JP2012228826A - Two-layer shape-memory ribbon and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-layer shape-memory ribbon having both high magnetic properties and shape-memory performance.SOLUTION: The two-layer shape-memory ribbon has a two-layer laminated structure comprising a first layer which is soft magnetic alloy of which magnetostriction constant is approximately zero and a second layer which is non-magnetic shape-memory alloy. An element of which content (mass%) is largest in a component composition of the soft magnetic alloy and an element of which content (mass%) in a component composition of the non-magnetic shape-memory alloy are identical to each other.

Description

  The present invention relates to a two-layer shape memory ribbon having sufficient ferromagnetism and capable of being applied to a complicated control system of an electric circuit, and a manufacturing method thereof.

  Conventionally, as a general shape memory alloy, a Ni—Ti alloy, a Cu—Al—Zn alloy, a Cu—Al—Ni alloy, and the like are well known. These shape memory alloys are mainly used for pipe joints and the like. These shape memory alloys are non-magnetic.

  If the shape memory alloy has ferromagnetism that reacts to an external magnetic field, its application can be expanded to a magnetic sensor and a small actuator. In other words, if it is possible to manipulate a shape memory alloy using a magnetic field, it is possible to perform complicated control by converting an electrical signal of an electronic circuit, a sequence circuit, etc. into a magnetic field, and deforming the shape memory alloy with this magnetic field. Expected to be possible.

  Furthermore, if the magnetic permeability of the shape memory alloy is high, the heating efficiency becomes high. Therefore, the shape before deformation can be easily recovered using non-contact induction heating.

In recent years, iron-based shape memory alloys having ferromagnetism in addition to shape memory properties have been proposed. For example, Non-Patent Document 1 discloses a ferromagnetic shape memory alloy in which a ferromagnetic element (Co, Ni) is added to a nonmagnetic Fe—Mn—Si shape memory alloy. In addition, Patent Documents 1 to 5 disclose iron-based shape memory alloys.

JP 2005-146320 A Japanese Patent Publication No. 5-72464 JP-A-61-201761 JP-A-2-190448 Japanese Patent Laid-Open No. 2-77554

Takashi Totaka, Yuta Sato, Masato Gion, Magnetic Properties and Shape Memory Properties of Fe-Based Ferromagnetic Shape Memory Alloy, Journal of AEM Society of Japan VOL.16, No.2, 2008, PP.76-81

  Non-Patent Document 1 shows that magnetic properties (saturation magnetization) and shape memory properties (Shape Memory Effect, hereinafter referred to as “SME”) of ferromagnetic shape memory alloys have a trade-off relationship with each other.

  In the ferromagnetic shape memory alloy disclosed in Non-Patent Document 1, the saturation magnetization when SME is 100% is about 20 to 30 emu / g. Further, the SME when the saturation magnetization is 100 emu / g is about 10 to 35%.

  As described above, conventional ferromagnetic shape memory alloys are not sufficient in both magnetic properties and shape memory properties for use in magnetic sensors and small actuators.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a two-layer shape memory ribbon having both high magnetic characteristics and shape memory properties that have not been conventionally available.

  The present inventors diligently studied to obtain a two-layer shape memory ribbon having both high magnetic properties and shape memory properties. As a result, the present inventors succeeded in obtaining a two-layer shape memory ribbon having both high magnetic properties and shape memory properties by a method completely different from the conventional technique.

  That is, a molten metal having a component composition of a soft magnetic alloy and a molten metal having a component composition of a shape memory alloy are jetted from a nozzle, and each molten metal is rapidly cooled using a cooling roll, thereby soft magnetism. A ribbon having a two-layer structure in which a layer and a shape memory layer are fused and solidified at the boundary between the layers can be manufactured, and the obtained ribbon has both characteristics of soft magnetism and shape memory. I found.

  The present invention has been made based on the above findings, and the gist thereof is as follows.

(1) having a two-layer laminated structure including a first layer that is a soft magnetic alloy having a magnetostriction constant of substantially zero and a second layer that is a nonmagnetic shape memory alloy;
A two-layer shape memory ribbon, wherein the first layer and the second layer are fused and solidified at a boundary between the layers.

