and structure will be small, and if it exceeds 0.015%, the coercive force will decrease significantly.

Rare earth metal other than Sm, Pr and Y shown as R; 5% or less The reason for using one or two rare earth metals other than Sm, Pr and Y in the second invention is that this reduces the cost of the rare earth magnet alloy. This is to reduce the However, 5%
”, the coercive force and maximum energy product decrease.

Total amount of rare earth metals: 22 to 28% If this amount is less than 22%, the maximum energy product and coercive force required for a rare earth magnet cannot be obtained.

Moreover, if the content exceeds 28%, the residual magnetic flux density and the maximum energy product will decrease.

[Operation] In the present invention, Sw, which is expensive and in dire need of resources,
Part of l is replaced with Pr and Y, and Mn, Ti, and B are added in combination. Therefore, it is possible to provide a rare earth magnet alloy that is inexpensive and has excellent coercive force and maximum energy product.

The reason why the rare earth magnet alloy of the present invention exhibits such excellent effects is considered to be due to the following reasons.

Sm Co Fe-Cu-Z shown in the prior art
In r-based rare earth magnet alloys, by performing aging treatment after solution treatment, the S'^2Co, phase (2-17 phase) is transformed into a fine cellular shape surrounded by the S'lICo7 phase (1-5 phase). However, with the conventional Pr, Y substitution type magnet alloy, even if the cell structure was formed, sufficient coercive force could not be obtained. Ta.

The reason is surmised as follows. That is, the above 2-
The coercive force of the two-phase structure of 17 phases and 1-5 phases is Living
Commentary by stone et al. [J, Appl, Pbys, 4
8 (1977), 1350], the 2-17 phase and the 1
It is proportional to the difference in domain wall energy of the five phases. And S m
When Pr and Y are substituted, the domain wall energy of both the 2-17 phase and the 1-5 phase decreases, and the difference between them also decreases, resulting in a decrease in coercive force. As the coercivity decreases and the squareness of the demagnetization curve decreases, the maximum energy product decreases.

On the other hand, in the Pr, Y substitution type magnet alloy of the present invention, compared to the conventional Nd, Pr substitution type magnet alloy,
Both coercive force and maximum energy product are greatly improved. Although this mechanism is unknown, it is inferred as follows. That is, in the magnetic alloy of the present invention, Zr, Ti-rich (S m, P r, Y
) 2 (ColFe, Cu) 7 phase to firmly pin the domain wall by realizing fine and uniform precipitation. For this reason, we have increased coercive force and improved squareness.
As a result, the maximum power = 12- energy product can be significantly improved.

[Example] The rare earth magnet alloy of the present invention will be explained together with comparative examples and conventional examples to clarify the effects of the present invention.

The metal raw materials were mixed and melted in the proportions shown in Table 1, the resulting magnetic alloy was ground to an average particle size of 2 to 5 μm, and magnetic field press molding was performed in the magnetic field of 1 (IKG) at 1150 to 1200°C.
After sintering for 2 to 4 hours, aging treatment was performed for 2 to 6 hours at a temperature 20 to 40° C. lower than the sintering temperature. Then 750
Aging treatment was performed at ~900°C, slow cooling was performed at 0.5~b, and then rapid cooling was performed. Note that the range of manufacturing conditions is due to the fact that the optimum conditions for magnetic properties vary depending on the alloy composition.

The magnetic properties of the obtained magnet alloy, i.e. coercive force i Hc
(K Oe), residual magnetic flux density B "(K G ), maximum energy product B Hmax (K G Oe) were measured and shown in Table 1. In addition, in Table 1, C
The display of the amount (remainder) was omitted.

(The following is a margin) In Table 1, No. 1 to 6 are examples of the present invention;
Nos. 7 to 26 are comparative examples, and the conventional example No. 27 is Example 1 of JP-A-62-243731.

As is known from Table 1, Comparative Example No. 7, which does not contain Mn, Ti, and B, has a lower coercive force and a lower maximum energy product than the present invention. Also, no.

Comparative examples No. 8 to No. 10 are comparative examples in which two of Mn, Ti, and B are added. Although improvements in coercive force can be seen in those with Ti added, the maximum energy products are all lower than those of the present invention alloy.

No. 11 to 18 are Mn, Ti, B, AI
, Cr, ■, Mo, and Nb, all of which have low coercive force and maximum energy product. Nos. 19 to 24 have the same component system, but S
This is a comparative example in which the contents of tn, Nd, Mn, and Ti-H are outside the range of the present invention, and although No. 21 has an excellent coercive force, the maximum energy product is low, and the others have a low coercive force, Both the maximum energy products have decreased significantly.

In addition, Nos. 25 to 26 are comparative examples in which the amount of rare earth metal is outside the range of the present invention, but No. 25 has an excellent coercive force but a low maximum energy product, and No. 26 has a low coercive force,
Both maximum energy products are low. Furthermore, in the conventional example, although the residual magnetic flux density is slightly low, the maximum energy product,
Both coercive force is low.

On the other hand, the present invention examples Nos. 1 to 6 have a coercive force of 1.
It was confirmed that it was possible to obtain a rare earth magnet alloy having excellent magnetic properties of 0 KOe or more, residual magnetic flux density of 10.5 K G or more, and maximum energy product of about 28 M G Oe. It was also confirmed that the addition of Mn and B expands the optimal range of sintering temperature and solution temperature.
This reduces quality variations due to temperature variations in the sintering or solution treatment process in industrial production.

Additionally, Pr-substituted alloys have been found to have improved grindability, which reduces the incidence of cracking and chipping and increases product yield.

[Effects of the Invention] As explained above, the rare earth magnet alloy of the present invention has Sm-
In Co-Fe-Cu-Zr type 2-17 rare earth magnet alloy, by adding Mn, Ti, and B in combination,
In addition to replacing expensive Sm with Pr and Y, we have found a composition range of Fe, Cu, Zr, and rare earth metals that exhibits excellent magnetic properties, and has a coercive force of 10 KOe or more.
It is a rare earth magnet alloy that has a residual magnetic flux density of 10°5 K G or more, a maximum energy product of about 28 M G Oe, and is inexpensive and has excellent magnetic properties.

[Brief explanation of drawings]

Figure 1 is a diagram showing the saturation magnetic flux density of various rare earth cobalt compounds at room temperature. Figure 2 is a diagram showing the relationship between S weight, maximum energy product, coercive force, and residual magnetic flux density in conventional C4 magnet alloys. , FIG. 3 is a diagram showing the relationship between the amount of Pr and coercive force in a conventional Pr-substituted magnet alloy.

Claims (2)

[Claims] (1) Weight ratio Sm: 8-20%, one or two selected from Pr and Y; 6-20%, Fe: 10-25
%, Cu; 5-10%, one or two of Zr and Hf
Seed: 1-4%, Mn: 0.1-1%, Ti: 0.1-1
%, B; 0.003 to 0.015%, the balance being Co, and Sm+Pr+Y being in the range of 22 to 28%. (2) Weight ratio Sm: 8-20%, one or two selected from Pr and Y; 6-20%, Fe: 10-25
%, Cu; 5-10%, one or two of Zr and Hf
Seed: 1-4%, Mn: 0.1-1%, Ti: 0.1-1
%, B: 0.003 to 0.015%, the balance being Co, and containing 5% or less of one or more rare earth metals R excluding Sm, Pr, and Y, and further Sm+Pr+Y+
A rare earth magnetic alloy characterized in that R is in the range of 22 to 28%.