JP2015120127A - Metallic porous body having shape memory characteristics, and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic porous body capable of arbitrarily changing the extent of opening which can be used for filter or the like.SOLUTION: A metallic porous body which is wound with a composite wire 2 having a shape memory layer 4 on an outer circumference, the composite wires 2, 2 being connected 5 to each other and changes a shape at a transformation point of the shape memory layer 4 as the boundary, includes: a process of preparing a raw wire 2 provided with a metal layer containing a second metal component which chemically combines with a first metal component to form the shape memory layer 4 on the outer circumference of the metal wire containing the first metal component; a process of repeating a first sub process of winding the wound raw wire around a shaft while inclining the raw wire in one direction and a second sub process of winding the raw wire around the shaft while inclining the raw wire in a direction reverse to the one direction; a process of forming the composite wire 2 having the shape memory layer 4 in which the first metal component and the second component are caused to diffuse to each other by heating the wound raw wires; and a process of connecting the composite wires 2 to each other. The composite wire has a nickel-titanium intermetallic compound as the shape memory layer 4 on an outer circumference of a titanium core material 3.

Description

  The present invention relates to a metal porous body having shape memory characteristics and a method for manufacturing the metal porous body, and more particularly, to a metal porous body including a composite wire having shape memory characteristics and having an opening that changes depending on temperature, and a method for manufacturing the metal porous body. .

  A metal porous body formed by winding a metal wire around an axis is conventionally known. Patent Document 1 proposes a metal porous body used as a filter for removing unnecessary substances and the like from the fuel of an internal combustion engine. The metal porous body is formed by winding a metal wire such as a stainless steel wire around an axis to form a cylindrical shape, and then sintering the wires.

  Patent Document 2 proposes a metal porous body used as a filter for an airbag inflator. This metal porous body uses a single metal wire having a rectangular cross section (flat rectangular shape), one end of the wire is locked in place on the jig, and the wire is wound around the jig to form a cylindrical body. Then, the other end of the wire is joined to an appropriate position of the cylindrical body, and a jig is extracted from the cylindrical body to form a hollow shape.

  Patent Document 3 proposes a technique for the purpose of providing a metal fiber three-dimensional structure having an intermetallic compound formed at the contact portion of the metal fiber and having excellent shape memory characteristics and superelastic characteristics. In this technique, pure titanium fibers and pure nickel fibers form a three-dimensional structure having a predetermined porosity, and an intermetallic compound is formed at the contact portion between both fibers. Such a metal fiber three-dimensional structure is a non-woven structure having a high porosity, and has high shape retention and shape memory characteristics, so that it is a coronary stent, an artificial bone, an artificial tooth root, and an electric device. It is said that a member having a complicated shape such as an electrode and a filter of an air conditioner can be easily manufactured.

JP 2011-178212 A Special table 2009-533221 gazette JP 2006-241582 A

  The conventional metal porous body for filter applications proposed in Patent Documents 1 and 2 joins metal wires by sintering, eliminates the movement of the wires, and fixes the openings to maintain a stable filter function. It is manufactured. However, if the opening can be arbitrarily changed, various filter applications may be expanded.

  Moreover, the metal fiber three-dimensional structure proposed in Patent Document 3 has high shape retention due to an intermetallic compound having shape memory characteristics formed by a contact portion between pure titanium fiber and pure nickel fiber. Has been. However, even in such a metal fiber three-dimensional structure, as described above, if the mesh opening can be arbitrarily changed, various filter applications may be expanded.

  The present invention has been made to solve the above-described problems, and its object is to provide a new metallic porous body that can arbitrarily change the degree of opening of the metallic porous body that can be used for a filter or the like. And providing a manufacturing method.

  (1) A metal porous body according to the present invention for solving the above-described problem is a porous body formed by winding a composite wire having a shape memory layer having shape memory characteristics on the outer periphery and joining the composite wires together. And the shape of the said porous body changes on the boundary of the transformation point of the said shape memory layer, It is characterized by the above-mentioned.

  According to the present invention, the shape of the porous body wound with the composite wire having the shape memory layer on the outer periphery and joined to each other is changed at the transformation point of the shape memory layer. The shape at a temperature below the point and the shape at a temperature equal to or higher than the transformation point can be changed, and the degree of opening of the metal porous body usable for a filter or the like can be arbitrarily changed. For example, what is in a predetermined open state at normal temperature can be returned to the original open state by enlarging or reducing the open state by heating and returning to normal temperature. Such enlargement or reduction has an advantage that, for example, in a filter application, the filter effect based on the change in the mesh opening can be changed by heating the metal porous body. In addition, since the composite wires are joined to each other by sintering, the overall shape of the metal porous body can be maintained without significant disturbance. The metal porous body according to the present invention that can change the degree of opening according to temperature is different from the conventional filter in which the opening is fixed by firmly sintering the composite wire and eliminating the movement of the composite wire. The opening can be controlled by temperature and can be used as various filters.

  The metal porous body which concerns on this invention WHEREIN: The said composite wire can be comprised so that it may have a nickel titanium intermetallic compound layer in the outer periphery of a titanium core material.

  According to this invention, since the nickel titanium intermetallic compound layer which is a shape memory layer is provided on the outer periphery of the titanium core material, the above shape memory characteristics are exhibited at the transformation point of the nickel titanium intermetallic compound layer. be able to.

  In the metal porous body according to the present invention, the ratio (B / A) between the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer of the composite wire is 0.3 or more and 0.8 or less. It is preferable to be within the range.

  According to this invention, when the ratio (B / A) of the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer is within the above range, the deformation at the transformation point occurs more effectively, Since the opening state can be changed, it can be preferably applied as a filter application capable of controlling the opening according to temperature, for example.

  In the metal porous body according to the present invention, the composite wire is preferably a flat wire.

  (2) A method for manufacturing a metal porous body according to the present invention for solving the above-described problem is to form a shape memory layer by combining with the first metal component on the outer periphery of a metal wire including the first metal component. Preparing a strand provided with a metal layer containing two metal components, a first sub-step of winding the strand at a predetermined pitch around an axis while inclining the strand in one direction, and the strand in the one direction And a second sub-step of winding around the axis at a predetermined pitch while inclining in a direction opposite to the direction, heating the wound wire, the first metal component and the second It has the process of forming the composite wire which has the shape memory layer which diffused the metal component in the outer periphery, and the process of joining the said composite wires.

  According to the present invention, the composite having the shape memory layer on the outer periphery in which the wire is wound around the shaft and then heated to diffuse the first metal component contained in the metal wire and the second metal component contained in the metal layer. Since the line is formed, the shape of the composite wire can be changed at the transformation point of the shape memory layer, and the shape of the metal porous body can be changed. As a result, it is possible to produce a metal porous body that can change the shape at a temperature below the transformation point and the shape at a temperature above the transformation point, and can arbitrarily change the degree of opening. It can be used for various filters. In addition, since the composite wires are joined together, a metal porous body that can hold the entire shape without significant disturbance can be manufactured.

  In the method for producing a metal porous body according to the present invention, the first metal component may be titanium and the second metal component may be nickel. In particular, it is preferable that the metal wire is a titanium wire and the metal layer is a nickel layer.

  According to this invention, since the first metal component is titanium and the second metal component is nickel, the nickel-titanium intermetallic compound layer into which they are diffused can exhibit shape memory characteristics.

  In the method for producing a metal porous body according to the present invention, the ratio (B / A) between the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer of the composite wire is 0.3 or more and 0. It is preferable that it is within the range of .8 or less.

  According to this invention, when the ratio (B / A) of the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer is within the above range, the deformation at the transformation point occurs more effectively, Since the opening state can be changed, it can be preferably applied as a filter application capable of controlling the opening according to temperature, for example.

  In the method for producing a metal porous body according to the present invention, the composite wire is preferably a flat wire.

  ADVANTAGE OF THE INVENTION According to this invention, the new metal porous body and manufacturing method which can change arbitrarily the grade of the opening of the metal porous body which can be used for a filter etc. can be provided. In particular, the degree of opening of a metal porous body that can be used for a filter or the like can be arbitrarily changed. The metal porous body, whose degree of opening can be changed depending on the temperature, is different from conventional filters in which the opening of the composite wire is fixed by firmly sintering the composite wire and the opening of the composite wire is fixed. Is available as

It is a perspective view which shows an example of the metal porous body which concerns on this invention. FIG. 2 is an enlarged view showing only two layers composed of composite wires constituting the metal porous body shown in FIG. 1. It is a cross-sectional form figure of the composite wire which comprises a metal porous body. It is explanatory drawing which shows the winding angle which the composite wire which comprises a metal porous body makes. It is the plane photograph (A) of the metal porous body produced in the Example, and its enlarged photograph (B). It is the cross-sectional photograph (A) of a strand, and the cross-sectional photograph (B) of a composite wire. It is the form (A) after deform | transforming the metallic porous body of Example 1 at room temperature, and the form (B) when heating the deformed metallic porous body. It is the form (B) when the composite wire peeled off from the metal porous body of Example 2 (A) and the composite wire are heated. It is the result of the differential scanning calorimetry which shows the shape memory characteristic of the composite wire peeled from the metal porous body of Example 2.

  Hereinafter, a metal porous body and a manufacturing method thereof according to the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited only to the following description and drawings.

[Metal porous body]
The metal porous body 1 according to the present invention is wound around a composite wire 2 having a shape memory layer 4 having shape memory characteristics on the outer periphery, as shown in FIGS. It is a porous body joined. The shape of the porous body is configured to change with the transformation point of the shape memory layer 4 as a boundary. As shown in FIG. 1, the metal porous body 1 has a tubular shape as a whole.

  In this metal porous body 1, the shape of the metal porous body 1 wound around the composite wire 2 having the shape memory layer 4 on the outer periphery and joined with the composite wires 2 and 2 is the shape memory layer 4. It changes at the boundary of the transformation point. Therefore, the shape at a temperature lower than the transformation point and the shape at a temperature higher than the transformation point can be changed, and the degree of opening of the metal porous body 1 usable for a filter or the like is arbitrarily changed. There is an unprecedented new effect that can be done.

  For example, what is in a predetermined open state at normal temperature can be returned to the original open state by enlarging or reducing the open state by heating and returning to normal temperature. Such enlargement or reduction has an advantage that, for example, in a filter application, the filter effect based on the change in the mesh opening can be changed by heating the metal porous body 1. In addition, since the composite wires 2 and 2 are joined by sintering, the composite wire 2 can hold | maintain the whole metal porous body 1 shape without big disorder. The metal porous body 1 according to the present invention that can change the degree of opening according to the temperature is a conventional filter in which the opening of the composite wire 2 is firmly sintered and the opening of the composite wire 2 is eliminated to fix the opening. Unlike the above, the opening can be controlled by temperature, and it can be used as various filters.

  Hereinafter, components of the metal porous body will be described in detail.

(Composite line)
The composite wire 2 has shape memory characteristics. The shape memory characteristic is generated by the shape memory layer 4 provided on the outer periphery of the core material 3 constituting the composite wire 2 as shown in FIG. Here, the shape memory characteristics are defined in JIS H7001: 2009 “shape memory alloy terminology”, and even if an alloy of a certain shape is deformed into a different shape in a low temperature phase (martensite) state, it is stable at a high temperature. When heated to a temperature at which it becomes a phase (austenite), the martensite reverse transformation occurs, thereby exhibiting a phenomenon of returning to the shape before deformation (also referred to as shape memory effect).

  The shape memory layer 4 is not particularly limited as long as it is a layer that exhibits shape memory characteristics. Preferred examples of the shape memory layer 4 include binary intermetallic compound layers such as nickel titanium, titanium niobium, and iron palladium. Of these, a nickel titanium intermetallic compound layer is preferred.

  The core material 3 may or may not have shape memory characteristics. In the examples described later, the core material 3 is titanium which does not have shape memory characteristics, and a nickel titanium intermetallic compound layer having shape memory characteristics is provided as a shape memory layer 4 on the outer periphery of the titanium core material 3. Yes. In addition, for example, the core material 3 is titanium having no shape memory characteristics, and a titanium niobium intermetallic compound layer having shape memory characteristics is provided as the shape memory layer 4 on the outer periphery of the titanium core material 3. The core material 3 may be iron that does not have shape memory characteristics, and an iron palladium intermetallic compound layer having shape memory characteristics may be provided as the shape memory layer 4 on the outer periphery of the iron core material 3. .

