JPS5852019B2 - Rare earth cobalt permanent magnet alloy - Google Patents

Description

Detailed Description of the Invention The present invention provides rare earth metals (R=Sm, Y) and 3d transition metals (
The present invention relates to a permanent magnet alloy characterized in that the main component is an R2T17 intermetallic compound composed of (T=Co, Fe, CU), and a part of this is replaced with Y.

R(Co) in which the Co component or the Co, Fe composite component is partially replaced with Cu in the intermediates of RCo5 and R2Co17 intermetallic compounds.

It is known from US Pat. No. 3,560,200 that alloys with the composition F e t Cu )

From subsequent research, the current residual magnetism Br = 9 ~ 10 KG (Kilo Gauss, Oersted) (BH) max = 20 MGO
e (Mega Gauss.

Alloys with magnetic properties of the order of 1.5 mm (Oersted) have been commercialized industrially.

However, the above performance is R2T1? The theoretical magnetic performance originally possessed by intermetallic compounds, such as Sm2 (
co, Fe) 1-7 intermetallic compound with Br:1
2~14KG, (BH)maX: 36~50MGOe1
This value was still lower than that of .

The reason for this is that in precipitation hardening magnets given by R(Co t Fe , Cu ) This is because the Cu component becomes essential and the saturation magnetization value of the alloy is reduced by that amount.

In addition, a coercive force suitable for practical use is shown only in the composition region where and R2Tl? The performance of the compound is intermediate, resulting in a decrease in the theoretical magnetic performance of the R2T17 compound, especially the Br value.

As a measure to increase the Br value or saturation magnetization value in the R(Co, Fe.Cu) There is a method using rare earth components with high values.

Therefore, the saturation magnetization values of various types of R2T17 alloys that have been investigated so far are shown in FIG.

From this figure, Y, Nd, Pr, L are rare earth elements with higher saturation magnetization values than S~2C017.
There is a u.

In the Nd2T17 alloy, the easy magnetization direction is not in the C-axis direction of the crystal, which is necessary to generate a high coercive force, but in the direction perpendicular to the C-axis, so even if an increase in saturation magnetization is obtained, the coercive force is extremely low and unsuitable. .

Next, Y, Pr. About Lu Sm (Co, Fe, Cu)
When Sm in x was partially replaced and the magnetic performance was measured, only the Y-substituted alloy maintained a high coercive force while increasing the Br and Bs values.

The present invention is Srn (CotFetCu)
By substituting a part of Sm with Y in an x-based precipitation hardening magnet, a high-performance permanent magnet with high saturation magnetization and residual magnetization values is provided. Y) 11.7-12.4% Y
: 0.2-5.0%, Sm: 6.7-12.2%; F
e: 0.4-12.4%t Cu: 10.5
-14.2%, Co: 61.3-77.8%.

The general method for manufacturing the permanent magnet alloy according to the present invention is carried out in the following order: melting, crushing, orientation, compression molding, sintering, rapid cooling, and annealing.

First, a specified amount of raw materials are mixed and melted in an arc furnace or high-frequency furnace in an inert atmosphere to form an ingot.
get.

The ingot is then ground to a particle size of 1-100 μm.

At this time, the influence of the particle size on the magnetic properties of the final magnet alloy is less strict than that of conventional SmCo5-based sintered alloys, and coarser particles of 50 to 100 μm are more effective in terms of coercivity.

However, in order to improve the particle orientation rate and increase residual magnetization, it is effective to use finer particles (1 to 50...).

Therefore, by adjusting the particle size during the crushing process, it is possible to obtain magnetism that meets the requirements.

The powder is then oriented in a magnetic field and compression molded.

A magnetic field of about 10 KCe is sufficient for the orientation of the magnetic alloy of the present invention.

This molded body is heated in an inert atmosphere or in a vacuum at 1180~
Sintering is carried out within a temperature range of 1250°C for a suitable period of time, and immediately after sintering, it is rapidly cooled to 900°C.

In general, R2T1□ compounds have a stable phase of low symmetry crystals (hexagonal in this case) that exhibit high magnetocrystalline anisotropy only in high-temperature regions, and in order to maintain this high-temperature stable phase down to low temperatures, the magnet alloy of the present invention A rapid cooling step is also required, and an alloy with high coercivity can be obtained if the cooling rate is 1° C./second or higher.

Next, it is reheated at a relatively low temperature range of 750 to 900°C to cause precipitation and separation into a fine ferromagnetic phase and a weaker phase.

In this annealing process, the alloy that has been rapidly cooled from the sintering temperature to below 900°C is continuously held at the annealing temperature for an appropriate period of time, or the alloy that has been rapidly cooled from the sintering temperature to below 900°C is slowly cooled to room temperature to achieve sufficient magnetic performance. shows.

