Surface smoothed metal member

Abstract

This invention provides a surface-smoothed metal component and a simple and efficient manufacturing method thereof. The surface of a large metal component made of titanium or titanium alloy is smoothed until the maximum height roughness (Rz) of the flat portion is less than 1.1 μm, and the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm. The manufacturing method of the surface-smoothed metal component of this invention involves anodizing a substrate made of titanium or titanium alloy to form an anodized film on the surface of the substrate, and then removing the anodized film to smooth the surface of the substrate.

Description

Technical Field

[0001] This invention relates to a titanium or titanium alloy metal component requiring surface smoothing and a method for manufacturing the same. Prior Technology

[0002] In addition to being lightweight, titanium and titanium alloys also have excellent corrosion resistance and high specific strength, and are widely used in various applications such as structural components of aircraft and bicycles, engine parts, optical components, electronic components and decorations.

[0003] In this context, especially in optical components and decorative items, the condition of the component surface is of great importance, and methods for smoothing the surface of components made of titanium or titanium alloys are constantly being reviewed.

[0004] For example, Patent Document 1 (Japanese Patent Application Publication No. 2008-223139) discloses an electropolishing and / or electrochemical deburring method for electropolishing and / or electrochemically deburring the surface of titanium or titanium alloys. The electrolyte used contains methanesulfonic acid and one or more alkane-diphosphonic acids, which can be selectively replaced with hydroxyl and / or amino groups.

[0005] In the electropolishing and / or electrochemical deburring method described in the aforementioned Patent Document 1, the electrolyte used is non-flammable, especially non-corrosive, and easy to handle. In general operation, it does not pose a high risk to people working in or around the electropolishing plant, nor does it pose a high risk to the environment. In particular, the electrolyte described herein does not produce toxic gases or vapors.

[0006] Furthermore, Patent Document 2 (Japanese Patent Application Publication No. 2004-43850) discloses an etching method for titanium or titanium alloys, which involves treating the material with an aqueous solution containing (a) 5-30 wt% hydrogen peroxide, (b) 1-20 wt% fluoride, (c) 1-10 wt% of at least one selected from sulfuric acid, nitric acid, and phosphoric acid, and (d) 0.001-0.1 wt% fluorine-based surfactant, wherein the weight ratio of [(a) hydrogen peroxide concentration] to [(b) fluoride fluoride concentration] is 1.5-3.0.

[0007] In the etching method for titanium or titanium alloy described in the aforementioned Patent Document 2, etching is performed by adding an aqueous solution containing hydrogen peroxide, fluoride, inorganic acid and fluorine surfactant, thereby simultaneously achieving the removal and smoothing of surface oxides on titanium or titanium alloy. [Previous Technical Documents] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2008-223139 [Patent Document 2] Japanese Patent Application Publication No. 2004-43850 Summary of the Invention

[0009] [The problem that the invention aims to solve]

[0010] However, in the electropolishing and / or electrochemical deburring method described in the aforementioned Patent Document 1, although a good working environment is obtained, it is not improved in terms of smoothness compared to the prior art, even if it is not better.

[0011] Furthermore, in the etching method for titanium or titanium alloy described in the aforementioned Patent Document 2, although surface oxide removal and smoothing can be achieved simultaneously, the surface roughness obtained through smoothing is about 0.4 μm, which is insufficient to meet the requirements of higher smoothness.

[0012] Furthermore, obtaining a good smooth surface using the methods described in Patent Documents 1 and 2 is difficult within a relatively narrow range, as it is challenging to efficiently reduce foreign matter and achieve a mirror-like finish across the entire surface of large metal components. Moreover, smoothing the inner surfaces of metal components with corners having extremely small radii of curvature, or with openings or through holes, is extremely difficult.

[0013] In view of the problems in the prior art as described above, the present invention aims to provide a surface-smoothed metal component and a simple and efficient manufacturing method thereof, wherein the surface of a large metal component made of titanium or titanium alloy is smoothed until the maximum height roughness (Rz) of the flat portion is less than 1.1 μm, and the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm.

