JP2008133542A - Surface treatment method for ornament, and ornament - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ornament which can retain a superior hardness and aesthetic appearance for a long period of time, and to provide a surface treatment method for providing the ornament. <P>SOLUTION: The surface treatment method used for the ornament comprises: a step (2b) of hardening at least one part (2a) of a substrate 2 through nitriding treatment or carburization treatment; and a step (2c) of forming an underlayer 40 on at least one part of the hardened substrate 2; and a step (2d) of forming a coating 30 on at least one part of the underlayer 40 with an ion plating method. The underlayer 40 is composed of Ti, Cr or an alloy containing at least one of them. The coating 30 is composed of a material containing at least one compound selected from the group consisting of TiN, TiC, TiCN, TiO, CrN, CrC, CrCN and CrO. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface treatment method for a decorative article and a decorative article.

A decorative product such as a watch exterior part is required to have an excellent aesthetic appearance.
Conventionally, in order to achieve such an object, for example, a silver-white metal material such as Pd, Rd, Pt or the like has been used as a constituent material of an ornament. However, these metal materials are all noble metals, and have problems such as an increase in the manufacturing cost of decorative products. Moreover, Ti, stainless steel, etc. are used as a silver-white material which replaces the above-mentioned noble metal.

Further, as described above, a decorative article is required to have an excellent aesthetic appearance. However, a decorative article (particularly, a watch exterior part or a jewelry accessory) made of the above-described materials has scratches on its surface. There was a problem that it was easy to stick and the aesthetic appearance was remarkably deteriorated after long-term use.
In order to solve such problems, as a technique for hardening the base material, for example, a technique for nitriding the surface of a base material made of stainless steel or Ti with nitrogen (for example, refer to Patent Document 1), or carbon is injected. A technique (for example, see Patent Document 2) that hardens the surface by carburizing treatment is used.

However, the nitriding treatment and the carburizing treatment cause surface roughness, so that the polished appearance changes. Mirror surface products are particularly rough and cloudy, and cannot be used as decorations as they are.
Therefore, as a post process, a method of polishing to a mirror surface by mechanical polishing has been adopted. However, this method has a drawback that the hardened layer is excessively scraped by polishing and the hardness is lowered, or a shape that cannot be polished afterwards (a shape that does not hit the buff) cannot be processed.

Japanese Patent Laid-Open No. 11-318520 JP-A-11-229114

  An object of the present invention is to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a long period of time, and to provide a surface treatment method that can provide the decorative article.

Such an object is achieved by the present invention described below.
The surface treatment method of a decorative article of the present invention includes a step of performing a hardening treatment by nitriding treatment or carburizing treatment on at least a portion of a base material at least part of which is mainly composed of Ti and / or stainless steel,
Forming a film made of a material containing Ti and / or Cr on the base material subjected to the curing treatment by dry plating.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a long period of time.

The surface treatment method of a decorative article of the present invention includes a step of performing a hardening treatment by nitriding treatment or carburizing treatment on at least a portion of a base material at least part of which is mainly composed of Ti and / or stainless steel,
Forming at least one underlayer on the base material subjected to the curing treatment;
Forming a film made of a material containing Ti and / or Cr on the underlayer by dry plating.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a long period of time. Moreover, by forming the base layer, it is possible to improve the adhesion between the base material and the coating film, and to more effectively relieve the unevenness of the base material surface. In addition, the decorative article obtained by this method is particularly difficult to produce a dent such as a dent.

In the decorative article surface treatment method of the present invention, it is preferable that the step of forming the base layer and the step of forming the coating are repeated, and the base layer and the coating are laminated a plurality of times.
Thereby, the obtained decorative article can maintain excellent hardness and aesthetic appearance for a longer period of time. In addition, the decorative article obtained by this method is particularly difficult to produce a dent such as a dent.

In the decorative article surface treatment method of the present invention, it is preferable that at least one of the base layers is a leveling layer that relaxes irregularities on the surface of the substrate.
Thereby, even if it is a case where the surface roughness of a base material is comparatively large, the surface roughness of the ornament obtained can be made small enough.
In the decorative article surface treatment method of the present invention, the underlayer is preferably formed by dry plating.
Thereby, a foundation layer becomes a thing especially excellent in adhesiveness with a base material.

In the decorative article surface treatment method of the present invention, the underlayer is preferably composed of Ti, Cr, or an alloy containing at least one of them.
Thereby, a foundation layer becomes a thing especially excellent in adhesiveness with a base material. In addition, the decorative article obtained by this method is particularly difficult to produce a dent such as a dent.
In the decorative article surface treatment method of the present invention, it is preferable that the base material is subjected to surface processing selected from mirror processing, streak processing, and satin processing on at least a part of the surface thereof.
Thereby, the glare of a film, etc. are suppressed, and the obtained decorative article is particularly excellent in aesthetic appearance.

In the decorative article surface treatment method of the present invention, the base material preferably has a base portion and a surface layer provided on the base portion.
Thereby, by selecting the constituent material of the base portion, for example, the degree of freedom of molding of the base material can be increased, and even a more complicated shaped ornament can be manufactured relatively easily.
In the decorative article surface treatment method of the present invention, the thickness of the surface layer is preferably 0.1 to 50 μm.
Thereby, the intensity | strength of the base material after a hardening process can be made especially excellent, and the obtained decorative article becomes a thing with a crack etc. especially difficult to attach.

In the decorative article surface treatment method of the present invention, the nitriding treatment is ion nitriding in which the substrate is held at a temperature of 300 to 500 ° C. and glow discharge is performed in an atmosphere containing ammonia gas and hydrogen gas. Is preferred.
Thereby, the strength of the base material after nitriding can be made particularly excellent, and the surface roughness of the base material can be made relatively small. As a result, the resulting decorative article can maintain a particularly excellent hardness and aesthetic appearance over a longer period of time.
In the decorative article surface treatment method of the present invention, the nitride layer formed by the nitriding treatment preferably has a thickness of 0.1 to 200 μm.
Thereby, the hardness of the substrate can be made particularly excellent, and the specular gloss can be maintained for a longer time.

In the decorative article surface treatment method of the present invention, the carburizing treatment is preferably a plasma carburizing treatment that is performed in an atmosphere containing a hydrocarbon-based gas of 10 to 700 Pa and a temperature of 400 to 900 ° C.
Thereby, the strength of the base material after the carburizing treatment can be made particularly excellent, and the surface roughness of the base material can be made relatively small. As a result, the resulting decorative article can maintain a particularly excellent hardness and aesthetic appearance over a longer period of time.
In the decorative article surface treatment method of the present invention, the thickness of the carburized layer formed by the carburizing treatment is preferably 0.1 to 200 μm.
Thereby, the hardness of the substrate can be made particularly excellent, and the specular gloss can be maintained for a longer time.

In the decorative article surface treatment method of the present invention, the coating is preferably formed by an ion plating method.
Thereby, it is possible to relatively easily form a film that is more homogeneous and has particularly excellent adhesion to the substrate and the base layer. As a result, the durability of the resulting decorative article is particularly excellent. Further, by using the ion plating method, a particularly high-density coating can be formed, and the resulting decorative article can maintain a particularly excellent aesthetic appearance over a long period of time.

In the decorative article surface treatment method of the present invention, the ionization voltage during the ion plating is preferably 15 to 200V.
Thereby, the film excellent in adhesiveness with a base material or a base layer can be formed.
In the decorative article surface treatment method of the present invention, the ionization current during the ion plating is preferably 5 to 150 A.
Thereby, the film excellent in adhesiveness with a base material or a base layer can be formed.
In the decorative article surface treatment method of the present invention, the pressure of the atmosphere during the ion plating is preferably 1 × 10 ^{−3 to} 1.5 Pa.
Thereby, the film excellent in adhesiveness with a base material or a base layer can be formed.

In the decorative article surface treatment method of the present invention, the coating film is made of a material containing at least one selected from the group consisting of TiN, TiC, TiCN, TiO, CrN, CrC, CrCN, and CrO. It is preferable.
Thereby, the aesthetic appearance of the obtained decorative article can be made particularly excellent, and the strength (difficulty of scratches etc.) of the entire decorative article can be made particularly excellent.
In the decorative article surface treatment method of the present invention, the thickness of the coating is preferably 2 to 10 μm.
Thereby, the film has a more excellent aesthetic appearance and scratch resistance.

The decorative article of the present invention is manufactured using the surface treatment method for a decorative article of the present invention.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a long period of time.
The decorative article of the present invention includes a substrate having a hardened layer formed by nitriding or carburizing,
And a coating film formed by dry plating on the substrate and made of a material containing Ti and / or Cr.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a long period of time.

The decorative article of the present invention includes a substrate having a hardened layer formed by nitriding or carburizing,
At least one underlayer formed on the cured layer;
And a film formed by dry plating on the underlayer and made of a material containing Ti and / or Cr.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a longer period of time. Moreover, by forming the base layer, it is possible to improve the adhesion between the base material and the coating film, and to more effectively relieve the unevenness of the base material surface. This also makes it difficult for dents and the like to be formed.

