Decorative member and method for manufacturing decorative member

Abstract

Provided is a decorative member (1, 2, 2', 3, 3 ') in which a substrate (12, 22, 32) is covered with: a first region (14R, 24R, 34R) comprising a cured layer (14, 24, 34); and a second region (16R, 26R, 36R) comprising an oxide layer (16, 26, 36). The cured layer (14, 24, 43) constituting the first region (14R, 24R, 34R) and the oxide layer (16, 26, 36) constituting the second region (16R, 26R, 36R) are harder than the substrate (12, 22, 32). The oxide layer (16, 26, 36) constituting the second region (16R, 26R, 36R) colors due to structural color.

Description

Decorative member and method for manufacturing the same

[0001] The present invention relates to a decorative member and a method for manufacturing a decorative member.

[0002] Patent Document 1 describes a watch component whose surface is decorated by laser irradiation, and which has an oxide film formed by multiple laser irradiations with different spot overlap amounts, the oxide film having a thickness that varies depending on the density of the spot overlap amount, and which has a gradation corresponding to the density due to light interference. Patent Document 1 also describes that the watch component is made of any of titanium, stainless steel, nickel silver, pure iron, brass, duralumin, and alloys.

[0003] JP 2022-106384 A

[0004] However, the metal parts of Patent Document 1 have the problem of being easily damaged.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a decorative member that is colored by a structural color, has excellent decorative properties, and is scratch-resistant.

[0006] In the decorative member of the present invention, a substrate is covered with a first region composed of a hardened layer and a second region composed of an oxidized layer, and the hardened layer constituting the first region and the oxidized layer constituting the second region are harder than the substrate, and the oxidized layer constituting the second region exhibits a structural color.

[0007] The decorative member of the present invention is colored by a structural color, has excellent decorative properties, and is also scratch-resistant.

[0008] FIG. 1 is a diagram illustrating a decorative member of Embodiment 1. FIG. 2 is a diagram illustrating a decorative member of Embodiment 1. FIG. 3 is a diagram illustrating a decorative member of Embodiment 2. FIG. 4 is a diagram illustrating a decorative member of a modified example of Embodiment 2. FIG. 5 is a diagram illustrating a decorative member of a modified example of Embodiment 2. FIG. 6 is a diagram illustrating a decorative member of Embodiment 3. FIG. 7 is a diagram illustrating a decorative member of Embodiment 3. FIG. 8 is a diagram illustrating a decorative member of a modified example of Embodiment 3. FIG. 9 is a diagram illustrating a decorative member of a modified example of Embodiment 3. FIG. 10 is a diagram illustrating the results of a composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS) of the first region 14R of decorative member 1-1. FIG. 11 is a diagram illustrating the results of a composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS) of the second region 16R of decorative member 1-1. FIG. 12 is a diagram illustrating the results of a composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS) of the first region 24R of decorative member 2'-1. Fig. 13 shows the results of a depth-direction composition analysis of the second region 26R of the decorative member 2'-1 by X-ray photoelectron spectroscopy (XPS). Fig. 14 shows the results of a depth-direction composition analysis of the second region 26R of the decorative member 2'-2 by X-ray photoelectron spectroscopy (XPS). Fig. 15 shows the results of a depth-direction composition analysis of the laser-irradiated region of the decorative member of Reference Example 1-1 by X-ray photoelectron spectroscopy (XPS).

[0009] Modes (embodiments) for carrying out the present invention will be described in detail. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configurations can be made within the scope of the gist of the present invention.

[0010] [Embodiment 1] FIGS. 1 and 2 are diagrams illustrating a decorative member according to Embodiment 1 and are schematic cross-sectional views of the decorative member 1. In the decorative member 1, a substrate 12 is covered with a first region 14R formed by a hardened layer 14 and a second region 16R formed by an oxide layer 16. That is, the surface of the decorative member 1 is covered with the first region 14R, where the surface of the hardened layer 14 is exposed, and the second region 16R, where the surface of the oxide layer 16 is exposed. Various decorative patterns can be expressed by varying the shape of the second region 16R. Typically, the second region 16R is recessed toward the substrate 12 relative to the first region 14R, forming a recess 16r. The second region 16R and the first region 14R may be flush with each other. The surface of the oxide layer 16 facing the substrate 12 may be in contact with the substrate 12 as shown in FIG. 1 or may be in contact with the hardened layer 14 as shown in FIG. 2.

[0011] The substrate 12 contains titanium. The surface of the substrate 12 on which the hardened layer 14 is formed may be subjected to mechanical processing such as mirror finishing, blasting, or hairline finishing.

[0012] The hardened layer 14 is a layer containing titanium in which nitrogen and oxygen elements are dissolved. The hardened layer 14 in the first region 14R formed on the substrate 12 has excellent hardness and is scratch-resistant. From the viewpoint of hardness, it is preferable that nitrogen be dissolved in an amount of 0.6 mass% to 8.0 mass% and oxygen be dissolved in an amount of 1.0 mass% to 14.0 mass% relative to 100 mass% titanium. The amount of nitrogen and oxygen dissolved in the depth direction D does not have to be constant. For example, the amount of nitrogen and oxygen dissolved in the depth direction D may gradually decrease. Furthermore, the distribution of nitrogen in the depth direction D may differ from the distribution of oxygen in the depth direction D. For example, oxygen may be dissolved deeper in the depth direction D than nitrogen. Note that in the hardened layer 14, a portion of the nitrogen or oxygen may form a compound with titanium. From the viewpoint of hardness, it is preferable that the thickness of the hardened layer 14 in the first region 14R is 1 μm to 20 μm.

[0013] The oxide layer 16 contains titanium oxide. The oxide layer 16 in the second region 16R is formed so as to contact the substrate 12 or the hardened layer 14, and is highly hard and scratch-resistant. The oxide layer 16 typically contains titanium oxide in which nitrogen element is dissolved. When nitrogen is dissolved, the oxide layer 16 is more hard and more scratch-resistant. In the oxide layer 16, a portion of the nitrogen may form a compound with titanium oxide. From the viewpoint of color development, which will be described later, the thickness of the oxide layer 16 in the second region 16R is preferably 10 nm or more and 300 nm or less.