[0014] Furthermore, the present invention also aims to provide a surface-smoothed metal component and a simple and efficient manufacturing method thereof, which can smooth even large metal components, metal components made of titanium or titanium alloy with openings or through holes, until the maximum height roughness (Rz) of the inner wall of the through holes and openings is less than 2 μm. [Methods used to solve problems]

[0015] In order to achieve the above-mentioned objective, the inventors have repeatedly studied the surface smoothing method for metal components made of titanium or titanium alloys and found that it is extremely effective in removing the anodic oxide film formed under appropriate conditions, thus achieving the present invention.

[0016] That is, the present invention also provides a surface-smoothed metal component. Metal components made of titanium or titanium alloys, The maximum length of the aforementioned metal components is 50~1000mm. The maximum height roughness (Rz) of the flat portion of the aforementioned metal component is less than 1.1 μm. The maximum height roughness (Rz) of the portion of the surface of the aforementioned metal component with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm.

[0017] The maximum length of the metal component is preferably 50 to 1000 mm, more preferably 100 to 500 mm. While smoothing the entire surface of a large metal component using conventional methods is difficult, the surface-smoothed metal component of this invention achieves a maximum height roughness (Rz) of less than 1.1 μm for the flat portion, even for a metal component with a maximum length of 50 mm or more, and a maximum height roughness (Rz) of less than 2 μm for the portion with a radius of curvature of 0.05 to 2.5 mm. Furthermore, by making the maximum length of the metal component 1000 mm or less, it is also possible to reliably ensure that the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm.

[0018] The surface-smoothing metal component of the present invention preferably has through holes and / or openings, and the maximum height roughness (Rz) of the inner wall of the through holes and / or openings is less than 2 μm. In conventional surface-smoothing metal components, the area with a good smooth surface is limited, especially the inner wall of through holes and openings, which is extremely difficult to smooth. However, in the surface-smoothing metal component of the present invention, the entire surface is sufficiently smoothed.

[0019] Furthermore, the present invention also provides a surface-smoothed metal component. Metal components made of titanium or titanium alloys, The maximum length of the aforementioned metal components is 50~1000mm. The arithmetic mean roughness (Ra) of the portion of the surface of the aforementioned metal component with a radius of curvature of 0.05 to 2.5 mm is less than 0.4 μm.

[0020] The maximum length of the metal component is preferably 50 to 1000 mm, more preferably 100 to 500 mm. While smoothing the entire surface of a large metal component using conventional methods is difficult, the surface-smoothed metal component of the present invention, even with a maximum length of 50 mm or more, still achieves an arithmetic mean roughness (Ra) of less than 0.4 μm for the portion of the component surface with a radius of curvature of 0.05 to 2.5 mm. Furthermore, by limiting the maximum length of the metal component to 1000 mm or less, it is reliably possible to ensure that the arithmetic mean roughness (Ra) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 0.4 μm.

[0021] The surface-smoothed metal component of the present invention preferably has through holes and / or openings, and the arithmetic mean roughness (Ra) of the inner walls of the through holes and / or openings is less than 0.4 μm. In conventional surface-smoothed metal components, the area with a good smooth surface is limited, especially the inner walls of through holes and openings, which are extremely difficult to smooth. However, in the surface-smoothed metal component of the present invention, the entire surface is sufficiently smoothed.

[0022] In the surface-smoothing metal component of the present invention, the equivalent circular diameter of the aforementioned through-hole and / or the aforementioned opening portion is preferably 0.1 to 5 mm. A more preferred equivalent circular diameter is 0.2 to 2 mm, and the most preferred is 0.5 to 1 mm. Even in the case of fine through-holes and / or opening portions with an equivalent circular diameter of 5 mm or less, the arithmetic mean roughness (Ra) and maximum height roughness (Rz) of the inner surface can be sufficiently reduced in the surface-smoothing metal component of the present invention. Furthermore, when the equivalent circular diameter of the through-hole and / or opening portion is 0.1 mm or more, the variability of the arithmetic mean roughness (Ra) and maximum height roughness (Rz) of the inner wall can be reduced.

[0023] Furthermore, in the surface-smoothing metal component of the present invention, the depth of the aforementioned through-hole and / or the aforementioned opening portion is preferably 1 to 50 mm. More preferably, the depth of the opening portion is 1 to 10 mm, and most preferably, the depth of the opening portion is 2 to 8 mm. In the surface-smoothing metal component of the present invention, even when deep through-holes and / or opening portions with a depth of 1 mm or more are formed, the arithmetic mean roughness (Ra) and maximum height roughness (Rz) of the inner surface can still be sufficiently reduced. Furthermore, when the depth of the through-hole and / or opening portion is 50 mm or less, the variability of the arithmetic mean roughness (Ra) and maximum height roughness (Rz) of the inner wall can be reduced.