  (2) The two-layer shape memory ribbon according to (1), wherein the soft magnetic alloy is an Fe—Si based alloy, and the shape memory alloy is an Fe—Mn—Si based alloy.

  (3) The two-layer shape memory ribbon according to (1), wherein the soft magnetic alloy is an Fe—Si—Al alloy, and the shape memory alloy is an Fe—Mn—Si alloy.

  (4) The two-layer shape memory ribbon according to (1), wherein the soft magnetic alloy is a Ni—Fe alloy, and the shape memory alloy is a Ni—Ti alloy.

  (5) The two-layer shape memory ribbon according to any one of (1) to (4), wherein the thickness is 50 to 100 μm.

  (6) Molten metal having a component composition of a soft magnetic alloy having a magnetostriction constant of almost zero and a molten metal having a component composition of a nonmagnetic shape memory alloy are respectively applied to the cooling surface of a cooling roll that rotates the molten metal from a nozzle. At the same time, the first layer made of the soft magnetic alloy and the second layer made of the shape memory alloy were fused and solidified at the boundary between the layers by continuously injecting and rapidly solidifying at the cooling surface. A method for producing a two-layer shape memory ribbon, comprising producing a ribbon having a layered structure.

  According to the present invention, a two-layer shape memory ribbon having both high magnetic properties and shape memory properties can be obtained.

It is a figure which shows the outline of the manufacturing method of the two-layer shape memory ribbon of this invention by a super quenching method. It is a figure which shows an example of a nozzle which can be used for manufacture of the two-layer shape memory ribbon of this invention. It is a figure which shows an example of a nozzle which can be used for manufacture of the two-layer shape memory ribbon of this invention. It is a figure explaining the evaluation method of a shape memory effect (SME). It is a figure which shows the X-ray-diffraction peak of the surface of the double layer shape memory ribbon produced in the Example of this invention. It is a figure which shows the X-ray-diffraction peak of the surface of the double layer shape memory ribbon produced in the Example of this invention.

  Hereinafter, the two-layer shape memory ribbon of the present invention will be described in detail. Hereinafter, “%” indicates “% by mass”.

The two-layer shape memory ribbon of the present invention has a two-layer laminated structure including a first layer that is a soft magnetic alloy having a magnetostriction constant of substantially zero and a second layer that is a nonmagnetic shape memory alloy. Here, “the magnetostriction constant is almost zero” means that the magnetostriction constant is 1 × 10 ⁻⁶ or less in absolute value.

  Even if a soft magnetic alloy having a magnetostriction constant of almost zero and a nonmagnetic shape memory alloy are alloyed or ribboned in an alloyed state, the same properties as the two-layer shape memory ribbon of the present invention are obtained. I can't get it. That is, it is divided into a first layer made of a soft magnetic alloy and a second layer made of a shape memory alloy, and the first layer and the second layer have a laminated structure in which the first layer and the second layer are fused and solidified at the boundary between the layers. It is important for obtaining shape memory.

  A part of the soft magnetic alloy and the shape memory alloy may be alloyed at the boundary between the first layer and the second layer, but the lower the rate of alloying, the better the magnetic characteristics and the shape memory characteristics. A two-layer shape memory ribbon is obtained. The ratio of the alloyed region is preferably 10% or less of the total thickness, more preferably 5% or less, and still more preferably 1% or less.

  The first layer of the two-layer shape memory ribbon of the present invention is made of a soft magnetic alloy having a magnetostriction constant of substantially zero, and the characteristics of this soft magnetic alloy are the magnetic characteristics of the two-layer shape memory ribbon of the present invention. Since the magnetostriction constant is substantially zero, the magnetic characteristics do not change even when pressure (tension) is applied to the ribbon. Therefore, the two-layer shape memory ribbon of the present invention is suitable for a magnetic sensor or a small actuator.

  As a magnetic alloy whose magnetostriction constant is almost zero, for example, an Fe—Si based alloy, an Fe—Si—Al based alloy, a Ni—Fe based alloy, a Ni—Mn based alloy, and the like are known. Can be appropriately selected. From the viewpoint of magnetic properties, the first layer is preferably an Fe—Si based alloy, an Fe—Si—Al based alloy, or a Ni—Fe based alloy.