[0014] The hardened layer 14 constituting the first region 14R and the oxidized layer 16 constituting the second region 16R are harder than the substrate 12. This is because, as described above, the hardened layer 14 exposed as the first region 14R and the oxidized layer 16 exposed as the second region 16R are composed of the above-mentioned specific components. Therefore, the entire surface of the decorative member 1 has excellent hardness and is scratch-resistant. Furthermore, it is preferable that the oxidized layer 16 constituting the second region 16R is harder than the hardened layer 14 constituting the first region 14R. In this case, the occurrence of scratches on the decorative pattern can be further suppressed, and the decorativeness of the decorative member can be more reliably maintained.

[0015] The oxide layer 16 constituting the second region 16R exhibits a structural color. In other words, the second region 16R exhibits a color due to interference of internally reflected light reflected at the interface between the oxide layer 16 and the underlying layer (the substrate 12 or the cured layer 14 to which the oxide layer 16 is in contact). Therefore, the decorative member 1 exhibits a structural color, which provides excellent decorativeness and scratch resistance.

[0016] Here, a method for manufacturing the decorative member of the first embodiment will be described. For example, first, a hardened layer 14 is formed on a substrate 12. The substrate 12 contains titanium. The surface of the substrate 12 on which the hardened layer 14 is formed may be subjected to the above-mentioned machining process. Furthermore, the substrate 12 may be annealed in advance to alleviate the work-induced strain layer generated on the surface by the hot forging process or the subsequent polishing process.

[0017] Specifically, the substrate 12 is introduced into a vacuum chamber. A nitrogen-based mixed gas containing a trace amount of oxygen is then introduced into the vacuum chamber, and the substrate 12 is heated at a temperature of 700°C to 800°C for a predetermined time under a predetermined reduced pressure. To incorporate a trace amount of oxygen into the mixed gas, oxygen gas, hydrogen gas, water vapor, ethyl alcohol, methyl alcohol, or the like is used. Hydrogen gas is preferably used in combination with oxygen gas. Carbon dioxide gas or carbon monoxide gas may also be used together with water vapor. The concentration of oxygen relative to nitrogen in the mixed gas is preferably adjusted to 100 ppm to 30,000 ppm. The pressure in the vacuum chamber is preferably adjusted to 0.01 Torr to 10 Torr. The heating process diffuses and dissolves nitrogen and oxygen from the surface of the substrate 12 into its interior. The substrate 12 is then cooled to room temperature. Cooling is preferably performed in an inert gas atmosphere such as argon or helium. That is, it is preferable to evacuate the vacuum chamber to a high vacuum to remove the mixed gas, and then cool to room temperature under reduced pressure by introducing an inert gas into the vacuum chamber. Cooling may also be performed in a vacuum atmosphere. By appropriately adjusting the oxygen component concentration in the mixed gas, the pressure in the vacuum chamber, the heating temperature, and the heating time, a hardened layer 14 having suitable hardness and thickness can be formed. In this way, a hardened layer 14 containing titanium in which nitrogen and oxygen elements are solid-solved is formed on the substrate 12, and the hardened layer 14 has excellent hardness and scratch resistance.

[0018] Alternatively, a nitrogen-based mixed gas containing a trace amount of oxygen may be introduced into the vacuum chamber, the pressure adjusted to atmospheric pressure, and the substrate 12 heated at a temperature of 700°C to 800°C for a predetermined time. This heating process allows nitrogen and oxygen to diffuse from the surface of the substrate 12 to the interior. The substrate 12 is then cooled to room temperature. Cooling is preferably performed in an inert gas atmosphere such as argon or helium. That is, the vacuum chamber is evacuated to a high vacuum to remove the mixed gas, and then the substrate is cooled to room temperature under reduced pressure with an inert gas introduced into the vacuum chamber. Cooling may also be performed in a vacuum atmosphere. In this manner, a hardened layer 14 containing titanium with nitrogen and oxygen elements dissolved therein may be formed on the substrate 12, which has excellent hardness and scratch resistance.

[0019] Next, the substrate 12 on which the hardened layer 14 has been formed is subjected to laser processing to remove the hardened layer 14 and form the oxide layer 16. The laser processing is performed by irradiating the hardened layer 14 with a laser using a laser marker as a processing device. During the laser processing, the region to be irradiated with the laser is appropriately set so as to obtain the second region 16R corresponding to the desired decorative pattern. Furthermore, solid-state lasers such as a YAG (yttrium aluminum garnet) laser and a YVO4 (yttrium vanadate) laser are preferably used as the laser, with a YVO4 laser being more preferably used. The laser irradiation is preferably performed in an oxygen-containing atmosphere, for example, in air.

[0020] In the laser-irradiated region, the hardened layer 14 is partially or completely removed in the depth direction D. The exposed surface is oxidized to form an oxide layer 16 containing titanium oxide. Specifically, in the example shown in FIG. 1 , the substrate 12 is replaced with the oxide layer 16, and in the example shown in FIG. 2 , the hardened layer 14 is replaced with the oxide layer 16. Meanwhile, in the non-laser-irradiated region, the hardened layer 14 remains. That is, the surface of the substrate 12 is covered with a first region 14R where the remaining hardened layer 14 is exposed and a second region 16R where the newly formed oxide layer 16 is exposed. Therefore, the entire surface of the decorative member 1 is highly hard and scratch-resistant. Furthermore, the oxide layer 16 formed as described above typically contains titanium oxide in which nitrogen, an element derived from the atmosphere, is dissolved. The dissolved nitrogen enhances the hardness and scratch resistance of the oxide layer 16. In this case, the entire surface of the decorative member 1 is highly hard and scratch-resistant. The oxide layer 16 constituting the second region 16R exhibits a structural color. Typically, the second region 16R is recessed closer to the substrate 12 than the first region 14R, forming a recess 16r. The second region 16R and the first region 14R may be formed flush with each other.

