JP6693295B2 - Exterior parts for watches and watches - Google Patents

Description

The present invention relates to a timepiece exterior component and a timepiece.

  Decorative products such as exterior parts for watches are required to have an excellent aesthetic appearance. Conventionally, in order to achieve such an object, a metal material such as Pt or Ag has generally been used as a constituent material of an ornament.

  However, the hardness of metal materials is generally relatively low, and the surface of decorative articles (particularly watch exterior parts and accessories) made of the above-mentioned materials is liable to be scratched and should be used for a long time. Therefore, there is a problem that the aesthetic appearance is significantly reduced.

  In order to solve such a problem, a technique of nitriding the surface of a substrate made of, for example, stainless steel or Ti with nitrogen is used as a technique for hardening the substrate (see, for example, Patent Document 1). ..

  However, the nitriding treatment causes the surface to be rough, so that the polishing appearance is changed. The mirror-finished product is particularly rough and becomes cloudy, and cannot be used as a decoration as it is.

  In addition, the nitriding-treated decorative article has the effect of being less likely to be damaged by a relatively small external force, but when a relatively large external force is applied, the above-mentioned effect is obtained. However, there is a problem that a relatively large dent (for example, a dent caused by a drop or the like) is likely to occur and a small scratch is prevented, so that such a dent becomes more prominent.

JP-A-11-318520

An object of the present invention is to provide an exterior part for a timepiece that is difficult to have a dent such as a scratch or a dent and is less noticeable even when a relatively large external force is applied to cause the dent, and the exterior for the timepiece. It is to provide a timepiece equipped with parts .

Such an object is achieved by the present invention described below.
The timepiece exterior component of the present invention comprises a base material at least a part of the surface of which is mainly composed of Ti or stainless steel,
Provided on the base material, it possesses a coating composed mainly TiC,
The coating film is a laminate having at least a first layer and a second layer provided on a surface side of the first layer facing the base material,
The elastic modulus of the second layer is higher than the elastic modulus of the first layer.

Thus, it is possible to provide a timepiece exterior component in which a dent such as a scratch or a dent is unlikely to be formed, and the dent is less noticeable even when a relatively large external force is applied to the dent.

In the timepiece exterior component of the invention, it is preferable that the C content in the first layer is 45% by mass or more and 60% by mass or less.

  As a result, the hardness of the outer surface of the coating is made higher, the dent due to a relatively small external force is less likely to be formed, and the coating is less likely to cause defects such as cracks.

In the exterior component for a timepiece of the present invention, it is preferable that the content ratio of C in the second layer is 35% by mass or more and 55% by mass or less.

As a result, the self-repairing function of the second layer can be made more prominent while the hardness of the coating as a whole is higher. Further, the adhesion between the first layer and the second layer can be made more excellent, and delamination between the first layer and the second layer can be prevented more effectively. be able to. As a result, the durability and reliability of the timepiece exterior component can be further improved.

In the exterior part for a timepiece of the invention, when the C content in the first layer is X ₁ [mass%] and the C content in the second layer is X ₂ [mass%], It is preferable to satisfy the relationship of 5 ≦ X ₁ −X ₂ ≦ 25.

As a result, the self-repairing function of the second layer can be made more prominent while the hardness of the coating as a whole is higher. Further, the adhesion between the first layer and the second layer can be made more excellent, and delamination between the first layer and the second layer can be prevented more effectively. be able to. As a result, the durability and reliability of the timepiece exterior component can be further improved.

In the timepiece exterior component of the invention, it is preferable that the average thickness of the first layer is 0.10 μm or more and 0.30 μm or less.

  As a result, the hardness of the outer surface of the coating is made higher, the dent due to a relatively small external force is less likely to be formed, and the coating is less likely to cause defects such as cracks.

In the timepiece exterior component of the present invention, the second layer preferably has an average thickness of 0.60 μm or more and 1.0 μm or less.

  As a result, the self-repairing function of the second layer can be made more prominent while preventing the hardness of the entire coating film from decreasing.

In the timepiece exterior component of the present invention, the average thickness of the coating film is preferably 1.1 μm or more and 1.9 μm or less.

This makes it possible to sufficiently prevent the internal stress of the coating film from increasing and to make the depression more inconspicuous even when a relatively large external force is applied to cause the depression. Therefore, the durability of the timepiece exterior component can be further improved.

In the timepiece exterior component of the present invention, the coating further has a third layer having a larger elastic modulus than the second layer on a surface side of the second layer facing the base material. Preferably.

  As a result, the self-healing function of the second layer is exerted, and the self-healing function of the third layer is also exerted, so that even when a relatively large external force is applied to cause a recess, the recess is less noticeable. can do. Further, the adhesion of the coating film to the base material can be made more excellent, and peeling of the coating film from the base material can be more effectively prevented.

In the exterior component for a timepiece of the present invention, it is preferable that the content ratio of C in the third layer is 15% by mass or more and 35% by mass or less.

As a result, the self-repairing function of the third layer can be made more prominent while the hardness of the coating as a whole is higher. Further, the adhesiveness between the second layer and the third layer and the adhesiveness between the base material and the third layer can be further improved, and the adhesiveness between the second layer and the third layer can be improved. It is possible to more effectively prevent delamination between the substrate and the third layer. As a result, the durability and reliability of the timepiece exterior component can be further improved.

In the exterior component for a timepiece of the invention, when the C content in the second layer is X ₂ [mass%] and the C content in the third layer is X ₃ [mass%], It is preferable to satisfy the relationship of 5 ≦ X ₂ −X ₃ ≦ 40.

As a result, the self-repairing function of the third layer can be made more prominent while the hardness of the coating as a whole is higher. Further, the adhesiveness between the second layer and the third layer and the adhesiveness between the base material and the third layer can be further improved, and the adhesiveness between the second layer and the third layer can be improved. It is possible to more effectively prevent delamination between the substrate and the third layer. As a result, the durability and reliability of the timepiece exterior component can be further improved.

In the timepiece exterior component of the present invention, the average thickness of the third layer is preferably 0.40 μm or more and 0.60 μm or less.

  This makes it possible to make the self-repairing function of the third layer more prominent while preventing the hardness of the entire coating film from decreasing.

The timepiece exterior component of the present invention is preferably at least one of a bezel, a body, a crown, a case back and a timepiece band .
These members have a great influence on the overall appearance of the watch, and are also susceptible to damage (such as scratches and dents) due to a relatively large impact from the outside during normal use of the watch. The member is required to have particularly excellent durability as well as aesthetic appearance, but according to the present invention, these requirements can be satisfied. That is, when the present invention is applied to the timepiece exterior component as described above, the effect of the present invention is more remarkably exhibited.

The timepiece of the invention is characterized by including the timepiece exterior component of the invention.
Accordingly, it is possible to provide a timepiece including a timepiece exterior component in which a dent such as a scratch or a dent is unlikely to be formed and the dent is less noticeable even when a relatively large external force is applied to the dent.

It is sectional drawing which shows typically the suitable embodiment of the decorative article of this invention. It is sectional drawing which shows typically the state immediately after a large external force is applied to the decorative article of this invention. It is a sectional view showing typically the state where a predetermined time passed, after a big external force was added to the ornament of the present invention. It is sectional drawing which shows typically the process (base material preparation process) of suitable embodiment of the manufacturing method of a decorative article. It is sectional drawing which shows typically the process (3rd layer forming process) of suitable embodiment of the manufacturing method of an ornament. It is sectional drawing which shows typically the process (2nd layer forming process) of suitable embodiment of the manufacturing method of an ornament. It is sectional drawing which shows typically the process (1st layer forming process) of suitable embodiment of the manufacturing method of a decorative article. It is a flowchart which shows an example of the manufacturing method of an ornament. It is a fragmentary sectional view showing typically a suitable embodiment of the timepiece (portable timepiece) of the present invention. It is a figure for demonstrating how to obtain elastic deformation work.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.
<< ornaments >>
First, the decorative article of the present invention will be described.

  FIG. 1 is a sectional view schematically showing a preferred embodiment of the decorative article of the present invention. Further, FIG. 2 is a cross-sectional view schematically showing a state immediately after a large external force is applied to the decorative article of the present invention, and FIG. 3 is a state in which a predetermined time has elapsed after the large external force was applied to the decorative article of the present invention. FIG. 10 is a cross-sectional view schematically showing the above, and FIG. 10 is a diagram for explaining how to obtain the elastic deformation work.

  The decorative article 10 of the present embodiment has a base material 1 and a coating film 2 which is provided on the base material 1 and is mainly made of TiC.

<< Substrate >>
At least a part of the surface of the base material 1 is mainly composed of Ti or stainless steel.

  Examples of the material mainly composed of Ti include Ti (Ti as a simple substance) and a Ti-based alloy.

  Examples of the stainless steel include Fe-Cr alloys and Fe-Cr-Ni alloys, and more specifically, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, SUS304, SUS303, and the like. SUS316, SUS316L, SUS316J1, SUS316J1L and the like can be mentioned.

  When a material other than a material mainly composed of Ti and a stainless steel is mainly used, it is difficult to sufficiently increase the hardness of the finally obtained decorative article. In addition, when a material mainly composed of Ti, or a material mainly composed of stainless steel is not used, the decorative article finally obtained has an excellent aesthetic appearance (especially for exterior parts for watches and the like) for a sufficiently long period of time. It becomes difficult to maintain the aesthetic appearance required for ornaments.

  In the present invention, “mainly” means that 50% by mass or more of the corresponding part is composed of the component, and particularly 70% by mass or more of the corresponding part is composed of the component. Is preferable, and it is more preferable that 80% by mass or more of the corresponding portion is composed of the component.

  The base material 1 may have a substantially uniform composition at each site, or may have a different composition at each site. For example, the base material 1 may have a base portion and a surface layer provided on the base portion.

  When the base material 1 has such a structure, the degree of freedom in molding the base material 1 can be increased by selecting the constituent material of the base portion, and even the ornament 10 having a more complicated shape can be obtained. , Can be manufactured relatively easily.

  When the substrate 1 has a base and a surface layer, the thickness (average value) of the surface layer is not particularly limited, but is preferably 0.1 μm or more and 50 μm or less, and 1.0 μm or more and 10 μm or less. Is more preferable.

  When the base material 1 has a base portion and a surface layer, the above-mentioned materials can be preferably used as the constituent material of the surface layer. Further, as the constituent material of the base, for example, a metal material, a non-metal material or the like can be used.

  When the base is made of a metal material, it is possible to provide the decorative article 10 having particularly excellent strength characteristics.

  In addition, when the base is made of a metal material, even if the surface roughness of the base is relatively large, the resulting decorative article 10 can be obtained due to the leveling effect when forming the surface layer, the coating film 2 and the like described later. The surface roughness of can be reduced. For example, it is possible to perform mirror finishing even if machining such as cutting or polishing on the surface of the base is omitted, or the base is formed by the MIM method, and the surface is a satin finish. Even in the case, it can be easily mirror-finished. This makes it possible to obtain a decorative article having excellent gloss.

  When the base is made of a non-metallic material, it is possible to provide the decorative article 10 that is relatively lightweight, easy to carry, and has a heavy appearance.

When the base is made of a non-metallic material, it can be molded into a desired shape with relative ease.
Also, when the base is made of a non-metallic material, an effect of shielding electromagnetic noise can be obtained.

  Examples of the metal material forming the base include various metals such as Fe, Cu, Zn, Ni, Ti, Mg, Cr, Mn, Mo, Nb, Al, V, Zr, Sn, Au, Pd, Pt, and Ag. And alloys containing at least one of these. Among them, Cu, Zn, Ni, Ti, Al or an alloy containing at least one of these is particularly preferable.

  When the base is made of the material as described above, the adhesion between the base and the surface layer can be made particularly excellent, the workability of the base is improved, and the base material 1 as a whole is molded. The degree of freedom of is increased.

  Further, examples of the non-metal material forming the base include ceramics, plastics (particularly heat resistant plastics), stone materials, wood and the like.

Examples of the ceramics include oxide ceramics such as Al ₂ O ₃ , SiO ₂ , TiO ₂ , Ti ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , barium titanate, and strontium titanate, AlN, Si ₃ N _4. , SiN, TiN, BN, BN, ZrN, HfN, VN, TaN, NbN, CrN, Cr ₂ N and other nitride ceramics, graphite, SiC, ZrC, Al ₄ C ₃ , CaC ₂ , WC, TiC, HfC, VC , TaC, NbC, and other carbide-based ceramics, ZrB ₂ , MoB, and other boride-based ceramics, or composite ceramics obtained by arbitrarily combining two or more of these.

  When the base is made of the above ceramics, the decorative article 10 having particularly excellent strength and hardness can be obtained.

  Examples of the plastic material forming the base include various thermoplastic resins and various thermosetting resins, such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA). Polyolefin, cyclic polyolefin, modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide (eg nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6-12, nylon 6) -66), polyimide, polyamideimide, polycarbonate (PC), poly- (4-methylpentene-1), ionomer, acrylic resin, polymethylmethacrylate, acrylonitrile-butadiene-styrene copolymer (ABS resin) , Acrylonitrile-styrene copolymer (AS resin), butadiene-styrene copolymer, polyoxymethylene, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyethylene terephthalate (PET), polybutylene terephthalate ( PBT), polyester such as polycyclohexane terephthalate (PCT), polyether, polyether ketone (PEK), polyether ether ketone (PEEK), polyether imide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polysulfone, poly Ether sulfone, polyphenylene sulfide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride , Other fluorinated resins, styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, chlorinated polyethylene-based thermoplastic elastomers, epoxies Resin, phenolic resin, urea resin, melamine resin, unsaturated polyester, silicone resin, urethane resin, polyparaxylylene (poly-para-xylylene), polymonochloroparaxylylene (poly-monochloro-para-xylylene), Polypara such as poly-dichloro-para-xylylene, poly-monofluoro-para-xylylene, poly-monoethyl-para-xylylene Xylylene resin, etc., or copolymers, blends, polymer Etc., and singly or in combination of two or more of these (e.g., a blend resin, polymer alloy, as a laminate or the like) can be used.

  The shape and size of the base material 1 are not particularly limited, and are usually determined based on the shape and size of the ornament 10.

<< coating >>
On the surface of the base material 1, a coating film 2 mainly composed of TiC is provided.