[0024] Furthermore, in the surface-smoothing metal component of the present invention, the aforementioned metal component is preferably a frame. By making the metal component a frame, it can be suitably used, for example, as a protective film frame.

[0025] Furthermore, the present invention also provides a method for manufacturing a surface-smoothed metal component. Anodizing is performed on a substrate made of titanium or titanium alloy to form an anodized film on the surface of the substrate. The aforementioned anodic oxide film is detached, thereby smoothing the surface of the aforementioned substrate.

[0026] In the manufacturing method of the surface-smoothed metal component of the present invention, the formation of an anodized film consumes the protrusions on the surface of the substrate (the surface of the metal component), resulting in smoothing progress, and a surface smoothed by the detachment of the anodized film can be obtained. Furthermore, foreign matter adhering to the surface of the substrate is removed by the detachment of the anodized film, thus obtaining a clean surface. Moreover, the anodized film can also be formed on large substrates, enabling the smoothing of the surface of large metal components.

[0027] Furthermore, in the manufacturing method of the surface-smoothed metal component of the present invention, it is preferable that the thickness of the aforementioned anodic oxide film is 2 to 10 μm. More preferably, the thickness of the anodic oxide film is 4 to 6 μm, so that in addition to efficiently consuming the protrusions on the substrate surface, the anodic oxide film can be naturally detached without performing any special procedures.

[0028] Furthermore, in the manufacturing method of the surface-smoothed metal component of the present invention, it is preferable to apply a voltage of 20 to 100V during the aforementioned anodizing process. The anodizing conditions are not particularly limited as long as they do not impair the effect of the present invention. Although various known processing conditions can be used, it is more preferable to apply a voltage of 40 to 50V, so that in addition to efficiently consuming the protrusions on the substrate surface, the anodized film can be naturally detached without performing any special procedures.

[0029] Furthermore, in the manufacturing method of the surface-smoothed metal component of the present invention, preferably, the formation and removal of the aforementioned anodic oxide film are repeated on the aforementioned surface of the aforementioned substrate until an arithmetic mean roughness (Ra) of less than 0.4 μm and / or a maximum height roughness (Rz) of less than 2 μm is obtained.

[0030] The smoothing of the substrate surface is achieved through the formation and removal of the anodic oxide film. By repeating this process, an arithmetic mean roughness (Ra) of less than 0.4 μm and / or a maximum height roughness (Rz) of less than 2 μm can be reliably obtained on the substrate surface. [Invention Benefits]

[0031] According to the present invention, a surface-smoothed metal component and a simple and efficient manufacturing method thereof are provided. The surface of a large metal component made of titanium or titanium alloy is smoothed until the maximum height roughness (Rz) of the flat portion is less than 1.1 μm, and the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm. Furthermore, according to the present invention, a surface-smoothed metal component and a simple and efficient manufacturing method thereof are provided, even for large metal components, and for titanium or titanium alloy metal components with openings or through holes, smoothing is achieved until the maximum height roughness (Rz) of the inner wall of the through hole or opening is less than 2 μm. Simple Explanation of the Diagram

[0032] [Figure 1] is a schematic diagram of the protective film frame of a surface-smoothing metal component of the present invention. [Figure 2] is the B-B' cross-sectional view of Figure 1. [Figure 3] is a schematic diagram of the surface smoothing procedure in this invention. [Figure 4] shows SEM images of the surface of the protective film frame substrate before anodizing, the surface of the anodized film, and the surface of the protective film frame substrate after the anodized film has been removed. [Figure 5] is a cross-sectional SEM image of the anodic oxide film and the substrate used for the protective film frame after detachment. [Figure 6] shows SEM images of the substrate surface, the surface of the anodized film, and the cross-section of the anodized film after the anodized film has been removed under various voltage conditions. [Figure 7] shows SEM images of the side of the through hole before and after the anodized film is removed. [Figure 8] is a schematic diagram showing the measurement lines for the maximum height roughness (Rz) and the arithmetic mean roughness (Ra). [Figure 9] shows the microscopic images of the surface of pure titanium square material before and after anodizing treatment. [Figure 10] shows the microscopic images of the inner surface of the through hole before and after anodizing. [Figure 11] shows SEM images of the inner surface of the through hole before and after anodizing. Implementation

