JP6103749B2 - FeCo-based magnetostrictive alloy and method for producing the same - Google Patents

Description

  The present invention relates to an FeCo-based magnetostrictive alloy having a function of expanding and contracting itself with the application of magnetic force from the outside, and a method for producing the same.

  In general, in a ferromagnetic material that is magnetized by an external magnetic field, an expansion and contraction phenomenon occurs as the S and N poles of the spontaneous magnetic domains existing in the crystal are reversed and rotated with the application of the external magnetic field. This is called a magnetostriction phenomenon (see Non-Patent Document 1). When an alternating current is made to flow through a coil installed around a magnetic material to create an alternating magnetic field, it can be applied as an active element.

  This magnetostrictive effect has a larger energy density at the start-up than the piezoelectric and electrostrictive effects of ceramics, and also has material strength due to the alloy, and it is easy to bulkize, so large seafloor exploration and fish school detection Application to ultrasonic sonar and ultrasonic transducer for searching underground resources has been studied, and recently, application to vibration power generation using inverse magnetostriction effect has also been studied.

  It can also be used for a force sensor utilizing the inverse magnetostriction effect in a magnetostrictive alloy. For example, in intelligent robots with soft, high-definition work functions, such as human hands required in the next generation, and manipulators and robot hand units in minimally invasive medical devices, the hands must have force and touch. Therefore, it is required to measure and control the rotation angle and torsional force with high accuracy not only at the fingertips but also at the joints of the fingers.

  However, there is no commercially available torque sensor with a small size, light weight, simple structure, and high sensitivity that can be incorporated into mobile devices and intelligent robots at the present time. Development of a sensitive torque sensor is required. In this torque sensor system, the leakage magnetic flux generated from the magnetostrictive alloy surface when stress is applied to the rotating shaft uses the principle proportional to the load force, so the sensor sensitivity depends greatly on the magnetic properties of the magnetostrictive alloy, Production and material selection of magnetostrictive alloys with excellent material properties are important.

The main features of the vibration element (actuator) and sensor element using the magnetostrictive effect are as follows.
(1) Since it is a metal material, it can be easily processed into a complicated shape when it is installed on the exciting coil.
(2) The material is metal, high in strength, strong, durable against repeated vibration deformation over a long period of time, and durable.
(3) It can be driven by an external magnetic field coil in a non-contact wireless manner. Therefore, there is a degree of freedom in which actuator elements and the like in the fluid and the living body can be remotely installed remotely.
(4) High power generation characteristics with resonance vibration can be obtained.
(5) With low output impedance, it can be driven with a voltage lower than that of the piezoelectric body, and it is easy to apply impedance matching with the mother structure side and control impedance matching, and a large actuator can be designed easily.
(6) The magnetostrictive alloy is in a temperature range where the Curie temperature is high, and a wide use temperature range can be taken (-100 ° C to 500 ° C).
(7) Since the coil is used, it is inevitable that the actuator volume increases.
(8) A cooling device for preventing heat generation with a high-frequency vibrator is required.
(9) A container (housing) for blocking electromagnetic noise leakage is required.

  Actually, in an industrial application as a vibration element (actuator) or sensor element of a magnetostrictive material, until now, a compressive force in a uniaxial direction has been applied to a giant magnetostrictive material (Tb-Dy-Fe alloy) (see Non-Patent Document 1). However, this material contains rare earth elements, has low ductility, and has a high product cost, so that the use environment is limited.

  Recently, practical use of a magnetostrictive vibration element (see Non-Patent Document 3) has been promoted using a single crystal and directional polycrystalline FeGa alloy (Galfenol) (see Non-Patent Document 2) having workability. It is coming.

  These FeGa alloys utilize magnetostriction of 300 ppm at the maximum, but in that case, since the material is limited to a single crystal or a coarse crystal structure having directionality, the material is soft and the longitudinal elastic modulus (Young's modulus) is 50 to 50. It becomes 60 GPa, and it is inevitable that the mechanical strength is lowered. However, even with current FeGa alloys, the magnetostrictive energy density is still low, and the production of single crystals is very expensive. For this reason, it has not reached an application level that matches various fields of use of general-purpose industrial equipment in terms of mass productivity of magnetostrictive samples and processing and molding costs of vibration elements.

  Also, heretofore, an example of focusing on an alloy based on an FeCo-based alloy that is a general iron-based magnetostrictive material, made of a ferromagnetic Co (cobalt) element, and having high rigidity and high saturation magnetic flux density. Are disclosed (Non-Patent Documents 4 to 7).