  A composite wire 2 composed of a core material 3 having no shape memory characteristics and a shape memory layer 4 provided on the outer periphery of the core material 3 is, for example, a nickel layer 4 ′ on a metal wire 3 ′ made of titanium. A wire 2 'provided with a niobium layer 4' on a metal wire 3 'made of titanium, a wire 2' provided with a palladium layer 4 'on a metal wire 3' made of iron, It is particularly preferable because it has a great advantage that it can be manufactured very easily by heat treatment.

  As shown in FIG. 6, the composite wire 2 shown in the embodiment forms, for example, a nickel titanium intermetallic compound layer that is a shape memory layer 4 by combining with titanium on the outer periphery of a metal wire 3 ′ made of titanium. This is obtained by heating the strand 2 ′ provided with the nickel layer 4 ′. By the heating, the titanium component constituting the metal wire 3 ′ and the nickel component constituting the metal layer 4 are thermally diffused and combined to form a nickel titanium intermetallic compound layer. Such a composite wire 2 can exhibit shape memory characteristics at the transformation point of the nickel titanium intermetallic compound layer. Similarly, the composite wire 2 provided with the above-described nickel-niobium intermetallic compound layer or iron palladium intermetallic compound layer can also exhibit shape memory characteristics at the transformation point of the intermetallic compound layer.

  The shape memory layer 4 provided on the composite wire 2 can be specified by its area ratio. The specific area ratio is such that the ratio (B / A) between the cross-sectional area A of the composite wire 2 and the cross-sectional area B of the shape memory layer 4 of the composite wire 2 is in the range of 0.3 to 0.8. It is preferable that When the area ratio is within this range, deformation at the transformation point occurs more effectively, and the opening state of the obtained metal porous body 1 can be changed. It can be preferably applied as a filter application capable of controlling the above. In particular, as described in the Examples, the composite wire 2 having a nickel titanium intermetallic compound layer as the shape memory layer 4 on the outer periphery of the titanium core shows preferable shape memory characteristics within the above range. The same applies to the composite wire 2 provided with the nickel niobium intermetallic compound layer and the iron palladium intermetallic compound layer. The area ratio was evaluated based on the result of measurement using a composition image obtained with an electron microscope.

  Even if the area ratio is less than the above range, the shape memory characteristics are exhibited, but a large change in the opening based on the large shape memory characteristics is unlikely to occur. On the other hand, when the area ratio exceeds the above range, the shape memory characteristics are sufficiently exhibited, but it becomes difficult to form the shape memory layer 4 composed of the intermetallic compound layer by, for example, heat diffusion as in the examples described later. Sometimes. Therefore, the area ratio within the above range is preferable. In addition, the thickness of the shape memory layer 4 can be converted according to the above-described area ratio.

  The shape of the composite wire 2 is preferably a rectangular wire obtained by rolling a round wire. The diameter of the round wire before rolling is preferably in the range of 0.05 mm or more and 0.2 mm or less, for example. Such a round line is crushed by rolling, and is expanded in the width direction and compressed in the thickness direction orthogonal to the width direction, for example, as shown in FIG. The rolling rate of the composite wire 2 after being rolled is preferably in the range of 20% to 70%. “Rolling ratio” means that the diameter of the round wire before rolling is d1, and the thickness in the thickness direction (compressed direction) of the flat wire after being rolled and compressed is d2. The numerical value represented by the following equation (1). (Rolling ratio) = [(d1-d2) / d1] × 100 (1)

  The shape memory effect is a phenomenon common to not only nickel titanium intermetallic compounds but also alloys which form a regular lattice and undergo thermoelastic martensitic transformation, and the shape memory layer 4 exhibits thermoelastic martensitic transformation. It consists of elements that make up intermetallic compounds. For example, nickel-titanium intermetallic compound is nickel and titanium, titanium-niobium intermetallic compound is titanium and niobium, and iron-palladium intermetallic compound is iron and palladium, but does not hinder its shape memory characteristics. Other elements may be included within the range. As other elements, one or more elements selected from transition elements such as copper, aluminum, vanadium, zirconium, molybdenum, chromium, iron, cobalt, rare earth elements, and inevitable impurities may be included.