From the above process, 13r: loKG or more, iHc: 4K
It has been found that a high-performance permanent magnet alloy with Oe or more, (BH)max: 20 MGOe or more can be easily manufactured on an industrial production scale.

The reason for limiting each component of the present invention as specified above is that if Y is 0.2% or less in a total rare earth component of 11.7 to 12.4%, it will not be effective in increasing the residual magnetization value and saturation magnetization value, which is the objective of the present invention. 5. Since there is no coercive force and the coercive force decreases when it exceeds 5.0%.
The upper limit was 0%.

The remainder becomes Sm.

In addition, although the Fe component exhibits a certain degree of magnetic performance even if it is not contained, 0.4% or more is necessary in order to stabilize the low symmetry crystal (here, hexagonal crystal) and improve the magnetization value.
If it exceeds 2.4%, Fe substitution of Co will be saturated, and on the contrary, magnetically soft substances will be produced, deteriorating the coercivity of the entire alloy, so the upper limit was set at 124%.

Next, the upper limit of the Cu component was set at 14.2% because if it is less than 10.5%, the coercive force increasing effect due to sufficient precipitation hardening cannot be obtained, and if it is more than 14.2%, the magnetization value is extremely reduced.

The remainder above is given by the Co component.

Therefore, the effective range of the magnetic alloy of the present invention is 11.7 to 12.4% of the rare earth components (Sm and Y), Y: 0.2 to 5%.
．． 0%, Sm: 6.7-12.2%; Fe: 0.
4-12.4%, Cu: 10.5-14.2%, Co
It becomes 61.3-77.8%.

Hereinafter, the present invention will be explained in detail by way of examples.

Example l 5rn1-xYx(CoO,8oFeO,06Cu
Six types of alloys shown in Table 1 with a composition formula of O, 14) 7.3 and X as a parameter were arc melted in Ar, and ingots were produced in a water-cooled copper mold.

This ingot was crushed to a particle size of approximately 20μm, and approximately 10K
Pressure molding was carried out in a magnetic field of Oe.

Next, the molded body was sintered at 1220° C. for 30 minutes in an Ar flow, and then cooled to room temperature at an average rate of 10° C./sec.

This sintered body was reheated at 800° C. for 30 minutes, and then cooled in a furnace to room temperature.

When the magnetic properties of the sintered alloy thus obtained were measured, as shown in Fig. 2, the Br value increased due to Y substitution, and the Br value increased from 9.7 KG at X = O to B at x = 0.2.
r: 10.3 KG) The maximum energy product showed a local maximum value (BH) max: 26 MGOe at x = 0.1 due to the decrease in coercive force as Y increases.

Example 2 Yl, 2%ysm10.4%, Fe3.5% in atomic ratio
, Cu 12.4%, Co 72.5% was made into a molded body in the same manner as in Example-1, and molded in vacuum (10'
Sintering was performed at 120° C. for 1 hour (approximately 1 oz Hg), followed by rapid cooling and annealing in the same manner as in Example 1. The magnetic properties were measured and found to be Br 10.3 KG and iHc.

4.0 (BH)max: 22.5KGOe.

As detailed above, the magnetic alloy of the present invention is R2T1
7 Intermetallic compound as the main component, and in order to obtain higher residual magnetization and saturation magnetization of a part of Sm which is R, R2T1
□High-performance Sm substituted with Y, which has a high magnetization value in a compound state
, Y(Co, Fe.

This product provides a Cu)x-based precipitation-hardened magnet alloy, which exhibits higher magnetization than conventional R-Co-based magnets, improving the performance of small rotating machines, audio equipment, etc. that previously used high-grade alnico magnets. It has a great effect on improving the size and reducing the size and weight of products.

[Brief explanation of drawings]

Figure 1 shows the saturation magnetization value of the R2C017 compound along with RCo and the magnetization value of the compound, and Figure 2 shows the saturation magnetization value of the R2C017 compound.
m1-xYx(Co0.80 FeO,06Cu0.
14) 7.3 shows the change in magnetic properties as X increases.

Claims (1)

[Claims] 1. Rare earth components (consisting of samarium and yttrium) are 11.7 to 12.4% and iron is 0.4 to 12% in atomic ratio.
．． 4%, copper 10.5-14.2%, cobalt 61.
It has a composition amount within the range of 3 to 77.8%, and 0.2 to 5.0% of the rare earth components are yttrium and 6.7 to 12%.
．． A permanent magnetic alloy characterized by 2% samarium. 2 Atomic ratio of rare earth components (consisting of samarium and yttrium) is 11.7 to 12.4%, copper is 10.5 to 1
4.2%, cobalt in the range of 73.5 to 78.2%, and of the rare earth components, 0.2 to 5.0% is yttrium and 6.7 to 12.2% is samarium. A permanent magnetic alloy characterized by: