阅读说明：本技术 电铸部件和钟表 (Electroformed component and timepiece ) 是由 岸松雄 高滨未英 于 2019-07-17 设计创作，主要内容包括：本发明的目的在于,提供适合于钟表等组装部件的电铸部件和使用该电铸部件的钟表。本发明涉及电铸部件,其是包含由镍、铁和不可避免的杂质构成,且以质量%计含有5~25%的铁的镍-铁合金的电铸部件,其特征在于,具有重复层合多个铁含量在厚度方向倾斜的层合部而得到的近似层状形态部。上述层合部优选由平均粒径为50nm以下的晶粒构成。(The present invention relates to an electroformed component comprising a nickel-iron alloy that is composed of nickel, iron, and unavoidable impurities and that contains 5 ~ 25% by mass of iron, characterized by having a substantially laminar morphology obtained by repeatedly laminating a plurality of laminated portions in which the iron content is inclined in the thickness direction, the laminated portions preferably being composed of crystal grains having an average grain diameter of 50nm or less.)

1. An electroformed component comprising a nickel-iron alloy that is composed of Ni, Fe and unavoidable impurities and contains 5 ~ 25% by mass of Fe, characterized by having a substantially laminar morphology portion obtained by repeatedly laminating a plurality of laminated portions in which the Fe content is inclined in the thickness direction.

2. The electroformed component according to claim 1, wherein the laminated portion is composed of crystal grains having an average grain diameter of 50nm or less obtained by an X-ray diffraction method.

3. The electroformed component according to claim 1 or 2, wherein crystal grains constituting the laminated portion have a crystal form of a face-centered cubic lattice monolayer, and a part of nickel atoms is replaced with iron atoms.

4. The electroformed component according to claim 1 or 2, wherein a gradient of Fe content is formed by laminating crystal grains having different Fe contents in the laminated portion.

5. The electroformed component according to claim 1 or 2, wherein the Fe content in each of the crystal grains constituting the laminated portion has an inclined gradient, and the size of the crystal grains in the laminated portion changes in approximately one direction.

6. The electroformed component according to claim 1 or 2, wherein the composition of Fe is inclined within a concentration difference range of ± 15% or more and ± 50% or less of an intermediate concentration that is a median value between a maximum concentration and a minimum concentration of Fe in the inclined composition of Fe in the laminated portion.

7. The electroformed component according to claim 1 or 2, wherein the layer thickness of the laminated portion is 500nm or more and 10nm or lessμm is less than or equal to m.

8. The electroformed component according to claim 1 or 2, wherein a direction approximately parallel to the layers constituting the laminated portion is set as a mechanical load direction.

9. A timepiece, wherein an assembled component including the electroformed component according to claim 8 of claim 1 ~ is provided.

10. The timepiece as claimed in claim 9, wherein said assembling member is a spring member.

Technical Field

The present invention relates to an electroformed component by an electroplating method and a timepiece using the electroformed component.

Background

Conventionally, a wristwatch, which is one of small precision machines, particularly a mechanical wristwatch, is equipped with a large number of small mechanical components such as gears and springs.

Such small machine parts have been conventionally produced mainly by machining such as cutting and pressing, but in recent years, a production method by an electroforming method has been widely used. This is because a machine component using the electroforming method has advantages that the dimensional tolerance is smaller than that of a component using the machining method, and the machine component can be manufactured with high accuracy even in a complicated shape. In particular, an electroforming member with extremely high accuracy can be manufactured by a technique called uvliga (lithograph galvanofoaming extracting) in which a photolithography method and an electroplating method are combined (for example, see patent document 1).

On the other hand, as a material widely used for the electroformed part, there is a nickel electroformed body, but this material is inferior in creep property and stress relaxation property, and therefore, it is difficult to use it as a spring part.

Under such circumstances, attempts have been made to apply an alloy containing nickel and iron, which is excellent in creep resistance and stress relaxation resistance, to an electroformed component, and techniques have been developed in which the composition, the size of crystal grains, the hardness, and the like are optimized, and further, the characteristics are improved by heat treatment and the like (for example, see patent document 2).

Disclosure of Invention

Problems to be solved by the invention

However, in order to improve creep resistance and stress relaxation resistance of an electroformed nickel-iron alloy part, it is necessary to increase the iron content percentage (content ratio), but if the iron content percentage exceeds about 25%, the electroformed part becomes unstable, and it becomes difficult to obtain a dense and tough electroformed part.