  It is known that the Fe—Si based alloy has a Si content of around 6.5%, and the remaining alloy of iron has a magnetostriction constant of almost zero. It is known that the Fe-Si-Al-based alloy has an Si content of around 9.6%, an Al content of around 5.4%, and the remaining alloy of iron has a magnetostriction constant of almost zero. It has been. It is known that the Ni-Fe alloy has a Ni content of around 81% and a magnetostriction constant of almost zero.

  In addition, if the magnetic alloy of the first layer of the two-layer shape memory ribbon of the present invention is a magnetic alloy having a magnetostriction constant of almost zero, an element such as Mo, B, or Co is further added to the above component system. For example, an alloy such as 5% Mo-79% Ni-16% Fe may be added.

  The second layer of the two-layer shape memory ribbon of the present invention is made of a nonmagnetic shape memory alloy. Here, “non-magnetic” means that there is no magnetism at all and that the magnetism is low enough not to affect the gist of the present invention, and is paramagnetic, antiferromagnetic, or diamagnetic at room temperature. including.

  When the shape memory alloy of the second layer has magnetism, a part of the magnetic flux leaks from the first layer to the second layer. Therefore, the magnetic properties of the soft magnetic alloy of the first layer are represented by the two-layer shape of the present invention. The memory ribbon as a whole cannot be obtained.

  Moreover, by making the composition of the first layer and the second layer close, it becomes possible to increase the adhesion between the layers, and a ribbon having a two-layer laminated structure having an adhesion without any practical problem can be obtained. .

  For example, when the first layer is an Fe—Si based alloy or an Fe—Si—Al based alloy, the second layer is preferably an Fe—Mn—Si based shape memory alloy. In the case where the first layer is a Ni—Fe based alloy, the second layer is preferably a Ni—Ti based shape memory alloy.

  These alloys include those added with elements such as B, Mo, Cr, Co and Cu as appropriate for the purpose of preventing oxidation and refining crystal grains in addition to the elements described above. .

  B can be added in a range of 1% or less for the purpose of refining crystal grains. Mo and Co can be added in the range of 6% or less and 15% or less, respectively, for the purpose of improving the magnetic permeability. Cr can be added in a range of 12% or less for the purpose of improving oxidation resistance. Cu can be added in a range of 6% or less for the purpose of improving magnetic permeability and ductility.

  Specific examples of suitable first layer and second layer alloys are shown in Table 1. These combinations are examples, and other alloys may be used as long as they are a combination of a soft magnetic alloy having a magnetostriction constant of almost zero and a nonmagnetic shape memory alloy.

  Since the two-layer shape memory ribbon of the present invention is soft magnetic as a whole, the magnetic permeability is high and the heating efficiency is high. As a result, the shape before deformation can be easily recovered by non-contact induction heating or the like.

  The thickness of the two-layer shape memory ribbon of the present invention is not particularly limited. In order to obtain high magnetic properties and shape memory properties as a whole ribbon, about 50 to 100 μm is preferable. When the thickness is less than 50 μm, it becomes difficult to stably manufacture the ribbon. When the thickness exceeds 100 μm, it is difficult to stably produce the ribbon, and the ribbon is fragile.

  Next, the manufacturing method of the two-layer shape memory ribbon of this invention is demonstrated.

  The two-layer shape memory ribbon of the present invention can be manufactured using, for example, a single roll apparatus having a nozzle 10 for injecting molten metal and a cooling roll 20 as shown in FIG.

  Specifically, the molten metal having the component composition of the soft magnetic alloy of the first layer and the molten metal having the component composition of the shape memory alloy of the second layer are respectively spaced apart from each other by a predetermined interval. From separate nozzles placed close together, molten metal is simultaneously and continuously jetted onto the cooling surface of the chill roll and rapidly solidified on the cooling surface.

  Although not particularly limited, the interval between the nozzles of each nozzle is preferably 2 mm or less. Although not particularly limited, the molten metal is solidified by being injected and solidified from a nozzle positioned in the range of about ± 5 to 6 ° in the roll rotation direction from the top of the cooling roll. Is easy and preferable.

  The molten metal injected from the nozzle is injected by pressurizing, for example, introducing argon gas from a gas introduction pipe (not shown) on the opposite side of the injection port.