  Since TiC is a hard material, having the coating film 2 made of such a material makes it difficult for the ornament 10 to have a dent such as a scratch or a dent.

  The coating film 2 is a laminated body including a first layer 21 and a second layer 22 provided on the surface side of the first layer 21 facing the base material 1.

The elastic modulus of the second layer 22 is larger than the elastic modulus of the first layer 21.
As a result, when the outer surface side of the coating film 2 has a higher hardness, when the coating film 2 has a relatively large dent, a self-repairing force for repairing the shape works.

  Therefore, when a relatively small external force acts, not only is it difficult for the surface to have a dent such as a scratch or dent, but also when a relatively large external force acts to cause a deep dent (see FIG. 2). ), The self-repairing force makes the dent small (see FIG. 3), and the dent becomes inconspicuous. In particular, not only the shape of the second layer 22 is repaired, but also the size of the hole formed in the first layer 21 due to the effect of the repair of the shape of the second layer 22 becomes small, and the depression is It will be inconspicuous. As a result, the decorative article 10 can maintain an excellent aesthetic appearance for a long period of time.

  As the elastic modulus of each part, for example, the elastic deformation work amount obtained by the nanoindentation method can be adopted.

  In general, the elastic modulus and the elastic deformation work are numerical values in different units, but there is a correlation between the elastic modulus and the elastic deformation work, and when the elastic modulus becomes small, the elastic deformation work becomes small. The relationship holds that the work of elastic deformation increases as the elastic modulus increases.

  Next, a method of obtaining the elastic deformation work amount from the measurement by the nanoindentation method will be described with reference to FIG.

First, using a nano indenter, an indenter (measurement indenter) is brought close to and brought into contact with a target site of the subject (see point a in FIG. 10).
Then, the load applied to the indenter is increased at a predetermined speed (see the curve ab in FIG. 10).

When the load applied to the indenter reaches a preset maximum load (see point b in FIG. 10), the load applied to the indenter is reduced at a predetermined speed (see curve bc in FIG. 10).
The measurement ends when the load applied to the indenter becomes 0 (see point c in FIG. 10).

FIG. 10 is a chart when the load applied to the indenter is y and the indentation depth of the indenter is x when the above-described measurement is performed.
Point d is the intersection of the x-axis and a straight line passing through point b and parallel to the y-axis.

In this chart, the coordinates of the point a are (0,0), the coordinates of the point b are (xb, yb), the coordinates of the point c are (xc, 0), and the coordinates of the point d are ( xd , 0). You can

  The area of the region surrounded by the line segment bc, the line segment cd, and the line segment db (the region shown by the hatched portion in FIG. 10) is the elastic deformation work amount for the measurement site of the subject.

  The elastic deformation work is performed by, for example, producing a test piece on which a single-layer film having the same composition is formed under the same conditions as the measurement target site of the coating film 2, and performing nanoindentation on the single-layer film of the test piece. It can be determined by performing measurement by the method.

  Alternatively, the elastic deformation work may be obtained by cutting the decorative article 10 in the thickness direction of the coating film 2 and measuring the cut surface by the nanoindentation method.

  When the cut surface of the ornamental article 10 is measured, the ornamental article 10 can be cut using, for example, an IsoMet5000 (manufactured by BUEHLER) as an automatic precision cutting machine. At this time, as the cutting whetstone, for example, A100N manufactured by Heiwa Technica Co., Ltd. can be used. Further, the rotation speed of the grindstone can be 4000 rpm.

  When the cut surface of the ornamental article 10 is measured, the measurement may be performed in a state where the resin is embedded in the voids of the cut surface.

  As a result, it is possible to more reliably prevent undesired deformation of the layer to be measured during measurement (such as peeling of a part of the layer), and it is possible to more suitably perform measurement by the nanoindentation method. In the measurement by the nanoindentation method, if the indenter is in contact with the constituent material of the layer to be measured and is not in contact with the embedded resin, the embedded resin does not adversely affect the measurement.

  The resin embedding can be performed using, for example, a SimpliMet 3000 (manufactured by BUEHLER) as a resin embedding device.

A curable resin is preferably used as the resin to be embedded in the cut surface of the ornament 10.
As a result, it is possible to more reliably prevent undesired deformation of the layer to be measured (such as peeling of a part of the layer) during measurement, and it is possible to perform the measurement by the nanoindentation method more preferably. Further, polishing as described below can also be suitably performed.

The cut surface may be measured after polishing.
As a result, it is possible to eliminate undesired irregularities on the cut surface, and it is possible to more suitably perform measurement by the nanoindentation method.

  Polishing of the cut surface is preferably performed after the resin is embedded, and particularly when a curable resin is used as the embedded resin, it is preferably performed after the curable resin is cured.

  As a result, it is possible to more effectively prevent the indenter from inadvertently contacting the embedded resin during measurement, and it is possible to more suitably perform measurement by the nanoindentation method.

  Polishing of the cut surface can be performed using, for example, Ecomet 300 (manufactured by BUEHLER) as a polishing machine.

  The polishing of the cut surface may be performed in two or more stages, for example. More specifically, after the rough polishing with the polishing cloth paper grain size P400, the final polishing may be performed with the polishing cloth paper grain size P1500.

  The elastic deformation work can be obtained by measurement using various nanoindenters. Specifically, for example, the elastic deformation work can be obtained by measurement using ENT-2100 (manufactured by Elionix). As the measurement indenter, for example, Berkovich Indenter No. 5964 or the like can be used.

  The measurement conditions by the nanoindentation method are not particularly limited, but for example, measurement temperature: 25 ° C., maximum load: 1 mN, load speed: 2 mN / min, unloading speed: 2 mN / min, maximum load holding time: 0 seconds It can be a condition that.

(First layer)
The first layer 21 is a layer provided in a region on the outer surface side of the coating film 2, and has a higher hardness than the second layer 22 described in detail later.

  As a result, the hardness of the outer surface of the coating film 2 is high, and the coating film 2 is unlikely to have a recess due to a relatively small external force.

  The first layer 21 preferably has a higher C (carbon) content than the second layer 22 described in detail later.

  The C content in the first layer 21 is preferably 45% by mass or more and 60% by mass or less, and more preferably 47% by mass or more and 55% by mass or less.

  As a result, the hardness of the outer surface of the coating 2 becomes higher, and it becomes more difficult to form a recess due to a relatively small external force, and the coating 2 becomes less likely to cause defects such as cracks.

  The average thickness of the first layer is preferably 0.10 μm or more and 0.30 μm or less, and more preferably 0.12 μm or more and 0.25 μm or less.

  As a result, the hardness of the outer surface of the coating 2 becomes higher, and it becomes more difficult to form a recess due to a relatively small external force, and the coating 2 becomes less likely to cause defects such as cracks.

  The elastic deformation work of the first layer 21 (elastic deformation work obtained by measurement with the nanoindentation method) is not particularly limited, but is preferably 60 pJ or more and 120 pJ or less, and 70 pJ or more and 110 pJ or less. Is more preferable.

  As a result, the hardness of the outer surface side of the coating film 2 can be increased, and the self-repairing force when the coating film 2 has a relatively large depression can be increased.

(Second layer)
The second layer 22 is a layer provided closer to the base material 1 side than the first layer 21, and has a higher elastic modulus (elastic deformation work amount) than the first layer 21.

