KR100831401B1 - Method for manufacturing aluminium coated Nd-Fe-B magnet - Google Patents

Abstract

The present invention provides an Nd-Fe-B-based magnet manufacturing method having improved adhesion and corrosion resistance of the aluminum plating layer and excellent surface shape and color. The manufacturing method comprises the steps of preparing a degreasing treatment Nd-Fe-B-based sample of a certain form; Vacuum depositing copper to a thickness of 10 nm or more on the sample; And vacuum depositing aluminum on the copper-deposited sample. The Nd-Fe-B-based magnet manufactured by such a method includes a Nd-Fe-B-based sample body, a copper layer deposited on the Nd-Fe-B-based sample body at a thickness of about 10 to 120 nm, and the copper. It consists of an aluminum layer deposited at a plating amount of about 5 to 900 g / m 2 over the layer surface.

Magnet, Nd-Fe-B type, adhesiveness, corrosion resistance, copper layer.

Description

Neodymium-iron-boron magnet manufacturing method {Method for manufacturing aluminum coated Nd-Fe-B magnet}

1 is a schematic view showing a vacuum deposition apparatus for manufacturing a neodymium-iron-boron-based magnet according to the present invention.

Figure 2 is a graph evaluating the adhesion through the peeling test using an aluminum plating layer of a neodymium-iron-boron-based magnet prepared according to the present invention.

Figure 3 is a graph showing the results of experiments in salt water atmosphere corrosion resistance of neodymium-iron-boron-based magnets prepared in accordance with the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

10: main body 12: sample basket

14: sample heater 16: copper evaporation source

18: aluminum evaporation source 20: plating thickness meter

The present invention relates to a method for manufacturing a neodymium-iron-boron (Nd-Fe-B) -based magnet, and more particularly to a method for producing an aluminum vacuum vapor deposition neodymium-iron-boron-based magnet having better adhesion and corrosion resistance It is about.

In general, Nd-Fe-B magnets were developed and commercialized by Sumitomo Special Metals in Japan in 1982, and are strong permanent magnets with the largest maximum magnetic energy. This magnet is cheaper than SmCo magnets, has less resource constraints, and can be manufactured using powder metallurgy processes suitable for mass production.

Such a conventional neodymium-iron-boron-based magnet has a weak corrosion resistance. Accordingly, conventionally, in order to improve corrosion resistance, the surface of the magnet is coated with a resin, wet plating Cr, Al is vacuum deposited, or ion plating.

That is, since an oxide layer of about 5 nm is naturally formed on the metal surface to lower the bonding strength with the plating layer, during the vacuum deposition of Al, an inert gas such as Ar is introduced into the vacuum evaporator, or sputtering is performed at a high pressure. In order to increase adhesion, an ion plating method of ionizing and depositing Al is performed.

However, the method as described above, a power supply for applying a high pressure to the sample, a device for supplying a certain amount of gas, etc. must be additionally installed, there is a problem that the process is complicated and the overall coating time is prolonged.

Accordingly, the present invention has been invented to solve the above problems, and an object of the present invention is to provide a method of manufacturing an Nd-Fe-B-based magnet excellent in corrosion resistance and adhesion in an easy, simple and inexpensive manner.                         

Another object of the present invention is to produce a Nd-Fe-B-based magnets having a simple process and excellent adhesion and corrosion resistance by depositing 10 nm or more of copper before depositing aluminum on the Nd-Fe-B-based magnets and then by depositing aluminum. To provide a way.

Still another object of the present invention is to provide an Nd-Fe-B magnet manufactured by the above method.

These objects, in the Nd-Fe-B-based magnet manufacturing method, comprising the steps of preparing a degreasing treatment of the Nd-Fe-B-based sample of a certain form; Vacuum depositing copper to a thickness of 10 nm or more on the sample; And it can be achieved by the Nd-Fe-B-based magnet manufacturing method comprising the step of vacuum-depositing aluminum on the copper-deposited sample.

According to one feature of the invention, the copper vacuum deposition step includes a resistive heat evaporation step of copper, and the aluminum vacuum deposition step includes a resistive heat evaporation step of aluminum.