[0021] In addition, the laser irradiation conditions are preferably a power of 2.5 W to 22.5 W, a scan speed of 50 mm / s to 2000 mm / s, a pulse frequency of 25 kHz to 400 kHz, and a fill interval of 0.001 mm to 0.200 mm. These irradiation conditions allow for both coloring and hardness of the decorative member. More preferably, the power is 5.0 W to 12.5 W, a scan speed of 100 mm / s to 1000 mm / s, a pulse frequency of 200 kHz to 380 kHz, and a fill interval of 0.010 mm to 0.030 mm. These irradiation conditions allow for coloring of the decorative member to achieve a more desirable appearance and more reliably improve the hardness of the laser-processed area. The fill interval refers to the center-to-center distance between adjacent laser spots. The decorative pattern may be formed by printing in a grid pattern. For example, a decorative pattern may be formed by combining multiple substantially linear prints extending in one direction with multiple substantially linear prints extending in another direction intersecting the first direction. The number of prints constituting the decorative pattern may be adjusted appropriately depending on the shape or dimensions of the desired decorative pattern. The number of prints (irradiations) as a laser irradiation condition may be adjusted appropriately depending on, for example, the color tone of the desired decorative pattern. The number of prints refers to the number of times the laser is irradiated onto the portion of the substrate where the decorative pattern is to be formed. For example, the decorative pattern may be formed by repeatedly irradiating a predetermined portion of the substrate with the laser five to 20 times depending on the intended color tone. By appropriately adjusting the irradiation conditions described above, the color tone as well as the thickness of the oxide layer 16 can be controlled. In this manner, a decorative member 1 having the above-described characteristics can be manufactured.

[0022] [Embodiment 2] Figure 3 is a diagram illustrating a decorative member according to Embodiment 2, and is a schematic cross-sectional view of the decorative member 2. In the decorative member 2, a substrate 22 is covered with a first region 24R formed by a hardened layer 24 and a second region 26R formed by an oxide layer 26. That is, the surface of the decorative member 2 is covered with the first region 24R, where the surface of the hardened layer 24 is exposed, and the second region 26R, where the surface of the oxide layer 26 is exposed. Various decorative patterns can be expressed by varying the shape of the second region 26R. Typically, the second region 26R is recessed toward the substrate 22 relative to the first region 24R, forming a recess 26r. The second region 26R and the first region 24R may be flush with each other. Furthermore, the surface of the oxide layer 26 facing the substrate 22 is in contact with the substrate 22, as shown in Figure 3.

[0023] The substrate 22 includes titanium. The surface of the substrate 22 on which the hardened layer 24 is formed may be subjected to mechanical processing such as mirror finishing, blasting, or hairline finishing.

[0024] The hardened layer 24 is a layer containing diamond-like carbon (DLC). DLC contains carbon and hydrogen and has a sp 3 carbon with bonds and sp corresponding to the graphite structure 2 The hardened layer 24 in the first region 24R formed on the substrate 22 has an amorphous structure in which carbon atoms with bonds are irregularly mixed. The hardened layer 24 in the first region 24R has excellent hardness and is scratch-resistant. From the viewpoint of hardness, the thickness of the hardened layer 24 in the first region 24R is preferably 0.4 μm or more and 1.2 μm or less.

[0025] The oxide layer 26 contains titanium oxide. The oxide layer 26 in the second region 26R is formed so as to contact the base material 22, and is highly hard and scratch-resistant. The oxide layer 26 typically contains titanium oxide in which nitrogen element is dissolved. When nitrogen is dissolved, the oxide layer 26 is more hard and more scratch-resistant. In the oxide layer 26, a portion of the nitrogen may form a compound with titanium oxide. From the viewpoint of color development, which will be described later, the thickness of the oxide layer 26 in the second region 26R is preferably 10 nm or more and 300 nm or less.

[0026] The hardened layer 24 constituting the first region 24R and the oxide layer 26 constituting the second region 26R are harder than the substrate 22. This is because, as described above, the hardened layer 24 exposed as the first region 24R and the oxide layer 26 exposed as the second region 26R are composed of the specific components described above. Therefore, the entire surface of the decorative member 2 is highly hard and scratch-resistant. Furthermore, it is preferable that the oxide layer 26 constituting the second region 26R is harder than the hardened layer 24 constituting the first region 24R. In this case, scratches on the decorative pattern can be further suppressed, and the decorativeness of the decorative member can be more reliably maintained.

[0027] The oxide layer 26 constituting the second region 26R exhibits a structural color. In other words, the second region 26R exhibits a color due to interference of internally reflected light that is reflected at the interface between the oxide layer 26 and the layer below it (the substrate 22 to which the oxide layer 26 is in contact). Therefore, the decorative member 2 exhibits a structural color, providing excellent decorativeness and scratch resistance.

[0028] Here, a method for manufacturing a decorative member according to the second embodiment will be described. For example, first, a hardened layer 24 is formed on a substrate 22. The substrate 22 contains titanium. The surface of the substrate 22 on which the hardened layer 24 is formed may be subjected to the above-mentioned machining process. Furthermore, the substrate 22 may be annealed in advance to alleviate the work-strain layer that occurs on the surface due to the hot forging process or the subsequent polishing process.

[0029] Specifically, a hardened layer 24 containing DLC ​​is formed on the substrate 22 by plasma CVD while applying a negative bias voltage of 0.05 kV to 5 kV to the substrate 22 placed in a vacuum chamber. That is, a gas containing a raw material is converted into plasma, and the raw material is deposited on the substrate to form the hardened layer 24. Hydrocarbon gases such as methane, acetylene, and benzene are preferably used as the gas containing the raw material. The film formation time is, for example, 7 minutes to 120 minutes. By appropriately adjusting the voltage application time (film formation time), a hardened layer 24 having a suitable thickness can be formed. Furthermore, by appropriately adjusting the negative bias voltage or film formation time, a hardened layer 24 having a suitable hardness can be formed. In this manner, a hardened layer 24 containing DLC, which has excellent hardness and is scratch-resistant, is formed on the substrate 22.