This is because, in addition to the stability of the electrocasting solution being deteriorated when forming the electrocast body, the iron content is about 25%, and iron is stably incorporated in the face-centered cubic structure as a crystal of nickel in a substitutional structure, but if the iron content is further increased, the deformation (distortion) becomes large, and further a body-centered cubic phase as a structure of iron is formed, so that the electrocast body becomes a very unstable structure, which causes problems of brittleness and strength reduction as a structure.

The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide an electroformed component having high accuracy, excellent hardness and young's modulus, and excellent stress relaxation resistance; and a timepiece using the electroformed component as an assembled component.

Means for solving the problems

"1" in order to solve the above-described problem, an electroformed component according to one embodiment of the present invention is an electroformed component comprising a nickel-iron alloy that is composed of Ni, Fe, and unavoidable impurities and that contains 5 ~ 25% by mass of Fe, and is characterized by having a substantially laminar morphology portion obtained by repeatedly laminating a plurality of laminated portions in which the Fe content is inclined in the thickness direction.

"2" in the electroformed component according to the above-described one embodiment, it is preferable that the laminated portion is composed of crystal grains having an average particle diameter of 50nm or less obtained by an X-ray diffraction method.

"3" in the electroformed component according to the above-described one embodiment, it is preferable that the crystal grains constituting the laminated portion have a crystal form of a face-centered cubic lattice monolayer, and a part of nickel atoms is substituted with iron atoms.

"4" in the electroformed component according to the above-described one embodiment, it is preferable that the grain having different Fe contents be laminated in the laminated portion to form a gradient of the Fe content.

"5" in the electroformed component of the above-described one embodiment, it is preferable that the iron content in each of the crystal grains constituting the laminated portion has an inclined gradient, and the size of the crystal grains in the laminated portion changes in approximately one direction.

"6" in the electroformed component of the above-described one embodiment, it is preferable that, in the composition of iron in the laminated portion, the composition of iron is inclined within a concentration difference range of ± 15% or more and ± 50% or less of an intermediate concentration that is an intermediate value between the maximum concentration and the minimum concentration of iron.

"7" in the electroformed component according to the above-described one embodiment, the layer thickness of the laminated portion is preferably 500nm or more and 10nm or lessμm is less than or equal to m.

"8" in the electroformed component of the above-described one embodiment, a direction substantially parallel to the layers constituting the laminated portion is preferably set as a mechanical load direction.

"9" a timepiece according to an aspect of the invention is characterized by being provided with an assembly member including the electroformed member described in any one of the above.

"10" in the timepiece according to the present embodiment, it is preferable that the assembly member be a spring member.

Effects of the invention

According to the electroformed component of the present embodiment, since the substantially layered portion is formed by repeatedly laminating the laminated portions, each of which includes the nickel-iron alloy containing 5 ~ 25% of Fe on average and has an Fe content inclined in the thickness direction, a component having excellent creep resistance and stress resistance, high accuracy, and excellent spring characteristics can be obtained.

Therefore, a high-precision electroformed component can be applied to a spring component, and the precision of a device (for example, a timepiece or the like) using a high-precision component is also improved. Further, since the electroformed component has an increased degree of freedom in the shape of the component, it also contributes to downsizing of the mechanism and the component, which are difficult for conventional materials to be machined.

Drawings

[ FIG. 1 ] A]Is a drawing showing an electroformed body according to embodiment 1 of the present invention, wherein (a) is a side view showing the overall shape of the electroformed body, and (b) is a-A along the electroformed body₁A partially enlarged cross-sectional view of a line.

FIG. 2 is an enlarged view showing a part of the structure of the electroformed body, (a) is an enlarged view showing the outline of a laminated portion having an inclined composition, and (b) is an enlarged view showing the outline of a laminated portion having an inclined composition of Fe composed of crystal grains having different compositions.

Fig. 3 is a view showing an example of a method for producing the electroformed body, where (a) is a cross-sectional view showing a state where an electrode layer is formed on a substrate, (b) is a cross-sectional view showing a state where a photoresist is laminated on the electrode layer, (c) is a cross-sectional view showing a state where an electroforming mold (gimballing type) is formed by etching a part of the photoresist, (d) is a cross-sectional view showing a state where the electroformed body is formed in the electroforming mold, (e) is a cross-sectional view showing a state where the surface of the electroformed body is flattened, and (f) is a cross-sectional view showing the electroformed body taken out of the electroforming mold.