[0033] Hereinafter, although a pellicle frame is used as a representative example of a surface-smoothing metal component, a representative embodiment of the surface-smoothing metal component and its manufacturing method according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, some or all of the constituent elements in the embodiments may be combined as appropriate. Additionally, in the following description, the same or equivalent parts are sometimes labeled with the same symbols, and repeated descriptions are omitted. Furthermore, in the drawings, since they are for the purpose of conceptually illustrating the present invention, the dimensions and proportions of the constituent elements shown may sometimes differ from the actual dimensions.

[0034] 1. Surface-smoothed metal components Figure 1 shows a schematic diagram of a protective film frame, which is a surface-smoothing metal component of the present invention. The protective film frame 1 is made of titanium or titanium alloy, and its entire surface is smoothed.

[0035] The maximum length of the protective film frame 1 is 50 to 1000 mm. Here, the maximum length of the protective film frame 1 is the length of the diagonal line indicated by A in Figure 1. The maximum length is preferably 100 to 500 mm, and more preferably 150 to 300 mm. Although it is difficult to smooth the entire surface of a large metal component using conventional methods, with the protective film frame 1, even when the maximum length is 50 mm or more, the maximum height roughness (Rz) of the flat portion of the surface is still less than 1.1 μm, and the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm. Furthermore, by making the maximum length of the protective film frame 1 1000 mm or less, it is possible to reliably ensure that the maximum height roughness (Rz) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm.

[0036] Furthermore, even when the maximum length of the protective membrane frame 1 is 50 mm or more, the arithmetic mean roughness (Ra) of the portion with a radius of curvature of 0.05 to 2.5 mm is still less than 0.4 μm. Moreover, by keeping the maximum length to 1000 mm or less, it is reliably possible to ensure that the arithmetic mean roughness (Ra) of the portion with a radius of curvature of 0.05 to 2.5 mm is less than 0.4 μm.

[0037] The protective membrane frame 1 has through holes and / or openings, preferably with a maximum vertical roughness (Rz) of less than 2 μm and an arithmetic mean roughness (Ra) of less than 0.4 μm on the inner wall of the through holes and / or the aforementioned openings. Figure 1 shows the case where there are through holes 2, and Figure 2 shows the B-B' cross-sectional view of Figure 1. The inner surface of the through hole 2, indicated by the dotted line, is also sufficiently smoothed, with a maximum vertical roughness (Rz) of less than 2 μm and an arithmetic mean roughness (Ra) of less than 0.4 μm.

[0038] The equivalent circular diameter (R in FIG2) of the opening portion of the through hole 2 is preferably 0.1 to 5 mm. A more preferred equivalent circular diameter is 0.2 to 2 mm, and the most preferred is 0.5 to 1 mm. Even when the through hole 2 with an equivalent circular diameter of 5 mm or less is formed in the protective membrane frame 1, the maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the inner surface can still be significantly reduced. Furthermore, when the equivalent circular diameter of the through hole 2 is 0.1 mm or more, the variability of the maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the inner wall can be reduced.

[0039] Furthermore, the depth of the through hole 2 (D in FIG. 2) is preferably 1 to 50 mm. A more preferred depth is 1 to 10 mm, and a most preferred depth is 2 to 8 mm. For the protective membrane frame 1, even when a deep through hole of 1 mm or more is formed, the maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the inner surface can be sufficiently reduced. Furthermore, when the depth of the through hole 2 is 50 mm or less, the variability of the maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the inner wall can be reduced.

[0040] The shape of the protective film frame 1 is not particularly limited as long as it does not impair the effect of the present invention. It can take various shapes known in the past, depending on the shape of the original exposure plate. Generally speaking, the planar shape of the protective film frame 1 is ring-shaped, rectangular, or square, and it has the size and shape to cover the circuit pattern portion provided on the original exposure plate.

[0041] The height (thickness) of the protective film frame 1 is preferably 0.5~10mm, more preferably 1~7mm, and most preferably 1.0~3.0mm. Making the height (thickness) of the protective film frame 1 to this value can suppress deformation of the protective film frame 1 while ensuring good handling properties.

