JPH09108852A - High density amorphous alloy junction body and cystallite alloy junction body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amorphous alloy joined body capable of keeping the amorphous structure and high in the density and strength. SOLUTION: In an amorphous alloy joined body, a plurality of amorphous alloy thin strips are laminated, and the adjacent amorphous alloy thin strips are joined with each other through a melted part dotted on the laminated interface. Fine crystals may be precipitated by the heat treatment of the joined body. Because the adjacent thin strips are joined with each other at the joined parts dotted in the laminated interface, the joined body high in the density and strength can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous alloy bonded body in which laminated amorphous alloy ribbons are bonded to each other and a microcrystalline alloy bonded body in which fine crystals are precipitated by heat treatment.

[0002]

2. Description of the Related Art Amorphous alloys are manufactured by quenching and solidifying a molten alloy, and the usual melting / casting method cannot be adopted. Therefore, the form of the obtained amorphous alloy is also limited to a ribbon or a powder, and in the case of a ribbon, it is almost wound and used. As a means for obtaining a bulk from such a form, there are a method of joining and integrating a plurality of ribbons, a method of sintering powder, and the like. In the sintering method, a bulk is manufactured by sintering an amorphous alloy powder under a high pressure at a temperature equal to or lower than a crystallization start temperature. At this time, if the amorphous alloy powder is heated to a sufficiently high temperature that the densification proceeds due to the plastic deformation of the powder particles and the thermal diffusion of the constituent elements, the crystallization reaction proceeds and the physical properties of the obtained sintered body deteriorate. To do. Therefore, the sintering temperature had to be set low, and a sintered body having high density and high strength could not be obtained.

In the method of joining amorphous alloy ribbons into a bulk, the temperature at the time of joining becomes a problem. Generally, joining at low temperature is very difficult, and the obtained bulk body cannot secure sufficient strength. When the joining temperature is set to a high temperature, crystallization occurs and the physical properties of the obtained bulk body are deteriorated. Therefore, the amorphous alloy ribbon is adhered using an adhesive such as a resin, and the relative density of the bulk body is very low, so that the industrial characteristics are not satisfied.

[0004]

In the case of joining the amorphous alloy ribbons, the mechanical strength of the alloy itself is not sufficient as described above, and the number of voids between the layers is very large. The percentage of effective materials was low.
For example, in the case of an amorphous alloy magnetic body, the relative density (space factor) of the parts obtained by adhering the laminated ribbons is about 80%, and it has not been possible to sufficiently meet the demand for miniaturization and the like. . Further, even in the case where the thin strip is pressure-welded, the relative density is only slightly improved, and the mechanical strength of the bonded body is extremely low. Therefore, it should be used as a bonded body having a thickness of 0.1 to 0.2 mm. Was the limit. On the other hand, the amorphous alloy ribbon is crystallized when subjected to heat history, and the characteristics are extremely deteriorated. Therefore, it is impossible to manufacture a joined body by, for example, spot welding. Also, regarding microcrystalline alloys,
Especially when magnetism and high strength are required, an amorphous alloy is often used as a starting material. Again, in this case,
Since the microcrystal precipitation temperature is relatively low, and the precipitation conditions and the joining conditions are different, it is not possible to obtain a microcrystal joined body that satisfies industrial requirements.

However, the industrial demands for amorphous alloy materials and microcrystalline alloy materials are increasing, and there is an increasing need for a bonded body having a high density and excellent magnetic properties and mechanical properties. The present invention has been devised to meet such a demand, and by joining thin ribbons through a partially melted interface, without destroying an amorphous structure or a microcrystalline structure. The object is to provide a bonded body having high density and excellent magnetic properties and mechanical properties.

[0006]

In order to achieve the object, the bonded body of the present invention has a plurality of amorphous alloy ribbons laminated, and the amorphous alloys adjacent to each other via a fusion zone scattered at the lamination interface. The thin alloy ribbons are bonded to each other, and an oxide film remains at the non-bonded laminated interface. This bonded body is also used as a microcrystalline bonded body in which microcrystals are deposited by heat treatment.