(Winding form)
As shown in FIG. 2, the metal porous body 1 includes a layer 11 in which the composite wire 2 is inclined in one direction and is wound around the axis at a predetermined pitch, and the composite wire 2 is in the one direction. Is inclined in the opposite direction, and the layer 12 formed by being wound around the axis at a predetermined pitch is sequentially laminated, and the composite wires are joined to each other. Note that FIG. 2 shows only two layers (the reference numeral 11 layer and the reference numeral 12 layer) formed by the composite wire 2 constituting the metal porous body 1.

  As a typical form of the metal porous body 1, the tubular metal porous body shown in FIG. 1 can be mentioned. This metallic porous body 1 has a form in which both ends in the longitudinal direction are opened. In addition to the form shown in FIG. 1, the tubular metal porous body 1 is a metal porous body (not shown) in which one end in the longitudinal direction is open and the other end is closed, or a conical metal porous body. Examples include a body (not shown).

  The number of layers is set to 500 layers to 3000 layers according to the thickness of the metal porous body 1. For example, in the case of the below-mentioned Example, it is set to 1000 layers-1500 layers. Such a metal porous body 1 is bonded to each other by being sintered.

  The winding angle of the composite wire 2 is an angle at which the metal porous body 1 can be formed within a range of 5 ° or more and less than 90 °. More specifically, the winding angle is in the range of 40 ° to 80 °. The “winding angle” is an angle represented by θ in FIG. 4, and the composite wire 11 inclined in one direction and the composite wire 12 inclined in a direction opposite to the one direction Means the angle between The porosity of the metal porous body 1 is not particularly limited, but is, for example, in the range of 32% or more and 62% or less. “Void ratio” is the ratio of the volume of the gap to the total volume of the product, which can be expressed by [(material specific gravity−product density) / material specific gravity] × 100. Moreover, as a dimension of the metal porous body 1, the outer diameter is formed within a range of 1 mm or more and 15 mm or less, and the inner diameter is formed within a range of 0.5 mm or more and 14 mm or less.

  Such a metal porous body 1 can be used for applications such as a filter, a sensor cover, a catheter, a silencer, a foam, a diffusion material, and a guide. When using a metal porous body as a filter, one end in the longitudinal direction may be opened and the other end may be closed. Not only the peripheral surface of the metal porous body 1 but also the other closed end Functions as a filter. In addition, the annular metal porous body can be used for applications such as a filter, a silencer, a foam, a diffusion material, and a fluid material.

[Method for producing metal porous body]
The manufacturing method of the metal porous body 1 according to the present invention includes a metal layer including a second metal component that forms a shape memory layer 4 by combining with the first metal component on the outer periphery of the metal wire 3 ′ including the first metal component. A step of preparing a strand 2 'provided with 4', a first sub-step of winding the strand 2 'around a shaft while tilting the strand 2' in one direction and the strand 2 'in the one direction Is a winding step that repeats the second sub-step of winding around the axis at a predetermined pitch while inclining in the opposite direction, and heating the wound wire 2 'to provide a first metal component and a second metal component And the step of forming the composite wire 2 having the shape memory layer 4 diffused on the outer periphery and the step of joining the composite wires 2 and 2 together.

  In this manufacturing method, the shape memory layer in which the first metal component contained in the metal wire 3 ′ and the second metal component contained in the metal layer 4 ′ are diffused by heating after winding the wire 2 ′ around the shaft. Since the composite wire 2 having 4 on the outer periphery is formed, the shape of the composite wire 2 can be changed at the transformation point of the shape memory layer 4 and the shape of the metal porous body 1 can be changed. As a result, the metal porous body 1 that can change the shape at a temperature lower than the transformation point and the shape at a temperature higher than the transformation point and can arbitrarily change the degree of opening is manufactured. Can be used for various filters. Moreover, since the joint part of composite wires 2 and 2 is joined, the metal porous body which can hold | maintain the whole shape without big disorder | damage | failure can be manufactured.

  Hereinafter, the manufacturing process will be described. Here, a case where a nickel titanium intermetallic compound layer is mainly formed as the shape memory layer 4 will be described as an example, but the present invention is not limited thereto.