[0042] The cross-sectional shape of the protective film frame 1 is not particularly limited without impairing the effects of the present invention, and various known shapes may be used. However, it is preferred that the upper and lower sides be parallel quadrilaterals. The upper side of the protective film frame 1 needs to provide width for applying the protective film, and the lower side needs to provide width for applying the adhesive layer for bonding to the exposure master. For this reason, the upper and lower widths of the protective film frame 1 are preferably about 1 to 3 mm.

[0043] The protective membrane frame 1 is made of titanium or titanium alloy, thus possessing higher strength and Young's modulus compared to the commonly used aluminum alloy protective membrane frames. Furthermore, titanium and titanium alloys have a relatively low specific gravity of approximately 4.5, which helps to prevent an increase in the weight of the protective membrane frame 1.

[0044] Furthermore, the protective membrane frame 1 is made of titanium or titanium alloy, which has a lower coefficient of linear expansion than aluminum, effectively suppressing warping during heating. In addition, titanium or titanium alloy is a metallic material, possessing superior toughness compared to ceramics and superhard alloys, making it easy to process. Moreover, besides reducing manufacturing costs due to its good machinability, the protective membrane frame 1 can be given high dimensional accuracy.

[0045] Furthermore, when the surface-smoothing metal component of the present invention is a various optical component, the coefficient of linear expansion of the optical component is preferably 6×10⁻⁶ to 11×10⁻⁶ / K. Making the coefficient of linear expansion 6×10⁻⁶ K or higher ensures that the coefficient of thermal expansion of the optical component is close to that of the material made of ceramic, silicon, etc. This reduces distortion and breakage caused by the difference in deformation due to thermal expansion when the optical component and the component made of ceramic, silicon, etc., increase in temperature. For example, an optical component used as a lens holder and a component made of ceramic, silicon, etc., used as a lens in a camera, etc. Furthermore, making the coefficient of linear expansion 11×10⁻⁶ K or lower reduces distortion during heating. A coefficient of linear expansion of 7×10⁻⁶ to 10×10⁻⁶ / K is more preferred, and a coefficient of linear expansion of 8×10⁻⁶ to 9×10⁻⁶ / K is most preferred. In this specification, the coefficient of linear expansion is considered to be a value expressed in the temperature range of 0 to 100°C. Such coefficients of linear expansion can be achieved, for example, by making optical components of titanium or titanium alloys.

[0046] The titanium alloy used for the protective membrane frame 1 is not particularly limited, and various well-known titanium alloys can be used as long as it does not impair the effect of the present invention. Examples of titanium alloys include Ti-6Al-4V alloy, Ti-6Al-6V-2Sn alloy, Ti-6Al-2Sn-4Zr-6Mo alloy, Ti-10V-2Fe-3Al alloy, Ti-7Al-4Mo alloy, Ti-5Al-2.5Sn alloy, Ti-6Al-5Zr-0.5Mo-0.2Si alloy, and Ti-5.5Al-3.5Sn-3Zr-0.3Mo-1Nb-0.3S. Ti-8Al-1Mo-1V alloy, Ti-6Al-2Sn-4Zr-2Mo alloy, Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy, Ti-11.5Mo-6Zr-4.5Sn alloy, Ti-15V-3Cr-3Al-3Sn alloy, Ti-15Mo-5Zr-3Al alloy, Ti-15Mo-5Zr alloy, or Ti-13V-11Cr-3Al alloy, etc.

[0047] When considering the importance of machinability and corrosion resistance, pure titanium is preferred. Based on the viewpoint of achieving both high strength and good machinability, α+β type alloy is preferred. Furthermore, based on the viewpoint of material price and ease of acquisition, Ti-6Al-4V alloy is a better choice.

[0048] In the above embodiments, although the protective film frame 1 has been described as a surface-smoothed metal component, the surface-smoothed metal component is not limited to this. For example, it can also be made into various optical components, such as protective film frames, lens holders, tubes, shades, and reflectors.

[0049] 2. Manufacturing method for surface-smoothed metal components When manufacturing a surface-smoothed protective film frame 1 using the manufacturing method of the surface-smoothed metal component of the present invention, anodizing treatment is performed on a frame made of titanium or titanium alloy to form an anodized film on the surface of the frame, and the anodized film is detached to smooth the surface of the frame.