FIG. 4 is a view for explaining details of a state in which electroforming is performed using an electroforming mold, wherein (a) is a sectional view showing the electroforming mold, and (b) is a sectional view showing a state immediately before iron ions and nickel ions are deposited in the state in which electroforming is performed.

FIG. 5 is a view for explaining details of a state in which electroforming is performed using an electroforming mold, wherein (a) is a sectional view showing a state in which a laminated portion having an inclined composition of iron is formed in the electroforming mold, and (b) is a sectional view showing a state in which an electroforming bath is stirred or shaken during electroforming.

FIG. 6 is a view showing an example of the results of measuring the Fe composition of the electroformed body of example 1 from the surface thereof in the depth direction by means of SEM (scanning electron microscope).

FIG. 7 is a graph showing the results of measurement of the electroformed product of example 2, wherein (a) is a graph showing an example of the results of measuring the Fe composition by SEM in the depth direction from the surface of the electroformed product, and (b) is an SEM image showing the direction of measurement in the cross section of the electroformed product.

FIG. 8 is a graph showing the results of measurement of the electroformed product of example 3, wherein (a) is a graph showing an example of the results of measuring the Fe composition by SEM in the depth direction from the surface of the electroformed product, and (b) is an SEM image showing the direction of measurement in the cross section of the electroformed product.

FIG. 9 is a view showing the measurement results of an electroformed body of a conventional example, wherein (a) is a view showing an example of the results obtained by measuring the Fe composition by SEM in the depth direction from the surface of the electroformed body, and (b) is an SEM image showing the direction of measurement in the cross section of the electroformed body.

Detailed Description

Hereinafter, an example of an electroformed body (electroformed component) according to embodiment 1 of the present invention will be described in detail with reference to fig. 1 and 2. In the drawings used in the following description, since each portion is formed into a recognizable size, the scale showing each portion is appropriately changed. Accordingly, the relative sizes of the various parts are not limited to the manner shown in the drawings.

Electroformed component "

As shown in fig. 1(a), the electroformed product (electroformed component) 1 of the present embodiment is, for example, a plate-like body, and preferably has a composition containing 5% by mass of Fe 5 ~ 25% and the balance Ni and unavoidable impurities, and may contain, as the unavoidable impurities, S that is inevitably introduced from an electroforming bath described later in a range of about 0.005 ~ 0.2.2%.

A-A as shown in FIG. 1(b)₁As shown in the cross section of fig. 2(a) and the cross section of the electroformed body 1 of the present embodiment, the substantially lamellar morphology portion 1A is obtained by repeatedly laminating a plurality of laminated portions 1A having an iron content inclined in the thickness direction (the vertical direction in fig. 1(b) and fig. 2). The electroformed body 1 in a plan view (in-plane viewing angle) shown in fig. 1A is in a long, slender shape (in-plane viewing angle) including a long side 1A in a longitudinal direction thereof and a short side 1B in a width direction thereof, and when a direction parallel to the short side 1B is an X direction and a direction parallel to the long side 1A is a Y direction, a Z direction is a thickness direction of the electroformed body 1.

The electroformed body 1 of the present embodiment is, for example, a machine component used as a leaf spring, and is preferably used with a load applied in the direction of arrow a, i.e., in a manner of bending in the ± X direction or applying a mechanical force.

Fig. 2(a) shows an outline of a laminated portion 1a of the structure constituting the electroformed body 1, and fig. 2(b) shows a detailed enlarged partial sectional structure of the laminated portion 1 a.

Since the laminated portion 1a constituting the electroformed body 1 is formed by the electroforming method described later, the electroformed body 1 is formed by depositing crystal grains at various positions in the film formation position or the thickness direction and growing the film, unlike a laminate of a uniform laminated film such as a single-layer film laminated by a film formation method such as a sputtering method. Therefore, as shown in fig. 2 a, the laminated portion 1a does not grow uniformly in the film thickness direction (vertical direction) and the plane direction (horizontal direction) in fig. 2 a, but accumulates while growing with some positional deviation in these directions. While an overview of this state is shown in fig. 2(a), when a plurality of boundary lines 1S schematically showing the boundaries of the Fe content gradient are drawn, in fig. 2(a), 3 regions S1 which can be distinguished by collecting ( め る) the boundary lines 1S are arranged in the 1 st layer to form a laminated part 1a, and 2 additional regions S1 are further arranged above them and laminated to form a laminated part 1a of the 2 nd layer.

