JPH10106815A - Permanent magnetic for ultra high vacuum and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet for ultra high vacuum which has good adhesion of a coating film thereon, is tight, can prevent the generation and release of gas from the magnet body, and has a high magnetic characteristic used for an undulator, etc., in the ultra high vacuum of below 1×10<-9> Pa. SOLUTION: After the surface of an Fe-B-R permanent magnet body is cleaned by an ion sputtering method, etc., a titanium coating film of 0.1 to 3.0μm thickness is formed on the surface of the permanent magnet body by a method for forming a thin film such as an ion plating method, etc. An aluminum coating film of 0.1 to 5μm thickness is then formed on the titanium coating film by a method for forming a thin film such as an ion plating method, etc., and furthermore a Ti1- XAlXN (where 0.03<x<0.70) coating film of 0.5 to 10μm thickness is formed on the aluminum coating film in an atmosphere of N2 - containing gas by a method for forming a thin film such as an ion reaction plating method, etc. This can prevent the generation of a gas adhering to the magnet or absorbed by the magnet, and enables effective use of high magnetic characteristics of the magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high vacuum permanent magnet which has excellent adhesion of a coating film and has high magnetic properties which can be used as an undulator in an ultra-high vacuum atmosphere. After sequentially laminating a film and an Al film, Ti _1-x A
By forming the l _x N coating layer, the adhesion is excellent, the density is high, and the generation and release of gas from the magnet body are prevented.
The present invention relates to an ultra-high vacuum magnet which can be used in an ultra-high vacuum of 0 ^-9 Pa or less and has extremely stable magnetic properties, and a method for manufacturing the same.

[0002]

2. Description of the Related Art First, using rare earths, which are abundant in resources, mainly Nd and Pr, B and Fe as main components, do not contain expensive Sm and Co, and are the highest among conventional rare earth cobalt magnets. As a new high-performance permanent magnet that greatly exceeds the characteristics,
-Fe-B permanent magnets have been proposed (Japanese Patent Laid-Open No. 59-5978).
46008, JP-A-59-89401).

The Curie point of the above magnet alloy is generally 30
0 ° C. to 370 ° C., but having a higher Curie point by substituting part of Fe with Co.
B-based permanent magnets (JP-A-59-64733, JP-A-59-64733)
-132104), and has a Curie point equal to or higher than that of the R-Fe-B-based rare earth permanent magnet containing Co and a higher (BH) max, and improves its temperature characteristics, particularly iHc. Therefore, as a rare earth element (R), a Co-containing R centered on a light rare earth such as Nd or Pr.
By including at least one of heavy rare earths such as Dy and Tb in a part of R of the Fe-B based rare earth permanent magnet, iHc can be further increased while retaining a very high (BH) max of 25 MGOe or more. Improved Co-containing R
-Fe-B rare earth permanent magnet proposed (Japanese Patent Laid-Open No. 60-34)
005).

Conventionally, ferrite magnets have been used as vacuum atmosphere magnets in a vacuum of the order of ^10.sup.-3 Pa. However, ferrite magnets have low magnetic properties and do not have sufficient magnetic properties for use in undulators and the like. .

[0005] Ultra-high vacuum magnets that can be used in ultra-high vacuum of 1 × 10 ^-9 Pa or less include (1) excellent magnet properties, and (2) release and emission of built-in gas and attached gas from the magnet. (3) 1 × 10 ^-9 Pa mounted inside the device
It is important that the following can be achieved:

Therefore, as described above, since the Fe-BR based magnet has high magnetic properties, it can be used for an undulator for an ultrahigh vacuum of 1 × 10 ⁻⁹ Pa or less.
Because the BR magnet absorbs and absorbs gas, the degree of vacuum is 1 × due to the gas generated and released from the magnet in a vacuum atmosphere.
In an ultra-high vacuum atmosphere of 10 ⁻⁹ Pa or less, it was difficult to use a Fe—BR magnet.

Conventionally, Ni-plated Fe-
When a BR magnet is used in an ultra-high vacuum, the magnet cannot be placed in the ultra-high vacuum chamber, and a magnet is attached from the outside,
Since the undulator and the like were manufactured, the size of the apparatus was increased, and the high magnetic properties of the Fe-BR-based magnet could not be effectively used.