[0050] Figure 3 shows a schematic diagram of the surface smoothing process. The formation of the anodic oxide film consumes the protrusions on the frame surface, leading to smoothing progress. A smoothed surface is obtained due to the detachment of the anodic oxide film. Furthermore, foreign matter adhering to the frame surface is removed due to the detachment of the anodic oxide film, thus obtaining a clean surface.

[0051] While it is extremely difficult to smooth the surface of large components uniformly and easily using conventional surface smoothing methods, the use of anodizing makes it possible to smooth the entire surface of a large protective film frame 1 with a maximum length of 50 to 1000 mm.

[0052] Furthermore, the thickness of the anodic oxide film formed on the surface of the frame is preferably 2 to 10 μm. More preferably, the thickness of the anodic oxide film is 4 to 6 μm, which allows the protrusions on the frame surface to be efficiently consumed, and the anodic oxide film to detach naturally without special procedures. Alternatively, if the anodic oxide film remains, it can also be removed by applying ultrasonic vibration, reverse electrolysis, or other methods.

[0053] Furthermore, the applied voltage during the anodizing process is preferably set to 20-100V. The anodizing conditions are not particularly limited as long as they do not impair the effect of the present invention. Although various known processing conditions can be used, it is more preferred to apply a voltage of 40-50V, so that in addition to the efficient consumption of the protrusions on the surface of the frame, the anodized film can be naturally detached without performing any special procedures.

[0054] Furthermore, if the maximum vertical roughness (Rz) of the frame surface is 2 μm or more after a single anodized film formation and removal, it is preferable to repeat the formation and removal of the anodized film until this value becomes less than 2 μm. The smoothing of the frame surface is achieved through the formation and removal of the anodized film; therefore, by repeating this process, the maximum vertical roughness (Rz) of the substrate surface can be reliably reduced to less than 2 μm.

[0055] Furthermore, if the arithmetic mean roughness (Ra) of the frame surface is 0.4 μm or more after a single anodized film formation and removal, it is preferable to repeatedly form and remove the anodized film until this value becomes less than 0.4 μm. The smoothing of the frame surface is achieved through the formation and removal of the anodized film; therefore, by repeating this process, the arithmetic mean roughness (Ra) of the substrate surface can be reliably reduced to less than 0.4 μm.

[0056] While the above description focuses on representative embodiments of the present invention, the present invention is not limited thereto, and various design changes can be made, all of which are included within the technical scope of the present invention. [Example]

[0057] <Example 1> A substrate for the protective film frame was fabricated by cutting out a frame made of pure titanium with a long side of 160mm and a short side of 130mm. The substrate for the protective film frame has the same thickness and width, which are 1mm and 4mm respectively.

[0058] The obtained protective film frame substrate was subjected to anodizing treatment, forming an anodized film over the entire surface area. The anodizing conditions were as follows: an aqueous solution containing 5 g / L ammonium fluoride and 134 g / L ammonium sulfate was used as the anodizing bath, and the treatment was carried out at a bath temperature of 55°C and a voltage of 30~80V for 15 minutes.

[0059] For the case where the voltage is 45V, scanning electron microscope (SEM) images of the substrate surface before anodizing, the surface of the anodized film, and the surface of the substrate surface after the anodized film has detached are shown in Figure 4. Furthermore, SEM images of the detached anodized film and a cross-section of the substrate surface in the detached area are shown in Figure 5. Here, almost all of the anodized film detached naturally during the anodizing process.

[0060] It can be seen that the surface of the substrate for the protective film frame is significantly smoothed due to the removal of the anodized film, resulting in a smooth surface completely free of foreign matter. Furthermore, cross-sectional photographs confirm that the surface roughness of the substrate is less than 0.4 μm. This smooth surface is formed over the entire surface area of ​​the substrate for the protective film frame.

[0061] Figure 6 shows SEM images of the substrate surface, the surface of the anodized film, and the cross-section of the anodized film after detachment from the substrate substrate subjected to anodizing treatment at various voltages. Furthermore, the film thickness and detachment status of the anodized film were evaluated, and the results are also shown. Additionally, no spontaneous detachment of the anodized film was observed at a voltage of 30V.