  Non-Patent Document 4 investigates the Co dependence of the longitudinal elastic modulus (Young's modulus). According to this, the Co composition shows a maximum value (about 210 GPa) around 30 atomic%, and then Co = 50. The maximum value is maintained up to the vicinity of atomic%, and then the Young's modulus gradually decreases as the Co concentration increases, and reaches a minimum value (about 182 GPa) near Co = 85 atomic%.

  Non-Patent Document 5 describes an example in which an alloy material is melted in an induction electric furnace in a vacuum, cast using a metal mold, and then heat-treated in a vacuum furnace at 1050 ° C. for 1.5 hours. ing. For example, in a Co = 70 atomic% FeCo alloy, a magnetostriction amount of 90 ppm is obtained at a magnetic field of 1000 Oe.

  Non-Patent Document 6 discloses that an alloy material is arc-melted in an argon atmosphere, further heat-treated at 1000 ° C. for 3 days, and further in each atmosphere such as 300 ° C. and 350 ° C. for each sample in an argon atmosphere. An example of performing heat treatment is described. For example, in the case of Co = 70 atomic% FeCo alloy, 150 ppm is obtained by | vertical strain−transverse strain | when heat treatment at 840 ° C. is performed. However, since the definition of magnetostriction of non-single crystal is λ = (2/3) × (longitudinal strain−lateral strain), the magnetostriction amount is estimated to be 100 ppm.

  Non-Patent Document 7 describes an example in which an FeCo alloy film is formed on a cantilever base by sputtering, then heat-treated at 800 ° C. for 1 hour, and rapidly cooled with water. For example, a magnetostrictive amount of 260 ± 10 ppm is obtained in an FeCo alloy thin film of Co = 66 atomic%.

A. E. Clark and Hiroshi Eda, “Super Magnetostrictive Materials”, Nikkan Kogyo Shimbun (1995), pp. 94-100, p143 and p170. A. E. Clark, J. et al. B. Restorff, M.M. Wun-Fogle, T.W. A. Lagrasso and D.M. L. Schlagel, IEEE Trans. Magn. 36, 2000, 239-244 T. T. Ueno and S.M. Yamada, Study on Micro-energy Harvesting Device Using Iron-Gallium Alloy, Journal of the Magnetics Society of Japan, vol. 35, no. 2, 2011, 88-91 Miki Yamamoto, Young's Modulus of Elasticity and Its Change with Magnetization in Iron-Cobalt Alloys, Sci. Rep. Tohoku Imp. Univ. , 30, 1941, 768 Yosio Masayama, On the Magnetostriction of Iron-Cobalt Alloys. The 294th report of the Research Institute for Iron, Steel and Other Metals. Liang Dai and Manfred Wuttig, Magnetostriction in Co-rich bcc CoFe Solid Solutions, Submitted for publication in Script Mat. October 9, 2007 Dight Hunter, Will Osborn, Ke Wang, Nataliya Kazantseva, Jason Hattrick-Simpers, Richard Suchoski, Ryota Takahashi, Marcus L. Young, Apura Mehta, Leonid A. et al. Bendersky, Sam E. et al. Loland, Manfred Wuttig & Ichiro Takeuchi, Giant magnetostriction in annealed Co1-xFex thin-films, natural COMMUNICATIONS, ATICLE p21

  Since FeCo alloy has a higher Young's modulus than FeGa alloy, it has high mechanical strength and is promising for practical use of magnetostrictive vibration elements. However, in the above-mentioned Non-Patent Documents 5 and 6 relating to the FeCo alloy, there is no description about the definition of the degree of orientation effective in increasing the magnetostriction, and there is a limit to improving the magnetostriction. Although Non-Patent Document 7 has a high magnetostriction, there is a problem that it cannot be applied to a bulk alloy because it is a FeCo alloy using a thin film formed on a cantilever base. Of course, Non-Patent Document 7 does not describe the degree of orientation.

  The present invention has been made in consideration of such problems. By defining the degree of orientation, the amount of magnetostriction of the bulk alloy can be increased, and the practical application of magnetostrictive vibration elements and the like can be promoted. An object of the present invention is to provide a magnetostrictive alloy. Here, the bulk alloy has a lump shape, a column shape, a cubic shape, a rectangular parallelepiped shape, a thin plate shape, and the like, and does not include a thin film.

  Another object of the present invention is to increase the degree of orientation to 19% or more, thereby increasing the amount of magnetostriction, and easily producing an excellent magnetostrictive alloy that can promote the practical use of magnetostrictive vibration elements and the like. An object of the present invention is to provide a method of producing an FeCo magnetostrictive alloy that can be produced.