  As a result, when a relatively large dent (a dent reaching the second layer 22) is formed in the coating film 2, a self-repairing force that tries to restore the shape works, and even if a large dent is generated, the self-repair is performed. Due to the action, the dent becomes small, and the dent becomes inconspicuous.

  The second layer 22 preferably has a lower C (carbon) content than the first layer 21.

  As a result, the hardness of the entire coating 2 is sufficiently high, and the elastic modulus (elastic deformation work amount) of the second layer 22 is higher than the elastic modulus (elastic deformation work amount) of the first layer 21. Therefore, it can be adjusted appropriately.

  The C content in the second layer 22 is preferably 35% by mass or more and 55% by mass or less, and more preferably 38% by mass or more and 50% by mass or less.

  Thereby, the self-repairing function of the second layer 22 can be made more remarkable while the hardness of the coating film 2 as a whole is higher. Further, the adhesion between the first layer 21 and the second layer 22 can be made more excellent, and the delamination between the first layer 21 and the second layer 22 is more effective. Can be prevented. As a result, it is possible to further improve the durability and reliability of the decorative article 10.

When the content rate of C in the first layer 21 is X ₁ [mass%] and the content rate of C in the second layer 22 is X ₂ [mass%], 5 ≦ X ₁ −X ₂ ≦ 25 Is preferably satisfied, and more preferably 8 ≦ X ₁ −X ₂ ≦ 22.

  Thereby, the self-repairing function of the second layer 22 can be made more remarkable while the hardness of the coating film 2 as a whole is higher. Further, the adhesion between the first layer 21 and the second layer 22 can be made more excellent, and the delamination between the first layer 21 and the second layer 22 is more effective. Can be prevented. As a result, it is possible to further improve the durability and reliability of the decorative article 10.

  The average thickness of the second layer 22 is preferably 0.60 μm or more and 1.0 μm or less, and more preferably 0.65 μm or more and 0.95 μm or less.

  As a result, the self-repairing function of the second layer 22 can be made more prominent while preventing the hardness of the coating film 2 as a whole from decreasing.

  The elastic deformation work of the second layer 22 (elastic deformation work calculated by the nanoindentation method) is not particularly limited, but is preferably 120 pJ or more and 180 pJ or less, and 130 pJ or more and 170 pJ or less. Is more preferable.

  As a result, the hardness of the coating film 2 as a whole can be made higher, and the self-repairing force when the coating film 2 has a relatively large depression can be made larger.

(Third layer)
In the present embodiment, the coating film 2 includes, in addition to the first layer 21 and the second layer 22 described above, a surface side of the second layer 22 that faces the base material 1 (in the configuration shown in the figure, contacts the base material 1). The third layer 23 having a larger elastic modulus (work amount of elastic deformation) than the second layer 22 is further provided in the portion to be processed).

  As a result, the self-healing function of the second layer 22 is exerted, and the self-healing function of the third layer 23 is also exerted, so that even when a relatively large external force is applied to cause a recess, the recess is less noticeable. Can be something. In particular, when the depression caused by the external force reaches the third layer 23, the holes formed in the second layer 22 and the first layer 21 under the influence of the restoration of the shape of the third layer 23. The size of is also small, and the dents are inconspicuous. Further, the adhesion of the coating film 2 to the base material 1 can be made more excellent, and peeling of the coating film 2 from the base material 1 can be more effectively prevented.

  The third layer 23 preferably has a lower C (carbon) content than the second layer 22.

  As a result, the hardness of the entire coating 2 is sufficiently high, and the elastic modulus (elastic deformation work amount) of the third layer 23 is higher than the elastic modulus (elastic deformation work amount) of the second layer 22. Therefore, it can be adjusted appropriately.

  The content of C in the third layer 23 is preferably 15% by mass or more and 35% by mass or less, and more preferably 18% by mass or more and 30% by mass or less.

  Thereby, the self-repairing function of the third layer 23 can be made more prominent while the hardness of the coating 2 as a whole is higher. Further, the adhesiveness between the second layer 22 and the third layer 23 and the adhesiveness between the base material 1 and the third layer 23 can be made more excellent, and the second layer 22 and the third layer 23 can be improved. It is possible to more effectively prevent delamination from the layer 23, layer delamination from the substrate 1 and the third layer 23, and the like. As a result, it is possible to further improve the durability and reliability of the decorative article 10.

When the content rate of C in the second layer 22 is X ₂ [mass%] and the content rate of C in the third layer 23 is X ₃ [mass%], 5 ≦ X ₂ −X ₃ ≦ 40 It is preferable to satisfy the relationship of 10 ≦ X ₂ −X ₃ ≦ 35, and it is more preferable to satisfy the relationship of 15 ≦ X ₂ −X ₃ ≦ 30.

  Thereby, the self-repairing function of the third layer 23 can be made more prominent while the hardness of the coating 2 as a whole is higher. Further, the adhesiveness between the second layer 22 and the third layer 23 and the adhesiveness between the base material 1 and the third layer 23 can be made more excellent, and the second layer 22 and the third layer 23 can be improved. It is possible to more effectively prevent delamination from the layer 23, layer delamination from the substrate 1 and the third layer 23, and the like. As a result, it is possible to further improve the durability and reliability of the decorative article 10.

  The average thickness of the third layer 23 is preferably 0.40 μm or more and 0.60 μm or less, and more preferably 0.43 μm or more and 0.57 μm or less.

  As a result, the self-repairing function of the third layer 23 can be made more prominent while preventing the hardness of the entire coating film 2 from decreasing.

  The elastic deformation work of the third layer 23 (elastic deformation work calculated by the nanoindentation method) is not particularly limited, but is preferably 180 pJ or more and 260 pJ or less, and 190 pJ or more and 250 pJ or less. Is more preferable.

  As a result, the hardness of the coating film 2 as a whole can be made higher, and the self-repairing force when the coating film 2 has a relatively large depression can be made larger.

  The respective elastic moduli K1, K2 and K3 of the first layer 21, the second layer 22 and the third layer 23 as described above have a relationship of K1 <K2 <K3.

  The elastic deformation work W1, W2, and W3 of each of the first layer 21, the second layer 22, and the third layer 23 have a relationship of W1 <W2 <W3.

  In particular, the elastic deformation work W1, W2, and W3 of each of the first layer 21, the second layer 22, and the third layer 23 preferably have a relationship of W1 ≦ 0.9W2 ≦ 0.8W3, It is more preferable to show the relationship of W1 ≦ 0.8W2 ≦ 0.65W3.

  As a result, the difference in elastic modulus (work of elastic deformation) of the first layer 21, the second layer 22, and the third layer 23 becomes clearer, and the above-mentioned effects are more remarkably exhibited.

  The average thickness of the coating film 2 is preferably 1.1 μm or more and 1.9 μm or less, and more preferably 1.2 μm or more and 1.7 μm or less.

  Accordingly, it is possible to sufficiently prevent the internal stress of the coating film 2 from increasing, and to make the recess more inconspicuous even when a relatively large external force is applied to form the recess. Therefore, the durability of the decorative article 10 can be made more excellent.