[0030] Next, the substrate 22 on which the hardened layer 24 has been formed is subjected to laser processing to remove the hardened layer 24 and form an oxide layer 26. Specifically, as shown in Figure 3, the substrate 22 is replaced with the oxide layer 26. In the second embodiment, the laser processing is the same as that described in the first embodiment. In this manner, the decorative member 2 having the above-described characteristics can be manufactured.

[0031] 4 and 5 are diagrams for explaining a decorative member according to a modification of the second embodiment, and are schematic diagrams showing a cross section of a decorative member 2'. In the decorative member 2', a first adhesion layer 281 and a second adhesion layer 282 are formed, in this order from the substrate 22 side, between the substrate 22 and the hardened layer 24. This modification of the second embodiment is the same as the second embodiment, except that the first adhesion layer 281 and the second adhesion layer 282 are formed. Therefore, a description of the same points as the second embodiment will be omitted, and the differences from the second embodiment will be described below.

[0032] The formation of the first adhesion layer 281 and the second adhesion layer 282 further improves the adhesion between the substrate 22 and the hardened layer 24 compared to the decorative member of embodiment 2. The first adhesion layer 281 preferably contains at least one element selected from Ti and Cr, more preferably Ti. From the viewpoint of adhesion, the first adhesion layer 281 preferably has a thickness of 0.1 μm or more and 0.2 μm or less. The second adhesion layer 282 preferably contains at least one element selected from Si and Ge, more preferably Si. Specifically, the second adhesion layer 282 may contain a nitride, carbide, or carbonitride of at least one element selected from Si and Ge. Examples of nitrides, carbides, and carbonitrides include SiN, SiC, SiCN, GeN, GeC, and GeCN. From the viewpoint of adhesion, the second adhesion layer 282 preferably has a thickness of 0.1 μm or more and 0.2 μm or less.

[0033] Here, a method for manufacturing a decorative member according to a modified example of embodiment 2 will be described. For example, first, a first adhesion layer 281 containing at least one element selected from Ti and Cr is formed on a substrate 22. Next, a second adhesion layer 282 containing at least one element selected from Si and Ge is formed on the first adhesion layer 281. The substrate 22 is the same as in embodiment 2. Specifically, the first adhesion layer 281 and the second adhesion layer 282 can be formed by sputtering, arc ion plating, or ion plating.

[0034] Next, the hardened layer 24 is formed on the second adhesive layer 282. The formation of the hardened layer 24 and the subsequent formation of the oxide layer 26 are similar to those in the second embodiment. In the laser-irradiated region, the hardened layer 24 is removed in the depth direction D. This hardened layer 24 is removed together with the first adhesive layer 281 and the second adhesive layer 282, or the hardened layer 24 is removed together with the second adhesive layer 282, and the exposed surface is oxidized to form the oxide layer 26 containing titanium oxide. Specifically, in the example shown in FIG. 4, the substrate 22 is replaced with the oxide layer 26, and in the example shown in FIG. 5, the first adhesive layer 281 is replaced with the oxide layer 26. In this manner, a decorative member according to a modification of the second embodiment having the above-described characteristics can be manufactured.

[0035] [Decorative Member of Embodiment 3] Figures 6 and 7 are diagrams illustrating a decorative member of Embodiment 3 and are schematic cross-sectional views of the decorative member 3. In the decorative member 3, a substrate 32 is covered with a first region 34R composed of a hardened layer 34 and a second region 36R composed of an oxide layer 36. That is, the surface of the decorative member 3 is covered with the first region 34R, where the surface of the hardened layer 34 is exposed, and the second region 36R, where the surface of the oxide layer 36 is exposed. Various decorative patterns can be expressed by changing the shape of the second region 36R. Typically, the second region 36R is recessed toward the substrate 32 relative to the first region 34R, forming a recess 36r. The second region 36R and the first region 34R may be flush with each other. The surface of the oxide layer 36 facing the substrate 32 may be in contact with the substrate 32 as shown in Figure 6, or may be in contact with the hardened layer 34 as shown in Figure 7.

[0036] The substrate 32 includes titanium. The surface of the substrate 32 on which the hardened layer 34 is formed may be subjected to mechanical processing such as mirror finishing, blasting, or hairline finishing.

[0037] The hardened layer 34 is a layer containing titanium carbide. The hardened layer 34 in the first region 34R formed on the substrate 32 has excellent hardness and is scratch-resistant. From the viewpoint of hardness, the thickness of the hardened layer 34 in the first region 34R is preferably 0.2 μm or more and 1.5 μm or less, and more preferably 0.5 μm or more and 1.0 μm or less.

[0038] The oxide layer 36 contains titanium oxide. The oxide layer 36 in the second region 36R is formed so as to contact the substrate 32 or the hardened layer 34, and is highly hard and scratch-resistant. The oxide layer 36 typically contains titanium oxide in which nitrogen element is dissolved. When nitrogen is dissolved, the oxide layer 36 is more hard and more scratch-resistant. In the oxide layer 36, a portion of the nitrogen may form a compound with titanium oxide. From the viewpoint of color development, which will be described later, the thickness of the oxide layer 36 in the second region 36R is preferably 10 nm or more and 300 nm or less.

[0039] The hardened layer 34 constituting the first region 34R and the oxide layer 36 constituting the second region 36R are harder than the substrate 32. This is because, as described above, the hardened layer 34 exposed as the first region 34R and the oxide layer 36 exposed as the second region 36R are composed of the above-mentioned specific components. Therefore, the entire surface of the decorative member 3 is highly hard and scratch-resistant. Furthermore, it is preferable that the oxide layer 36 constituting the second region 36R is harder than the hardened layer 34 constituting the first region 34R. In this case, scratches on the decorative pattern can be further suppressed, and the decorativeness of the decorative member can be more reliably maintained.