[1] The FeCo magnetostrictive alloy according to the first aspect of the present invention is a magnetostrictive alloy composed of Fe (iron) and Co (cobalt) and having a body-centered cubic structure containing 50 atomic% to 70 atomic% of Co. The orientation degree (Lotgering factor) of the (110) plane represented by the following formula (1) based on the X-ray diffraction result using the Kα characteristic X-ray of Cu (copper) is 19% or more and is effective. The magnetostriction amount in a magnetic field H = 1000 Oe is 100 ppm or more.
Degree of orientation = (P−P ₀ ) / (1−P ₀ ) (1)
Here, P = ΣI (110) / {ΣI (110) + ΣI (200) + ΣI (211))}
P ₀ = ΣI ₀ (110) / {ΣI ₀ (110) + ΣI ₀ (200) + ΣI ₀ (211)}
Where ΣI (110), ΣI (200) and ΣI (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane and (211) plane, respectively, and ΣI ₀ (110), ΣI ₀ (200) and ΣI ₀ (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane, and (211) plane in an ideal non-oriented sample, respectively.

[2] In the first aspect of the present invention, the half width of the peak waveform of the (110) plane in the X-ray diffraction result may be 0.1 ° or more and 0.5 ° or less.

[3] More preferably, the half width of the peak waveform on the (110) plane in the X-ray diffraction result is 0.1 ° or more and 0.3 ° or less.

[4] In the first aspect of the present invention, the alloy material may be melted and then cooled at a cooling rate of 1500 ° C./min or more.

[5] In this case, the heat treatment may be further performed at a temperature ± 40 ° C. of ¼ of the melting point for 24 hours or more.

[6] A method for producing an FeCo magnetostrictive alloy according to the second aspect of the present invention is a method for producing a magnetostrictive alloy comprising Fe (iron) and Co (cobalt) and containing 50 atomic% to 70 atomic% of Co. After melting the material, it is cooled at a cooling rate of 1500 ° C./min or more, and is represented by the following formula (1) based on the X-ray diffraction result using the Kα characteristic X-ray of Cu (copper) (110) A magnetostrictive alloy having a plane orientation degree of 19% or more and a magnetostriction amount in an effective magnetic field H = 1000 Oe of 100 ppm or more is manufactured.
Degree of orientation = (P−P ₀ ) / (1−P ₀ ) (1)
Here, P = ΣI (110) / {ΣI (110) + ΣI (200) + ΣI (211))}
P ₀ = ΣI ₀ (110) / {ΣI ₀ (110) + ΣI ₀ (200) + ΣI ₀ (211)}
Where ΣI (110), ΣI (200) and ΣI (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane and (211) plane, respectively, and ΣI ₀ (110), ΣI ₀ (200) and ΣI ₀ (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane, and (211) plane in an ideal non-oriented sample, respectively.

[7] In this case, the full width at half maximum of the peak waveform of the (110) plane in the X-ray diffraction result of the magnetostrictive alloy to be manufactured is 0.1 ° to 0.5 °.

[8] In the second aspect of the present invention, after the cooling, heat treatment may be performed for 24 hours or more at a temperature ± 40 ° C. that is ¼ of the melting point of the magnetostrictive alloy.

[9] In this case, the full width at half maximum of the peak waveform of the (110) plane in the X-ray diffraction result of the magnetostrictive alloy to be produced is 0.1 ° or more and 0.3 ° or less.

  As described above, according to the FeCo magnetostrictive alloy according to the present invention, by defining the degree of orientation, the amount of magnetostriction of the bulk alloy can be increased, and the practical use of a magnetostrictive vibration element or the like can be promoted. .

  In addition, according to the method for producing an FeCo magnetostrictive alloy according to the present invention, the alloy material is melted and then rapidly cooled at a cooling rate of 1500 ° C./min or more, so that the degree of orientation can be increased to 19% or more. In addition, the amount of magnetostriction can be increased as the degree of orientation is improved. As a result, it is possible to easily produce an excellent magnetostrictive alloy that can promote the practical use of a magnetostrictive vibration element or the like.

It is process drawing which shows the manufacturing method (1st manufacturing method) which concerns on 1st this Embodiment. FIG. 2A is a graph showing an X-ray diffraction result of a first magnetostrictive alloy (Co ratio = 50 atomic%) manufactured by the first manufacturing method, and FIG. 2B is a graph showing an enlarged horizontal axis of FIG. 2A. . FIG. 3A is a graph showing an X-ray diffraction result of the second magnetostrictive alloy (Co ratio = 70 atomic%) manufactured by the first manufacturing method, and FIG. 3B is a graph showing the horizontal axis of FIG. 3A in an enlarged manner. . It is process drawing which shows the manufacturing method (2nd manufacturing method) based on 2nd this Embodiment. FIG. 5A is a graph showing an X-ray diffraction result of a third magnetostrictive alloy (Co ratio = 50 atomic%) manufactured by the second manufacturing method, and FIG. 5B is a graph showing an enlarged horizontal axis of FIG. 5A. . FIG. 6A is a graph showing an X-ray diffraction result of the fourth magnetostrictive alloy (Co ratio = 70 atomic%) manufactured by the second manufacturing method, and FIG. 6B is a graph showing the horizontal axis of FIG. 6A in an enlarged manner. .