The decorative article of the present invention includes a substrate having a hardened layer formed by nitriding or carburizing,
Multiple underlayers;
A decorative article formed by dry plating and having a plurality of coatings made of a material containing Ti and / or Cr,
A plurality of the foundation layers and the coating films are alternately laminated.
As a result, it is possible to provide a decorative article that can maintain excellent hardness and aesthetic appearance over a longer period of time. Moreover, by forming the base layer, it is possible to improve the adhesion between the base material and the coating film, and to more effectively relieve the unevenness of the base material surface. This also makes it difficult for dents and other dents to occur.

In the decorative article of the present invention, it is preferable that at least a part thereof is used in contact with the skin.
Decorative products used in contact with the skin are required to have a beautiful appearance as decorative products, and as practical products, durability, corrosion resistance, scratch resistance, wear resistance, excellent tactile sensation, etc. are required. However, according to the present invention, all of these requirements can be satisfied.
The decorative article of the present invention is preferably a watch exterior part.
Watch exterior parts are generally decorative items that are susceptible to external impacts, and are required to have a beautiful appearance as decorative items, and as practical products, such as durability, corrosion resistance, scratch resistance, and wear resistance. However, according to the present invention, all of these requirements can be satisfied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a decorative article surface treatment method and a decorative article of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a first embodiment of the surface treatment method of the present invention.
As shown in FIG. 1, in the surface treatment method of the present embodiment, at least a part (1a) of the substrate 2 is subjected to a curing process (1b) by nitriding or carburizing, and a curing process is performed. A step (1c) of forming a coating 30 on at least a part of the substrate 2 by an ion plating method.

[Base material]
The base material (metal base material) 2 is at least partly composed of mainly Ti and / or stainless steel near the surface. Examples of the material mainly composed of Ti include Ti (Ti as a simple substance), Ti alloy, and the like. Examples of the stainless steel include Fe-Cr alloys, Fe-Cr-Ni alloys, and more specifically, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, etc., SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, etc. are mentioned. Examples of materials that can be nitrided or carburized include materials other than those composed of Ti and / or stainless steel as described above, but such materials (mainly Ti and / or stainless steel). In the case of using a configured material), it is difficult to sufficiently increase the hardness of the finally obtained decorative article. In addition, when a material mainly composed of Ti and / or stainless steel is not used, the final decorative product has an excellent aesthetic appearance for a sufficiently long period of time (especially in decorative products such as watch exterior parts). It is difficult to maintain an aesthetic appearance).

  Moreover, the base material 2 may have a substantially uniform composition at each site, or may have a different composition depending on the site. For example, the base material 2 may have a base portion and a surface layer provided on the base portion. When the base material 2 has such a configuration, for example, the degree of freedom in forming the base material 2 can be increased by selecting the constituent material of the base, and even if the decorative article 1A has a more complicated shape. Can be manufactured relatively easily. When the base material 2 has a base and a surface layer, the thickness (average value) of the surface layer is not particularly limited, but is preferably 0.1 to 50 μm, and preferably 1.0 to 10 μm. Is more preferable. When the thickness of the surface layer is within the above range, the strength of the base material 2 after the curing treatment can be made particularly excellent, and unintentional peeling from the base of the surface layer can be more reliably performed. Can be prevented.

When the base material 2 has a base and a surface layer, as the constituent material of the surface layer, for example, the materials described above can be suitably used. Moreover, as a 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 1A having particularly excellent strength characteristics.

  Further, when the base is made of a metal material, even if the surface roughness of the base is relatively large, the decorative article 1A obtained by the leveling effect when forming the surface layer, the coating film 30 or the like described later, etc. The surface roughness can be reduced. For example, it is possible to perform mirror finish even if machining such as cutting and polishing on the surface of the base is omitted, or the base is formed by the MIM method, and the surface is pear-ground. Even in this case, it can be easily mirror-finished. As a result, a decorative article having excellent gloss can be obtained.

When the base is made of a nonmetallic material, it is possible to provide the decorative article 1A that is relatively light and easy to carry and has a heavy appearance.
Further, when the base is made of a non-metallic material, it can be formed into a desired shape relatively easily.
Further, when the base is made of a nonmetallic material, an effect of shielding electromagnetic noise can be obtained.

  As the metal material constituting the base, for example, various metals such as Fe, Cu, Zn, Ni, Mg, Cr, Mn, Mo, Nb, Al, V, Zr, Sn, Au, Pd, Pt, Ag, An alloy containing at least one of these may be used. Among these, Cu, Zn, Ni, Ti, Al or an alloy containing at least one of these is preferable. When the base is composed 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 2 as a whole is molded. The degree of freedom increases further.

Moreover, as a nonmetallic material which comprises a base, ceramics, a plastics (especially heat resistant plastic), a stone material, wood, etc. are mentioned, for example.
As ceramics, for example, Al ₂ O ₃ , SiO ₂ , TiO ₂ , Ti ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , oxide-based ceramics such as barium titanate and strontium titanate, AlN, Si ₃ N ₄ , SiN, TiN, 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 , Carbide ceramics such as TaC and NbC, boride ceramics such as ZrB ₂ and MoB, or composite ceramics in which two or more of these are arbitrarily combined.
When the base is made of the ceramic as described above, a decorative article 1A having particularly excellent strength and hardness can be obtained.

The manufacturing method of the base material 2 is not specifically limited.
When the base material 2 is composed of a material having a substantially uniform composition (or when it does not have a surface layer as described above), as a manufacturing method thereof, for example, pressing, cutting, forging , Casting, powder metallurgy sintering, metal powder injection molding (MIM), lost wax method, etc., among which casting or metal powder injection molding (MIM) is particularly preferable. Casting and metal powder injection molding (MIM) are particularly excellent in workability. For this reason, when these methods are used, the base material 2 having a complicated shape can be obtained relatively easily.

Metal powder injection molding (MIM) is usually performed as follows.
First, a material containing metal powder and an organic binder is mixed and kneaded to obtain a kneaded product.
Next, the kneaded product is injection molded to form a molded body.
Thereafter, the molded body is subjected to a degreasing process (debinding process) to obtain a degreased body. This degreasing treatment is usually performed by heating under reduced pressure conditions.
Furthermore, a sintered body is obtained by sintering the obtained degreased body. This sintering process is usually performed by heating at a higher temperature than the degreasing process.

In the present invention, the sintered body obtained as described above can be used as a base material.
Moreover, when the base material 2 has a base and a surface layer as described above, the base material 2 can be manufactured as follows. That is, the base material 2 can be obtained by forming a surface layer on the base manufactured by the method as described above. As a method for forming the surface layer, for example, coating such as dipping, brush coating, spray coating, electrostatic coating, electrodeposition coating, wet plating methods such as electrolytic plating, immersion plating, electroless plating, thermal CVD, plasma CVD, Examples include chemical vapor deposition (CVD) such as laser CVD, dry deposition such as vacuum deposition, sputtering and ion plating, and thermal spraying.

  The surface of the substrate 2 may be subjected to surface processing such as mirror surface processing, streak processing, and satin processing. Thereby, it becomes possible to give a variation in the glossiness of the surface of the obtained decorative article 1A, and the decorativeness of the obtained decorative article 1A can be further improved. The mirror surface processing can be performed using, for example, a well-known polishing method, and for example, buffing (bedding) polishing, barrel polishing, and other mechanical polishing can be employed.

  Moreover, the decorative article 1A manufactured using the base material 1 subjected to such surface processing has a glare of the coating film 30 as compared with that obtained by directly performing the surface processing on the coating film 30 described later. Etc. are suppressed, and the aesthetic appearance is particularly excellent. Further, as will be described in detail later, since the coating 30 is made of a hard material, when the surface processing is performed directly on the coating 30, defects such as chipping are caused on the coating 30 when the surface processing is performed. Although it is likely to occur and the yield of manufacturing the decorative article 1A may be remarkably reduced, the occurrence of such a problem can be effectively prevented by subjecting the base material 2 to surface treatment. Further, the surface treatment for the substrate 2 can be easily performed under mild conditions as compared with the surface treatment for the coating 30.

[Nitriding and carburizing]
The base material 2 is subjected to a hardening process by nitriding or carburizing (1b). By subjecting the base material 2 to nitriding treatment and carburizing treatment, a hardened layer (nitriding layer, carburized layer) having high hardness can be formed near the surface of the base material 2.
Hereinafter, these methods will be described.

(Carburization treatment)
First, a carburizing method will be described. In addition, although plasma carburizing process is demonstrated here as an example of carburizing process, the method of carburizing process is not limited to this.
In order to perform the plasma carburizing process, for example, a processing chamber surrounded by a heat insulating material such as graphite fiber is formed in a heating furnace, and this processing chamber is heated by a heating element made of rod graphite, and at the top of the processing chamber. Connect the positive electrode of the direct current glow discharge, connect the cathode to the stage where the processed products are placed, and install gas manifolds at key points in the processing chamber to clean process gases such as hydrocarbons, nitrogen, argon, hydrogen, etc. A known carburizing apparatus (for example, manufactured by JEOL Ltd.) that is introduced while appropriately dispersing the gas can be used.