[0008] Even conventional corrosion-resistant Fe-BR permanent magnets having various coatings for the purpose of improving the corrosion resistance of the conventional Fe-BR-based magnet body, the vacuum generated by the magnet in a vacuum atmosphere and the gas released therefrom cause a vacuum. It was difficult to use it in an ultra-high vacuum atmosphere having a degree of 1 × 10 ⁻⁹ Pa or less.

The present invention relates to a conventional corrosion-resistant F having various coatings for the purpose of improving the corrosion resistance of Fe-BR-based magnet bodies.
An undulator in an ultra-high vacuum atmosphere that is completely different from eBR type permanent magnets, has excellent adhesion to the surface of the magnet body, has a dense coating, and has a function of preventing gas generation and release from the magnet body. It is an object of the present invention to provide an ultra-high vacuum permanent magnet having high magnetic properties that can be used for such purposes.

[0010]

Means for Solving the Problems The inventors of the present invention have excellent adhesion to a base and can prevent generation of gas adhering to or occluded by a magnet by a dense metal coating applied thereto. As a result of various studies on the method of forming a Ti _1-x Al _x N coating on the surface of a permanent magnet body for the purpose of producing a stable Fe—BR based permanent magnet, the magnet body surface was cleaned by an ion sputtering method or the like. Then, a specific film thickness T is formed on the surface of the magnet body by a thin film forming method such as an ion plating method.
After sequentially forming the i-coating and the Al coating, a thin film forming method such as ion reaction plating is performed in an N ₂ -containing gas to form a Ti _1-x Al _x N coating having a specific thickness.
Found that the adhesiveness to the substrate was excellent.

Further, the present inventors have proposed that T
In forming the i _1-x Al _x N coating, the interface is Ti _{1 -x
■} AlαN _■ Ti, A satisfying (0 <α <1, 0 <β <1)
l, the composite coating is produced of N, the Ti _{1- ■} AlαN _■ composition, film thickness, substrate temperature, varies with the bias voltage, film formation speed, Ti _1-x Al x N composition, etc., Ti _{1- x} A
The composition is such that Ti and N continuously increase toward the l _x N interface, whereby the adhesion between the Al coating and the Ti _1-x Al _x N coating can be significantly improved. The present inventors have found that the present invention can achieve a degree of vacuum of 1 × 10 ⁻⁹ Pa or less by being mounted in an apparatus and can be used as an undulator for an ultra-high vacuum, and have completed the present invention.

That is, according to the present invention, a Ti coating having a thickness of 0.1 μm to 3.0 μm formed on the surface of an Fe—BR based permanent magnet body having a tetragonal phase as a main phase is formed on a Ti coating having a thickness of 0.1 μm to 3.0 μm. 1μ
0.5 μm to 10 μm in thickness through an Al coating of m to 5 μm
m Ti _1-x Al _x N (where 0.03 <x <0.70)
This is an ultra-high vacuum permanent magnet having a coating layer.

Further, the present invention provides a Ti coating having a film thickness of 0.1 μm to 3.0 μm on a cleaned surface of a Fe—BR based permanent magnet having a tetragonal phase as a main phase by a thin film forming method. Is formed, an Al film having a thickness of 0.1 μm to 5 μm is formed on the Ti film, and a 0.5 μm to
10 μm Ti _1-x Al _x N (provided that 0.03 <x <0.
70) A method for manufacturing an ultra-high vacuum permanent magnet for forming a coating layer.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, Fe-BR
Coating, Ti _1-x Al _x N on the surface of permanent magnet
As a method of forming a film, a so-called gas phase film forming method such as an ion plating method, an ion sputtering method, and a vapor deposition method can be appropriately used. Reactive ion plating is preferred.

The temperature of the permanent magnet serving as the substrate when the reaction film is formed is preferably set to 200 ° C. to 500 ° C. If the temperature is lower than 200 ° C., the reaction adhesion with the substrate magnet is not sufficient, and the temperature exceeds 500 ° C. The temperature difference between the temperature and normal temperature (25 ° C) increases, and the coating cracks in the cooling process after the treatment,
The temperature of the substrate magnet is set to 2
It is good to set to 00 degreeC-500 degreeC.