  Embodiments of an FeCo magnetostrictive alloy and a method for producing the same according to the present invention will be described below with reference to FIGS. In the present specification, “˜” indicating a numerical range is used as a meaning including numerical values described before and after the numerical value as a lower limit value and an upper limit value.

  First, a method for manufacturing an FeCo magnetostrictive alloy according to the first embodiment (hereinafter referred to as a first manufacturing method) will be described with reference to FIGS.

  In the first manufacturing method, first, in step S1 of FIG. 1, Fe (iron) and Co (cobalt) are weighed to produce an alloy material. In this case, Co is in the range of 50 atomic% to 80 atomic%.

  Thereafter, in step S2, the alloy material is melted to produce a mother alloy. In producing this mother alloy, for example, a plasma arc melting apparatus can be used.

  Thereafter, in step S3, the mother alloy is cooled at a cooling rate of 1000 ° C./min or more. That is, it cools rapidly. This rapid cooling treatment can be performed in a copper hearth where the mother alloy is water cooled. The cooling rate is preferably 1500 ° C./min to 3000 ° C./min, more preferably 1700 ° C./min to 2200 ° C./min.

  Thereafter, in step S4, the mother alloy is cut out to produce, for example, a rectangular parallelepiped (an example of a magnetostrictive alloy product model) of length × width × height = 20 mm × 2 mm × 1 mm.

When this product model was used as a test piece for evaluating magnetic properties and the magnetic properties were examined, it was expressed by the following formula (1) based on the X-ray diffraction result using the Kα characteristic X-ray of Cu (copper) ( 110) The orientation degree (Lotgering factor) of the plane was 19% or more, and the magnetostriction amount in the effective magnetic field H = 1000 Oe was 100 ppm or more.
Degree of orientation = (P−P ₀ ) / (1−P ₀ ) (1)
Here, P = ΣI (110) / {ΣI (110) + ΣI (200) + ΣI (211))}
P ₀ = ΣI ₀ (110) / {ΣI ₀ (110) + ΣI ₀ (200) + ΣI ₀ (211)}
Where ΣI (110), ΣI (200) and ΣI (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane and (211) plane, respectively, and ΣI ₀ (110), ΣI ₀ (200) and ΣI ₀ (211) indicate the integrated intensities of diffraction intensities of the (110) plane, (200) plane, and (211) plane in an ideal non-oriented sample, respectively.

  Here, as an example, an FeCo magnetostrictive alloy according to an embodiment containing 50 atomic% Co (hereinafter referred to as a first magnetostrictive alloy) and an FeCo magnetostrictive alloy according to an embodiment containing 70 atomic% Co (hereinafter referred to as “first magnetostrictive alloy”). Will be described as a second magnetostrictive alloy).

  2A and 2B show the X-ray diffraction results of the first magnetostrictive alloy, and FIGS. 3A and 3B show the X-ray diffraction results of the second magnetostrictive alloy. The X-ray diffraction results are shown in a graph showing the diffraction angle 2θ on the horizontal axis and the normalized diffraction intensity on the vertical axis. 2B and 3B are enlarged views of the horizontal axis (diffraction angle 2θ) of FIGS. 2A and 3A.

  In both the first magnetostrictive alloy and the second magnetostrictive alloy, peak waveforms appeared on the (110) plane, the (200) plane, and the (211) plane. Specifically, the results are shown in Table 1 below.

  Further, the half width of each peak waveform on the (110) plane of the first magnetostrictive alloy and the second magnetostrictive alloy was 0.38 ° for the first magnetostrictive alloy and 0.40 ° for the second magnetostrictive alloy. As shown in FIGS. 2B and 3B, the half-value width indicates a width Wa that is ½ of the height ha of the peak waveform.

  The magnetostriction amount of the first magnetostrictive alloy in the effective magnetic field H = 1000 Oe was 106 ppm, and the magnetostriction amount of the second magnetostrictive alloy was 110 ppm.

  As described above, the FeCo magnetostrictive alloy according to the present embodiment has a (110) plane orientation degree as high as 19% or higher (100% is the upper limit), and the magnetostriction amount in an effective magnetic field H = 1000 Oe is 100 ppm or higher. large.