The operation of the plasma carburizing process will be described in more detail. First, the base material 2 is charged into the processing chamber and evacuated, and then heated to 400 to 900 ° C. with a heater, for example, from an inert gas such as argon gas. A cleaning gas is introduced and a DC high voltage of 200 to 1500 V is applied and held for 10 to 60 minutes.
At this time, the introduced gas is turned into plasma, but the potential in the plasma is almost uniform from the anode to the cathode, and the potential drops rapidly in the vicinity of the cathode. For this reason, the inert gas such as argon ions Ar ⁺ in the plasma is accelerated by the cathode fall, and collides with the surface of the base material to jump off deposits on the surface to clean the surface of the base material 2. The longer the cleaning time, the later carburization is efficiently performed and the hardness of the carburized layer increases. However, if the processing time is too long, not only the effect of the cleaning process is saturated, but also the vicinity of the surface of the substrate 2 It will be more destructive than necessary. In addition, long processing is economically disadvantageous.

Next, a hydrocarbon-based gas is introduced in a pressure range of 10 to 700 Pa. As a result, ionized activated carbon (C ⁺ ) is generated in the plasma gas, which adheres to the surface of the base material 2 and diffuses into the base material 2. Examples of the hydrocarbon-based gas include chain hydrocarbons and cyclic hydrocarbons. Representative examples of chain hydrocarbons include methane hydrocarbons represented by the general formula C _n H _{2n + 2} , ethylene hydrocarbons (general formula C _n H _2n ), acetylene hydrocarbons (general formula C _n H _{2n -2} ), and may be a straight chain or a side chain. In particular, methane, ethane, propane, and butane that are gaseous at room temperature are preferable because they do not require vaporization equipment when used. Examples of cyclic hydrocarbons include aromatic hydrocarbons and alicyclic hydrocarbons. A typical example of the aromatic hydrocarbon is benzene (C ₆ H ₆ ).
When the base material 2 is mainly composed of Ti, a part of the activated carbon comes to exist in the carburized layer as carbon solid solution titanium by the above treatment, and the rest is combined with the base material. To become carbide.

By the way, in the plasma carburizing process, hydrogen gas (H ₂ ) or the like may be mixed with the hydrocarbon gas. For example, when a hydrocarbon-based gas is diluted with hydrogen gas, the amount of activated carbon produced can be adjusted due to the reducibility of H ₂ or the current flow can be improved by increasing the gas pressure in the furnace. it can.
When the hydrocarbon gas is used alone (when not mixed with a gas other than the hydrocarbon gas), the pressure is preferably 10 to 700 Pa, and more preferably 50 to 300 Pa. When using the mixed gas of hydrocarbon gas and dilution gas, such as hydrogen gas, the partial pressure of hydrocarbon gas is adjusted to the range of 10-700 Pa. Specifically, when using a mixed gas of hydrocarbon gas and hydrogen gas, the partial pressure of the hydrocarbon gas is 10 to 700 Pa, the partial pressure of the hydrogen gas is 20 to 2000 Pa, The total pressure is preferably 30 to 2700 Pa.
If the pressure (partial pressure) of the hydrocarbon-based gas is less than the lower limit, it is difficult to form a solid solution of carbide and carbon in the carburized layer, and the carburized layer may not be formed sufficiently deep. On the other hand, if the pressure (partial pressure) of the hydrocarbon-based gas exceeds the upper limit, a carbon film is formed on the surface of the substrate 2 and carbon may not easily diffuse into the interior.

The atmospheric temperature during the plasma carburizing treatment is not particularly limited, but is preferably 400 to 900 ° C. When the atmospheric temperature is less than the lower limit, sooting is likely to occur, and therefore the partial pressure of the dilution gas needs to be increased, and the carburization reaction may be difficult to occur. On the other hand, when the ambient temperature exceeds the upper limit, depending on the constituent material of the base material 2, the constituent material may be transformed, and the strength and dimensional accuracy of the base material 2 may be reduced.
As described above, the carburizing process is performed on the substrate 2 to form the carburized layer (hardened layer) 21.

  The thickness (average value) of the carburized layer 21 thus formed is not particularly limited, but is preferably 0.1 to 200 μm, more preferably 1.0 to 50 μm. When the thickness of the carburized layer 21 is a value within the above range, the hardness of the substrate 2 can be made particularly excellent and the specular gloss can be maintained for a long time. Thereby, for example, the decorative article 1A to be obtained is not particularly likely to have dents, scratches or the like, and can maintain an excellent aesthetic appearance over a longer period of time.

  Further, for the purpose of improving the adhesion between the base material 2 and the coating film 30, prior to the formation of the coating film 30 described later (before or after the nitriding treatment or carburizing treatment described above), the base material 2 is pretreated. May be applied. Examples of the pretreatment include blast treatment, alkali washing, acid washing, water washing, organic solvent washing, bombarding and other cleaning treatment, etching treatment, etc., among which cleaning treatment is particularly preferable. By subjecting the surface of the substrate 2 to a cleaning treatment, the adhesion between the substrate 2 and the coating 30 becomes particularly excellent.

(Nitriding treatment)
Next, a nitriding method will be described. Here, ion nitriding (radical nitriding) processing will be described as an example of nitriding processing, but the method of nitriding processing is not limited to this.
In this method, glow discharge is performed in an atmosphere containing ammonia gas and hydrogen gas, and the vicinity of the surface of the substrate 2 is ion-nitrided. By performing glow discharge in an atmosphere containing ammonia gas and hydrogen gas, nitrogen atoms and nitrogen ions are more likely to enter near the surface of the substrate 2.

  At this time, it is preferable to maintain the temperature of the base material 2 in a range of 300 to 500 ° C. By setting the temperature of the substrate 2 to a value within the above range, ion nitriding can be suitably performed. On the other hand, if the temperature of the substrate is less than the lower limit, ion nitriding does not proceed easily, and the production efficiency of the decorative article 1A decreases. Moreover, when the temperature of the base material 2 is extremely low, the decorative article 1A may not be manufactured substantially. On the other hand, when the temperature of the base material exceeds the upper limit, the corrosion resistance of the base material 2 after curing tends to decrease.

The current density of glow discharge is preferably 0.001 to ² mA / cm ² . By setting the current density of the glow discharge to a value within the above range, ion nitriding can be suitably performed.
As described above, the base material 2 is subjected to nitriding treatment to form a nitrided layer (cured layer) 22.

The thickness (average value) of the nitride layer 22 thus formed is not particularly limited, but is preferably 0.1 to 200 μm, more preferably 1.0 to 50 μm. When the thickness of the nitride layer 22 is a value within the above range, the hardness of the substrate 2 can be made particularly excellent and the specular gloss can be maintained for a long time. Thereby, for example, the decorative article 1A to be obtained is not particularly likely to have dents, scratches or the like, and can maintain an excellent aesthetic appearance over a longer period of time.
In the above description, the base material 2 has been described as performing only one of nitriding and carburizing, but both nitriding and carburizing may be performed.

[Formation of film]
A coating 30 made of a material containing Ti and / or Cr is formed on the surface of the base material 2 that has been subjected to the curing treatment (nitriding treatment, carburizing treatment) as described above (1c).
In the present invention, the coating 30 is formed by a dry plating method. Thereby, it is possible to relatively easily form the coating film 30 which is homogeneous and has particularly excellent adhesion to the base material 2 (in the embodiment described later, adhesion to the underlayer). As a result, the durability of the resulting decorative article 1A is further improved. Further, by using a dry plating method, it is possible to form a particularly high-density coating 30. As a result, the decorative article 1A can maintain a particularly excellent aesthetic appearance over a long period of time.

The coating 30 may be any material as long as it is made of a material containing Ti (Ti element) and / or Cr (Cr element), but is made of a material containing Ti compound and / or Cr compound. It is preferable that it is made of a material containing at least one selected from the group consisting of TiN, TiC, TiCN, TiO, CrN, CrC, CrCN and CrO. When the coating 30 is made of the material as described above, the aesthetic appearance of the resulting decorative article 1A can be made particularly excellent, and the strength of the decorative article 1A as a whole (difficulty of scratches, etc.) ) Can be made particularly excellent. In addition, the color of the coating 30 can be suitably adjusted by appropriately selecting the above materials (TiN, TiC, TiCN, TiO, CrN, CrC, CrCN and CrO). For example, when the coating 30 is made of TiN, the coating 30 has a gold color, when the coating 30 is made of TiC, the coating 30 has a dark gray color, and when the coating 30 is made of TiCN, the coating 30 When the coating film 30 is made of TiO, the coating film 30 has a blue color. When the coating film 30 is made of CrN, the coating film 30 has a bright silver color, and the coating film 30 is made of CrC. When constituted, the coating 30 has a dark to light gray color. When the coating 30 is made of CrCN, the coating 30 has a heavy silver color. When the coating 30 is made of CrO, the coating 30 is It will have a heavy silver color. By using a combination of two or more of the above materials and appropriately adjusting their blending ratio, a subtle hue can be expressed relatively easily. As a result, the finally obtained decorative article 1A can have, for example, a heavy metallic luster that has been difficult to manufacture conventionally.
Moreover, it is preferable that the constituent material of the coating film 30 includes at least one of materials constituting the base material 2 (constituent material of the portion where the coating film 30 is formed). In other words, the coating film 30 and the substrate 2 are preferably made of a material containing a common element. Thereby, the adhesiveness of the base material 2 and the coating film 30 further improves.