  The ornamental article 10 may be any article having a decorative property, for example, interiors such as figurines, exterior articles, jewellery, exterior parts for watches, glasses, tie pins, cufflinks, rings, necklaces, bracelets. , Accessories such as anklets, brooches, pendants, earrings, piercings, lighters or cases, automobile wheels, sports equipment such as golf clubs, nameplates, panels, awards, other equipment parts including housings, various containers, etc. Although it can be mentioned, the decorative article 10 is preferably an exterior part for a timepiece.

  While the exterior parts for a watch are required to have a beautiful appearance as a decorative item and durability as a practical item, the present invention can satisfy these requirements. Therefore, the effect of the present invention is more remarkably exhibited when the decorative article 10 is an exterior part for a timepiece.

  When the ornament 10 is a watch exterior part, examples of the watch exterior part include a case, a bezel, a case back, a band (including a band piece, a band clasp, a band / bangle attachment / detachment mechanism, etc.) Examples thereof include a plate, a clock hand, a crown (for example, a screw lock type crown, etc.), a button, a dial ring, a parting plate, and the like, and preferably selected from the group consisting of a case, a bezel and a band.

  These members have a great influence on the overall appearance of the watch, and are also susceptible to damage (such as scratches and dents) due to a relatively large impact from the outside during normal use of the watch. The member is required to have particularly excellent durability as well as aesthetic appearance, but according to the present invention, these requirements can be satisfied. That is, when the present invention is applied to the timepiece exterior component as described above, the effect of the present invention is more remarkably exhibited.

  In the present invention, the timepiece exterior component may be any member that can be visually recognized from the outside when the timepiece is used, and is not limited to the one exposed to the outside of the timepiece.

<< Manufacturing method of ornaments >>
Next, a method for manufacturing a decorative article that can suitably manufacture the decorative article of the present invention will be described.

  4 to 7 are cross-sectional views schematically showing the steps of a preferred embodiment of the method for manufacturing a decorative article. Further, FIG. 8 is a flowchart showing an example of a method for manufacturing a decorative article.

  In the method for manufacturing the decorative article 10 of the present embodiment, at least a part of the surface of the base material 1 is mainly composed of Ti or stainless steel, and a base material preparing step is performed, and a coating 2 mainly composed of TiC is formed. And a coating layer forming step. The coating layer forming step includes a third layer forming step of forming a third layer 23 on the surface of the base material 1, and a second layer 22 of forming a surface of the third layer 23. And a first layer forming step of forming the first layer 21 on the surface of the second layer 22.

<< Substrate preparation process >>
In the base material preparing step, the base material 1 as described above is prepared.

  The base material 1 may be molded by any method, and examples of the molding method of the base material 1 include pressing, cutting, forging, casting, powder metallurgy sintering, and metal powder injection. Molding (MIM), the lost wax method, etc. are mentioned.

  Moreover, when the base material 1 has the above-mentioned base and surface layer, the base material 1 can be manufactured as follows. That is, the substrate 1 can be obtained by forming the surface layer on the base manufactured by the method described above, injection molding, extrusion molding or the like. Examples of the method for forming the surface layer include, for example, dipping, brush coating, spray coating, electrostatic coating, coating such as electrodeposition coating, electrolytic plating, immersion plating, wet plating such as electroless plating, thermal CVD, plasma CVD, Examples thereof include chemical vapor deposition (CVD) such as laser CVD, vacuum vapor deposition, sputtering, dry plating such as ion plating, and thermal spraying.

  Further, prior to the steps described below, the surface of the base material 1 may be subjected to surface processing such as mirror surface processing, crease processing, and satin processing.

  As a result, it is possible to give the surface of the obtained decorative article 10 a variation in glossiness, and it is possible to further improve the decorativeness of the obtained decorative article 10. The mirror-finishing can be performed by using, for example, a well-known polishing method, and for example, buff (covering) polishing, barrel polishing, or other mechanical polishing can be adopted.

  In addition, the decorative article 10 manufactured by using the base material 1 subjected to such a surface treatment suppresses glare and the like of the coating film 2 as compared with an article obtained by directly performing the surface treatment on the coating film 2. And has an excellent aesthetic appearance. In addition, when the thickness of the coating 2 is relatively thin as described above, in the case where the surface processing is directly performed on the coating 2, defects such as chipping or peeling of the coating 2 when the surface processing is performed are performed. Occasionally, the production yield of the decorative article 10 may be significantly reduced, but by performing the surface processing on the base material 1, the occurrence of such a problem can be effectively prevented. Further, the surface processing on the substrate 1 can be easily performed under milder conditions than the surface processing on the coating film 2.

Further, prior to the film forming step, the substrate 1 may be subjected to a cleaning treatment such as a blasting treatment, an alkali washing, an acid washing, a water washing, an organic solvent washing, and a bombarding treatment.
Thereby, the adhesion between the base material 1 and the coating film 2 can be made particularly excellent.

<Film forming process>
In the film forming step, the film 2 is formed on the surface of the base material 1.

  The method for forming the coating film 2 is not particularly limited, and examples thereof include coating such as spin coating, dipping, brush coating, spray coating, electrostatic coating, and electrodeposition coating, and wet plating methods such as electrolytic plating, immersion plating, and electroless plating. And chemical vapor deposition (CVD) such as thermal CVD, plasma CVD, laser CVD, dry deposition (vapor deposition) such as vacuum deposition, sputtering and ion plating, and thermal spraying, but dry plating. (Vapor deposition method) is preferred.

  By applying the dry plating method (vapor phase film forming method) as the method of forming the coating film 2, it is possible to ensure the coating film 2 having a uniform film thickness, being uniform, and having particularly excellent adhesion to the substrate 1. Can be formed. As a result, the aesthetic appearance and durability of the finally obtained decorative article 10 can be made particularly excellent.

  Further, by applying a dry plating method (vapor phase film forming method) as a method of forming the coating film 2, each layer (first layer 21, second layer 22, third layer) forming the coating film 2 to be formed. Even if 23) is relatively thin, the variation in film thickness can be made sufficiently small. Therefore, it is also advantageous in improving the reliability of the decorative article 10.

  Further, by applying a dry plating method (vapor phase film forming method) as a method of forming the coating film 2, the respective portions (first layer 21, second layer 22, third layer 23) in the coating film 2 are formed. The content rate of C can be controlled more reliably.

  Among the dry plating methods (vapor phase film forming methods) described above, ion plating is particularly preferable.

  By applying ion plating as the method for forming the coating film 2, the above-mentioned effects become more remarkable. That is, by applying ion plating as a method of forming the coating film 2, it is possible to more reliably form the coating film 2 having a uniform film thickness, being uniform, and having particularly excellent adhesion to the substrate 1. You can As a result, it is possible to further improve the aesthetic appearance and durability of the finally obtained decorative article 10.

  Further, by applying ion plating as a method of forming the coating film 2, each layer (first layer 21, second layer 22, third layer 23) forming the coating film 2 to be formed is relatively thin. Even in this case, the variation in the film thickness can be made particularly small.

  Further, by applying ion plating as a method of forming the coating film 2, the content ratio of C in each portion (the first layer 21, the second layer 22, the third layer 23) in the coating film 2 can be more reliably achieved. Can be controlled.