(Wire preparation process)
The preparation step of the strand 2 ′ is a step of preparing the strand 2 ′ in which the metal layer 4 ′ is provided on the outer periphery of the metal wire 3 ′ including the first metal component. The metal layer 4 ′ includes a second metal component that forms a shape memory layer 4 by combining with the first metal component of the metal wire 3 ′.

  The element wire 2 ′ is a wire material having a layer structure in which the shape memory layer 4 can be formed by a subsequent heat treatment. As shown in FIG. 6 (A), the element wire 3 ′ is specifically a nickel-titanium intermetallic compound layer (shape memory layer) combined with the titanium on the outer periphery of a metal wire 3 ′ made of titanium, for example. For example, a layer provided with a nickel layer 4 ′ for forming 4) can be mentioned. The nickel titanium intermetallic compound layer (shape memory layer 4) is obtained by heating the strand 2 '.

  The strand 2 'may be a round wire or a flat wire, but is preferably a pre-rolled flat wire as shown in FIG. Since the form of the flat wire and the rolling rate have been described in the explanation section of the composite wire 2 described above, they are omitted here.

(Winding process)
The winding step includes a first sub-step of winding the strand 2 'around one axis while tilting the strand 2' in one direction, and the axis while tilting the strand 2 'in a direction opposite to the one direction. Is a step of repeating the second sub-step of winding around a predetermined pitch.

  The winding process includes a winding process of winding the rolled strand 3 'around a winding shaft (not shown), a sintering step of sintering the strand 3' wound around the winding shaft, and a sintered strand A swaging step of swaging 3 ′ while being wound around the winding shaft, and a winding shaft extraction step of extracting the winding shaft around which the strand 3 ′ is wound after the swaging step is completed. .

  The winding process is a process of forming a tubular member by winding the wire 3 'around a winding shaft. The winding process is performed using a winder (winding device) that is generally used when winding the wire 3 ′ around a winding shaft. The strand 3 'is wound around the outer peripheral surface of the winding shaft with a winder using a material previously rolled by a rolling mill, or is wound around the outer peripheral surface of the winding shaft while being rolled inside the winder.

  When the strand 3 ′ is wound around the winding shaft, the strand 3 ′ is inclined in one direction with respect to the winding shaft, and is directed from one end side to the other end side of the winding shaft at a predetermined pitch in the axial direction of the winding shaft. Are wound sequentially. The strand 3 ′ wound around the winding shaft in this way forms one layer 11 on the outer peripheral surface of the winding shaft as shown in FIG. 2. The strand 3 ′ is further wound around the outer periphery of one layer 11 formed in this way, and another layer 12 is formed as shown in FIG. 2. At this time, the strand 3 'is inclined in a direction opposite to the one direction described above with respect to the winding axis, and wound from the other end side of the winding axis toward the one end side at a predetermined pitch in the axial direction of the winding axis. It is done.

  In the winding process, the layer 11 formed by inclining in one direction and wound around the winding axis at a predetermined pitch, and inclined in a direction opposite to the one direction and inclined at a predetermined pitch around the winding axis. In this step, the layer 12 formed by winding is sequentially formed, and the layer of the strand 3 'is laminated to form a tubular member.

(Composite line forming process)
The formation process of the composite wire 2 is a process of forming the composite wire 2 having a shape memory layer 4 on the outer periphery by heating the wound wire 2 ′ and diffusing the first metal component and the second metal component. . By heating the strand 2 ', the titanium component constituting the metal wire 3' and the nickel component constituting the metal layer 4 are thermally diffused and combined to form a nickel titanium intermetallic compound layer. Such a composite wire 2 can exhibit shape memory characteristics at the transformation point of the nickel titanium intermetallic compound layer.

  The ratio (B / A) between the cross-sectional area A of the formed composite wire 2 and the cross-sectional area B of the shape memory layer 4 in the composite wire 2 is in the range of 0.3 to 0.8. preferable. When the cross-sectional area ratio (B / A) is within the above range, deformation at the transformation point occurs more effectively, and the opening state can be changed. For example, the filter can control the opening according to temperature. It can be preferably applied as a use.