The blank portions drawn as voids between the regions S1 in fig. 2(a) are not grains present in these portions, but grains are also present in these portions, but are not labeled as the region S1 because of the presence of grains that are not accumulated along the adjacent boundary line 1S and have Fe content. Therefore, fig. 2(a) shows only a state where crystal grains existing in each region S1 are stacked as a laminated portion 1A along a drawn boundary line 1S, and is a schematic view showing a state where a plurality of the laminated portions are stacked to form a substantially layered form portion 1A.

In this embodiment, the thickness of the laminated part 1a is 500nm ~ 10μAnd m is about.

In the present specification, the upper limit and the lower limit of the numerical range are ranges including the upper limit and the lower limit unless otherwise specified, when the upper limit and the lower limit are marked with "~"μm is 500nm or more and 10μm is in the range of not more than m.

Fig. 2(b) is a schematic partial sectional view showing the structure of the electroformed body 1 in a further enlarged scale. The magnitude of the Fe content in each region surrounded by the amorphous particle-like partition line (the vertical line) 1t is indicated by the gradient density (). In each region, the region with the highest diagonal line density is the crystal grain 1R with the highest Fe content, the region with the 2 nd diagonal line density is the crystal grain 1R with the 2 nd highest Fe content, the region with the 3 rd diagonal line density is the crystal grain 1R with the 3 rd highest Fe content, and the region with the 4 th diagonal line density is equivalent to the crystal grain 1R with the 4 th highest Fe content.

In fig. 2(b), for convenience, a layer containing 1 st concentrated Fe concentration crystal grains 1R is defined as a 1 st crystal layer 1b, a layer containing 2 nd concentrated Fe concentration crystal grains 1R is defined as a 2 nd crystal layer 1c, a layer containing 3 rd concentrated Fe concentration crystal grains 1R is defined as a 3 rd crystal layer 1d, and a layer containing 4 th concentrated Fe concentration crystal grains 1R is defined as a 4 th crystal layer 1e, and a state in which a laminated portion 1a is formed by an aggregate of 4 kinds of crystal layers is shown.

In fig. 2(b), as in the case of fig. 2(a), crystal grains are not present in the blank regions outside the respective regions surrounded by the dividing line 1t, but crystal grains are present in these blank regions, but the dividing line 1t and the oblique lines are not marked. Accordingly, fig. 2(b) can also be said to be a schematic diagram showing a state where only the Fe concentration of each region surrounded by the partition line 1t is marked.

In fig. 2 b, for the sake of simplicity, only the laminated portion 1a is drawn as a 4-layer frame part (body frame part) having only the crystal layers 1b ~ 1e for the sake of simplicity, but the actual electroformed body 1 is formed of a larger number of crystal layers, and the number of crystal layers in the laminated portion 1a will be described later.

In this embodiment, 1 region surrounded by the partition line 1t and 1 region having the same Fe concentration is considered to correspond to 1 crystal grain 1R, and the size of the crystal grain 1R is estimated to be, for example, 50nm or less, more specifically 20 ~ 30nm, and it is noted that, with respect to the specific size of the crystal grain 1R, X-ray analysis of a sample of example described later confirmed that the average grain size is 50nm or less, more specifically 20 ~ 30 nm.

As described above, the electroformed body 1 of the present embodiment has the nearly laminar morphology portion 1A obtained by repeatedly laminating a plurality of laminated portions 1A having an Fe content inclined in the thickness direction. Each of the laminated portions 1a has a laminated structure of a 1 st crystal layer 1b including crystal grains 1R having an approximately equal Fe concentration, a 2 nd crystal layer 1c including crystal grains 1R having an approximately equal Fe concentration, a 3 rd crystal layer 1d including crystal grains 1R having an approximately equal Fe concentration, and a 4 th crystal layer 1e including crystal grains 1R having an approximately equal Fe concentration. The number of the crystalline layers constituting each laminated portion 1a is not specifically 4, but includes an arbitrary number.

As an example, since the thickness of the laminated part 1a is 500nm ~ 10μm or so, when the average crystal grain size is 20 ~ 30nm, the crystal layer is composed of several tens of layers ~ and several hundreds of layersThe laminated portion 1a is formed.

In the electroformed body 1 of the present embodiment, the crystal grains 1R each have a crystal form of a face-centered cubic lattice monolayer, and preferably have a crystal form in which a portion of Ni atoms is replaced with Fe atoms, in the Ni — Fe alloy, if the content of Fe is in the range of 5 ~ 25% by mass%, the crystal form in which a portion of Ni atoms is replaced with Fe atoms can be maintained, and in this case, as described later, the electroformed body 1 having excellent mechanical properties can be obtained.