  When the dry plating method as described above is applied, the coating film 2 can be easily and reliably formed, for example, by using Ti as a target and performing the treatment in an atmosphere containing C (carbon). As such an atmosphere gas, for example, a hydrocarbon gas such as acetylene can be used. Then, by appropriately adjusting the gas supply amount and the like, the composition (content ratio of C) and the like of the formed coating film 2 can be adjusted.

  The atmosphere gas may contain an inert gas such as argon gas.

  This makes it possible to easily and reliably control the content ratio of C in the coating film 2 to be relatively low.

  When the coating film forming step is performed by a dry plating method, for example, the composition of the atmospheric gas in the vapor deposition apparatus (in the chamber) (for example, the mixing ratio of the hydrocarbon gas and the inert gas), the pressure of the gas ( By changing the (partial pressure), the base material 1 can be subjected to the formation steps (first layer formation step, second layer formation step, third layer formation step) of each layer constituting the coating film 2 in the same device. Can be subsequently carried out without removing from the inside of the device.

  As a result, the adhesion between the layers forming the coating 2 becomes particularly excellent, and the productivity of the decorative article 10 also improves.

  By the method as described above, it is possible to efficiently manufacture the decorative article 10 in which a dent such as a scratch or a dent is unlikely to be formed, and even when a relatively large external force is applied to form the dent, the dent is not noticeable.

  FIG. 8 is a flow chart summarizing the method of manufacturing the decorative article 10 as described above.

"clock"
Next, the timepiece of the invention will be described.

  FIG. 9 is a partial sectional view schematically showing a preferred embodiment of the timepiece (portable timepiece) of the invention.

  The wristwatch (portable timepiece) W10 of the present embodiment includes a body (case) W22, a back cover W23, a bezel (edge) W24, and a glass plate W25. In addition, a movement (not shown) (for example, one with a dial and hands) is housed in the case W22.

  A winding stem pipe W26 is fitted and fixed to the case W22, and a shaft portion W271 of a crown W27 is rotatably inserted in the winding stem pipe W26.

  The body W22 and the bezel W24 are fixed by a plastic packing W28, and the bezel W24 and the glass plate W25 are fixed by a plastic packing W29.

  Further, a back cover W23 is fitted (or screwed) to the body W22, and a ring-shaped rubber packing (back cover packing) W40 is inserted in a compressed state in these joint parts (seal parts) W50. Has been done. With this configuration, the seal portion W50 is liquid-tightly sealed and a waterproof function is obtained.

  A groove W272 is formed in the outer periphery of the shaft W271 of the crown W27 in the middle, and a ring-shaped rubber packing (crown packing) W30 is fitted in the groove W272. The rubber packing W30 is in close contact with the inner peripheral surface of the winding stem pipe W26 and is compressed between the inner peripheral surface and the inner surface of the groove W272. With this configuration, the space between the crown W27 and the winding stem pipe W26 is liquid-tightly sealed to provide a waterproof function. When the crown W27 is rotated, the rubber packing W30 rotates together with the shaft W271 and slides in the circumferential direction while being in close contact with the inner peripheral surface of the winding stem pipe W26.

  The wristwatch W10 as the timepiece of the present invention has at least one of the bezel W24, the body W22, the crown W27, the back cover W23, the watch band and other decorative items (particularly, the timepiece exterior parts) as described above. It is composed of ornaments. In other words, the timepiece of the invention comprises the ornament of the invention.

  With this, it is possible to provide a timepiece provided with an ornamental article which is unlikely to have a dent such as a scratch or a dent and which is less noticeable even when a relatively large external force is applied to cause the dent.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these.

For example, in the ornament and the timepiece of the present invention, the configuration of each part can be replaced with any configuration that exhibits the same function, or any configuration can be added.
For example, at least one intermediate layer may be provided between the base material and the coating.

  Thereby, for example, the adhesion between the substrate and the coating (adhesion through the intermediate layer) can be made more excellent.

  Further, in the above-described embodiment, the coating film is described as having the first layer, the second layer, and the third layer, but may further have a fourth layer different from these. ..

Further, in the present invention, a plurality of coatings as described above may be provided on the base material, and for example, the coating may have a structure in which these coatings are laminated.
Thereby, the reliability and durability of the decorative article can be made particularly excellent.

  Further, at least a part of the surface of the decorative article is provided with corrosion resistance, weather resistance, water resistance, oil resistance, scratch resistance, abrasion resistance, discoloration resistance, etc., and is rust-proof, anti-fouling, anti-fog, and anti-fouling. A coat layer (protective layer) for improving the effect of scratches or the like may be formed. Such a coat layer may be removed when the decorative article is used or the like.

  In addition, in the above-described embodiment, the case where the third layer is provided on the surface side of the second layer that faces the base material has been described, but the third layer is provided at other portions, for example, the first layer. It may be provided between the above layer and the second layer.

  Further, in the present invention, the coating film constituting the ornamental product may have at least the first layer and the second layer, and may not have the third layer.

Next, specific examples of the present invention will be described.
[1] Production of decorative article (Example 1)
A decorative article (wristwatch case) was manufactured by the following method.

  First, using stainless steel (SUS444), a base material having the shape of a wristwatch case was produced by casting, and thereafter, necessary portions were cut and polished.

  Next, this base material was washed. As the cleaning of the substrate, first, alkaline electrolytic degreasing was performed for 30 seconds, and then alkaline immersion degreasing was performed for 30 seconds. Then, neutralization was performed for 10 seconds, water washing for 10 seconds, and pure water washing for 10 seconds.

  A coating film (average thickness: 1.50 μm) composed of TiC was formed on the substrate cleaned as described above by using an ion plating device as follows.

First, while preheating the inside of the processing chamber of the ion plating apparatus, the inside of the processing chamber was evacuated (decompressed) to 3 × 10 ⁻³ Pa.

  Next, a cleaning argon gas was introduced into the processing chamber, and a cleaning process was performed for 5 minutes. The cleaning process was performed by applying a DC voltage of 350V.

Next, after evacuating (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, acetylene gas was introduced, and the atmospheric pressure (total pressure) in the processing chamber was set to 3.2 × 10 ⁻² Pa. In such a state (the state in which acetylene gas was continuously introduced), ion plating using Ti as a target was performed to form a third layer composed of TiC (third layer forming step). .. The average thickness of the formed third layer was 0.50 μm. The C content in the third layer was 25.0% by mass.

  Next, on the base material on which the third layer was formed, subsequently, the above-mentioned ion plating was used to form the second layer as follows.

After exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, acetylene gas was introduced, and the atmospheric pressure (total pressure) in the processing chamber was set to 4.0 × 10 ⁻² Pa. In such a state (a state in which acetylene gas was continuously introduced), ion plating using Ti as a target was performed to form a second layer composed of TiC (second layer forming step) ..
The average thickness of the formed second layer was 0.80 μm. The C content in the second layer was 45.0% by mass.

  Next, on the base material on which the third layer and the second layer were formed, subsequently, the above-mentioned ion plating was used to form the first layer as follows.

After exhausting (decompressing) the processing chamber to 2 × 10 ⁻³ Pa, acetylene gas was introduced, and the atmospheric pressure (total pressure) in the processing chamber was set to 5.0 × 10 ⁻² Pa. In such a state (the state in which acetylene gas was continuously introduced), ion plating using Ti as a target was performed to form a first layer composed of TiC (first layer forming step) ..
The average thickness of the formed first layer was 0.20 μm. The C content in the first layer was 50.0% by mass.