  For example, a molten metal having a magnetic alloy component composition and a molten metal having a shape memory alloy component composition as shown in FIGS. 2-1 and 2-2 are injected into the nozzle without mixing. A nozzle 11 is provided with a partition wall 11 to enable, and an injection port 12a for injecting a molten metal having a component composition of a magnetic alloy, and an injection port 12b for injecting a molten metal having a component composition of a shape memory alloy. A non-metallic nozzle made of glass or the like can also be used.

  The shape of the nozzle is not particularly limited, but from the viewpoint that the scar-shaped slit nozzle shown in (e-1) and (e-2) of FIG. Is preferred.

  By controlling the pressure of the argon gas that pressurizes the molten metal in the nozzle, the interval between the cooling roll and the nozzle, the number of rotations of the cooling roll, etc., the ribbon thickness can be controlled, and the two-layer shape memory of the present invention A ribbon can be obtained.

  The two-layer shape memory ribbon of the present invention can be produced in the air, in an argon gas atmosphere, in a vacuum, or the like. In addition to the single roll apparatus described above, the double-layer shape memory ribbon of the present invention can also be manufactured using a twin roll apparatus, a drawing and quenching apparatus using the inner wall of the drum, an apparatus using an endless belt, or the like. be able to.

  It can be confirmed by measuring the X-ray diffraction of each surface that one surface of the ribbon has a soft magnetic alloy and the other surface has a shape memory alloy. Moreover, even if the cross section of the ribbon is observed with a TEM, it can be confirmed that the ribbon has a two-layer laminated structure.

  Using the ultra-quenching apparatus shown in FIG. 1 and the nozzles shown in FIGS. 2-1 and 2-2, a soft magnetic alloy (6.5% Si-93.1% Fe-0) having a magnetostriction constant of almost zero. .4% B) and a non-magnetic shape memory alloy (57.8% Fe-26% Mn-10% Cr-6% Si-0.2% B) in a two-layer shape memory ribbon. did. As the cooling roll, a copper roll having a diameter of 20 cm and a cooling peripheral surface width of 20 mm was used.

  The soft magnetic alloy and the shape memory alloy are respectively housed in an internally divided nozzle, melted at the same time, and simultaneously shifted from the nozzle at the bottom of the container to a position shifted about 2 ° from the top of the rotating cooling roll. A ribbon having a two-layer structure in which a first layer made of a soft magnetic alloy and a second layer made of a shape memory alloy were fused and solidified was produced by jetting and quenching.

  The positions of the nozzle injection ports were arranged on the upstream side and the downstream side in the roll rotation direction immediately above the position shifted about 2 ° in the rotation direction from the top of the cooling roll. Whether the soft magnetic alloy and the shape memory alloy are sprayed from the upstream side or the downstream side of the nozzle nozzle does not affect the ribbon production.

  In this example, a shape memory alloy jet outlet is arranged on the upstream side, and a soft magnetic alloy jet outlet is arranged on the downstream side so that the shape memory alloy first contacts the cooling roll peripheral surface and solidifies.

  The ribbon was produced in the air and in argon gas. The metal was injected from the nozzle by pressurizing the molten metal in the nozzle with argon gas. The conditions shown in Table 2 were used for the argon gas injection pressure, the distance between the cooling roll and the nozzle tip, the number of rotations of the cooling roll, and the peripheral speed of the roll. The periphery of the cooling roll is purged with argon gas to prevent oxidation of the injected molten metal due to air entrainment.

  The produced ribbon was evaluated by measuring saturation magnetization, Curie temperature, and shape memory effect.

  The saturation magnetization was calculated from an MH curve measured with a vibrating sample magnetometer (hereinafter referred to as “VSM”) under an applied magnetic field of 10 kOe.

  The Curie temperature was calculated from an MT curve measured by VSM under an applied magnetic field of 20 Oe.

  As shown in FIG. 3, the shape memory effect is such that the ribbon is first memorized linearly by shape memory processing (a), then bent to 45 ° at room temperature (b), and then 10 ° C. at 300 ° C. in a muffle furnace. After heating for 2 seconds, the recovery angle α was measured (c). The bending was bent toward the soft magnetic layer side and the shape memory layer side, and the recovery angle was measured for each case.

