JPS6111445B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a so-called rare earth cobalt magnet containing a rare earth metal and cobalt (Co), and is particularly characterized by high coercive force (Hc), high residual magnetic flux (Br), and high energy product [(BH) max]. It is related to magnets. Conventionally, for rare earth cobalt magnets, _I Hc
＞5000Oe, Br＞11000G, (BH)max30M・
GOe and high-performance magnets have been developed, but magnets with even higher performance are desired. The first object of the present invention is to realize a magnet with higher performance by using a magnet with a composition different from conventional magnets. The second purpose is to exceed the above performance of conventional rare earth cobalt magnets (BH)max>30M・
The goal is to realize GOe magnets. A first embodiment of the present invention will be described below. That is, in a permanent magnet made of rare earth metal and Co, it contains Os, and R
The composition is (Co _1-xy MxOsy)z, R is composed of Y and one or more of lanthanum-based elements, and M is a 3d-transition metal and Cu, a, a,
Consisting of one or more metals of the a-group, z = 4.5 to 9.0, 0x < 0.45, 0 < y <
It is set to 0.25. A magnet with such a composition has larger Hc and (BH)max than a magnet with a composition where y=0, and has improved characteristics. Furthermore, if the manufacturing method is adjusted so that Hc is approximately the same value as that of the magnet with y=0, it is possible to achieve a larger Br than with the magnet with y=0. A second embodiment of the present invention will be described. In other words, a permanent magnet made of rare earth and Co contains Os, has a composition of R(Co _1-xy MxOsy)z, and R is composed of one or more of Sm, Pr, Ce, and Y. , Mx=M′x′M″x″, and M′
It is composed of Fe, Cu, Mn, and M″ is a-group (Zr,
Hf, Ti), 0.02x′<0.45,
0.005x″0.1, 0.004 at z=6.5~8.5
y<0.2. According to a magnet with such a composition, (BH)max is
It is possible to obtain unprecedented high performance of 30M・GOe or more. A method of manufacturing the magnets of the first and second embodiments will be described. The magnet of this example is basically produced in the same manner as in the conventional manufacturing method of rare earth cobalt magnets, in which raw metal is weighed to have a desired composition. Next, it is melted in a high-frequency induction furnace to create a uniform alloy.
At this time, it is dissolved in an atmosphere of inert gas such as Ar and cooled. Next, this alloy lump is pulverized and sized to form a fine powder of approximately 1 to several microns, and this fine powder is immersed in a medium such as toluene. This immersed fine powder is molded into a desired shape using a so-called wet magnetic field molding machine. Note that if the fine powder is molded immediately after manufacturing, it is not necessary to immerse it in toluene or the like. Also, as in the past, it is effective to arrange the direction of the pressing force during molding to be perpendicular to the molding magnetic field in order to achieve high performance. Furthermore, if necessary, the molded product may be compression molded under a hydrostatic pressure of 1 t/cm ² or more, thereby making it possible to produce a more dense molded product. The temperature of the molded body is 1100℃ or higher, 1300℃
Sinter by heating for 10 minutes or more at a temperature below ℃. The atmosphere during sintering is a high vacuum of approximately 10 ^-4 mmHg or more, and in some cases, an inert atmosphere such as Ar may be used. After sintering, depending on the composition, the material is rapidly cooled from the sintering temperature to approximately 900 to 1000°C, and slowly cooled below that temperature. In some cases, from the sintering temperature, for example, to the cold immediately after vaporizing liquid nitrogen.
Rapid cooling by spraying _N2 gas, etc.
This rapidly cooled body is again heated to a suitable temperature in the temperature range of, for example, 700 to 900°C, held at this temperature for 10 minutes or more, and then cooled or gradually cooled in a furnace. At this time, the atmosphere is basically a non-oxidizing atmosphere such as Ar. The obtained sintered magnet was measured using an electromagnet to measure the I-H hysteresis loop, which represents the relationship between magnetization I and applied magnetic field H, and the residual magnetic flux (Br = 4πIr), coercive force _I Hc, and energy product (BH ) Find max. At this time, the dimensions and shape of the sintered magnet are adjusted by machining such as grinding and polishing, if necessary. According to the embodiments of the present invention, a magnet with high _I Hc can be obtained as an effect of containing Os in a rare earth cobalt magnet. The degree of improvement in _I Hc is approximately equal to that of a magnet with a composition of y=0 when Br is approximately the same and the squareness of the demagnetization curve is approximately the same.