  The thicknesses of the first layer, the second layer, the third layer, and the coating were measured according to the microscope cross-section test method defined in JIS H5821.

  The elastic modulus K1 of the first layer, the elastic modulus K2 of the second layer, and the elastic modulus K3 of the third layer satisfied the relationship of K1 <K2 <K3.

  A single-layer film was formed on the surface of the substrate, which was made of SUS304 and was mirror-finished, under the same conditions as the formation conditions of each layer (first layer, second layer, and third layer) forming the coating film. Formed.

  The elastic deformation work of each layer was obtained by measuring these monolayer films by the nanoindentation method.

  ENT-2100 (manufactured by Elionix) was used for the measurement, and a Berkovich indenter No. 5964 was used.

  The measurement conditions by the nanoindentation method were: measurement temperature: 25 ° C., maximum load: 1 mN, load speed: 2 mN / min, unloading speed: 2 mN / min, maximum load holding time: 0 seconds.

  As a result, the elastic deformation work of the first layer was 90 pJ, the elastic deformation work of the second layer was 150 pJ, and the elastic deformation work of the third layer was 220 pJ.

  Moreover, the decorative article manufactured as described above is cut in the thickness direction of the coating film, and the cut surface is also measured by the nanoindentation method to form each layer (first layer, first layer, The elastic deformation work for the second layer and the third layer) was determined.

  The measurement of the cut surface was performed after cutting the ornamental product, embedding a curable resin in the cut surface, curing the curable resin, and further polishing the cut surface in which the curable resin was embedded. ..

  The ornaments were cut using an IsoMet5000 (manufactured by BUEHLER) as an automatic precision cutting machine. At this time, as a cutting grindstone, A100N manufactured by Heiwa Technica Co., Ltd. was used. The rotational speed of the grindstone at the time of cutting the ornament was 4000 rpm.

  Further, the embedding of the resin in the cut surface was performed by using SimpliMet 3000 (manufactured by BUEHLER) at a molding time of 4 minutes.

Further, as an embedding resin, Epomet (a thermosetting epoxy resin containing TiO ₂ ) manufactured by BUEHLER was used, and it was completely cured by irradiation with ultraviolet rays.

  For the polishing of the cut surface, an Ecomet 300 (manufactured by BUEHLER) was used to perform rough polishing with a polishing cloth paper grain size P400 and subsequent finish polishing with a polishing cloth paper grain size P1500.

  ENT-2100 (manufactured by Elionix) was used for the measurement by the nanoindentation method, and the measurement indenter was a Berkovich indenter No. 5964 was used.

  The measurement conditions by the nanoindentation method were: measurement temperature: 25 ° C., maximum load: 1 mN, load speed: 2 mN / min, unloading speed: 2 mN / min, maximum load holding time: 0 seconds.

  As a result, the elastic deformation work of the first layer was 90 pJ, the elastic deformation work of the second layer was 150 pJ, and the elastic deformation work of the third layer was 220 pJ, as in the measurement of the single layer film. there were.

(Examples 2 to 5)
A decorative article (wristwatch case) was manufactured in the same manner as in Example 1 except that the constitution of the coating was changed as shown in Table 1 by changing the forming conditions of the layers constituting the coating.

(Example 6)
A decorative article (wristwatch case) was manufactured in the same manner as in Example 1 except that a base material made of Ti was used.

  As the base material, one prepared by metal powder injection molding (MIM) as described below was used.

First, a Ti powder having an average particle size of 52 μm manufactured by the gas atomizing method was prepared.
A material composed of this Ti powder: 75% by volume, polyethylene: 8% by volume, polypropylene: 7% by volume, and paraffin wax: 10% by volume was kneaded. A kneader was used for kneading the materials. The material temperature during kneading was 60 ° C.

Next, the obtained kneaded product was pulverized and classified to obtain pellets having an average particle size of 3 mm. Using the pellets, metal powder injection molding (MIM) was carried out by an injection molding machine to manufacture a molded product having a watch case shape. At this time, the molded body was molded in consideration of the binder removal treatment and shrinkage during sintering. The molding conditions during injection molding were a mold temperature of 40 ° C., an injection pressure of 80 kgf / cm ² , an injection time of 20 seconds, and a cooling time of 40 seconds.

Then, the molded body was subjected to a binder removal treatment using a degreasing furnace to obtain a degreased body. This debinding treatment was performed in an argon gas atmosphere of 1.0 × 10 ⁻¹ Pa at 80 ° C. for 1 hour and then heated to 400 ° C. at a rate of 10 ° C./hour. The weight of the sample during the heat treatment was measured, and the time point at which there was no decrease in weight was taken as the time point at which the binder removal was completed.

Next, the degreased body thus obtained was sintered in a sintering furnace to obtain a base material. This sintering was performed by performing a heat treatment at 900 to 1100 ° C. for 6 hours in an argon gas atmosphere of 1.3 × 10 ^{−3 to} 1.3 × 10 ⁻⁴ Pa.

  After cutting and polishing the necessary parts of the base material obtained as described above, this base material was washed. As the cleaning of the substrate, first, alkaline electrolytic degreasing was performed for 30 seconds, and then alkaline immersion degreasing was performed for 30 seconds. Then, neutralization was performed for 10 seconds, water washing for 10 seconds, and pure water washing for 10 seconds.

(Examples 7 to 10)
A decorative article (watch case) was manufactured in the same manner as in Example 6 except that the constitution of the coating was changed as shown in Table 1 by changing the forming conditions of the layers constituting the coating.

(Comparative Example 1)
A decorative article (wristwatch case) was manufactured by the following method.

First, a Ti base material was prepared in the same manner as in Example 6.
Next, this base material was washed. As the cleaning of the substrate, first, alkaline electrolytic degreasing was performed for 30 seconds, and then alkaline immersion degreasing was performed for 30 seconds. Then, neutralization was performed for 10 seconds, water washing for 10 seconds, and pure water washing for 10 seconds.

  The base material washed as described above was carburized to obtain a decorative article (wristwatch case).

The carburizing treatment was performed by plasma carburizing treatment as described below.
That is, there is a treatment chamber surrounded by a heat insulating material such as graphite fiber in the heating furnace, and the treatment chamber is heated by a heating element made of rod graphite, and a positive electrode of DC glow discharge is connected to the upper portion of the treatment chamber. In addition, a cathode is connected to the processing table and a gas manifold is installed at a key point in the processing chamber to introduce process gas (carburizing gas and diluting gas) such as hydrocarbon, nitrogen, argon and hydrogen as needed. A carburizing treatment device was prepared.

  Then, first, the base material was installed in the processing chamber of the carburizing processing apparatus, and the pressure inside the processing chamber was reduced to 1.3 Pa. In this way, the substrate was heated to about 300 ° C. by the heater while the pressure inside the processing chamber was reduced.

  Then, an argon gas for cleaning was introduced into the processing chamber to carry out a cleaning process for 5 minutes. The cleaning process was performed by applying a DC voltage of 350V.