After a Ti coating layer is formed on the surface of the Fe—BR system permanent magnet, Ti _1-x Al _x N (where 0.03 <x) is passed through an Al coating layer formed on the Ti coating layer. <0.70)
An example of the method for manufacturing a permanent magnet for ultrahigh vacuum of the present invention, which is provided with a coating layer, will be described in detail below. 1) For example, after evacuating the vacuum container to an ultimate degree of vacuum of 1 × 10 ⁻³ pa or less using an arc ion plating apparatus, R-Fe is subjected to surface sputtering with Ar ions at an Ar gas pressure of 10 pa and −500 V to perform R-Fe sputtering. -Clean the surface of the B-based magnet body. Next, the target Ti is evaporated by an Ar gas pressure of 0.1 pa and a bias voltage of -80 V, and a Ti coating layer having a thickness of 0.1 μm to 3.0 μm is formed on the surface of the magnet body by an arc ion plating method. Form.

2) Next, the target Al is evaporated with an Ar gas pressure of 0.1 pa and a bias voltage of −50 V, and a 0.1 μm to 5 μm thick film is formed on the Ti coating layer by an arc ion plating method. An Al coating layer is formed. 3) Subsequently, using an alloy Ti _1-x Al _x (however, 0.03 <x <0.80) as a target, keeping the substrate magnet temperature at 250 ° C., N ₂ gas pressure 3 pa, and bias voltage − Under a condition of 120V, a specific thickness of Ti
Form a _1-x Al _x N coating layer.

In the present invention, the reason why the thickness of the Ti coating on the surface of the magnet body is limited to 0.1 μm to 3.0 μm is as follows.
If it is less than μm, the adhesion to the magnet surface is not sufficient, and
When the thickness exceeds μm, there is no problem effectively, but the cost of the underlayer is increased, which is not practical and not preferable. Therefore, the thickness of the Ti coating is set to 0.1 μm to 3.0 μm.

In the present invention, the reason why the thickness of the Al coating formed on the Ti coating is limited to 0.1 μm to 5 μm is that if it is less than 0.1 μm, it is difficult for Al to uniformly adhere to the surface of the Ti coating, and The effect as a film is not sufficient, and if it exceeds 5 μm, there is no problem. However, it is not preferable because the cost of the intermediate layer is increased, so that the thickness of the Al coating is set to 0.1 μm to 5 μm.

In addition, Ti _1-x Al _x N (however, 0.03 <
x <0.70) The reason for limiting the coating thickness to 0.5 μm to 10 μm is that if the coating thickness is less than 0.5 μm, the corrosion resistance and abrasion resistance of the Ti _1-x Al _x N coating are not sufficient, and if it exceeds 10 μm, the effect is increased. Although there is no problem in terms of production, it is not preferable because it causes an increase in manufacturing cost. Further, in the Ti _1-x Al _x N of the coating, when x is 0.03 or less, the performance (corrosion resistance, wear resistance, etc.) as Ti _1-x Al _x N is not sufficient, and when x is 0.70 or more, the performance is not sufficient. It is not preferable because no improvement is observed and it is difficult to obtain a uniform composition, and x is limited to a range exceeding 0.03 and less than 0.70.

The rare earth element R used in the permanent magnet of the present invention
Accounts for 10 to 30 atomic% of the composition, but Nd,
At least one of Pr, Dy, Ho, and Tb; or La, Ce, Sm, Gd, Er, Eu, T
Those containing at least one of m, Yb, Lu, and Y are preferable. Also, usually one of R is sufficient,
In practice, a mixture of two or more kinds (mish metal, dymium, etc.) can be used for reasons such as convenience in obtaining. Note that R may not be a pure rare earth element, and may contain impurities which are unavoidable in production within the industrially available range.

R is an essential element in the above-mentioned permanent magnets. If it is less than 10 atomic%, the crystal structure becomes a cubic structure having the same structure as that of α-iron, so that high magnetic properties, particularly high coercive force cannot be obtained. , More than 30 atomic%, the R-rich nonmagnetic phase increases, the residual magnetic flux density (Br) decreases, and a permanent magnet having excellent characteristics cannot be obtained. Therefore, R10 atomic% or more
A range of 30 atomic% is desirable.

B is an essential element in the above permanent magnets. If it is less than 2 atomic%, the rhombohedral structure becomes the main phase, and a high coercive force (iHc) cannot be obtained. If it exceeds 28 atomic%, B becomes rich. Increase in non-magnetic phase, residual magnetic flux density (Br)
, The excellent permanent magnet cannot be obtained. Therefore, B is desirably in the range of 2 to 28 atomic%.