  In other words, it is a magnetostrictive alloy composed of Fe (iron) and Co (cobalt) and containing 50 atomic% to 80 atomic% of Co, and by defining the degree of orientation to 19% or more, the magnetostriction in the effective magnetic field H = 1000 Oe. It was found that a large magnetostriction amount of 100 ppm or more can be expressed. Both Fe and Co are ferromagnetic materials, and have a higher saturation magnetic flux density (Bs) and magnetic permeability (μ) than the conventional FeGa system (Galfenol) made of nonmagnetic Ga, and the Young's modulus reaches 210 GPa at the maximum. Therefore, it can be a magnetostrictive alloy having high strength, durability and soft magnetic properties.

  Moreover, since it is a non-rare earth system, it is not brittle, is cheaper than a giant magnetostrictive material (Tb-Dy-Fe alloy), and Co has an advantage that it has a large amount of resources and can be mass-produced.

  Therefore, by using this magnetostrictive alloy, practical application of a magnetostrictive vibration element or the like can be promoted. For example, it is advantageous for application to large-scale seabed exploration, fish detection sonar, ultrasonic transducers for underground resource search, and vibration power generation using the inverse magnetostriction effect.

  Furthermore, as described above, in a torque sensor system assumed to be used in an intelligent robot having a soft and high-definition work function, a manipulator or a robot hand unit in a minimally invasive medical device, Since the magnetic flux leakage generated from the surface of the magnetostrictive alloy at the time of stress loading uses the principle proportional to the load force, the sensor sensitivity greatly depends on the magnetic characteristics of the magnetostrictive alloy. Since the magnetostrictive alloy has excellent magnetic properties and material properties as described above, it is suitable as a magnetostrictive alloy for a torque sensor system.

  Further, according to the first manufacturing method described above, after the alloy material is melted, cooling control is performed at a cooling rate of 1500 ° C./min to 3000 ° C./min, whereby the degree of orientation on the (110) plane is 19%. The amount of magnetostriction can be increased as the degree of orientation is improved. As a result, it is possible to easily produce an excellent magnetostrictive alloy that can promote the practical use of a magnetostrictive vibration element or the like.

  Next, a method of manufacturing an FeCo magnetostrictive alloy according to the second embodiment (hereinafter referred to as a second manufacturing method) will be described with reference to FIGS. 4 to 6B.

  First, since the process shown in step S101 to step S104 in FIG. 4 is substantially the same as the process shown in step S1 to step S4 in the first manufacturing method described above, the duplicate description is omitted. A material is prepared, and a master alloy is prepared in step S102. Thereafter, in step S103, the mother alloy is rapidly cooled at a cooling rate of 1500 ° C./min or more, and in step S104, the mother alloy is cut out, for example, a rectangular parallelepiped (magnetostrictive alloy of length × width × height = 20 mm × 2 mm × 1 mm). An example of a product model is produced.

  In the next step S105, the product model is subjected to heat treatment for 24 hours or more at a temperature ± 40 ° C. that is ¼ of the melting point of the product model.

  When this product model was used as a test piece for evaluating magnetic properties and the magnetic properties were examined, the integrated intensities of the (110) plane, (200) plane, and (211) plane in the X-ray diffraction results were I (110), respectively. , I (200) and I (211), the orientation degree of the (110) plane represented by the above formula (1) is 19% or more, and the magnetostriction amount in the effective magnetic field H = 1000 Oe is 100 ppm or more. Met.

  Here, as an example, the FeCo-based magnetostrictive alloy (hereinafter referred to as a third magnetostrictive alloy) according to the embodiment after heat treatment containing 50 atomic% Co (step S105), and the implementation after heat treatment containing 70 atomic% Co. An FeCo magnetostrictive alloy (hereinafter referred to as a fourth magnetostrictive alloy) according to the embodiment will be described.

  The X-ray diffraction results of the third magnetostrictive alloy are shown in FIGS. 5A and 5B, and the X-ray diffraction results of the fourth magnetostrictive alloy are shown in FIGS. 6A and 6B. 5B and 6B are enlarged views of the horizontal axis of FIGS. 5A and 6A.

  In both the third magnetostrictive alloy and the fourth magnetostrictive alloy, peak waveforms appeared on the (110) plane, the (200) plane, and the (211) plane. Specifically, the results shown in Table 2 below were obtained.

  The half width of each peak waveform on the (110) plane of the third and fourth magnetostrictive alloys was 0.19 ° for the third magnetostrictive alloy and 0.24 ° for the fourth magnetostrictive alloy. As shown in FIGS. 5B and 6B, the half-value width indicates a width Wa that is ½ of the height ha of the peak waveform. The third magnetostrictive alloy and the fourth magnetostrictive alloy have a half width of 40% or more narrower than the first magnetostrictive alloy and the second magnetostrictive alloy before the heat treatment described above, and the crystallinity is improved. Recognize.