  Then, by introducing propane gas into the processing chamber, the gas composition in the processing chamber is set to almost 100% propane gas, the gas pressure is set to 53 Pa, a DC voltage of 400 V is applied, and the plasma carburization processing is performed for 120 minutes. I went. Then, argon gas and nitrogen gas were pressed into the processing chamber to cool the substrate to room temperature. By such carburizing treatment, a carburized layer having a thickness of about 15 μm was formed.

(Comparative example 2)
Example 1 except that the coating has a uniform composition at each site and is composed of TiC with a C content of 50.0 mass% by changing the conditions during coating formation. An ornament (watch case) was manufactured in the same manner as in (1).

(Comparative example 3)
Example 1 except that the coating film was made of TiC having a uniform composition at each site and a C content of 45.0 mass% by changing the conditions at the time of forming the coating film. An ornament (watch case) was manufactured in the same manner as in (1).

  Table 1 shows the structures of the decorative articles of Examples and Comparative Examples. In addition, the content of each of the components shown in the table was 99.9% by mass or more in each part constituting the decorative article. Further, in each of the examples and comparative examples, the single-layer film and the cut surface of the decorative article were measured by the nanoindentation method under the same conditions as described above. As a result, in each of the examples, the elastic deformation work of the first layer is 70 pJ or more and 110 pJ or less, and the elastic deformation work of the second layer is 130 pJ or more and 170 pJ or less, and the elastic deformation work of the third layer was a value within the range of 190 pJ or more and 250 pJ or less. On the other hand, in Comparative Example 1, the elastic deformation work of the carburized layer was 75 pJ.

[2] Appearance Evaluation of Ornaments The ornaments produced in the above Examples and Comparative Examples were visually and microscopically observed, and their appearances were evaluated according to the following four-step criteria.

A: Excellent appearance.
B: Good appearance.
C: Appearance somewhat bad.
D: Poor appearance.

[3] Evaluation of Adhesion of Film The adhesion of the film was evaluated by performing the following tests on each of the decorative articles manufactured in the above Examples and Comparative Examples.

Each ornament was subjected to the following thermal cycle test.
First, the decorative article is placed in a 20 ° C. environment for 1.5 hours, then in a 60 ° C. environment for 2 hours, then in a 20 ° C. environment for 1.5 hours, and then in a −20 ° C. environment. Let stand for 3 hours. Then, the environmental temperature was returned to 20 ° C. again, and this was set as one cycle (8 hours), and this cycle was repeated 3 times in total (24 hours in total).

  After that, the appearance of the decorative article was visually observed, and these appearances were evaluated according to the following four-step criteria.

A: No floating or peeling of the coating film is observed.
B: Floating of the coating is hardly recognized.
C: Lifting of the film is clearly recognized.
D: Cracks and peeling of the coating are clearly recognized.

[4] Evaluation of Scratch Resistance The following tests were carried out on each of the decorative articles produced in the above Examples and Comparative Examples to evaluate the scratch resistance.

  A stainless steel brush was pressed against the surface of each decorative article on which the coating was provided and slid for 50 reciprocations. The pressing load at this time was 0.2 kgf.

  Then, the surface of the decorative article was visually observed, and the appearance thereof was evaluated according to the following four-step criteria.

A: No scratches were observed on the surface of the coating.
B: Almost no scratch is observed on the surface of the coating.
C: Scratches are slightly observed on the surface of the coating.
D: Scratches are remarkably observed on the surface of the coating.

[5] Evaluation of dent resistance (difficulty of dents) The dent resistance was evaluated by performing the following tests on each of the decorative articles manufactured in the above Examples and Comparative Examples.

  A sphere made of stainless steel (diameter 1 cm) is dropped from a position of 50 cm above each ornament, and the size of the dent on the surface of the ornament (diameter of the dent mark) is measured. It evaluated according to the standard.

A: The diameter of the dent mark is less than 1 mm, or no dent mark is observed.
B: The diameter of the recess mark is 1 mm or more and less than 2 mm.
C: The diameter of the dent mark is 2 mm or more and less than 3 mm.
D: The diameter of the recess mark is 3 mm or more.
The results are shown in Table 2.

  As is clear from Table 2, the present invention having a coating film composed of TiC and including a first layer and a second layer having a larger elastic modulus (elastic deformation work) than the first layer. All of the decorative articles described in 1 above were not likely to have dents such as scratches and dents, and even when a relatively large external force was applied to cause dents, the dents were not noticeable. On the other hand, in the comparative example, a satisfactory result was not obtained.

  Moreover, a wristwatch as shown in FIG. 9 was assembled using the ornamental products manufactured in each of the examples and comparative examples. When these wrist watches were evaluated in the same manner as above, the same results as above were obtained.

  10 ... Ornaments, 1 ... Base material, 2 ... Coating, 21 ... First layer, 22 ... Second layer, 23 ... Third layer, W10 ... Wristwatch (mobile watch), W22 ... Body (case), W23 ... case back, W24 ... bezel (rim), W25 ... glass plate, W26 ... winding stem pipe, W27 ... crown, W271 ... shaft part, W272 ... groove, W28 ... plastic packing, W29 ... plastic packing, W30 ... rubber Packing (crown packing), W40 ... Rubber packing (back cover packing), W50 ... Joint part (seal part), a ... point, b ... point, c ... point, d ... point

Claims (13)

A base material at least a part of the surface of which is mainly composed of Ti or stainless steel,
Provided on the base material, it possesses a coating composed mainly TiC,
The coating film is a laminate having at least a first layer and a second layer provided on a surface side of the first layer facing the base material,
The exterior component for a timepiece , wherein the elastic modulus of the second layer is larger than the elastic modulus of the first layer. The timepiece exterior component according to claim 1, wherein the content of C in the first layer is 45% by mass or more and 60% by mass or less. The timepiece exterior component according to claim 1 or 2, wherein the content of C in the second layer is 35% by mass or more and 55% by mass or less. When the content rate of C in the first layer is X ₁ [mass%] and the content rate of C in the second layer is X ₂ [mass%], 5 ≦ X ₁ −X ₂ ≦ 25 The exterior component for a timepiece according to any one of claims 1 to 3, which satisfies the relationship of. The exterior component for a timepiece according to claim 1, wherein the first layer has an average thickness of 0.10 μm or more and 0.30 μm or less. The timepiece exterior component according to any one of claims 1 to 5, wherein an average thickness of the second layer is 0.60 µm or more and 1.0 µm or less. The watch exterior component according to claim 1, wherein the coating has an average thickness of 1.1 μm or more and 1.9 μm or less. 8. The coating film further comprises a third layer having a larger elastic modulus than the second layer on a surface side of the second layer facing the base material. The exterior component for a watch described in the item. The timepiece exterior component according to claim 8, wherein the content of C in the third layer is 15% by mass or more and 35% by mass or less. When the content rate of C in the second layer is X ₂ [mass%] and the content rate of C in the third layer is X ₃ [mass%], 5 ≦ X ₂ −X ₃ ≦ 40 The exterior part for a timepiece according to claim 8 or 9, which satisfies the relationship of. The timepiece exterior component according to any one of claims 8 to 10, wherein an average thickness of the third layer is 0.40 µm or more and 0.60 µm or less.   The timepiece exterior component according to any one of claims 1 to 11, which is at least one of a bezel, a body, a crown, a case back, and a timepiece band. A timepiece comprising the timepiece exterior component according to any one of claims 1 to 12.

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