[0040] The oxide layer 36 constituting the second region 36R exhibits a structural color. In other words, the second region 36R exhibits a color due to interference of internally reflected light reflected at the interface between the oxide layer 36 and the layer below it (the substrate 32 or the cured layer 34 to which the oxide layer 36 is in contact). Therefore, the decorative member 3 exhibits a structural color, providing excellent decorativeness and scratch resistance.

[0041] Here, a method for manufacturing a decorative member according to a third embodiment will be described. For example, first, a hardened layer 34 is formed on a substrate 32. The substrate 32 contains titanium. The surface of the substrate 32 on which the hardened layer 34 is formed may be subjected to the above-mentioned machining process. Furthermore, the substrate 32 may be annealed in advance to alleviate the work-strain layer that occurs on the surface due to the hot forging process or the subsequent polishing process.

[0042] Specifically, a hardened layer 34 containing titanium carbide, which has excellent hardness and is scratch-resistant, is formed on the substrate 32 by sputtering, ion plating, or arc deposition. By appropriately adjusting the conditions such as the deposition time, a hardened layer 34 having suitable hardness and thickness can be formed.

[0043] Next, the substrate 32 with the first region 34R formed thereon is subjected to laser processing to remove the hardened layer 34 and form an oxide layer 36. Specifically, in the example shown in Fig. 6, the substrate 32 is replaced with the oxide layer 36, and in the example shown in Fig. 7, the hardened layer 34 is replaced with the oxide layer 36. In the third embodiment, the laser processing is the same as that described in the first embodiment. In this manner, the decorative member 3 having the above-described characteristics can be manufactured.

[0044] 8 and 9 are diagrams for explaining a decorative member according to a modification of the third embodiment, and are schematic cross-sectional views of a decorative member 3'. In the decorative member 3', an adhesive layer 38 is formed between the substrate 32 and the hardened layer 34. This modification of the third embodiment is the same as the third embodiment except for the adhesive layer 38. Therefore, a description of the same points as the third embodiment will be omitted, and only the points that differ from the third embodiment will be described below.

[0045] The formation of the adhesion layer 38 can further improve the adhesion between the substrate 32 and the hardened layer 34 compared to the decorative member of embodiment 3. The adhesion layer 38 preferably contains Ti. From the viewpoint of adhesion, the thickness of the adhesion layer 38 is preferably 0.02 μm or more and 0.2 μm or less.

[0046] Here, we will describe a manufacturing method for a decorative member according to a modification of embodiment 3. For example, first, an adhesion layer 38 containing Ti is formed on a substrate 32. The substrate 32 is the same as in embodiment 3. Specifically, the adhesion layer 38 can be formed by sputtering, arc ion plating, or ion plating.

[0047] Next, a hardened layer 34 is formed on the adhesive layer 38. The formation of the hardened layer 34 and the subsequent formation of the oxide layer 36 are similar to those in the third embodiment. In the laser-irradiated region, the hardened layer 34 is partially or completely removed in the depth direction D. This hardened layer 34 is removed together with the adhesive layer 38, or the hardened layer 34 is partially removed, and the exposed surface is oxidized to form the oxide layer 36 containing titanium oxide. Specifically, in the example shown in FIG. 8, the substrate 32 is replaced with the oxide layer 36, and in the example shown in FIG. 9, the hardened layer 34 is replaced with the oxide layer 36. In this manner, a decorative member according to a modification of the third embodiment having the above-described characteristics can be manufactured.

[0048] [Other Modifications] In the first to third embodiments, the substrate contains titanium, but is not limited thereto. The substrate may also contain a titanium alloy, chromium, niobium, or stainless steel. In these cases, the oxide layer contains an oxide of the metal contained in the substrate. As in the first to third embodiments, such decorative members are colored by structural colors, providing excellent decorativeness and scratch resistance.

[0049] All of the decorative members described above are suitable for use as watch exterior parts such as watch cases, watch bands, watch crowns, and watch back covers, as well as belt buckles, rings, necklaces, bracelets, earrings, pendants, brooches, cufflinks, tie clips, badges, medals, eyeglass frames, camera bodies, doorknobs, and the like.

[0050] EXAMPLES The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples.

[0051] [Example 1-1] A decorative member according to the first embodiment was fabricated (Figure 2). A titanium plate (JIS-2 type) was used as the substrate 12, and a hardened layer 14 was formed on the substrate 12. The substrate 12 was placed in a vacuum chamber. Next, a mixed gas was introduced into the vacuum chamber, and the substrate 12 was heated at 700°C for 5 hours under a reduced pressure of 0.2 Torr. Oxygen gas was used to incorporate a trace amount of oxygen into the mixed gas. A mixed gas containing 99.5% nitrogen with 5000 ppm (0.5%) oxygen added was used. This heating caused nitrogen and oxygen to diffuse and solid-solve from the surface of the substrate 12 to its interior. Next, the supply of the mixed gas was stopped, and the substrate 12 was cooled to room temperature while evacuating. In this manner, a hardened layer 14 containing titanium with nitrogen and oxygen elements solid-solved was formed on the substrate 12.

[0052] Next, the substrate 12 on which the cured layer 14 was formed was subjected to laser processing, replacing a portion of the cured layer 14 with an oxide layer 16. The laser processing was performed in the atmosphere by irradiating the cured layer 14 with a laser (YVO4 laser) using a known laser marker as a processing device. The laser irradiation area was set so as to obtain a 10 mm x 10 mm rectangular second region 16R as a decorative pattern. The laser irradiation conditions were Condition 1 in Table 1. Specifically, the laser irradiation conditions were a power of 10.75 W, a scan speed of 300 mm / s, a pulse frequency of 250 kHz, and a fill interval of 0.018 mm. To form the decorative pattern, printing was performed five times. Only coating was performed; the rectangular outline was not printed. In the laser-irradiated area, the cured layer 14 was partially removed in the depth direction D. The surface exposed by the removal of the cured layer 14 was oxidized, forming an oxide layer 16 containing titanium oxide. On the other hand, the hardened layer 14 remained in the area not irradiated with the laser. That is, the surface of the substrate 12 was covered with a first area 14R where the remaining hardened layer 14 was exposed and a second area 16R where the newly formed oxide layer 16 was exposed. Furthermore, the oxide layer 16 constituting the second area 16R was colored blue due to structural color. In this way, the decorative member 1-1 was produced.