  Examples of the dry plating method applied to the formation of the coating 30 include chemical vapor deposition (CVD) such as thermal CVD, plasma CVD, and laser CVD, vacuum vapor deposition, sputtering, and ion plating. Is preferred. Thereby, it is possible to relatively easily form a film that is more homogeneous and has particularly excellent adhesion to the substrate and the base layer. As a result, the durability of the resulting decorative article is particularly excellent. Further, by using the ion plating method, a particularly high-density coating can be formed, and the resulting decorative article can maintain a particularly excellent aesthetic appearance over a long period of time.

For example, the ion plating is preferably performed under the following conditions.
The ionization voltage at the time of ion plating is, for example, preferably 15 to 200 V, and more preferably 20 to 130 V. When the ionization voltage is a value within the above range, it is possible to form the coating 30 having excellent adhesion to the substrate 2. In addition, the coating film 30 has a small variation in film thickness at each part, a small internal stress, and a crack is hardly generated.

  For example, the ionization current during ion plating is preferably 5 to 150 A, and more preferably 10 to 30 A. When the ionization current is a value within the above range, the coating film 30 having excellent adhesion to the substrate 2 can be formed. In addition, the coating film 30 has a small variation in film thickness at each part, a small internal stress, and a crack is hardly generated.

The composition of the film 30 can be controlled by adjusting the composition of the atmospheric gas during ion plating.
For example, the coating 30 made of an oxide of titanium or chromium can be formed by performing ion plating as described above in an atmosphere gas containing oxygen. Similarly, by performing ion plating in an atmosphere gas containing nitrogen, a film 30 made of nitride of titanium or chromium can be formed, and in an atmosphere gas containing a hydrocarbon such as acetylene By performing the above, it is possible to form the coating 30 made of a carbide of titanium or chromium.
Thus, in ion plating, the coating film 30 having a desired composition can be easily formed by appropriately selecting the composition of the atmospheric gas. Thus, by easily adjusting the composition of the coating film 30, it becomes possible to adjust the characteristics (for example, color, glossiness, hardness, etc.) of the coating film 30.

The pressure of the atmosphere at the time of ion plating is not particularly limited, but is preferably about 1 × 10 ^{−2 to} 5 × 10 ⁻¹ Pa, preferably about 1 × 10 ^{−1 to} 3 × 10 ⁻¹ Pa. Is preferred.
The thickness (average value) of the coating film 30 formed by the ion plating method is preferably 2 to 10 μm, and more preferably 2 to 5 μm. When the thickness of the coating 30 is within the above range, the coating 30 has particularly excellent gloss and scratch resistance. As a result, it is possible to obtain a decorative article 1A having an excellent aesthetic appearance over a longer period.

  On the other hand, when the thickness of the coating 30 is less than the lower limit, the effect of the coating 30 cannot be sufficiently obtained. In addition, pinholes are easily generated in the coating 30, and the aesthetic appearance of the resulting decorative article 1A is degraded. Moreover, when the thickness of the coating film 30 exceeds the upper limit, the internal stress of the coating film 30 increases, and the adhesion between the coating film 30 and the base material 2 is reduced, or cracks are likely to occur. As a result, the durability of the decorative article 1A is reduced, and a stable aesthetic appearance cannot be obtained.

Further, the coating 30 preferably has a Vickers hardness Hv of 1500 or more, more preferably 1800 or more, and further preferably 2100 or more. If the Vickers hardness Hv of the coating 30 is less than the lower limit, sufficient scratch resistance may not be obtained depending on the use of the decorative article 1A.
Further, the wear coefficient (steel resistance) of the surface of the coating 30 varies depending on the use of the decorative article 1A, etc., but is preferably 0.8 or less, preferably 0.75 or less, and 0.7 or less. More preferably. When the wear coefficient of the surface of the coating 30 is the above value, the slipperiness of the decorative article 1A can be improved and the rough feeling can be reduced or prevented, and the sense of incongruity when the decorative article 1A contacts the skin or the like. , Can reduce or prevent discomfort.

In addition, the composition in each part of the film 30 may be constant or may not be constant. For example, the coating 30 may be one having a composition that changes sequentially along the thickness direction (gradient material), or may be a laminate including a plurality of layers.
Further, the coating 30 is formed on the entire surface of the substrate 2 in the illustrated configuration, but may be formed on at least a part of the surface of the substrate 2.

[Decoration]
The decorative article 1A is obtained by the surface treatment method as described above.
The decorative item 1A may be any item as long as it has a decorative property. For example, an interior such as a figurine, an exterior article, a jewelry, a watch case (a trunk, a back cover, etc.), a watch band (a band Nakadome, (Including band and bangle attachment / detachment mechanism), dial, clock hands, bezel (for example, rotating bezel), crown (for example, screw lock type crown), watch exterior parts such as buttons, movement base plate, Interior parts for watches such as gears, train wheels, rotating weights, glasses, tie pins, cufflinks, rings, necklaces, bracelets, anklets, brooches, pendants, earrings, earrings and other accessories, lighters or their cases, automobile wheels Sports equipment such as golf clubs, nameplates, panels, prize cups, other equipment parts including housings, various containers, etc. It is. Among these, in particular, those which are used in contact with at least a part of the skin are preferred, and watch exterior parts are more preferred. A watch exterior part is required to have a beautiful appearance as a decorative product, and as a practical product, durability, corrosion resistance, scratch resistance, wear resistance, and excellent tactile sensation are required. Therefore, all these requirements can be satisfied.

Next, a second embodiment of the surface treatment method and decorative article of the present invention will be described.
FIG. 2 is a cross-sectional view showing a second embodiment of the surface treatment method of the present invention.
Hereinafter, the surface treatment method according to the second embodiment and the decorative article according to the second embodiment manufactured using the method will be described with a focus on differences from the first embodiment, and the description of similar matters will be described. The description is omitted.

As shown in FIG. 2, in the surface treatment method of the present embodiment, at least a part (2a) of the base material 2 is subjected to an effect treatment by nitriding treatment or carburizing treatment (2b) and a hardening treatment. It has the process (2c) which forms the base layer 40 in at least one part on the base material 2, and the process (2d) which forms the film 30 in at least one part on the base layer 40 by the dry-type plating method.
That is, it is the same as in the first embodiment described above except that the base layer 40 is formed on at least a part of the substrate 2 prior to the formation of the coating 30.

Hereinafter, the underlayer 40 will be described in detail.
[Underlayer]
The underlayer 40 has, for example, a function adhesion that improves the adhesion between the base material 2 and the coating film 30 (function as an adhesion improvement layer), and a function that repairs holes, scratches, and the like of the base material 2 by leveling. (Function as a leveling layer) The obtained decorative article may have any function such as a function to reduce external impact (function as a cushion layer).

Examples of the method for forming the underlayer 40 include wet plating methods such as electrolytic plating, immersion plating, and electroless plating, chemical vapor deposition methods (CVD) such as thermal CVD, plasma CVD, and laser CVD, vacuum deposition, sputtering, and ion plating. Examples thereof include dry plating methods such as coating, thermal spraying, joining of metal foils, etc. Among these, dry plating methods are particularly preferable.
By using a dry plating method as the formation method of the foundation layer 40, the foundation layer 40 to be formed becomes particularly excellent in adhesion to the substrate 2. As a result, the long-term durability of the resulting decorative article 1B is particularly excellent.

  The constituent material of the underlayer 40 is not particularly limited, and for example, a metal material such as Ti, Zr, Hf, V, Nb, Ta, Cr, Al or an alloy containing at least one of these, or the metal material Nitride, carbonitride, carbide, carbonitride, carbonate, oxide and the like of Ti, Cr, or an alloy containing at least one of them is preferable. When the foundation layer 40 is made of such a material, the adhesion between the foundation layer 40 and the base material 2 is particularly excellent, and the leveling layer that relieves unevenness on the surface of the base material 2 This function is more prominent. In addition, when the underlayer 40 is made of the material as described above, the underlayer 40 functions more effectively as a cushioning layer that reduces external impact in the resulting decorative article 1B. In the decorative article 1B, a dent such as a dent is particularly difficult to occur.