  In addition, the magnetostriction amount of the third magnetostrictive alloy in the effective magnetic field H = 1000 Oe was 100 ppm, and the magnetostriction amount of the fourth magnetostrictive alloy was 102 ppm, which was found to be almost the same as the first magnetostrictive alloy and the second magnetostrictive alloy.

  From this, it is possible to obtain a magnetostrictive alloy with improved crystallinity while maintaining the degree of orientation of the (110) plane by performing the heat treatment described above, and to provide a vibration element that reacts sensitively to changes in the magnetic field. It becomes possible to provide. In other words, the merit of improving crystallinity varies depending on the crystallinity and grain size (crystallite size) effect. In this case, if limited to relaxation of lattice strain (relaxation / uniformization of internal stress), the magnetic flux Pinning (effect of obstructing rotation of magnetic moment and movement of domain wall) is reduced. Compared with the case where the crystallinity is unstable, the magnetization process becomes smooth, so that the magnetic strain rises with a high magnetic permeability, that is, with a low magnetic field. In other words, since the magnetostriction susceptibility increases, it can be said that it has become “sensitive to changes in the magnetic field”.

[First embodiment]
About Examples 1-4 and Comparative Examples 1-4, the magnetostriction amount in the effective magnetic field H = 1000 Oe was confirmed. The breakdown of Examples 1-4 and Comparative Examples 1-4 is as follows.

Example 1
A test piece according to Example 1 was manufactured according to the first manufacturing method (see FIG. 1). That is, Fe and Co are weighed to prepare an alloy material having a Co ratio of 50 atomic%, and then the alloy material is water-cooled using a plasma arc melting apparatus (TIG-400F: manufactured by Toei Scientific Industrial Co., Ltd.). A mother alloy was prepared by melting in a copper hearth. Thereafter, the mother alloy was cast in a copper hearth which was water-cooled while cooling was controlled at a cooling rate of 1500 ° C./min to 3000 ° C./min. Thereafter, the cast alloy was cut out to prepare a test piece according to Example 1 for evaluating magnetic properties of length × width × height = 20 mm × 2 mm × 1 mm.

(Examples 2 to 4)
Examples 2, 3 and 4 were produced in the same manner as Example 1 described above, except that alloy materials having a Co ratio of 60 atomic%, 65 atomic% and 70 atomic% were used.

(Comparative Example 1)
A test piece according to Comparative Example 1 was produced by the method shown in Non-Patent Document 5 described above. That is, Fe and Co are weighed to prepare an alloy material having a Co ratio of 50 atomic%, the alloy material is melted in an induction electric furnace in a vacuum, and further cast using a metal mold to form a master alloy. Produced. Thereafter, the mother alloy was cut out to produce a rectangular parallelepiped of length × width × height = 20 mm × 2 mm × 1 mm, and this rectangular parallelepiped was subjected to a heat treatment at 1050 ° C. for 1.5 hours in a vacuum furnace. Such a test piece was prepared.

(Comparative Examples 2 to 4)
Comparative Examples 2, 3 and 4 were prepared in the same manner as Comparative Example 1 described above, except that alloy materials having a Co ratio of 60 atomic%, 65 atomic% and 70 atomic% were used.

<Evaluation>
For Examples 1 to 4 and Comparative Examples 1 to 4, magnetostriction was analyzed and evaluated using a strain gauge method, and magnetic characteristics were analyzed using a vibrating sample magnetometer (VSM).

<Evaluation results>
Table 3 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4.

  From Table 3, Examples 1-4 produced according to the 1st manufacturing method were all good with the magnetostriction amount being 100 ppm or more. On the other hand, among Comparative Examples 1 to 4 produced by the method of Non-Patent Document 5, Comparative Example 4 had a good magnetostriction amount of 90 ppm, but the other Comparative Examples 1, 2 and 3 had a low magnetostriction amount, Moreover, the variation was large depending on the Co ratio. In Examples 1 to 4, the amount of magnetostriction increased because the means according to the present invention, that is, the alloy material was melted and then rapidly cooled at a cooling rate of 1500 ° C./min or more, so This is thought to be due to the higher degree of orientation.

[Second Embodiment]
For Examples 5 to 9 and Comparative Examples 5 and 6 produced by the first manufacturing method (see FIG. 1), the magnetostriction amount in the effective magnetic field H = 1000 Oe, and the above formula (1) in the X-ray diffraction results are represented. Differences in the degree of orientation of the (110) plane and the half width of the peak waveform of the (110) plane in the X-ray diffraction results were confirmed. The breakdown of Examples 5 to 9 and Comparative Examples 5 and 6 is as follows.