Fe is an essential element in the above-mentioned permanent magnets. When the content is less than 65 atomic%, the residual magnetic flux density (Br) decreases, and when it exceeds 80 atomic%, a high coercive force cannot be obtained. % To 80 atomic%.
Further, substituting a part of Fe with Co can improve the temperature characteristics without impairing the magnetic characteristics of the obtained magnet. However, when the Co substitution amount exceeds 20% of Fe, conversely, It is not preferable because the magnetic properties deteriorate. When the substitution amount of Co is 5 atomic% to 15 atomic% in the total amount of Fe and Co, (Br) increases as compared with the case where the substitution is not performed, so that it is preferable to obtain a high magnetic flux density.

In addition to R, B, and Fe, the presence of unavoidable impurities in industrial production can be tolerated. For example, part of B may be 4.0 wt% or less of C, 2.0 wt% or less of P, .0
By replacing at least one of S by wt% or less and Cu by 2.0 wt% or less with a total amount of 2.0 wt% or less, it is possible to improve the productivity and reduce the cost of the permanent magnet.

Further, Al, Ti, V, Cr, Mn, B
i, Nb, Ta, Mo, W, Sb, Ge, Sn, Zr,
At least one of Ni, Si, Zn, and Hf is R
-It can be added to the Fe-B-based permanent magnet material because it has the effect of improving the coercive force and the squareness of the demagnetization curve, improving the productivity, and reducing the price. The upper limit of the addition amount is preferably in a range that satisfies the above condition, since Br needs to be at least 9 kG or more in order to make (BH) max of the magnet material 20 MGOe or more.

The permanent magnet of the present invention comprises a compound having a tetragonal crystal structure having an average crystal grain size in the range of 1 to 80 μm as a main phase, and a nonmagnetic phase (1% to 50% by volume). (Excluding the oxide phase). The permanent magnet according to the present invention exhibits a coercive force iHc ≧ 1 kOe, a residual magnetic flux density Br> 4 kG, and a maximum energy product (BH) m
ax indicates (BH) max ≧ 10 MGOe, and the maximum value reaches 25 MGOe or more.

[0028]

【Example】

Example 1 A known casting ingot was pulverized, finely pulverized, molded, sintered, and then heat-treated to obtain a magnet test piece having a composition of 16Nd-76Fe-8B having an outer diameter of 12 mm and a thickness of 2 mm. The magnet is put in a vacuum vessel, and the inside of the vacuum vessel is 1 × 10 ⁻³ pa
After evacuating and cleaning the surface of the magnet body by performing surface sputtering at an Ar gas pressure of 5 Pa and -600 V for 20 minutes, an Ar gas pressure of 0.2 Pa, a bias voltage of -80 V and a substrate magnet temperature of 250 ° C. Metal Ti as a target is 1 μm on the surface of the magnet body by arc ion plating.
A thick Ti coating layer is formed.

Then, a 2 μm thick Al film was formed on the surface of the Ti film by arc ion plating using a metal Al as a target at an Ar gas pressure of 0.1 Pa, a bias voltage of −50 V, a substrate magnet temperature of 250 ° C. A coating layer was formed.

Next, at a substrate temperature of 320 ° C.,
A Ti _1-x Al _x N film having a thickness of 3 μm was formed on the surface of the Al film by an arc ion plating method using an alloy Ti _0.4 Al _0.6 as a target at 120 V and 3 Pa of N ₂ gas. The coating composition was Ti _0.45 Al _0.55 N. Thereafter, after allowing to cool, the magnetic properties of the obtained permanent magnet having the TiN coating were measured, and the results are shown in Table 1. The ultimate vacuum degree of the obtained permanent magnet was measured by the ultrahigh vacuum apparatus shown in FIG. FIG. 2 shows the measurement results.

The method of measuring the ultimate vacuum degree by the ultra-high vacuum apparatus shown in FIG. 1 will be described. The ultra-high vacuum apparatus 1 has a long cylindrical main body 2, a Ti getter pump 4, an ion pump 5, and a BA gauge. 6 and an extractor gauge 7 are provided, respectively.
Is provided.

First, without inserting the magnet sample 8 into the sample chamber 3, the titanium getter pump 4 and the ion pump 5 were operated and baked at 150 to 200 ° C. for 48 hours while evacuating. After the temperature in 2 becomes 70 ° C. or lower, the BA gauge 6 and the extractor gauge 7 are operated to measure the ultimate vacuum degree. The final vacuum degree was 7 × 10 ⁻¹⁰ Pa. This is indicated by a in FIG.