It is preferable that not only the Fe content in each of the crystal grains constituting the laminated portion 1a has an inclined gradient, but also the size of the crystal grains 1R in the laminated portion 1a changes in approximately one direction.

For example, as the Fe content becomes smaller, the grain size of the crystal grains 1R becomes larger. In the case of forming the laminated portion 1a, the grain size of the crystal grains 1R becomes larger in the lateral direction (direction perpendicular to the growth direction of the laminated portion 1 a) as the lamination progresses (thickness direction).

In the electroformed body 1, the grain diameter of the crystal grains 1R tends to decrease as the Fe content increases. Therefore, when the Fe content is small, the grain size of the crystal grains 1R tends to be large. Therefore, the layer (crystal grains) having a large Fe content is re-grown in the portion where the grain diameter of the crystal grains 1R is large, and grows as the crystal grains become larger. Therefore, the crystal grains 1R tend to become larger in the growth direction. Further, since the composition is controlled in the thickness direction, the size of the crystal grains 1R is difficult to increase in the thickness direction with lamination, and tends to increase in the lateral direction.

Method for preparing electroformed body "

Next, a method for producing the electroformed body configured as described above will be described.

In the case of producing the electroformed body 1, it is important to precipitate the electroformed body having the above composition, and therefore, it is preferable to perform electroforming by adjusting or blending the composition of the electroforming solution so as to have the above composition.

As the Ni source, nickel sulfate, nickel chloride, nickel sulfamate, or the like can be used, and as the Fe source, ferrous sulfate, ferrous chloride, ferrous sulfamate, or the like can be used. Further, boric acid, acetic acid, citric acid, etc. may be added to the electrocasting solution as a buffer.

Further, as the pinhole-resistant agent (ピット preventing agent), a surfactant such as a sulfate ester or an alkylsulfonic acid can be added to the electroforming solution. In addition, as a primary gloss agent, saccharin sodium, sodium naphthalenesulfonate, and p-toluenesulfonamide may be added to the electrocasting solution, and as a secondary gloss agent, butynediol, formaldehyde, or the like may be added to the electrocasting solution. In addition, an antioxidant such as ascorbic acid or isoascorbic acid, or a complexing agent such as malonic acid, tartaric acid, succinic acid, or the like may be added to the electrocasting solution.

The following describes an example of an electroforming bath composition and electroforming conditions suitable in the present embodiment, but the bath composition and conditions may be appropriately changed within a range not impairing the effects of the present invention, in other words, within a range in which an electroformed body containing 5% of Fe 5 ~ 25% and the balance Ni and inevitable impurities is precipitated, and the present invention is not limited to the following examples.

However, in the case of producing the electroformed body 1 as described later, in the process of producing the electroformed body 1 by depositing particles by electroforming, it is necessary to stir the electroforming solution at predetermined intervals, or shake, vibrate or rotate the electroforming mold immersed in the electroforming solution at predetermined intervals.

In the case of rotating the electroforming mold, the electroforming step can be performed by repeating the rotation speed of 10rpm, the rotation time of 5 ~ 20 seconds, and the rest time of 100 ~ 115 seconds.

(electrocasting bath composition)

Nickel sulfamate tetrahydrate 200 ~ 300g/L

Nickel chloride hexahydrate 2 ~ 10g/L

Ferrous sulfamate pentahydrate of 5 ~ 50g/L

Boric acid 10 ~ 50g/L

Surfactant 0.1 ~ 10g/L

Primary gloss agent 1 ~ 15g/L

0.05 ~ 5g/L of secondary gloss agent

Antioxidant 0.1 ~ 10g/L

pH value of 2 ~ 4

Bath temperature 40 ~ 60 deg.C

(electroforming Condition)

Cathode current density 1 ~ 10A/dm²

The electroformed body 1 can be produced by performing an electroforming process using an electroforming apparatus having the electroforming bath configured as described above.

In the present embodiment, although "S: 0.005 ~ 0.2.2%" is defined, the S source of the present embodiment is contained in nickel sulfamate tetrahydrate, ferrous sulfamate pentahydrate, a surfactant, and a primary brightener in the electroforming bath composition, and in the electroforming step, metal ions are reacted at the cathode to precipitate metal, but at this time, the non-metal ions, the brightener, and the like adhering to the cathode surface are collectively absorbed (り Write まれ る) and, therefore, elements contained in the bath composition such as S, O, H, which is an inevitable impurity, are commonly precipitated together.