[0007]

The bonded body of the present invention is manufactured by applying high frequency high current and high voltage to the laminated amorphous ribbons for a short time. This joining method is disclosed by the present inventors in Japanese Patent Application No. 7-222.
It was filed as No. 88, but high frequency high current,
The surface layer of the amorphous alloy ribbon is preferentially heated and melted by the skin effect due to the application of high voltage. When pressurizing in this state,
While maintaining the amorphous structure, the alloy ribbons are bonded to each other through the melted interface. In the bonded body obtained by this method, the laminated interface partially disappears at the bonded portion, the oxide film remains on the laminated interface other than the bonded portion, and the inside of the ribbon and the bonded interface have the original amorphous structure. Has become. Due to this special structure, the bonding strength is high, and the magnetic properties are hardly deteriorated as compared with the amorphous alloy as the starting material. Moreover, since the density of the bonded body is high, excellent characteristics not found in the conventional amorphous alloy or microcrystalline alloy are exhibited. Further, the microcrystalline phase can be precipitated by subjecting the bonded body to an appropriate heat treatment.

When joining the laminated amorphous alloy ribbons, a capacitor that withstands a predetermined voltage is used. The amorphous alloy ribbon is electrically heated by discharging the electric power charged in the capacitor. Alternatively, the amorphous alloy ribbon is electrically heated by applying a voltage and current within a predetermined range of a frequency of 1 kHz or more obtained by a pulse power generator or the like for a short time of 50 microseconds to 500 milliseconds. A skin effect occurs in the energized amorphous alloy, and the current mainly flows on the surface of the amorphous alloy ribbon. At this time, the contact resistance between the adjacent ribbons is locally different due to the fine irregularities on the surface of the ribbon and the surface oxide film, so that the interface of the laminated ribbons is partially melted and joined. This partial melting / bonding occurs in a very short time, and the part other than the interface with low electric resistance acts as a heat sink, so that the amorphous structure is maintained not only inside the ribbon but also at the bond interface.

As described above, unlike the conventional method of uniformly heating the entire material, the surface portion and the peripheral portion of the amorphous alloy ribbon are concentratedly heated, and the inside is hardly heated. for that reason,
The heat generated by energization is efficiently consumed for joining the amorphous alloy ribbons, the energization time can be set to an extremely short time, and the amorphous structure is not deteriorated. Further, the oxide in the joint is destroyed by the rapid heating, and the adjacent ribbons are joined with good strength. In fact, as a result of observing the joint, it was confirmed that impurities such as oxides were not present at the interface. The bonded body thus obtained has a high relative density,
Also, the breaking strength is high. Further, since the surface oxide remains at the portions other than the portions where the ribbons are partially joined, the decrease in the electrical resistance between the ribbons is very small. That is, the adjacent ribbons are electrically connected to each other through the joint, and are substantially insulated at the interface other than the joint. As a result of such a structure, characteristics which have not been obtained can be obtained. For example, looking at the application to magnetic parts, which is the largest industrial use,
The joined body of the present invention has direct current magnetic characteristics equivalent to those of the amorphous alloy ribbon as a starting material, and also has high frequency magnetic characteristics such as iron loss and the like. Since the relative density is improved by 15 to 20% as compared with the commercially available rolled material, the magnetic characteristics per unit volume are improved by 15 to 20%, and various magnetic parts can be miniaturized. . Further, the restrictions imposed on the shape such as the size and thickness of the bonded body are remarkably relaxed as compared with the conventional thermocompression bonding material, and the application to a large magnetic component such as a power transformer is sufficiently possible.

[0010]

【Example】

Example 1 Fe ₇₈ Si ₉ B having a thickness of 25 μm and 10 mm square
100 ₁₃ (atomic%) amorphous alloy ribbons were laminated on an insulating mold, and the amorphous alloy ribbons were bonded in the atmosphere under the conditions shown in Table 1. When the cross section of the obtained joined body was observed with an optical microscope, as shown in FIG. 1, adjacent thin strips were joined at the joints scattered at the lamination interface, and the oxide film remained on the thin ribbon surface at the joined portion. Was observed. On the other hand, in the commercial product used as the wound toroidal core, a continuous oxide layer was observed at the lamination interface as shown in FIG.