(Joining process)
The joining process is a process of joining the composite wires 2 and 2 together. In the sintering step, a tubular member made of the composite wire 2 is put into a furnace together with the winding shaft and sintered, and the composite wires are joined together. The furnace may be a vacuum furnace or a furnace containing a reducing gas for preventing oxidation. Sintering is performed at a temperature in the range of 800 ° C. or higher and 1300 ° C. or lower for about 180 minutes. By such a sintering process, the composite wires are diffusion bonded. Note that this sintering step may be performed in two steps before and after the next swaging step.

  The swaging process at this time is a cold forging process for adjusting the outer diameter of the tubular member made of the composite wire 2 to a desired dimension. The swaging step is performed, for example, by rotating the divided molds and reducing the outer diameter of the tubular member while hitting.

  The winding shaft extraction step is a step of extracting the winding shaft from the tubular member made of the composite wire 2 to form the metal porous body 1 having a desired inner diameter and outer diameter. As shown in FIGS. 5A and 5B, the tubular member from which the winding shaft is extracted has an inner diameter that matches the outer diameter of the winding shaft, and corresponds to the number of layers of the laminated composite wire 2. The metal porous body 1 has an outer diameter.

  After passing through the process demonstrated above, the metal porous body 1 is wash | cleaned and completed through a required test | inspection.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

[Example 1]
As the strand 2 ', as shown in FIG. 6A, a nickel titanium intermetallic compound which is a shape memory layer 4 combined with the titanium component of the titanium wire on the outer periphery of a titanium wire 3' having a diameter of 0.1 mm. A layer provided with a nickel plating layer 4 ′ having a thickness of 12 μm was prepared by rolling at a rolling rate of 40%. A metal porous body 1 was produced using this strand 2 ′. The produced metal porous body 1 has an inner diameter of 1.6 mm, an outer diameter of 2.5 mm, a total length of 34.9 mm, and a weight of 0.27 g. The metal porous body 1 has a bulk density of 2.61 g / cm ³ and a porosity of 67.2%. The winding angle is 47.4 °.

  The metal porous body 1 of Example 1 was produced through the following steps. First, a round wire was rolled inside the winder to form a strand having a rolling rate of 40% as shown in FIG. Next, the rolled wire was wound around a winding shaft (not shown) to form a tubular member on the outer peripheral surface of the winding shaft. Specifically, as shown in FIG. 2, first, the wire 3 ′ is inclined in one direction with respect to the winding axis, and is sequentially wound around the winding axis in one direction in the axial direction of the winding axis. One layer 11 was formed. Next, the strand 3 ′ is inclined from the outer periphery of the one layer 11 in the direction opposite to the winding axis, and wound around the winding axis at a constant pitch in the direction opposite to the axial direction of the winding axis. Layer 12 was formed. Such a procedure was repeated 300 times to form a plurality of layers composed of the composite wire 2 on the outer peripheral surface of the winding shaft, thereby producing a tubular member on the outer peripheral surface of the winding shaft.

  Next, heat treatment was performed. The heat treatment was performed for 180 minutes at a temperature of 900 ° C. by placing the tubular member together with the winding shaft in a vacuum furnace. By performing such heat treatment, a nickel titanium intermetallic compound layer was formed on the wire 2 ′, and the composite wire 2 was formed with the nickel titanium intermetallic compound layer formed thereon. Simultaneously with this change, the composite wires were sintered together. FIG. 6B shows a cross-sectional form of the composite wire 2 after sintering.

  Thereafter, the tubular member wound around the outer peripheral surface of the winding shaft was swaged so that the outer diameter of the tubular member was formed to a predetermined dimension. After performing the swaging, the tubular member was placed in the vacuum furnace together with the winding shaft, and heat treatment was performed again. The heat treatment was performed at a temperature of 900 ° C. for 180 minutes. After the second heat treatment, the winding shaft was removed, and a metal porous body 1 of Example 1 as shown in FIGS. 5A and 5B was obtained.