S is an impurity, and the smaller the content thereof, the more preferable the content is in terms of the characteristics of the alloy, but since an excessive reduction may increase the electroforming cost, the preferable range is 0.005% ~ 0.2.2% in the present embodiment.

The electrocast body according to the present embodiment may contain other trace elements in a range not impairing the effects of the present invention, although it has the above-described composition.

Next, an electrode for electroforming used in electroforming will be described.

Fig. 3 is a diagram illustrating a step of forming an electroforming electrode.

First, as shown in fig. 3(a), an electrode 3 to be a cathode in an electroforming step is formed on a substrate 2.

Various materials such as stainless steel and Ti can be used for the substrate in addition to silicon, quartz and sapphire. As the material of the electrode 3, Cu, Au, Cr, Ti, or the like can be used. In the case of using a metal material for the substrate 2, the electrode 3 may not be formed. In this case, the substrate 2 can be made to function as an electrode (cathode) for electroforming.

The thickness of the substrate 2 is preferably set to 100μm ~ 1mm so as to be independent (self-supporting) in the subsequent step, and the thickness of the electrode 3 is preferably 10nm or more from the viewpoint of ensuring stable conduction and minimum strength in the electroforming step described later, and on the other hand, if the thickness of the electrode 3 is too thick, peeling may occur due to stress, or a problem of taking time for film formation may occur, and therefore, it is preferably 10μm is less than or equal to m.

Fig. 3(b) is a diagram illustrating a resist forming process.

As shown in fig. 3(b), a photoresist 4 is formed on the electrode 3. The photoresist 4 may be a negative type or a positive type, and may be formed by spin coating or dip coating. When a dry film resist is used as the photoresist, the film can be formed by a lamination method.

The thickness of the photoresist 4 is set to be equal to or greater than the thickness of the electroformed body 1 formed in the subsequent step.

In the following description, a case where a negative type is used for the photoresist 4 will be described.

Fig. 3(c) is a diagram showing a distinct image process.

As shown in fig. 3 c, first, the photoresist 4 is irradiated with ultraviolet rays using a photomask (not shown) for forming an outer shape pattern of the electroformed body 1 (see fig. 3 f) formed in the subsequent step, thereby curing the photoresist 4 except for the portion where the electroformed product is deposited in the electroforming step in the subsequent step. Next, the uncured photoresist 4 (the portion where the electroformed body is precipitated) is removed, thereby forming the electroformed mold 7 having the pattern portion P for forming the outer shape of the electroformed body 1 (see fig. 3 (f)). The pattern portion P shown in the figure includes a concave portion 6 for forming the outer shape of the electroformed body 1. Although not shown, a plurality of the above-described pattern portions P are formed in the electroforming mold 7 in the row and column direction.

Although the method of forming the electroforming mold 7 in the present embodiment has been described by taking, as an example, the development step in the electroforming electrode forming step ~ shown in fig. 3(a) ~ (c), the present invention is not limited to this, and other known methods may be used as the method of forming the electroforming mold 7.

The electrocasting mold 7 is attached to an electrocasting apparatus (not shown) to form an electrocast body 1 containing a Ni — Fe alloy on the exposed electrode 3 as shown in fig. 3 (d).

The electrocasting apparatus has an electrocasting tank for storing the electrocasting solution containing Ni ions and Fe ions, and includes an anode immersed in the electrocasting solution and a power supply unit connected to the anode and an electrode (cathode) 3 of an electrocasting mold 7 via electric wiring.

After the electroforming mold 7 is immersed in the electroforming solution in a state of being attached to a jig, which is not shown, the power supply unit is activated to apply a voltage between the anode and the cathode. Thus, Ni ions and Fe ions in the electroforming solution move to the cathode side in the solution, and are deposited as an Ni — Fe alloy on the surface of the cathode 3, and further grow into the metal laminate 10.

Fig. 4(a) shows an enlarged structure of the electroforming mold 7, and fig. 4(b) schematically shows a state where the electroforming mold 7 is immersed in the electroforming solution and Ni ions and Fe ions in the electroforming solution are present around the concave portion 6. In fig. 4(b), white circles indicate Ni ions 8, and hatched circles indicate Fe ions 9. In the state of fig. 4(b), Ni ions 8 and Fe ions 9 are dispersed almost uniformly in the inside of the concave portion 6.