The above-mentioned objects also include an Nd-Fe-B-based sample body, a copper layer deposited on the Nd-Fe-B-based sample body at a thickness of about 10 to 120 nm, and about 5 to 900 g / m 2 around the copper layer. It can be achieved by the Nd-Fe-B-based magnet having an aluminum layer deposited in an amount of.

The present invention relates to a method of manufacturing an Nd-Fe-B magnet by using an aluminum vapor deposition method, wherein the copper is vacuum-deposited to a thickness of 10 nm or more before the aluminum is deposited on the Nd-Fe-B magnet. The present invention relates to an aluminum vapor-deposited Nd-Fe-B-based magnet manufacturing excellent in corrosion resistance.

In more detail, as described above, an oxide layer having a thickness of about 5 nm is naturally formed on the surface of the metal, and this oxide layer is a factor that degrades the bond with the coating layer, and thus the Nd-Fe-B magnet In the case of aluminum deposition due to the surface oxide layer, the adhesion between the aluminum layer and the Nd-Fe-B-based magnet is reduced. However, the bonding between the oxide layer formed on the surface of the Nd-Fe-B magnet and the copper is excellent, as well as the bonding between copper and aluminum. At this time, it should be understood that the excellent bonding between copper and aluminum is based on the premise that the coating is performed in a vacuum without fear of surface oxidation.

Therefore, the present invention is based on this theoretical basis, after depositing the copper of the appropriate thickness on the Nd-Fe-B-based magnet, and then aluminum is deposited, the copper significantly increases the adhesion between the Nd-Fe-B-based magnet and the aluminum plating layer In this case, the corrosion resistance of the entire magnet is improved by the aluminum plating layer having excellent adhesion.

On the other hand, the adhesion improvement of the aluminum plating film by the adhesion of copper and the improvement of corrosion resistance by the aluminum plating layer appear when the adhesion thickness of copper is 10 nm or more, but it turned out that adhesiveness falls below that. Accordingly, the deposition or deposition thickness of copper is preferably set to 10 nm or more.

In the present invention, after depositing copper on the Nd-Fe-B-based magnet as described above, aluminum is deposited by the electron beam evaporation method. At this time, the degree of vacuum is maintained below 10 ^-4 Torr, or preferably deposited in a low vacuum of pure argon atmosphere. This is because when the degree of vacuum is poor or when oxygen in the container is applied at a partial pressure of a predetermined amount or more, the oxygen in the vacuum container may oxidize copper and lower the adhesion.

Hereinafter, a preferred embodiment of the vacuum deposition method of aluminum in the Nd-Fe-B-based magnet manufacturing method according to the present invention will be described with reference to the drawings.

Referring to FIG. 1 showing a schematic view of a vacuum deposition apparatus provided with a resistive heating evaporation source for copper evaporation applied to the present invention, the vacuum deposition apparatus includes a rectangular main body 10 and a sample basket for fixing a sample in the main body ( 12), a sample heating device 14 for heating a sample contained in the sample basket 12, a copper evaporation source 16, an aluminum evaporation source 18, and a plating thickness measuring device for measuring the thickness of the plating ( 20) and a shutter 22 for performing selective exposure between the sample and each evaporation source. In particular, it is preferable that both the copper evaporation source 16 and the aluminum evaporation source 18 applied to the deposition apparatus applied to the Nd-Fe-B-based magnet manufacturing method according to the present invention are inexpensive resistance heating evaporation sources.

According to the method for producing an Nd-Fe-B magnet, first, an Nd-Fe-B magnet (hereinafter referred to as a sample) is charged into a vacuum deposition apparatus through a normal degreasing process in the air. At this time, the sample is preferably placed in the mesh basket 12 of the main body 10 to rotate during vacuum deposition so that the copper and aluminum uniformly plated on the Nd-Fe-B-based magnet.                     