(Example 5)
Similar to Example 1 described above, Fe and Co are weighed to produce an alloy material having a Co ratio of 50 atomic%, and then a plasma arc melting apparatus (TIG-400F: manufactured by Toei Scientific Industrial Co., Ltd.) is used. Then, after melting the alloy material, casting was performed while cooling control was performed at a cooling rate of 1500 ° C./min or more. Thereafter, the cast alloy was cut out to prepare a test piece according to Example 5 for evaluating magnetic properties of length × width × height = 20 mm × 2 mm × 1 mm.

(Examples 6 to 9)
Examples 6, 7, 8 and 9 were the same as Example 5 described above, except that alloy materials having a Co ratio of 55 atomic%, 60 atomic%, 65 atomic% and 70 atomic% were used. Made.

(Comparative Examples 5 and 6)
Comparative Examples 5 and 6 were produced in the same manner as in Example 5 described above, except that alloy materials having Co ratios of 45 atomic% and 75 atomic% were used.

<Evaluation>
For each of the test pieces according to Examples 5 to 9 and Comparative Examples 5 and 6, the crystal structure analysis of the magnetostrictive alloy is the X-ray diffraction method (XRD), the magnetostriction is the strain gauge method, and the magnetic properties are the vibrating sample magnetometer (VSM). ) Was used for analysis and evaluation.

<Evaluation results>
Table 4 shows the evaluation results of Examples 5 to 9 and Comparative Examples 5 and 6.

  From the results of Table 4, for magnetostrictive alloys (Examples 5 to 9) made of Fe and Co and having a Co ratio of 50 atomic% to 70 atomic% (Examples 5 to 9), It was found that the degree of orientation of the (110) plane expressed as follows was 19% or higher and both were high, and the magnetostriction amount in the effective magnetic field H = 1000 Oe was 100 ppm or more. In addition, the half width of the peak waveform on the (110) plane in the X-ray diffraction result was 0.38 ° to 0.40 °. On the other hand, in both Comparative Examples 5 and 6, the magnetostriction amount was higher than Comparative Examples 1, 2, and 3 described above, but was less than 100 ppm.

  Therefore, it can be seen that the preferable Co ratio when evaluated by the amount of magnetostriction is 50 to 70 atomic%, preferably 60 to 70 atomic%.

[Third embodiment]
About Examples 10-14 produced by the 2nd manufacturing method (refer FIG. 4) and Comparative Examples 7 and 8, the magnetostriction amount in effective magnetic field H = 1000 Oe, It represents with the said Formula (1) in a X-ray-diffraction result. Differences in the degree of orientation of the (110) plane and the half width of the peak waveform of the (110) plane in the X-ray diffraction results were confirmed. The breakdown of Examples 10 to 14 and Comparative Examples 7 and 8 is as follows.

(Example 10)
According to the second manufacturing method, Fe and Co are weighed to prepare an alloy material having a Co ratio of 50 atomic%, and then the alloy is formed using a plasma arc melting apparatus (TIG-400F: manufactured by Toei Kagaku Sangyo Co., Ltd.). The material was melted in a copper hearth with water cooling to produce a master alloy. Thereafter, the mother alloy was cast while being cooled at a cooling rate of 1500 ° C./min or higher in a water-cooled copper hearth. Thereafter, the cast alloy was cut out to prepare a test piece for evaluating magnetic properties of length × width × height = 20 mm × 2 mm × 1 mm. Then, this test piece was subjected to heat treatment for 24 hours or more at a temperature ± 40 ° C. that is ¼ of the melting point of the test piece.

(Examples 11-14)
Examples 11, 12, 13 and 14 are the same as Example 10 described above except that alloy materials having Co ratios of 55 atomic%, 60 atomic%, 65 atomic%, and 70 atomic% are used. Made.

(Comparative Examples 7 and 8)
Comparative Examples 7 and 8 were produced in the same manner as in Example 10 described above, except that alloy materials having a Co ratio of 45 atomic% and 75 atomic%, respectively, were used.

<Evaluation>
For each of the test pieces according to Examples 10 to 14 and Comparative Examples 7 and 8, the crystal structure analysis of the magnetostrictive alloy is the X-ray diffraction method (XRD), the magnetostriction is the strain gauge method, and the magnetic characteristics are the vibration sample magnetometer (VSM). ) Was used for analysis and evaluation.

<Evaluation results>
Table 5 shows the evaluation results of Examples 10 to 14 and Comparative Examples 7 and 8.