  In addition, the constituent material of the base layer 40 preferably includes at least one of a material constituting the base material 2 (a constituent material of a portion where the coating film 30 is formed) or a material constituting the coating film 30. In other words, the coating 30 is preferably composed of a material containing a common element with an element contained in the constituent material of the substrate 2 or an element contained in the constituent material of the coating 30. Thereby, the foundation layer 40 has particularly excellent adhesion to the base material 2 and the coating film 30. Further, when the underlayer 40 and the coating 30 are made of a material containing a common element (metal element), the metal source and the reaction gas are controlled to continuously use the same apparatus. The underlayer 40 and the coating film 30 can be formed sequentially. Thereby, process efficiency can be improved.

  The thickness (average value) of the foundation layer 40 is not particularly limited, but is preferably 0.1 to 30 μm, and more preferably 1.0 to 10 μm, for example. If the average thickness of the underlayer 40 is less than the lower limit, the effects of the underlayer 40 as described above may not be sufficiently exhibited. On the other hand, when the average thickness of the foundation layer 40 exceeds the upper limit, the variation in film thickness at each portion of the foundation layer 40 tends to increase. Further, the internal stress of the underlayer 40 is increased, and cracks are easily generated.

  Prior to the formation of the base layer 40 as described above, a pretreatment may be performed on the base material 2 that has been subjected to the curing treatment (nitriding treatment, carburizing treatment). Examples of the pretreatment include blast treatment, alkali washing, acid washing, water washing, organic solvent washing, bombarding and other cleaning treatment, etching treatment, etc., among which cleaning treatment is particularly preferable. By subjecting the surface of the base material 2 to a cleaning treatment, the adhesion between the base material 2 and the base layer 40 can be made particularly excellent.

As described above, by forming the base layer 40, for example, the adhesion between the base material 2 and the coating 30 and the corrosion resistance of the decorative article 1B can be improved, or the stability against external impact can be improved. it can. As a result, the decorative article 1B can maintain an excellent aesthetic appearance for a longer period of time.
The underlayer 40 is formed on the entire surface of the base material 2 in the illustrated configuration, but may be formed on at least a part of the surface of the base material 2.

  Moreover, the composition in each part of the foundation layer 40 may be constant or not constant. For example, the underlayer 40 may be one whose composition changes sequentially along the thickness direction (gradient material). In the illustrated configuration, a configuration in which only one underlayer is formed has been described, but two or more underlayers may be provided (the underlayer 40 may be a laminate of two or more layers). ).

The underlayer 40 is not limited to the one having the above function. For example, the underlayer 40 functions as a buffer layer that relaxes the potential difference between the base material 2 and the coating 30, or prevents the occurrence of corrosion during storage (until the process of forming the coating 30). It may have.
Moreover, you may perform a process (nitriding process, carburizing process) as demonstrated in the said embodiment with respect to a base layer.

Next, a third embodiment of the surface treatment method and decorative article of the present invention will be described.
3, 4 and 5 are sectional views showing a third embodiment of the surface treatment method of the present invention.
Hereinafter, the surface treatment method according to the third embodiment and the decorative article according to the third embodiment manufactured using the method will be described with a focus on differences from the first and second embodiments. The explanation is omitted here.

As shown in FIGS. 3 to 5, the surface treatment method of the present embodiment includes a step (3b) of performing a curing treatment by nitriding treatment or carburizing treatment on at least a part (3a) of the substrate 2, and a curing treatment. A step (3c) of forming a first underlayer 41 on at least a part of the applied base material 2, and a first coating 31 is formed on at least a part of the first underlayer 41 by a dry plating method A step (3d) of forming, a step (3e) of forming a second underlayer 42 on at least a part of the first coating 31, and a dry plating method on at least a part of the second underlayer 42. A step (3f) of forming the second coating film 32, a step (3g) of forming the third foundation layer 43 on at least a part of the second coating film 32, and at least a part of the third foundation layer 43. A step (3h) of forming a third coating film 33 by dry plating, A step (3i) of forming a fourth underlayer 44 on at least a portion of the coating 33, and a step of forming a fourth coating 34 on at least a portion of the fourth underlayer 44 by dry plating ( 3j).
That is, the film (the first film 31 corresponding to the film 30 in the second embodiment) formed on the base layer (the first base layer 41 corresponding to the base layer 40 in the second embodiment). The second layer except that the base layer and the coating are repeatedly laminated in this order, the coating is provided between the base layer and the base layer, and the base layer is provided between the coating and the coating. This is the same as the embodiment.

Hereinafter, the first underlayer 41, the second underlayer 42, the third underlayer 43, the fourth underlayer 44, the first coating 31, the second coating 32, the third coating 33, and the fourth The coating 34 will be described.
[First ground layer, second ground layer, third ground layer, fourth ground layer]
The first underlayer 41, the second underlayer 42, the third underlayer 43, and the fourth underlayer 44 (hereinafter collectively referred to simply as “underlayer”) are all described above. It has the same function as the underlayer 40.

The formation method of the underlayer is preferably the same as the formation method of the underlayer 40 described above. However, the formation method and the formation conditions may be the same or different for each base layer.
Also, the constituent material of the underlayer is preferably the same as the constituent material of the underlayer 40 described above. However, the constituent materials may be the same or different for each base layer.

By the way, in the present embodiment, a plurality of underlayers (first underlayer 41, second underlayer 42, third underlayer 43, and fourth underlayer 44) are formed into a film (first film 31). The second film 32 and the third film 33) are stacked.
By having such a configuration, even if the thickness of each foundation layer is relatively thin, the function of the foundation layer (function of the foundation layer 40) described in the second embodiment is sufficiently exhibited. Can do. Further, by making the thickness of each underlayer relatively thin, it is possible to more effectively prevent the internal stress from being increased in each layer, and as a result, the resulting decorative article 1C has cracks and the like. Defects are particularly unlikely to occur.

Specifically, the thickness of each base layer (the first base layer 41, the second base layer 42, the third base layer 43, and the fourth base layer 44) is not particularly limited. It is preferably 1 to 5.0 μm, more preferably 0.1 to 3.0 μm.
Moreover, when it has a several base layer like this embodiment, it is preferable that the sum of the thickness of each base layer is 0.1-30 micrometers, and it is more preferable that it is 1-10 micrometers.

[First coating, second coating, third coating, fourth coating]
The first coating 31, the second coating 32, the third coating 33, and the fourth coating 34 (hereinafter collectively referred to simply as “coating”) are all the same as the coating 30 described above. It has a function.
The formation method and formation conditions of the coating are preferably the same as the formation method and formation conditions of the coating 30 described above. However, the formation method and the formation conditions may be the same or different for each film.
Also, the constituent material of the coating is preferably the same as the constituent material of the coating 30 described above. However, the constituent materials may be the same or different for each coating.

By the way, in the present embodiment, a plurality of coatings (first coating 31, second coating 32, third coating 33, and fourth coating 34) are coated (second coating 32, third coating). 33 and the fourth coating 34).
By having such a configuration, even if the thickness of each coating is relatively thin, the function of the coating described in the first embodiment (the function of the coating 30) can be sufficiently exhibited. Further, by making the thickness of each coating relatively thin, it is possible to more effectively prevent the internal stress from being increased in each layer, and as a result, the resulting decorative article 1C has defects such as cracks. This is particularly difficult to occur.
Specifically, the thickness of the coating (the first coating 31, the second coating 32, the third coating 33, and the fourth coating 34) is not particularly limited, but is, for example, 0.1 to 50 μm. Is preferable, and it is more preferable that it is 1-10 micrometers.

  As described above, in the present embodiment, the base layer and the coating are provided alternately. Thus, by providing the underlayer and the coating alternately, even if the thickness of each layer (underlayer, coating) is relatively thin, it has sufficient hardness and can be deformed by an impact from the outside. It is difficult to occur and has an excellent aesthetic appearance. In particular, when each underlayer is made of Ti, Cr, or an alloy containing at least one of these, the above-described function as a cushion layer is more remarkably exhibited. That is, if each underlayer is made of the material as described above, the decorative article 1C is particularly difficult to cause a dent such as a dent even when subjected to an external impact or the like. It becomes. As a result, ornaments (especially ornaments that are worn on the surface and are susceptible to external impacts, such as diver watches and mountaineering watches), have excellent aesthetics over a longer period of time. Appearance can be maintained.

  In addition, it is preferable that two adjacent layers (underlayer or film) are made of a material containing a common element. Thereby, the adhesiveness between the adjacent layers is further improved. When adjacent layers (underlayers or coatings) are composed of materials containing elements common to each other (metal elements), the same apparatus can be used continuously by controlling the metal source and the reaction gas. Thus, the underlayer and the coating can be formed sequentially. Thereby, process efficiency can be improved.