When the power supply unit is started from this state and a voltage is applied between the anode and the electrode (cathode) 3 as described above, Ni ions 8 and Fe ions 9 are deposited on the surface of the electrode 3 to deposit the laminated portion 1a made of Ni — Fe alloy, but since Fe ions 9 are preferentially deposited over Ni ions 8, crystal grains 1R having a high Fe concentration are deposited in the laminated portion 1 a. When the deposition is performed, the Fe ions existing inside the concave portion 6 gradually decrease, and therefore, the crystal grains 1R having a low Fe concentration are gradually deposited as the deposition proceeds. Therefore, a concentration gradient of Fe is generated in the laminated portion 1a in the thickness direction thereof.

Fig. 5(a) shows a state in which Fe ions 9 in the concave portion 6 are reduced by continuing the electroforming. In the state shown in fig. 5(a), only 1 layer of the layered portion 1a having the concentration gradient of Fe is formed on the surface of the electrode 3 in the recess 6.

When the above-mentioned deposition is continued for a predetermined time, for example, about 100 ~ 120 seconds, the electrocasting solution is stirred, or the electrocasting solution is rotated or shaken for each jig 7.

When the electroforming mold 7 is rotated, the rotation operation is preferably performed at a speed of about 10rpm for about 5 ~ 30 seconds.

By either operation, the electrocasting solution present in the recessed portion 6 is exchanged with the electrocasting solution of the average ion concentration present around the electrocasting mold 7. This state is shown in fig. 5 (b).

In the state shown in FIG. 5(a), a crystalline layer 1b having a high Fe concentration is initially deposited on the electrode 3, and crystalline layers 1c, 1d, and 1e having a low Fe concentration are successively deposited. When the electrocasting solution is stirred or the electrocasting mold 7 is rotated to the state shown in FIG. 5(b), the crystal layer 1b having a high Fe concentration is deposited again from the beginning, and the crystal layers 1c, 1d, and 1e having a low Fe concentration are gradually deposited in this order.

Thus, the substantially lamellar morphology portion 1A is formed by repeating the lamination of the lamination portions 1A in which the Fe content is inclined in the thickness direction.

The Fe concentration difference in the laminated portion 1a is preferably such that the Fe concentration is inclined within a range of a concentration difference of ± 15% or more and ± 50% or less of an intermediate Fe concentration, which is an intermediate value between the maximum Fe concentration crystal layer and the minimum Fe concentration crystal layer.

Also within this range, the concentration difference is preferably within a range of ± 20% or more and ± 45% or less of the intermediate concentration, and most preferably within a range of ± 22% or more and ± 41% or less of the intermediate concentration.

By repeating the deposition for about 100 ~ 120 seconds and the rotation of the electroforming mold 7 (or the stirring of the electroforming solution or the shaking of the electroforming mold 7), the metal laminate 10 having the substantially laminar morphological portion 1A of a predetermined thickness obtained by repeating the lamination of the plurality of laminated portions 1A having an Fe content inclined in the thickness direction can be produced.

When the electrocasting is carried out using the electrocasting solution at the cathode current density,then the photoresist thickness is 100 ~ 300 aμm, the inner width of the opening part is 50 ~ 100μm, the thickness of the laminated part 1a may be 1 ~ 2μAnd (5) laminating with repetition period of about m.

The metal laminate 10 is deposited so as to have a thickness equal to or greater than the thickness of the recess 6. In other words, since the depth of the concave portion 6 is the thickness of the electroformed body 1, the Ni — Fe alloy is grown at least until the concave portion 6 of the electroformed mold 7 is buried by the metal laminated body 10. However, in the subsequent step, when the grinding/polishing step shown in fig. 3(e) is omitted, the metal laminate 10 is deposited so that the thickness thereof is the same as that of the electroformed body 1.

Fig. 3(e) is a diagram illustrating a grinding/polishing process. The metal laminate 10 obtained by the electroforming step is ground to a thickness corresponding to the thickness of the electroformed body 1, and the surface is polished to a mirror finish.

Specifically, after the electroforming mold 7 on which the metal laminated body 10 is formed is taken out from the electroforming tank, each electroforming mold 7 is ground in accordance with the thickness dimension of the metal laminated body 10 to be the electroformed body 1. In the present embodiment, grinding is performed by removing the surface portion of the metal laminated body 10 formed on the surface of the electroforming mold 7 (i.e., by removing the electroforming body 1 remaining in the recess 6).

FIG. 3(f) is a view for explaining a step of taking out the electroformed body.

In the electroformed body removing step, the substrate 2, the electrode 3, and the photoresist 4 are removed, but the method of removal is not particularly limited, and the removal may be performed by etching, for example. Further, a method of taking out the electroformed body 1 by applying a physical force may be performed. Thus, the desired electroformed body 1 comprising the Ni-Fe alloy can be obtained.