  From the results in Table 5, for magnetostrictive alloys (Examples 10 to 14) composed of Fe and Co and having a Co ratio of 50 atomic% to 70 atomic% (Examples 10 to 14), It was found that the degree of orientation of the (110) plane expressed as follows was 19% or higher and both were high, and the magnetostriction amount in the effective magnetic field H = 1000 Oe was 100 ppm or more. Moreover, the half width of the peak waveform of the (110) plane in the X-ray diffraction result is 0.19 ° to 0.24 °, as compared with Examples 1 to 7 manufactured by the first manufacturing method described above. The full width at half maximum is narrowed by about 40%, indicating that the crystallinity is improved. On the other hand, although both the comparative examples 7 and 8 had a magnetostriction amount higher than the comparative examples 1 and 2 mentioned above, they were less than 100 ppm.

  Therefore, it can be seen that the preferable Co ratio when evaluated by the magnetostriction amount is 50 atomic% or more and 70 atomic% or less, and preferably 65 atomic% or more and 70 atomic% or less.

  It should be noted that the FeCo magnetostrictive alloy and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

ha ... Height Wa ... Half-value width

Claims (7)

X-ray diffraction using a Kα characteristic X-ray of Cu (copper), which is a magnetostrictive alloy composed of Fe (iron) and Co (cobalt) and having a body-centered cubic structure containing 50 atomic% to 70 atomic% of Co. An FeCo magnetostrictive alloy characterized in that the degree of orientation of the (110) plane represented by the following formula (1) based on the results is 19% or more and the magnetostriction amount in an effective magnetic field H = 1000 Oe is 100 ppm or more. .
Degree of orientation = (P−P ₀ ) / (1−P ₀ ) (1)
Here, P = ΣI (110) / {ΣI (110) + ΣI (200) + ΣI (211))}
P ₀ = ΣI ₀ (110) / {ΣI ₀ (110) + ΣI ₀ (200) + ΣI ₀ (211)}
Where ΣI (110), ΣI (200) and ΣI (211) indicate the integrated intensities of the diffraction intensities of the (110) plane, (200) plane and (211) plane, respectively, and ΣI ₀ (110), ΣI ₀ (200) and ΣI ₀ (211) indicate the integrated intensities of diffraction intensities of the (110) plane, the (200) plane, and the (211) plane in an ideal non-oriented sample, respectively. In the FeCo magnetostrictive alloy according to claim 1,
A FeCo-based magnetostrictive alloy characterized in that the half width of the peak waveform of the (110) plane in the X-ray diffraction result is 0.1 ° or more and 0.5 ° or less. In the FeCo magnetostrictive alloy according to claim 1,
An FeCo magnetostrictive alloy characterized in that the half-value width of the peak waveform of the (110) plane in the X-ray diffraction result is 0.1 ° or more and 0.3 ° or less. In a method for producing an FeCo magnetostrictive alloy comprising Fe (iron) and Co (cobalt) and containing 50 atomic% to 70 atomic% of Co,
After melting the alloy material, the alloy material is cooled at a cooling rate of 1500 ° C./min or more, and expressed by the following formula (1) based on the X-ray diffraction result using the Kα characteristic X-ray of Cu (copper) (110) (2) A method for producing a FeCo magnetostrictive alloy, comprising producing a magnetostrictive alloy having a degree of orientation of a plane of 19% or more and a magnetostriction amount of 100 ppm or more in an effective magnetic field H = 1000 Oe.
Degree of orientation = (P−P ₀ ) / (1−P ₀ ) (1)
Here, P = ΣI (110) / {ΣI (110) + ΣI (200) + ΣI (211))}
P ₀ = ΣI ₀ (110) / {ΣI ₀ (110) + ΣI ₀ (200) + ΣI ₀ (211)}
Where ΣI (110), ΣI (200) and ΣI (211) indicate the integrated intensities of the diffraction intensities of the (110) plane, (200) plane and (211) plane, respectively, and ΣI ₀ (110), ΣI ₀ (200) and ΣI ₀ (211) indicate the integrated intensities of diffraction intensities of the (110) plane, the (200) plane, and the (211) plane in an ideal non-oriented sample, respectively. In the manufacturing method of the FeCo type magnetostrictive alloy according to claim 4 ,
A method for producing an FeCo-based magnetostrictive alloy, wherein a half width of a peak waveform of a (110) plane in the X-ray diffraction result of the produced magnetostrictive alloy is 0.1 ° or more and 0.5 ° or less. In the manufacturing method of the FeCo type magnetostrictive alloy according to claim 4 ,
After the cooling, a heat treatment is performed for 24 hours or more at a temperature ± 40 ° C. that is ¼ of the melting point of the magnetostrictive alloy. In the manufacturing method of the FeCo type magnetostrictive alloy according to claim 6 ,
A method for producing an FeCo-based magnetostrictive alloy, wherein a half width of a peak waveform of a (110) plane in the X-ray diffraction result of the produced magnetostrictive alloy is 0.1 ° or more and 0.3 ° or less.

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