Then, the copper evaporation material is charged to its evaporation source 16 and aluminum is charged to its evaporation source 18, and then the door of the main body 10 of the vacuum plating apparatus is closed and a flow pump or a booster pump is used. After exhausting the vacuum in the vacuum chamber to about 10 ^-3 Torr or less, the vacuum in the vacuum chamber is lowered to about 10 ^-5 Torr or less by using a diffusion pump, a turbo molecular pump or a cryo pump.

Next, when the Nd-Fe-B magnet, which is a sample, is heated by the sample heating device 14 and its temperature reaches an appropriate temperature of about 120 to 300 ^° C., a current is applied to the copper evaporation source 16 to evaporate copper. . Thereafter, the shutter 22 is opened and the copper evaporated from the copper evaporation source 16 is deposited on the sample about 10 nm, and then the shutter is closed. In the same way, aluminum is evaporated using the aluminum evaporation source 18 to deposit aluminum to the sample in the desired thickness. At this time, each deposition thickness can be measured by using the plating thickness meter 20 or multiplying the deposition rate by the deposition rate converted from the power of the resistance heating evaporation source. After the deposition of aluminum is completed, the shutter 22 is closed, and when the temperature of the sample drops to an appropriate level, the door of the vacuum container is opened and the plated Nd-Fe-B magnet is recovered, thereby recovering the Nd-Fe-B magnet. The manufacture of is complete.

If the Nd-Fe-B-based magnet is manufactured in the above manner, the adhesion of the aluminum plating layer can be significantly increased by electrodeposition of copper, and an Nd-Fe-B-based magnet having excellent corrosion resistance can be manufactured.

Hereinafter, the performance and mode of operation of the Nd-Fe-B-based magnet manufactured according to the present invention will be described in detail through the following examples.

Example

In the same manner as described above, copper was first deposited on a commercially available Nd-Fe-B magnet, and then aluminum was vacuum deposited. That is, aluminum was deposited after copper was deposited in a thickness range of 1 to 120 nm using a resistance heating copper evaporation source. In order to test the adhesion of the Nd-Fe-B magnets manufactured as described above, the adhesive force was evaluated by how much the plating layer adhered to the tape after peeling off the tape. The results are shown in the graph of FIG. 2. .

According to the graph of Figure 2, when the plating by the method of the present invention showed an excellent adhesion, the surface shape is excellent and the color of the silver-white metal light.

In addition, in order to evaluate corrosion resistance, a result of determining whether rust occurs in a state in which a plated Nd-Fe-B magnet is immersed in saline is shown as a graph in FIG. 3. As shown in the graph of Fig. 3, the plating of the present invention showed good corrosion resistance even in a salt water atmosphere.

Comparative example

On the other hand, when the aluminum was directly plated on the Nd-Fe-B magnet without using copper in advance by using an electron beam evaporation source and a resistive heating evaporation source, in both cases, the aluminum plated layer appeared as a result of a tape test, resulting in poor adhesion and brine. Rust also occurred in the atmosphere, indicating poor corrosion resistance.

As a result, according to the manufacturing method of the Nd-Fe-B magnet according to the present invention, copper is first vacuum-deposited to an appropriate thickness and used as a bonding medium layer between the Nd-Fe-B magnet and the aluminum layer, The adhesiveness is improved and the corrosion resistance is also improved, thereby improving the productability.

In addition, the surface shape of the manufactured Nd-Fe-B-based magnet is not only excellent, but even when the surface state of the Nd-Fe-B-based magnet is not uniform, the surface shape and color are excellent.

While a preferred embodiment according to the present invention has been described above, it will be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the appended claims.

Claims (3)

In the Nd-Fe-B-based magnet manufacturing method, Degreasing the Nd-Fe-B-based sample of a certain type to prepare Vacuum depositing copper on the sample by resistive heat evaporation to a thickness of 10 nm to 120 nm in a vacuum state; And Nd-Fe-B system comprising the step of vacuum evaporation to the copper-vapor-deposited sample, in a vacuum state, aluminum by resistance heat evaporation in the plating amount of about 5 to 900g / ㎡ over the entire surface of the copper layer Magnet manufacturing method. delete delete

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