Next, the dimensions, height 8 mm × width 8 are set in the sample chamber 3.
The magnet sample 8 having a size of 50 mm × length 50 mm and a quantity of 60 was inserted, and the Ti getter pump 4 and the ion pump 5 were operated and evacuated, baked at 150 to 200 ° C. for 48 hours, and then allowed to cool. After the temperature in the main body 2 becomes 70 ° C. or lower, the ultimate vacuum degree is measured by operating the BA gauge 6 and the extractor gauge 7. At this time, the relationship between the ultimate vacuum degree and the elapsed time until reaching the final vacuum degree is shown by a curve b in FIG. In addition, ○ indicates a measurement value using a BA gauge, and □ indicates a measurement value using an extractor gauge.

Comparative Example 1 A Ti film, an Al film, Ti
Table 1 shows the magnetic properties of the magnet test pieces without the _1-x Al _x N coating. After cleaning the surface of a magnet body test piece having the same size and quantity as in Example 1 under the same conditions as in Example 1, the ultimate vacuum degree was measured using the ultrahigh vacuum apparatus of FIG. 1 under the same conditions as in Example 1. . The result is shown by curve c in FIG.

Comparative Example 2 The surface of a magnet test piece having the same composition, the same dimensions and the same quantity as in Example 1 was cleaned under the same conditions as in Example 1, and then a 20 μm Ni film was formed by ordinary electroplating. The magnetic properties of the obtained Ni-plated magnet were measured, and the results are shown in Table 1. Then, after the surface of the Ni-plated magnet was washed, the ultimate vacuum degree was measured using the ultrahigh vacuum apparatus of FIG. 1 under the same conditions as in Example 1. The result is shown by a curve d in FIG.

A Fe-BR-based permanent magnet having a Ti _1-x Al _x N coating layer provided on a surface of a magnet according to the present invention after a Ti coating is formed on the magnet surface and an Al coating layer formed on the Ti coating. As in the embodiment, the body does not generate gas from the magnet body,
Although it is possible to achieve a degree of vacuum of 1 × 10 ⁻⁹ Pa or less, it can be seen that the desired ultimate degree of vacuum cannot be achieved due to the gas generated from the magnet body as it is for the magnet material or for the magnet body provided with the Ni plating film.

[0037]

[Table 1]

[0038]

According to the present invention, after a surface of an Fe-BR based permanent magnet is cleaned by an ion sputtering method or the like, a Ti film is formed on the surface of the magnet by a thin film forming method such as an ion plating method. Then, an Al film is formed on the Ti film by a thin film forming method such as ion plating, and a thin film forming method such as an ion reaction plating is performed on the Al film in a N ₂ -containing gas to obtain Ti _1-x Characterized by forming an Al _x N coating, the coating is dense, has excellent adhesion, has the function of preventing gas generation from the magnet body, and has high magnetic properties that can be used for undulators, etc. in ultra-high vacuum atmosphere. An Fe-BR-based permanent magnet for ultra-high vacuum having characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of an ultra-high vacuum device used for measuring a degree of ultimate vacuum.

FIG. 2 is a graph showing the relationship between ultimate vacuum and time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultra-high vacuum apparatus 2 Main body 3 Sample chamber 4 Ti getter pump 5 Ion pump 6 BA gauge 7 Extractor gauge 8 Magnet sample

Claims (2)

[Claims] 1. A film thickness of 0.1 .mu.m to 3.0 .mu.m formed on the surface of an Fe--BR--based permanent magnet body whose main phase is a tetragonal phase.
A Ti _1-x Al _x N film having a thickness of 0.5 μm to 10 μm is formed on a Ti film having a thickness of 0.1 μm to 5 μm through an Al film having a thickness of 0.1 μm to 5 μm.
(However, 0.03 <x <0.70) An ultra-high vacuum permanent magnet having a coating layer. 2. A method for forming a thin film on a cleaned surface of an Fe—BR—based permanent magnet body having a tetragonal phase as a main phase.
After forming a Ti film having a thickness of 0.1 μm to 3.0 μm, an Al film having a thickness of 0.1 μm to 5 μm is formed on the Ti film, and a Ti film having a thickness of 0.5 μm to 10 μm is formed on the Al film.
_A method for producing an ultra-high vacuum permanent magnet which forms a _1-x Al _x N (0.03 <x <0.70) coating layer.