  FIG. 5 is a plan photograph (A) of the metal porous body 1 of Example 1 and an enlarged photograph thereof. FIG. 7A shows a form in which the metal porous body 1 of Example 1 is stretched at room temperature (around 25 ° C.) in the axial direction, which is the longitudinal direction, and FIG. 7B is stretched. It is the form after heating the metal porous body 1 at 180 degreeC. As shown in the figure, it was confirmed that the shape memory layer 4 exhibited a shape memory effect by heating, and the extended metal porous body 1 recovered to the initial shape.

[Example 2]
Using the same wire 2 ′ as in Example 1, a metal porous body 1 was produced in the same manner as in Example 1, and the expression of shape memory characteristics was confirmed. The produced metal porous body 1 had an inner diameter of 6.03 mm, an outer diameter of 8.28 mm, a total length of 11.51 mm, and a weight of 0.28 g. The heat treatment for the metal porous body was performed at 900 ° C. for 8 hours.

  The metal porous body thus produced was compressed at room temperature (around 25 ° C.) with a Tensilon universal testing machine (Orientec Co., Ltd., model name: RTG-1310), and the dimensions are shown in Table 1. Then, the dimension after irradiating 400 degreeC hot air generated with the hot air machine for 1 minute was measured. The dimension measurement in Example 2 is performed with Lightmatic (Mitutoyo Corporation, model name: VL-50A). The results are summarized in Table 1.

  The change in the form shown in Table 1 is the action of the shape memory layer 4 of the composite wire 2, and as a result, the opening state of the metal porous body 1 can be changed by the action of the shape memory layer 4. confirmed.

  FIG. 8 is a photograph (A) of the composite wire 2 peeled from the metal porous body 1 of Example 2, and a form (B) when the composite wire 2 is heated at 180 ° C. From this result, the composite wire 2 extended when the composite wire 2 was peeled off from the metal porous body 1 was changed in shape by heating, deformed into a spiral shape, and exhibited shape memory characteristics.

  Moreover, FIG. 9 is the result (DSC curve) of the differential scanning calorimetry which shows the shape memory characteristic of the composite wire 2 peeled from the metal porous body of Example 2. In FIG. The DSC curve was measured using a differential scanning calorimeter (manufactured by Rigaku Corporation, model name: DSC8230) with the temperature lowered from 180 ° C. to −100 ° C. and then raised to 180 ° C. As a result, the shape memory characteristic as shown in FIG. 9 was shown. In addition, since such DSC curve is measured based on JISH7101, the same result can be measured even if it is apparatuses other than the above-mentioned differential scanning calorimeter.

DESCRIPTION OF SYMBOLS 1 Metal porous body 2 Composite wire 2 'Elementary wire 3 Core material 3' Metal wire 4 Shape memory layer 4 'Nickel layer 5 Joint part 11 Layer formed by inclining a wire in one direction and winding around a central axis 12 Layer formed by inclining the wire in the opposite direction and winding it around the central axis

Claims (7)

It is a porous body that is wound with a composite wire having a shape memory layer having shape memory characteristics on the outer periphery, and the composite wires are joined together,
The metal porous body, wherein the shape of the porous body changes at the transformation point of the shape memory layer.   The said composite wire is a metal porous body of Claim 1 which has a nickel titanium intermetallic compound layer in the outer periphery of a titanium core material.   The ratio (B / A) between the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer of the composite wire is in the range of 0.3 or more and 0.8 or less. 2. A metal porous body according to 2.   The metal porous body according to any one of claims 1 to 3, wherein the composite wire is a flat wire. Preparing a strand provided with a metal layer containing a second metal component that forms a shape memory layer by combining with the first metal component on the outer periphery of a metal wire containing the first metal component;
A first sub-step of winding the strand in a direction while tilting the strand in one direction and a predetermined pitch around the axis while tilting the strand in a direction opposite to the one direction A winding step of repeating the second sub-step of winding;
Heating the wound wire to form a composite wire having a shape memory layer on the outer periphery in which the first metal component and the second metal component are diffused;
And a step of joining the composite wires to each other.   The method for producing a metal porous body according to claim 5, wherein the first metal component is titanium and the second metal component is nickel. The ratio (B / A) between the cross-sectional area A of the composite wire and the cross-sectional area B of the shape memory layer of the composite wire is in the range of 0.3 to 0.8, 6 or 6. A method for producing a metal porous body according to 6.