[0053] [Example 1-2] Decorative member 1-2 was manufactured in the same manner as in Example 1-1, except that laser processing was performed under the following conditions. That is, the laser irradiation conditions were Condition 3 in Table 1. That is, the laser irradiation conditions were a power of 5.0 W, a scan speed of 300 mm / s, a pulse of 250 kHz, and a fill interval of 0.018 mm. In addition, printing was performed five times. Note that only painting was performed, and the outline of the rectangle was not printed. In decorative member 1-2, the oxide layer 16 constituting the second region 16R was colored yellow due to structural color.

[0054] [Example 1-3] Decorative member 1-3 was manufactured in the same manner as in Example 1-1, except that laser processing was performed under the following conditions. That is, the laser irradiation conditions were condition 4 in Table 1. That is, the laser irradiation conditions were a power of 7.5 W, a scan speed of 300 mm / s, a pulse of 250 kHz, and a fill interval of 0.018 mm. In addition, printing was performed five times. Note that only the coating was performed, and the rectangular outline was not printed. In decorative member 1-3, the oxide layer 16 constituting the second region 16R was colored purple due to structural color.

[0055] [Example 1-4] Decorative member 1-4 was produced in the same manner as in Example 1-1, except that laser processing was performed under the following conditions. That is, the laser irradiation conditions were condition 5 in Table 1. That is, the laser irradiation conditions were a power of 10.0 W, a scan speed of 300 mm / s, a pulse of 250 kHz, and a fill interval of 0.018 mm. In addition, printing was performed five times. Note that only painting was performed, and the outline of the rectangle was not printed. In decorative member 1-4, the oxide layer 16 constituting the second region 16R exhibited a blue color due to structural color.

[0056] [Example 1-5] Decorative member 1-5 was manufactured in the same manner as in Example 1-1, except that laser processing was performed under the following conditions. That is, the laser irradiation conditions were condition 6 in Table 1. That is, the laser irradiation conditions were a power of 12.5 W, a scan speed of 300 mm / s, a pulse of 250 kHz, and a fill interval of 0.018 mm. In addition, printing was performed five times. Note that only painting was performed, and the outline of the rectangle was not printed. In decorative member 1-5, the oxide layer 16 constituting the second region 16R developed a light blue color due to structural color.

[0057] Example 2-1: A decorative member according to a modification of Embodiment 2 was fabricated (see FIG. 5). A titanium plate (JIS Type 2) was used as the substrate 22. A first adhesive layer 281 (0.2 μm thick) containing Ti was formed on the substrate 22 by sputtering. A second adhesive layer 282 (0.2 μm thick) containing Si was then formed on the first adhesive layer 281 by sputtering. A hardened layer 24 was then formed on the second adhesive layer 282. The substrate 22 was placed in a vacuum chamber, and argon gas was introduced as an inert gas into the chamber, along with benzene as a raw material gas. The internal pressure of the chamber was maintained at 0.3 Pa, and the benzene was decomposed by plasma CVD to form a DLC layer on the substrate 22. The negative bias voltage was maintained constant at 3.5 kV from the start to the end of deposition. The deposition time was 90 minutes. In this manner, a hardened layer 24 containing DLC ​​was formed on the second adhesive layer 282. Next, laser processing was performed on the substrate 22 on which the cured layer 24 was formed, replacing a portion of the first adhesive layer 281 with the oxide layer 26. The laser processing was performed in the atmosphere by irradiating the cured layer 24 with a laser (YVO4 laser) using a known laser marker as a processing device. The laser irradiation area was set so as to obtain a 10 mm x 10 mm rectangular second region 26R as a decorative pattern. The laser irradiation conditions were Condition 1 in Table 1. Specifically, the laser irradiation conditions were a power of 10.75 W, a scan speed of 300 mm / s, a pulse frequency of 250 kHz, and a fill interval of 0.018 mm. To form the decorative pattern, printing was performed five times. Only coating was performed; the rectangular outline was not printed. In the laser-irradiated area, the cured layer 24 and the second adhesive layer 282 were completely removed in the depth direction D. The surface exposed after the hardened layer 24 and second adhesive layer 282 were removed was oxidized, forming an oxide layer 26 containing titanium oxide. Meanwhile, the hardened layer 24 remained in the area not irradiated with the laser. That is, the surface of the substrate 22 was covered with a first region 24R where the remaining hardened layer 24 was exposed and a second region 26R where the newly formed oxide layer 26 was exposed. Furthermore, the oxide layer 26 constituting the second region 26R was colored purple due to its structural color.In this way, a decorative member 2'-1 was produced.