The shape memory effect SME was calculated by the following formula (1).
SME [%] = (45 ° −α [°]) / 45 ° × 100 (1)

  The shape memory treatment was performed under the condition that the ribbon was heated at 1000 ° C. for 40 seconds and then quenched with water at about 20 ° C.

  The results are shown in Table 3. Sample No. Reference numerals 21 and 22 denote ribbons made of a single layer of a soft magnetic alloy and a shape memory alloy, respectively. In the notation of nozzles in Table 2, “a” and the like indicate the shapes shown in FIGS. 2-1 and 2-2 (a-1) and (a-2), respectively. “Normal” indicates that the nozzle is a type that ejects one type of molten metal from one ejection port.

  As for the size of the nozzle, a has an outer shape of 28.6 mm and an injection port diameter of 0.5 mm, b has an outer shape of 28.6 mm, an injection port diameter of 0.4 mm, and c and d have an outer shape of 15 mm and an injection port diameter of 0.5 mm. Moreover, a normal nozzle has an outer diameter of 15 mm and an injection port diameter of 0.5 mm.

  Sample No. manufactured using nozzles a, b and c 1 to 3, the shape memory effect on the shape memory layer side is 100%, and the saturation magnetization is 80 emu / g or higher, and higher is 170 emu / g, which is a high magnetic property compared to conventional ferromagnetic shape memory alloys. It was confirmed that it also has shape memory properties.

  Sample No. manufactured using nozzle d. No. 4 is a comparative example in which the partition wall of the nozzle is short, so that two types of alloys are mixed before jetting to form a two-layer laminated structure. Sample No. In No. 4, the magnetic characteristics were not different from those of other samples, but the shape memory effect was 32%, and a high shape memory effect was not obtained.

  FIGS. 4A and 4B show the results of measuring the X-ray diffraction of the surface of the manufactured ribbon. (1-1) is Sample No. X-ray diffraction peak on the magnetic layer side of FIG. 1 is an X-ray diffraction peak on the shape memory layer side. Sample No. The same applies to 2 and 3. Sample No. 1 to 3 have different diffraction peaks depending on the measured surface, and it was confirmed that a two-layer laminated structure was obtained.

  Sample No. For No. 4, the measurement results from either side were the same as shown in (4) of FIG. 4-2, and it was confirmed that the two-layer laminated structure was not obtained.

  According to the present invention, a two-layer shape memory ribbon having both high magnetic characteristics and shape memory characteristics can be obtained, and the present invention can be applied to a magnetic sensor and a small actuator. Therefore, industrial applicability is great.

DESCRIPTION OF SYMBOLS 1 Double layer shape memory ribbon 10 Nozzle 11 Partition 12a, 12b Injection port 20 Cooling roll 30 Heater

Claims (6)

It has a two-layer laminated structure consisting of a first layer that is a soft magnetic alloy having a magnetostriction constant of substantially zero and a second layer that is a nonmagnetic shape memory alloy,
A two-layer shape memory ribbon, wherein the first layer and the second layer are fused and solidified at a boundary between the layers.   The two-layer shape memory ribbon according to claim 1, wherein the soft magnetic alloy is an Fe-Si alloy, and the shape memory alloy is an Fe-Mn-Si alloy.   The double-layer shape memory ribbon according to claim 1, wherein the soft magnetic alloy is an Fe-Si-Al alloy, and the shape memory alloy is an Fe-Mn-Si alloy.   The two-layer shape memory ribbon according to claim 1, wherein the soft magnetic alloy is a Ni-Fe alloy, and the shape memory alloy is a Ni-Ti alloy.   The two-layer shape memory ribbon according to any one of claims 1 to 4, wherein the thickness is 50 to 100 µm.   A molten metal having a component composition of a soft magnetic alloy having a magnetostriction constant of almost zero and a molten metal having a component composition of a nonmagnetic shape memory alloy are respectively supplied from two injection holes arranged close to each other. A first layer made of the soft magnetic alloy and a second layer made of the shape memory alloy are layered by spraying continuously on the cooling surface of the rotating cooling roll and rapidly solidifying by cooling on the cooling surface. A manufacturing method of a two-layer shape memory ribbon, characterized by manufacturing a ribbon having a two-layer laminated structure fused and solidified at a boundary.

Images