[0062] Figure 6 shows that a suitable voltage range exists for the natural detachment of the anodic oxide film; an applied voltage of 40–50 V promotes detachment. Furthermore, the thickness of the anodic oxide film also affects the natural detachment phenomenon; a film thickness of 4–6 μm promotes detachment.

[0063] <Example 2> Except for the cylindrical through-hole with a diameter of 800 μm provided in the thickness direction of the substrate for the protective film frame, the process is the same as in Example 1, and an anodizing treatment is performed at a voltage of 45V for 10 minutes.

[0064] Figure 7 shows SEM images of the through-hole side before and after anodizing. Compared to before anodizing, the surface after anodizing is significantly smoother.

[0065] <Example 3> A square section of pure titanium, measuring 40mm × 4mm × 1mm, was cut out. A through hole with a diameter of 0.8mm was made on the 40mm × 1mm side, extending to the back side. Next, after physical polishing to remove burrs, the surface of the square section was chemically polished using a chemical polishing solution (TCP-08) at 30°C for 10 seconds. Following this, an anodizing treatment was performed for 10 minutes at 45V, identical to that in Example 1.

[0066] The maximum height roughness (Rz) and arithmetic mean roughness (Ra) of a 40 mm × 1 mm surface and the inner surface of a through-hole were measured before anodizing (after chemical polishing) and after anodizing (after the anodized film detachment). White light interferometry was used for the measurements. Figure 8 schematically shows the measurement lines of the 40 mm × 1 mm surface. The longitudinal measurement line is 322 μm long, and the transverse measurement line is 244 μm long. Furthermore, the measurement line for the inner surface of the through-hole is 322 μm long in the axial direction. Measurements were performed in three regions across nine fields of view, and the average of a total of 27 measurements was calculated. The results are shown in Table 1.

[0067]

[0068] The removal of the anodic oxide film reduces both the maximum vertical roughness (Rz) and the arithmetic mean roughness (Ra). It is observed that the maximum vertical roughness (Rz) of the flat surface becomes less than 1.1 μm, and the maximum vertical roughness (Rz) of the inner surface of the through-hole becomes less than 2 μm. Furthermore, after anodizing, the arithmetic mean roughness (Ra) becomes less than 0.4 μm across the entire measurement area.

[0069] The surface conditions before anodizing (after chemical polishing) and after anodizing (after the anodized film detachment) were observed using scanning electron microscopy (SEM) and a microscope. The microscope image of the 40mm × 1mm surface is shown in Figure 9, the microscope image of the inner surface of the through-hole is shown in Figure 10, and the SEM image of the inner surface of the through-hole is shown in Figure 11. It can be seen that in all observation images, the surface is smoothed due to the detachment of the anodized film.

[0070] 1: Protective film frame 2: Through hole

Claims

1. A surface-smoothed metal component, which is a metal component made of titanium or titanium alloy, wherein the maximum length of the metal component is 50 to 1000 mm, the maximum height roughness (Rz) of the flat portion of the surface of the metal component is less than 1.1 μm, the maximum height roughness (Rz) of the portion of the surface of the metal component with a radius of curvature of 0.05 to 2.5 mm is less than 2 μm, and the arithmetic mean roughness (Ra) of the portion of the surface of the metal component with a radius of curvature of 0.05 to 2.5 mm is less than 0.4 μm.

2. As in request item 1, a surface-smoothed metal component, wherein, In the aforementioned metal component, there are through holes and / or openings, and the maximum height roughness (Rz) of the inner wall of the aforementioned through holes and / or openings is less than 2 μm.

3. As in request item 1, a surface-smoothed metal component, wherein, In the aforementioned metal component, there are through holes and / or openings, and the arithmetic mean roughness (Ra) of the inner wall of the aforementioned through holes and / or openings is less than 0.4 μm.

4. Surface-smoothed metal components as requested in item 2 or 3, wherein, The equivalent diameter of the aforementioned through hole and / or the aforementioned opening portion is 0.1~5mm.

5. Surface-smoothed metal components as requested in item 2 or 3, wherein, The depth of the aforementioned through hole and / or the aforementioned opening is 1~50mm.

6. A surface-smoothed metal component as described in any of requests 1 to 3, wherein, The aforementioned metal component is a frame.

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