The preferred embodiments of the surface treatment method and decorative article of the present invention have been described above, but the present invention is not limited to these.
For example, in the decorative article surface treatment method of the present invention, an optional process can be added as necessary.
In the above-described third embodiment, the four underlayers (the first underlayer 41, the second underlayer 42, the third underlayer 43, and the fourth underlayer 44) and the four layers The description has been given of the structure in which the coatings (the first coating 31, the second coating 32, the third coating 33, and the fourth coating 34) are alternately laminated. Two layers may be provided, three layers may be provided, or five or more layers may be provided.

Moreover, the film may be composed of a laminate of two or more layers.
The underlayer may be composed of a laminate of two or more layers.
Moreover, when the base material has the base and the surface layer as described above, at least one intermediate layer may be formed between the base and the base layer.
Further, the substrate may be a laminate composed of a plurality of layers.
In addition, at least a part of the surface of the decorative article is given corrosion resistance, weather resistance, water resistance, oil resistance, scratch resistance, abrasion resistance, discoloration resistance, etc. A protective layer or the like that improves the effect of scratches or the like may be formed.

Next, specific examples of the present invention will be described.
1. Manufacture of decorative products (Example 1)
A decorative article (watch case (back cover)) was manufactured by performing the following surface treatment.

First, a base material having the shape of a watch case (back cover) was produced by casting using stainless steel (SUS444), and then 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
Carburizing treatment was performed on the surface of the substrate thus cleaned.

The carburizing process was performed by a plasma carburizing process as described below.
That is, it has a processing chamber surrounded by a heat insulating material such as graphite fiber in a heating furnace, the processing chamber is heated by a heating element made of rod graphite, and a positive electrode of a direct current glow discharge is connected to the upper portion of the processing 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 hydrocarbons, nitrogen, argon, hydrogen and other process gases (carburizing gas and dilution gas) as appropriate. A carburizing apparatus was prepared.

And first, the base material was installed in the processing chamber of the carburizing apparatus, and the processing chamber was depressurized to 1.3 Pa. In this way, the substrate was heated to about 300 ° C. by the heater while the processing chamber was decompressed.
Thereafter, a cleaning argon gas was introduced into the processing chamber to perform a cleaning process for 5 minutes. The cleaning process was performed by applying a DC voltage of 350V.

  Thereafter, by introducing propane gas into the processing chamber, the gas composition in the processing chamber is almost 100% propane gas, the gas pressure is 53 Pa, a DC voltage of 400 V is applied, and the plasma is held for 90 to 180 minutes. Carburizing treatment was performed. Thereafter, argon gas and nitrogen gas were injected into the processing chamber to cool the substrate to room temperature. By such a carburizing process, a carburized layer having a thickness of about 15 μm was formed.

Next, a coating composed of a chromium compound was formed on the base material that had been carburized as described above using an ion plating apparatus as follows.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, nitrogen gas was introduced into the treatment chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In such a state, Cr was used as a target, and the ionization voltage was set to 30 V and the ionization current was set to 140 A, thereby forming a film composed of CrN and obtaining an ornament. The average thickness of the formed film was 3 μm. The thickness of the coating was measured by the microscope cross-sectional test method of JIS H5821.

(Example 2)
A decorative article (watch case (body)) was manufactured by performing the following surface treatment.
First, a Ti base material having the shape of a watch case (body) was produced by metal powder injection molding (MIM).

The substrate made of Ti was produced as follows.
First, a Ti powder having an average particle diameter of 52 μm manufactured by a gas atomization method was prepared.
A material composed of Ti powder: 75 vol%, polyethylene: 8 vol%, polypropylene: 7 vol%, and paraffin wax: 10 vol% was kneaded. A kneader was used for kneading the materials. Moreover, the material temperature at the time of kneading | mixing was 60 degreeC.

Next, the obtained kneaded material was pulverized and classified into pellets having an average particle diameter of 3 mm. Using these pellets, metal powder injection molding (MIM) was performed with an injection molding machine to produce a molded body having the shape of a watch case. At this time, the molded body was molded in consideration of debinding treatment and shrinkage during sintering. The molding conditions at the time of 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.

Next, the molded body was subjected to a debinding process using a degreasing furnace to obtain a degreased body. This binder removal treatment was performed in an argon gas atmosphere of 1.0 × 10 ⁻¹ Pa at 80 ° C. for 1 hour and then at a rate of 10 ° C./hour up to 400 ° C. The weight of the sample at the time of heat treatment was measured, and the point at which the weight reduction disappeared was defined as the end of debinding.
Next, the degreased body thus obtained was sintered using 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.

About the base material obtained by making it above, after cutting the necessary part and grinding | polishing, this base material was wash | cleaned. 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
Nitriding treatment was performed on the surface of the substrate thus cleaned.

The nitriding treatment was performed by an ion nitriding treatment as described below.
First, the base material was installed in the processing chamber of the ion nitriding apparatus, and the processing chamber was depressurized to 1.3 × 10 ⁻³ Pa. In this way, the substrate was heated to 300 ° C. by the heater while the processing chamber was decompressed.
Next, hydrogen gas and ammonia gas were introduced into the treatment chamber. After the introduction, the partial pressure of hydrogen gas in the processing chamber was 1.3 × 10 ⁻⁴ Pa, and the partial pressure of ammonia gas was 1.2 × 10 ⁻⁴ Pa.
Thereafter, a DC voltage of 400 V was applied, heated to a temperature of 300 and maintained for 8 hours, glow discharge was performed, and nitriding was performed to form a nitride layer having a thickness of about 15 μm.

Next, a film composed of a titanium compound was formed on the base material subjected to the nitriding treatment as described above using an ion plating apparatus as follows.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, nitrogen gas was introduced into the treatment chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In such a state, using Ti as a target, setting the ionization voltage: 30 V, the ionization current: 140 A, and holding for 4 hours, a film composed of TiN was formed, and a decorative article was obtained. The average thickness of the formed film was 3 μm. The thickness of the coating was measured by the microscope cross-sectional test method of JIS H5821.

(Example 3)
A decorative article (watch case (back cover)) was manufactured by performing the following surface treatment.
First, a base material having the shape of a watch case (back cover) was produced by casting using stainless steel (SUS444), and then 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
The surface of the substrate thus cleaned was subjected to nitriding treatment under the same conditions as in Example 2.

Next, a base layer composed of Ti was formed on the base material subjected to nitriding treatment using an ion plating apparatus as follows.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, argon gas was introduced into the processing chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In such a state, using Ti as a target, setting the ionization voltage: 30 V, ionization current: 140 A, and holding for 1 hour, an underlayer composed of Ti was formed. The average thickness of the formed underlayer was 2.0 μm.

Next, a film composed of a titanium compound was formed on the base material on which the underlayer was formed using the above ion plating as follows.
First, while preheating the processing chamber, the processing chamber was evacuated (depressurized) to 3 × 10 ⁻³ Pa.
Next, bombarding was performed for 3 minutes at an argon gas flow rate of 100 ml / min. The pressure in the processing chamber in the bombarding process was 9 × 10 ⁻² Pa.

Next, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, nitrogen gas and acetylene gas were introduced at flow rates of 160 ml / min and 160 ml / min, respectively, and the pressure in the processing chamber was set to 3 × 10. ⁻¹ Pa. In such a state, using Ti as a target and setting the ionization voltage: 30 V and the ionization current: 140 A, a film composed of TiCN was formed, and an ornament was obtained. The average thickness of the formed film was 3 μm.
The thickness of the underlayer and the coating was measured by the microscope cross-sectional test method of JIS H 5821.

Example 4
A decorative article (watch case (back cover)) was manufactured by performing the following surface treatment.
First, a Ti base material having the shape of a watch case (back cover) was produced by metal powder injection molding (MIM). Metal powder injection molding (MIM) was performed under the same conditions as in Example 2.

Thereafter, necessary portions of the obtained base material were cut and polished, and then the 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
The surface of the substrate thus cleaned was carburized under the same conditions as in Example 1.

Next, a base layer composed of Zr was formed on the base material that had been subjected to carburizing treatment using an ion plating apparatus as follows.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, argon gas was introduced into the processing chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In such a state, using Zr as a target, setting the ionization voltage: 30 V, ionization current: 140 A, and holding for 1 hour, an underlayer composed of Zr was formed. The average thickness of the formed underlayer was 2.0 μm.

Next, a film composed of a chromium compound was formed on the base material on which the underlayer was formed using the above ion plating as follows.
First, while preheating the processing chamber, the processing chamber was evacuated (depressurized) to 3 × 10 ⁻³ Pa.
Next, bombarding was performed for 3 minutes at an argon gas flow rate of 100 ml / min. The pressure in the processing chamber in the bombarding process was 9 × 10 ⁻² Pa.