It becomes larger than 1000Oe. For this purpose, it is necessary that y>0.004 at least when expressed by the above compositional formula. When the value of y becomes extremely large,
Since the above-mentioned squareness is extremely impaired as Br decreases, good results are obtained if y<0.25, preferably 0.20 or less. As shown in the first embodiment, a rare earth cobalt-based magnet that exhibits such an Os content effect is composed of one or more of Y and lanthanum-based elements as rare earth metals, and requires cobalt or a part of cobalt. If there is a,
Substituted with 3d-transition metal and Cu, a, a, a- group metal. Here, the atomic ratio of cobalt or a partially substituted product of cobalt and the rare earth metal is z = 4.5 to 9.0, and within this range, the above
The improvement in Hc is more than 500 Oe. No improvement in Hc can be expected with atomic ratios other than this. In addition, as shown in the second example, a high-performance magnet with a structure in which an effect of improving Hc of 1000 Oe or more is recognized and an energy product of 30 M・GOe or more is mainly made of Sm as the rare earth metal, if necessary. For example, a part of Sm is replaced with Pr, Ce, and Y, and Co
Or a part of it is a material in which M′ is replaced with a metal selected from the group of Fe, Cu, and Mn, and M″ is replaced with a metal selected from the group of Ti, Zr, and Hf. Here, basically rare earth and cobalt atoms are substituted. If the ratio Z is not 6.5 to 8.5, Br
is not enough and also 0.02x′0.45，0.05x″
If it is not 0.1, Hc will be insufficient and 30M・GOe
It is not possible to obtain higher performance. Next, specific examples according to the first and second embodiments will be explained. Specific example 1 Sm (CO0.68Fe0.25Cu0.05Zr0.005Os0.015)
The raw materials were blended so as to have a particle size of 7.5, melted under high frequency in an Ar atmosphere, and cooled to produce a magnetic alloy, which was coarsely crushed using a geocrusher and then finely ground to an average particle size of 5 μm using a jet mill. 15mm of this fine powder
It was molded into a rectangular parallelepiped measuring 15 mm x 25 mm with a pressure of 100 kg/cm ² . During molding, a magnetic field of approximately 15,000 G was applied in the length direction of 25 mm. After compressing the magnetic field molded body under a hydrostatic pressure of 2 t/cm ² , the molded body was heated and sintered at 1200° C. for 1 hour. The atmosphere during sintering was a vacuum of 10 ^-5 mmHg, and after sintering, it was rapidly cooled to room temperature and cooled N ₂ gas was blown onto it. This cooling body was heated again to 850°C, maintained at this temperature for 1 hour, and then cooled in the furnace. The atmosphere at this time was Ar gas. This heat-treated magnet was polished and formed into a 10 mm rectangular parallelepiped, 15 mm in the magnetic field forming direction, 10 mm in the direction perpendicular to this direction, and I-H while applying an external magnetic field in the magnetic field forming direction (direction of easy magnetization). The hysteresis curve was measured. As a result, the residual magnetization was approximately 12000G, _I Hc was 9000Ce, and the maximum energy product was 34.2M・GOe. Specific Example 2 A magnet was manufactured using the same method as in Specific Example 1 with the composition shown in Table 1. However, the sintering conditions are 1150 to 1250
In the temperature range of °C, annealing was carried out in the range of 750 °C to 900 °C, and the conditions were adjusted to obtain the highest (BH)max. The properties of the obtained sintered body are shown in Table 1.

【table】

[Table] Specific Example 3 A magnet with the composition shown in Table 2 was manufactured by the same method as in Specific Example 1. For reference, a magnet with a composition of y = 0 was made, and the IH hysteresis curve was measured in the same way as in Example 1, and _I Hc (y) - _I Hc (y =
0)=ΔHc was determined, and the improvement in Hc due to the addition of Os was determined and shown in Table 2. According to the permanent magnet of the present invention, R is one or more of Y and lanthanum elements, and M is 3d
When one or more of transition metals and Cu, a, a, group a metals are used, the composition is R(Co _1-xy MxOsy)z, and Z = 4.5 ~
9.0, 0x<0.45, 0<y<0.25, so
It is possible to improve Hc and therefore provide a magnet with a high maximum energy product (for example, greater than 30M.GOe).

Claims (1)

[Claims] 1 R is one or more of Y and a lanthanum-based element, and M is a 3d transition metal and Cu, a,
When one or more metals of group a and a are used, the composition is R(Co _1-xy MxOsy)z, and Z=4.5 to 9.0, 0x<0.45, 0<y<
A magnetic material characterized by having a value of 0.25.