[0058] Example 2-2: A decorative member according to a modification of Embodiment 2 was fabricated (see FIG. 4). A titanium plate (JIS Type 2) was used as the substrate 22. A first adhesive layer 281 (0.2 μm thick) containing Ti was formed on the substrate 22 by sputtering. A second adhesive layer 282 (0.2 μm thick) containing Si was then formed on the first adhesive layer 281 by sputtering. A hardened layer 24 was then formed on the second adhesive layer 282. The substrate 22 was placed in a vacuum chamber, and argon gas was introduced as an inert gas into the chamber, along with benzene as a raw material gas. The internal pressure of the chamber was maintained at 0.3 Pa, and the benzene was decomposed by plasma CVD to form a DLC layer on the substrate 22. The negative bias voltage was maintained constant at 3.5 kV from the start to the end of deposition. The deposition time was 90 minutes. In this manner, a hardened layer 24 containing DLC ​​was formed on the second adhesive layer 282. Next, the substrate 22 on which the cured layer 24 was formed was subjected to laser processing, replacing a portion of the substrate 22 with an oxide layer 26. The laser processing was performed in the atmosphere by irradiating the cured layer 24 with a laser (YVO4 laser) using a known laser marker as a processing device. The laser irradiation area was set so as to obtain a 10 mm x 10 mm rectangular second region 26R as a decorative pattern. The laser irradiation conditions were Condition 2 in Table 1. Specifically, the laser irradiation conditions were a power of 10.75 W, a scan speed of 300 mm / s, a pulse frequency of 250 kHz, and a fill interval of 0.018 mm. To form the decorative pattern, 20 printings were performed. Only coating was performed; the rectangular outline was not printed. In the laser-irradiated area, the cured layer 24, the first adhesive layer 281, and the second adhesive layer 282 were all removed in the depth direction D. The surface exposed after the hardened layer 24, first adhesive layer 281, and second adhesive layer 282 were removed was oxidized, forming an oxide layer 26 containing titanium oxide. Meanwhile, the hardened layer 24 remained in the area not irradiated with the laser. That is, the surface of the substrate 22 was covered with a first area 24R where the remaining hardened layer 24 was exposed and a second area 26R where the newly formed oxide layer 26 was exposed. Furthermore, the oxide layer 26 constituting the second area 26R exhibited a blue structural color.In this way, a decorative member 2'-2 was produced.

[0059] Example 3-1: A decorative member according to a modification of the third embodiment was fabricated (see FIG. 8). A titanium plate (JIS Type 2) was used as the substrate 32. A 0.2 μm thick adhesive layer 38 containing Ti was formed on the substrate 32 by sputtering. A hardened layer 34 was then formed on the adhesive layer 38. The hardened layer 34 containing titanium carbide was then formed by sputtering. Laser processing was then performed on the substrate 32 with the hardened layer 34 formed, replacing a portion of the substrate 32 with an oxide layer 36. The laser processing was performed in the atmosphere by irradiating the hardened layer 34 with a YVO4 laser using a known laser marker. The laser irradiation area was set to obtain a 10 mm x 10 mm rectangular second region 36R as the decorative pattern. The laser irradiation conditions were Condition 1 in Table 1. Specifically, the laser irradiation conditions were a power of 10.75 W, a scan speed of 300 mm / s, a pulse frequency of 250 kHz, and a fill interval of 0.018 mm. To form the decorative pattern, five printing passes were performed. Note that only a single coating was performed; the rectangular outline was not printed. In the laser-irradiated area, the hardened layer 34 and adhesive layer 38 were completely removed in the depth direction D. The exposed surface after the hardened layer 34 and adhesive layer 38 were removed was oxidized, forming an oxide layer 36 containing titanium oxide. Meanwhile, the hardened layer 34 remained in the non-laser-irradiated area. The surface of the substrate 32 was covered with a first region 34R, where the remaining hardened layer 34 was exposed, and a second region 36R, where the newly formed oxide layer 36 was exposed. Furthermore, the oxide layer 36 constituting the second region 36R exhibited a blue structural color. In this manner, the decorative member 3'-1 was manufactured.

[0060] Reference Example 1-1 A decorative member of Reference Example 1-1 was produced. Titanium plate (JIS-2 type) was used as the substrate. Laser processing was performed on the substrate, replacing a portion of the substrate with an oxide layer. The laser processing was performed by irradiating the substrate with a laser (YVO4 laser) in the atmosphere using a known laser marker as a processing device. The laser irradiation area was set so as to obtain a 10 mm x 10 mm rectangular area as the decorative pattern. The laser irradiation conditions were Condition 1 in Table 1. Specifically, the laser irradiation conditions were a power of 10.75 W, a scan speed of 300 mm / s, a pulse of 250 kHz, and a fill interval of 0.018 mm. To form the decorative pattern, printing was performed five times. Note that only coating was performed; the outline of the rectangle was not printed. In the laser-irradiated area, a portion of the substrate was removed, and the exposed surface was oxidized, forming an oxide layer containing titanium oxide. On the other hand, the area that was not irradiated with the laser remained as the base material. The oxide layer also developed a blue color due to the structural color. In this way, a decorative member was produced.

[0061]

[0062] <Evaluation Method and Results> [Depth Composition Analysis] The prepared decorative member was subjected to depth composition analysis using X-ray photoelectron spectroscopy (XPS). Specifically, the first and second regions of the decorative member were analyzed. An X-ray photoelectron spectrometer (model: Nexsa, manufactured by Thermo Fisher Scientific) was used to obtain narrow spectra of Ti, O, N, C, and Si, which are thought to be contained as constituent elements. Analysis conditions: X-ray source AlKα, irradiation beam system 20 μmφ, neutralization gun, Snap measurement. Sputtering conditions: Ar ions 3 eV, raster size 1 mm, 20 sec cycle. Reference etching rate: SiO2 1.09 nm / sec.

[0063] Figure 10 shows the results of a depth-direction composition analysis of the first region 14R of decorative member 1-1 by X-ray photoelectron spectroscopy (XPS). Figure 11 shows the results of a depth-direction composition analysis of the second region 16R of decorative member 1-1 by X-ray photoelectron spectroscopy (XPS). Figure 12 shows the results of a depth-direction composition analysis of the first region 24R of decorative member 2'-1 by X-ray photoelectron spectroscopy (XPS). Figure 13 shows the results of a depth-direction composition analysis of the second region 26R of decorative member 2'-1 by X-ray photoelectron spectroscopy (XPS). Figure 14 shows the results of a depth-direction composition analysis of the second region 26R of decorative member 2'-2 by X-ray photoelectron spectroscopy (XPS). Figure 15 shows the results of a depth-direction composition analysis of the laser-irradiated region of the decorative member of Reference Example 1-1 by X-ray photoelectron spectroscopy (XPS).