[0011]

The obtained bonded body did not undergo delamination during normal handling, and it was found from various X-ray diffraction, structure observation and thermal analysis results that the amorphous structure was maintained after bonding. . This is because, as shown in FIG. 1, local melting / bonding is performed at a portion where the lamination interface of the amorphous alloy ribbon disappears, and the bonding portions are scattered at the lamination interface, so that adjacent thin films are formed. This is because the bands are firmly joined together. Further, even in the bonded portion, an amorphous structure was maintained because a rapid heating / cooling process was performed. As described above, the bonded body of the present invention has a cross-sectional structure greatly different from the cross-sectional structure of the commercially available product (FIG. 2). As is clear from this cross-sectional structure, the voids between the ribbons are significantly reduced, and it can be seen that this is a high-density bonded body. In fact, the measured result showed that the relative density of the bonded body was 97%. Moreover, it can be understood from the cross-sectional structure in FIG. 1 that the electric resistance due to the bonding is extremely small at the laminated interface other than the bonded portion, and the high frequency characteristics are excellent.

FIG. 3 shows the result of surface analysis of the cross section of the joined body by EPMA. When the secondary electron beam image (a) and the characteristic X-ray image of oxygen (b) are compared, the oxygen concentration analysis result at the site where the interface disappears reveals that the oxygen concentration at the joint is higher than that at the non-joint. You can see that it is decreasing. That is, in the bonding portion, the adjacent ribbons are bonded to each other with the surface oxide film of the ribbons removed. Based on such knowledge, the cross-sectional structure of the laminate of the present invention is schematically shown in FIG. That is, the adjacent ribbons are joined via the joining portion and face each other via the oxide film in the non-joining portion. Moreover, the interface between layers is very thin as compared with the conventional laminate. As a result, it is presumed that the density and the bonding strength are high and the excellent magnetic properties are exhibited.

Example 2: 10 μm square F with a thickness of 25 μm
e ₇₈ Si ₉ B ₁₃ (atomic%) amorphous alloy ribbon and Co ₆₆ F
An e ₄ Ni ₁ Si ₁₄ B ₁₅ (atomic%) amorphous alloy ribbon was bonded under the same conditions as in Example 1. The influence of the thickness of the laminated body on the relative density was investigated by changing the number of laminated layers. As shown in FIG. 5, which shows the investigation results, the relative density was hardly reduced even when the bonded body was thickened. Further, the structure having the cross-sectional structure shown in FIG. 1 was maintained regardless of the increase in thickness. In this example, a joined body having a maximum thickness of 100 mm was produced, and it was confirmed that an amorphous alloy joined body having a high relative density was produced.

Example 3: Fe ₇₈ Si ₉ B having a thickness of 25 μm
₁₃ (atomic%) amorphous alloy ribbon and Co ₆₆ Fe ₄ Ni ₁ S
i ₁₄ B ₁₅ (atomic%) Amorphous alloy ribbon with an outer diameter of 20 m
m and an inner diameter of 12 mm were processed and laminated, and joined under the same conditions as in Example 1. Regarding the obtained joined body,
The DC axis characteristics such as coercive force and saturation magnetic flux density were investigated. When the investigation results were arranged in relation to the thickness of the bonded body, they had a constant coercive force and a saturated magnetic flux density regardless of the thickness as shown in FIGS. 6 and 7, respectively. From this, it is understood that the obtained joined body has extremely good direct current magnetic characteristics. The comparative materials in FIGS. 6 and 7 are commercially available rolled materials. Further, when the relationship between the thickness of the joined body and the iron loss per unit volume was investigated, as shown in FIG. 8, almost no increase in iron loss was observed even if the thickness was increased.
That is, it can be seen that the joined body of the present example exhibits excellent high-frequency magnetic characteristics because the decrease in electric resistance due to joining is suppressed to a very small extent and the effect due to high density is exhibited. The comparative material of FIG. 8 also shows a commercially available rolled material.