Next, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, nitrogen gas and acetylene gas were introduced at flow rates of 160 ml / min and 160 ml / min, respectively, and the pressure in the processing chamber was set to 3 × 10. ⁻¹ Pa. In such a state, Cr was used as a target, and the ionization voltage was set to 30 V and the ionization current was set to 140 A, thereby forming a film composed of CrCN and obtaining an ornament. The average thickness of the formed film was 3 μm.
The thickness of the underlayer and the coating was measured by the microscope cross-sectional test method of JIS H 5821.

(Example 5)
A decorative article (watch case (body)) was manufactured by performing the following surface treatment.
First, an alumina (Al ₂ O ₃ ) powder was used to produce a member (base) having the shape of a watch case (body) by powder metallurgy sintering, and then necessary portions were cut and polished.

Next, this member was cleaned. 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
A surface layer composed of Ti was formed on the surface of the member thus cleaned, and a base material having a base portion and a surface layer was obtained.

The surface layer was formed as follows using an ion plating apparatus.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, argon gas was introduced into the processing chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In such a state, using Ti as a target, setting the ionization voltage: 30 V, ionization current: 140 A, and holding for 1 hour, a surface layer composed of Ti was formed. The average thickness of the formed surface layer was 2.0 μm.

Next, the base material manufactured as described above was washed. As this cleaning, first, alkaline electrolytic degreasing was performed for 30 seconds, and then alkaline immersion degreasing was performed for 30 seconds. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
The surface of the substrate thus cleaned was subjected to nitriding treatment under the same conditions as in Example 2.
Next, a base layer composed of Ti was formed on the base material subjected to nitriding treatment under the same conditions as in Example 3 using an ion plating apparatus.

Next, a film composed of a titanium compound was formed on the base material on which the base layer was formed by ion plating using the above nitriding apparatus as follows.
First, while preheating the processing chamber, the processing chamber was evacuated (depressurized) to 3 × 10 ⁻³ Pa.
Next, bombarding was performed for 3 minutes at an argon gas flow rate of 100 ml / min. The pressure in the processing chamber in the bombarding process was 9 × 10 ⁻² Pa.

Next, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, oxygen gas was introduced to set the pressure in the processing chamber to 1 × 10 ⁻¹ Pa. In such a state, Ti was used as a target, and an ionization voltage: 25 V and an ionization current: 110 A were set to form a coating film made of TiO to obtain a decorative article. The average thickness of the formed film was 10 μm.
The thickness of the surface layer, the underlayer, and the coating was measured by a microscope cross-sectional test method of JIS H5821.

(Example 6)
A decorative article (watch case (back cover)) was manufactured by performing the following surface treatment.
First, a base material having the shape of a watch case (back cover) was produced by casting using stainless steel (SUS444), and then 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
The surface of the substrate thus cleaned was subjected to nitriding treatment under the same conditions as in Example 2.

Next, a first underlayer composed of Cr was formed on the base material subjected to nitriding treatment using an ion plating apparatus as follows.
First, while preheating the processing chamber of the ion plating apparatus, the processing chamber was evacuated (depressurized) 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.

  Thereafter, argon gas was introduced into the processing chamber at a gas pressure of 53 Pa, and a DC voltage of 400 V was applied and held for 30 to 60 minutes. In this state, using Cr as a target, setting the ionization voltage: 30 V, ionization current: 140 A, and holding for 1 hour, the first underlayer composed of Cr was formed. The average thickness of the formed first underlayer was 2.0 μm.

Next, a first film composed of a chromium compound was formed on the base material on which the first underlayer was formed using the above ion plating as follows.
First, while preheating the processing chamber, the processing chamber was evacuated (depressurized) to 3 × 10 ⁻³ Pa.
Next, bombarding was performed for 3 minutes at an argon gas flow rate of 100 ml / min. The pressure in the processing chamber in the bombarding process was 9 × 10 ⁻² Pa.

Next, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, acetylene gas was introduced at a flow rate of 45 ml / min, and the pressure in the processing chamber was set to 3 × 10 ⁻¹ Pa. In this state, Cr was used as a target, and an ionization voltage: 30 V and an ionization current: 140 A were set to form a first film made of CrC. The average thickness of the formed first film was 5 μm.
After that, the second base layer, the second film, the third base layer, and the base material on which the first base layer and the first film are laminated, using the above nitriding apparatus, A third coating, a fourth underlayer, and a fourth coating were sequentially formed.

The second underlayer was formed by ion plating in the same manner as the first underlayer except that Al was used as a target. The third underlayer and the fourth underlayer were formed by ion plating in the same manner as the first underlayer except that Ti was used as a target. The average thicknesses of the formed second underlayer, third underlayer, and fourth underlayer were 1.0 μm, 1.0 μm, and 1.0 μm, respectively.
The second coating, the third coating, and the fourth coating were formed by ion plating in the same manner as the first coating except that the composition of the target and the atmosphere gas during ion plating was changed.

That is, the second coating is evacuated (depressurized) to 2 × 10 ⁻³ Pa in the processing chamber, and then introduced with nitrogen gas and acetylene gas at flow rates of 160 ml / min and 160 ml / min, respectively. The film was formed as CrCN by performing ion plating using Cr as a target in such a state at a pressure of 3 × 10 ⁻¹ Pa. The third coating is evacuated (depressurized) to 2 × 10 ⁻³ Pa in the processing chamber, and then introduced with nitrogen gas and acetylene gas at flow rates of 160 ml / min and 160 ml / min, respectively. The pressure was set to 3 × 10 ⁻¹ Pa, and in this state, the film was formed as TiCN by performing ion plating using Ti as a target. Moreover, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, the fourth film is introduced with nitrogen gas at a flow rate of 50 ml / min, and the pressure in the processing chamber is set to 3 × 10 ⁻¹ Pa. In this state, a film composed of TiN was formed by performing ion plating using Ti as a target. The average thicknesses of the formed second film, third film, and fourth film were 1.0 μm, 1.0 μm, and 1.0 μm, respectively.
Base layer (first base layer, second base layer, third base layer and fourth base layer), coating (first coating, second coating, third coating and fourth coating) The thickness of was measured by the microscope cross-sectional test method of JIS H 5821.

(Example 7)
A decorative article (watch case (back cover)) was manufactured by performing the following surface treatment.
First, a Ti base material having the shape of a watch case (back cover) was produced by metal powder injection molding (MIM). Metal powder injection molding (MIM) was performed under the same conditions as in Example 2.

Thereafter, necessary portions of the obtained base material were cut and polished, and then the 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. Thereafter, neutralization was performed for 10 seconds, washing with water for 10 seconds, and washing with pure water for 10 seconds.
The surface of the substrate thus cleaned was carburized under the same conditions as in Example 1.

Next, with respect to the base material that has been subjected to carburizing treatment, an ion plating apparatus is used to form a first base layer made of Ti under the same conditions as the base layer formation conditions in Example 3. Formed.
Next, a first film composed of a titanium compound was formed on the base material on which the first underlayer was formed using the ion plating apparatus as described below.
First, while preheating the processing chamber, the processing chamber was evacuated (depressurized) to 3 × 10 ⁻³ Pa.

Next, bombarding was performed for 3 minutes at an argon gas flow rate of 100 ml / min. The pressure in the processing chamber in the bombarding process was 9 × 10 ⁻² Pa.
Next, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, nitrogen gas and acetylene gas were introduced at flow rates of 160 ml / min and 160 ml / min, respectively, and the pressure in the processing chamber was set to 3 × 10. ⁻¹ Pa. In such a state, Ti was used as a target, and an ionization voltage: 30 V and an ionization current: 140 A were set, thereby forming a first film made of TiCN. The average thickness of the formed first film was 4 μm.

Thereafter, for the base material on which the first underlayer and the first film are laminated, the second underlayer, the second film, the third underlayer, A third coating, a fourth underlayer, and a fourth coating were sequentially formed.
The second underlayer, the third underlayer, and the fourth underlayer were formed by ion plating in the same manner as the first underlayer. The average thicknesses of the formed second underlayer, third underlayer, and fourth underlayer were 1.0 μm, 2.0 μm, and 3.0 μm, respectively.
The second coating, the third coating, and the fourth coating were formed by ion plating in the same manner as the first coating except that the composition of the atmospheric gas at the time of ion plating was changed.

That is, the second coating is evacuated (depressurized) to 2 × 10 ⁻³ Pa in the processing chamber, and then introduced with acetylene gas at a flow rate of 45 ml / min, and the pressure in the processing chamber is set to 3 × 10 ⁻¹ Pa. In this state, a film composed of TiC was formed by performing ion plating using Ti as a target. The third coating is evacuated (depressurized) to 2 × 10 ⁻³ Pa in the processing chamber, and then introduced with nitrogen gas and acetylene gas at flow rates of 160 ml / min and 160 ml / min, respectively. The pressure was set to 3 × 10 ⁻¹ Pa, and in this state, the film was formed as TiCN by performing ion plating using Ti as a target. Moreover, after exhausting (reducing pressure) the processing chamber to 2 × 10 ⁻³ Pa, the fourth film is introduced with nitrogen gas at a flow rate of 50 ml / min, and the pressure in the processing chamber is set to 3 × 10 ⁻¹ Pa. In this state, a film composed of TiN was formed by performing ion plating using Ti as a target. The average thicknesses of the formed second film, third film, and fourth film were 2.0 μm, 2.0 μm, and 2.0 μm, respectively.
Base layer (first base layer, second base layer, third base layer and fourth base layer), coating (first coating, second coating, third coating and fourth coating) The thickness of was measured by the microscope cross-sectional test method of JIS H 5821.