The electroformed body 1 can be subjected to a heating treatment at 250 ℃ for about 3 hours to uniformize the crystal structure.

In the electroformed body 1 prepared by the method described above, the following electroformed body 1 was obtained: the electroformed body is a plate-like body as shown in fig. 1(a), and as shown in fig. 1(b), a plurality of layered portions 1a are stacked in the thickness direction, in other words, in the electroforming growth direction, and the electroformed body 1 has a concentration gradient of Fe in each of the layered portions 1 a.

In this electroformed body 1, since the electroformed body is a Ni — Fe alloy containing 5 ~ 25% of Fe, an electroformed body excellent in mechanical properties and spring properties with a yield stress of about 1500MPa or more and a young's modulus of 150GPa or more can be obtained.

In addition, when the concave portion 6 formed in the photoresist 4 is formed by ultraviolet curing and etching by etching, the resultant electroformed body 1 can be formed with high dimensional accuracy because processing can be performed with extremely high accuracy as compared with ordinary machining.

The present applicant found that the above excellent mechanical properties are exhibited by an electroformed body 1 of a Ni-Fe alloy having the above composition, and that excellent Young's modulus, Vickers hardness, and the like can be obtained as an assembly member such as a timepiece member, as described in Japanese unexamined patent application publication No. 2014-198897, and that an electroformed body 1 of a Ni-Fe alloy having the above composition, for example, can obtain a Vickers hardness (Hv) of 580 or more, preferably about 620 ~ 630, and can obtain an electroformed body having a yield stress of 1400MPa or more and a Young's modulus of 150 ~ 170GPa or more.

In addition to these excellent mechanical properties, the electroformed body 1 of the present embodiment is more excellent in hardness and yield stress, and also excellent in stable young's modulus, and therefore is particularly excellent as a spring material in which a load acts in the direction of the arrow a shown in fig. 1(a), in other words, in the direction parallel to the layer of the laminated portion 1 a.

For example, an electroformed body 1 having a hardness of 670 ~ 720Hv level, a yield stress of 1500 ~ 1700MPa level, and a Young's modulus of 170MPa level and having excellent spring characteristics can be obtained.

Since the Ni — Fe alloy constituting the electroformed body 1 becomes brittle when the Fe content exceeds 25%, the upper limit is substantially set to about 15 ~ 20% when variations in Fe content are taken into consideration.

In the prior Japanese patent laid-open No. 2014-198897, the excellent mechanical properties found by the present applicant are those obtained in a Ni-Fe alloy containing about 25 mass% of Fe.

In the electroformed body 1 of the present embodiment, the substantially lamellar morphology portion 1A having a plurality of laminated portions 1A in which the Fe content is inclined in the thickness direction is repeatedly laminated can effectively function, and even if the Fe content is about 10 ~ 17%, the substantially lamellar morphology portion is not inferior to the Ni — Fe alloy having the Fe content of about 25%, and as described above, the electroformed body 1 capable of stably exhibiting excellent mechanical properties at a high level can be obtained.

According to the electroformed body 1 of the present embodiment, since the coarsening of crystal grains is suppressed and the mechanical properties such as young's modulus and yield stress are improved as described above as compared with the conventional Ni electroformed component or the like, a technique for producing a high-precision small component can be applied to a spring component as an assembly component of a timepiece, and the precision of a device (for example, a timepiece or the like) using a high-precision component is also improved. The spring member is applicable to a spring member such as a start/stop lever as an assembly member for a timepiece.

Further, since the method of manufacturing the electroformed body 1 employs the electroforming step using the photoresist 4 described above, the degree of freedom in the shape of the part is increased, and therefore, a mechanism which has been impossible for the conventional machined part can be realized, contributing to the downsizing of the mechanism, and contributing to the downsizing of products such as watches and the like using the small-sized mechanism.

In the electroformed body 1 of the present embodiment, a desired electroformed body can be obtained even if the substantially lamellar portion 1A is not obtained by stacking the laminated portions 1A in all structures.

For example, as shown in FIG. 2(a), even if crystal grains which cannot be expressed as the laminated portion 1A are partially contained, if the structure contains a substantially layer-shaped portion 1A obtained by stacking the laminated portions 1A, an electroformed body which can achieve the object of the present invention can be obtained.

As an example, it is preferable that 50% by volume or more of the structure is formed into the substantially lamellar morphology portion 1A in which the laminated portions 1A are stacked.