Example 4 Fe ₇₈ Si ₉ B ₁₃ (atomic%) amorphous alloy ribbons having a thickness of 25 μm, a width of 5 mm and a length of 50 mm were bonded under the same conditions as in Example 1. The obtained joined body was subjected to a tensile test, and the tensile strength was investigated along the direction parallel to the laminated surface and the direction orthogonal to the laminated surface. When the tensile strength in each direction was arranged by the thickness of the joined body, the relationship shown in FIG. 9 was obtained. As shown in FIG. 9, when the bonded body was pulled in parallel with the laminating direction, the strength substantially equal to that of the amorphous alloy ribbon as the starting material was obtained. This tensile strength is
Even if the thickness of the bonded body was increased, there was almost no change. On the other hand, the tensile strength in the direction orthogonal to the stacking direction was about 30 to 50 MPa, and it tended to slightly decrease as the thickness of the joined body increased. However, the tensile strength in the direction orthogonal to the laminated surface is significantly higher than the tensile strength of the conventional thermocompression bonding material, and it can be said that the bonded body has excellent mechanical strength.

Example 5: Fe _73.5 Si with a thickness of 15 μm
_{A 13.5} B ₉ Cu ₁ Nb ₃ (atomic%) amorphous alloy ribbon was processed into a ring shape with an outer diameter of 10 mm and an inner diameter of 6 mm and laminated, and joined under the same conditions as in Example 1 to obtain various thicknesses. I got a joint of Sano. Each joined body was subjected to heat treatment at 550 ° C. for 1 hour in vacuum to precipitate fine crystals having a grain size of about 10 nm.
The iron loss of the joined body after heat treatment was investigated, and the relationship between the joined body thickness and the iron loss per unit volume was obtained. The results of the investigation are shown in FIG. 10 using the conventional rolled material as a comparative material. FIG.
As can be seen in No. 0, the joined body of the present example showed almost no increase in iron loss even if the thickness was increased, and exhibited superior characteristics to the comparative material at any thickness. From this, it was confirmed that the joined body of the present example is a material excellent in high frequency magnetic characteristics as compared with the material manufactured by the conventional method.

[0018]

As described above, in the amorphous alloy ribbon bonded body of the present invention, the adjacent ribbons are bonded to each other through the bonding portions scattered on the laminated surface, and the laminated portions other than the bonding portion are laminated. Since the structure has an oxide film remaining at the interface, it has a high density and a high bonding strength, and the original excellent magnetic characteristics of the amorphous alloy are maintained. Therefore, it is used as a high-performance material for electronic parts such as cores, noise filters, choke coils, etc. as electronic parts and power transformers. Also, high corrosion resistance,
It is used in a wide range of fields as high-strength and designable parts.

[Brief description of the drawings]

FIG. 1 is a cross-sectional optical micrograph of the joined body obtained in Example 1.

[Fig. 2] Cross-sectional optical micrograph of a commercially available rolled material.

FIG. 3 shows a secondary electron beam image (a) and a characteristic X-ray image of oxygen (b) showing an analysis result of a bonding interface of the bonded body obtained in Example 1 by EPMA.

FIG. 4 is a schematic diagram of a cross-sectional structure of the joined body obtained in Example 1.

FIG. 5: Relationship between thickness and relative density of the joined body obtained in Example 2

FIG. 6 shows the relationship between the thickness of the bonded body obtained in Example 3 and the coercive force at direct current.

FIG. 7 shows the relationship between the thickness of the joined body obtained in Example 3 and the saturation magnetic flux density at direct current.

FIG. 8 shows the relationship between the thickness of the joined body obtained in Example 3 and the iron loss per unit volume.

FIG. 9: Relationship between thickness and tensile strength of the joined body obtained in Example 4

FIG. 10 shows the relationship between the thickness of the joined body obtained in Example 5 and the iron loss per unit volume.

Front Page Continuation (72) Inventor Yosuke Tanaka 7-1 Takaya Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd. (72) Inventor Koji Tanaka 7-1 Takaya Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd. Company Technical Research Center (72) Inventor Ayako Matsumoto 7-1 Takaya Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd. Technical Research Center

Claims (2)

[Claims] 1. A plurality of amorphous alloy ribbons are laminated, and adjacent amorphous alloy ribbons are joined to each other through a melted portion scattered on the laminated interface, and a laminated interface of a non-joined portion is formed. An amorphous alloy bonded body in which an oxide film remains. 2. A microcrystalline alloy joined body in which fine crystals are precipitated by heat-treating the joined body according to claim 1.