(Comparative Example 1)
A decorative article (watch case (back cover)) was produced in the same manner as in Example 1 except that no coating was formed after the carburizing treatment.
(Comparative Example 2)
A decorative article (watch case (body)) was produced in the same manner as in Example 2 except that no film was formed after the nitriding treatment.

(Comparative Example 3)
A decorative article (watch case (back cover)) was manufactured in the same manner as in Example 1 except that the coating was directly formed on the surface of the base material without carburizing.
(Comparative Example 4)
A decorative article (watch case (body)) was produced in the same manner as in Example 2 except that the film was formed directly on the surface of the substrate without performing nitriding.
Table 1 summarizes the conditions of the surface treatment method of each example and each comparative example.

2. Appearance evaluation of ornaments The ornaments manufactured in Examples 1 to 7 and Comparative Examples 1 to 4 were observed visually and with a microscope, and the appearance was evaluated according to the following four criteria.
A: Excellent appearance (high glossiness).
○: Appearance is good (medium gloss).
Δ: Slightly poor appearance (slight glossiness or rough surface)
X: Appearance defect (low gloss or remarkable surface roughness).

3. Evaluation of Scratch Resistance of Films Each decorative article manufactured in Examples 1 to 7 and Comparative Examples 1 to 4 was subjected to the following tests to evaluate the scratch resistance.
A stainless steel brush was pressed onto the surface of each decorative article and slid 50 times. The pressing load at this time was 0.2 kgf.

Thereafter, the surface of the decorative article was visually observed, and the appearance was evaluated according to the following four criteria.
A: No scratches are observed on the surface of the coating.
○: Scratches are hardly observed on the surface of the coating.
Δ: Slight scratches are observed on the surface of the coating.
X: Scratches are significantly observed on the surface of the coating.

4). Evaluation of anti-scratch property of decorative article About each decorative article manufactured in Examples 1 to 7 and Comparative Examples 1 to 4, the test as shown below was performed to evaluate the anti-scratch resistance.
A SUS ore ball (diameter 1 cm) is dropped from a position 50 cm high above each ornament, and the size of the dent on the surface of the ornament (the diameter of the dent mark) is measured. Evaluation was made according to the criteria.

(Double-circle): The diameter of a dent mark is less than 1 mm, or a dent mark is not calculated | required.
○: The diameter of the dent mark is 1 mm or more and less than 2 mm.
(Triangle | delta): The diameter of a dent mark is 2 mm or more and less than 3 mm.
X: The diameter of a dent mark is 3 mm or more.
These results are shown in Table 2 together with the color of the coating and the Vickers hardness Hv. In addition, as Vickers hardness Hv, the value measured with the measurement load of 100 gf about the coating film surface of each ornament is shown.

As is clear from Table 2, all the decorative articles produced using the surface treatment method of the present invention had an excellent aesthetic appearance and excellent scratch resistance.
Moreover, the decorative article manufactured using the surface treatment method of the present invention was also excellent in dent resistance. From these results, it can be seen that the decorative article of the present invention can maintain an excellent aesthetic appearance over a long period of time. In addition, the decorative article having the base layer has a smooth surface and a particularly excellent aesthetic appearance. Moreover, in the decorative article obtained by laminating the base layer and the coating several times (decorative articles of Examples 7 and 8), particularly excellent results were obtained.
Moreover, all the decorative articles manufactured using the surface treatment method of the present invention had an excellent tactile sensation with no roughness.
Moreover, in Examples 1-7, the film which has a desired composition and characteristic was able to be formed easily by selecting suitably the atmospheric composition at the time of ion plating.

It is sectional drawing which shows 1st Embodiment of the surface treatment method of this invention. It is sectional drawing which shows 2nd Embodiment of the surface treatment method of this invention. It is sectional drawing which shows 3rd Embodiment of the surface treatment method of this invention. It is sectional drawing which shows 3rd Embodiment of the surface treatment method of this invention. It is sectional drawing which shows 3rd Embodiment of the surface treatment method of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1A, 1B, 1C ... Decoration 2 ... Base material 21 ... Carburized layer 22 ... Nitrided layer 30 ... Coating 31 ... 1st coating 32 ... 2nd coating 33 ... 3rd coating 34 ... 4th coating 40 ... Bottom Base layer 41 ... first base layer 42 ... second base layer 43 ... third base layer 44 ... fourth base layer

Claims (25)

Applying at least a part of the base material mainly composed of Ti and / or stainless steel at least near the surface to a hardening treatment by nitriding or carburizing;
And a step of forming a film made of a material containing Ti and / or Cr on the base material subjected to the curing treatment by dry plating. Applying at least a part of the base material mainly composed of Ti and / or stainless steel at least near the surface to a hardening treatment by nitriding or carburizing;
Forming at least one underlayer on the base material subjected to the curing treatment;
And a step of forming a film made of a material containing Ti and / or Cr on the underlayer by dry plating.   The surface treatment method for a decorative article according to claim 2, wherein the step of forming the base layer and the step of forming the coating are repeated, and the base layer and the coating are laminated a plurality of times.   The surface treatment method for a decorative article according to claim 2 or 3, wherein at least one of the underlayers is a leveling layer that relieves irregularities on the surface of the substrate.   The surface treatment method for an ornament according to any one of claims 2 to 4, wherein the underlayer is formed by dry plating.   6. The decorative article surface treatment method according to claim 2, wherein the underlayer is made of Ti, Cr, or an alloy containing at least one of them.   The surface of the decorative article according to any one of claims 1 to 6, wherein at least a part of the surface of the base material is subjected to a surface processing selected from mirror surface processing, streak processing, and satin processing. Processing method.   The surface treatment method for a decorative article according to any one of claims 1 to 7, wherein the base material has a base and a surface layer provided on the base.   The surface treatment method for a decorative article according to any one of claims 1 to 8, wherein the surface layer has a thickness of 0.1 to 50 µm.   The decoration according to any one of claims 1 to 9, wherein the nitriding treatment is ion nitriding in which the base material is maintained at a temperature of 300 to 500 ° C and glow discharge is performed in an atmosphere containing ammonia gas and hydrogen gas. Product surface treatment method.   The surface treatment method for a decorative article according to any one of claims 1 to 10, wherein a thickness of the nitride layer formed by the nitriding treatment is 0.1 to 200 µm.   The surface treatment of a decorative article according to any one of claims 1 to 11, wherein the carburizing treatment is a plasma carburizing treatment that includes a hydrocarbon-based gas of 10 to 700 Pa and is performed in an atmosphere having a temperature of 400 to 900 ° C. Method.   The surface treatment method for a decorative article according to any one of claims 1 to 12, wherein a thickness of the carburized layer formed by the carburizing treatment is 0.1 to 200 µm.   14. The decorative article surface treatment method according to claim 1, wherein the coating film is formed by an ion plating method.   The surface treatment method for a decorative article according to claim 14, wherein an ionization voltage during the ion plating is 15 to 200V.   The surface treatment method for a decorative article according to claim 14 or 15, wherein an ionization current during the ion plating is 5 to 150A. The surface treatment method for a decorative article according to any one of claims 14 to 16, wherein the pressure of the atmosphere at the time of ion plating is 1 x ^{10-3 to} 1.5 Pa.   The said coating film is comprised with the material containing at least 1 sort (s) selected from the group which consists of TiN, TiC, TiCN, TiO, CrN, CrC, CrCN, and CrO. A method for surface treatment of ornaments.   The surface treatment method for a decorative article according to any one of claims 1 to 18, wherein the thickness of the coating is 2 to 10 µm.   A decorative article manufactured using the surface treatment method for a decorative article according to any one of claims 1 to 19. A substrate having a hardened layer formed by nitriding or carburizing;
A decorative article comprising: a coating formed of a material containing Ti and / or Cr on the substrate by dry plating. A substrate having a hardened layer formed by nitriding or carburizing;
At least one underlayer formed on the cured layer;
A decorative article comprising: a coating formed of a material containing Ti and / or Cr on the underlayer by dry plating. A substrate having a hardened layer formed by nitriding or carburizing;
Multiple underlayers;
A decorative article formed by dry plating and having a plurality of coatings made of a material containing Ti and / or Cr,
A decorative article, wherein a plurality of the base layers and the coating films are alternately laminated.   The decorative article according to any one of claims 20 to 23, wherein at least a part thereof is used in contact with the skin.   The decorative article according to any one of claims 20 to 24, wherein the decorative article is a watch exterior part.

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