[0064] In Figure 11, from the oxygen profile in the range of 0 to 15,000 times, this range is thought to be oxide layer 16. Furthermore, oxygen and nitrogen were detected in the range of 15,000 to 20,000 times, so this range is thought to be hardened layer 14. In Figure 13, N and O were detected in the range of 15,000 to 20,000 times, so it is thought that the analysis did not reach substrate 22 in Figure 5. In Figure 14, almost only Ti was detected in the range of 15,000 to 20,000 times, which is thought to correspond to substrate 22 in Figure 4.

[0065] It can be seen that titanium oxide with nitrogen dissolved therein is formed in the second region 16R of decorative member 1-1, the second region 26R of decorative member 2'-1, the second region 26R of decorative member 2'-2, and the regions of the decorative member of reference example 1-1 that were irradiated with the laser.

[0066] [Hardness Measurement] The prepared decorative members were measured for hardness using a hardness measuring device (model: Fischer Nanoindenter HM-2000, manufactured by Fischer Instruments GmbH) with loads of 5 mN and 20 mN selected for measuring the hardness of the surface layer, and 500 mN, which is approximately the same as the 50 g Vickers hardness measurement condition for surface-nitrided samples. Specifically, for the decorative members of the examples, the hardened layer constituting the first region and the oxidized layer constituting the second region were measured, and for the decorative members of the reference examples, the substrate and oxidized layer were measured.

[0067] [Measurement of Recess Depth] The depth of the recess in the second region of the prepared decorative member was measured using a stylus-type step gauge (model: α-Step IQ, manufactured by KLATencor). The measurement load was set to 10 mg, the scan speed was set to 20 μm / sec, and the recess depth was measured by scanning from the first region to the second region and measuring the step. Table 2 shows the measurement results for the hardness measurement and the depth measurement of the recess in the second region.

[0068]

[0069] A comparison of the measured values ​​of the hardened layer constituting the first region and the oxidized layer constituting the second region of decorative member 1-1 with the measured values ​​of the substrate of decorative member of Reference Example 1-1 reveals that the hardened layer constituting the first region and the oxidized layer constituting the second region of decorative member 1-1 are harder than the substrate. The same is true for decorative members 2'-1 and 3'-1.

[0070] [Abrasion Resistance Test] When the decorative members were subjected to an abrasion resistance test, no significant changes were observed in the appearance of the oxidized layer in any of the decorative members produced in the examples. In other words, the decorative members according to the embodiments were able to suppress changes in the color of the oxidized layer and the occurrence of scratches during the abrasion resistance test. The abrasion resistance test was conducted by rubbing the unused side of a sand eraser against the surface of the decorative member with a predetermined load and a predetermined number of strokes. Furthermore, the presence or absence of scratches on the surface of the decorative member after the abrasion resistance test, and the extent of any scratches that occurred, were evaluated by visual observation.

[0071] The present invention relates to the following: [1] A decorative member in which a substrate is covered with a first region composed of a hardened layer and a second region composed of an oxide layer, the hardened layer constituting the first region and the oxide layer constituting the second region being harder than the substrate, and the oxide layer constituting the second region exhibits a structural color. [2] The decorative member described in [1], in which the oxide layer constituting the second region is harder than the hardened layer constituting the first region. [3] The decorative member described in [1] or [2], in which the substrate contains titanium, and the oxide layer is a layer containing titanium oxide with nitrogen as a solid solution. [4] The decorative member described in [1] or [2], in which the substrate contains titanium, and the hardened layer is a layer containing titanium with nitrogen and oxygen as a solid solution. [5] The decorative member described in [1] or [2], in which the hardened layer is a layer containing diamond-like carbon. [6] The decorative member described in [1] or [2], in which the hardened layer is a layer containing titanium carbide. [7] The decorative member according to [1] or [2], wherein the second region is recessed toward the substrate relative to the first region. [8] A method for manufacturing a decorative member, comprising the steps of: forming a hardened layer on a substrate; and performing laser processing on the substrate with the hardened layer formed thereon to remove the hardened layer and form an oxide layer, wherein the substrate is covered with a first region formed by the hardened layer and a second region formed by the oxide layer, the hardened layer forming the first region and the oxide layer forming the second region being harder than the substrate, and the oxide layer forming the second region exhibits a structural color.

[0072] 1, 2, 2', 3, 3' Decorative member, 12, 22, 32 Base material, 14, 24, 34 Hardened layer, 14R, 24R, 34R First region, 16, 26, 36 Oxidized layer, 16R, 26R, 36R Second region, 16r, 26r, 36r Recess, 281 First adhesive layer, 282 Second adhesive layer, 38 Adhesion layer

Claims

1. A decorative component in which a base material is covered with a first region made of a hardened layer and a second region made of an oxidized layer, the hardened layer making up the first region and the oxidized layer making up the second region are harder than the base material, and the oxidized layer making up the second region exhibits a structural color.

2. The decorative member according to claim 1, wherein the oxidized layer constituting the second region is harder than the hardened layer constituting the first region.

3. The decorative member according to claim 1 or 2, wherein the substrate contains titanium, and the oxide layer is a layer containing titanium oxide in which nitrogen has formed a solid solution.

4. The decorative member according to claim 1 or 2, wherein the substrate contains titanium, and the hardened layer is a layer containing titanium in which nitrogen and oxygen have formed a solid solution.

5. The decorative member according to claim 1 or 2, wherein the hardened layer is a layer containing diamond-like carbon.

6. The decorative member according to claim 1 or 2, wherein the hardened layer is a layer containing titanium carbide.

7. A decorative member according to claim 1 or 2, wherein the second region is recessed closer to the base material than the first region.

8. A method for manufacturing a decorative member, comprising: a step of forming a hardened layer on a substrate; and a step of performing laser processing on the substrate on which the hardened layer has been formed to remove the hardened layer and form an oxide layer, wherein the substrate is covered with a first region made up of the hardened layer and a second region made up of the oxide layer, the hardened layer making up the first region and the oxide layer making up the second region being harder than the substrate, and the oxide layer making up the second region exhibits a structural color.

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