Titanium material and method for manufacturing titanium material

Abstract

This titanium material has a substrate of pure titanium or a titanium alloy, a surface oxide film having an average thickness of 100.0 to 500.0 nm being provided on the substrate. The surface oxide film, when subjected to a depth profile analysis using glow discharge optical emission spectroscopy, exhibits a maximum oxygen concentration of 50.0 atomic% or more, and a ratio of the maximum carbon concentration to the maximum oxygen concentration of 0.50 or less. The chroma C*ab of the surface of the titanium material, as measured in accordance with JIS Z 8781-4: 2013, is 20.0 or more.

Description

Titanium material and method for manufacturing titanium material

[0001] This application claims priority to Japanese Patent Application No. 2024-114662, filed on July 18, 2024, the contents of which are incorporated herein by reference.

[0002] Titanium materials are broadly divided into uncolored materials that exhibit the silver color of metallic titanium and colored materials that exhibit interference colors. Colored materials develop their color through the optical interference effect of a surface oxide film formed on the surface, and are produced by controlling the thickness of the surface oxide film using techniques such as anodization. Conventionally, when producing colored materials by anodization, the saturation of the titanium material surface is low when an applied voltage of 50 V or higher is applied, and the color is perceived as dull.

[0003] Conventional techniques for addressing saturation decline include a technique for controlling the constituent elements of the surface oxide film by the composition of the titanium base material (Patent Document 1), and a technique for maintaining a constant electrical resistivity on the same surface by forming titanium nitride (TiN) within a predetermined concentration range on the surface of the titanium material (Patent Document 2), thereby maintaining a constant growth rate of the surface oxide film when a voltage is applied. Furthermore, Patent Document 3 discloses a conventional technique for suppressing discoloration over the long term, which involves controlling the crystalline structure of Ti on the surface.

[0004] Japanese Patent Publication No. 2023-69440 Japanese Patent Publication No. 2022-120642 International Publication No. 2023 / 170979

[0005] Patent Documents 1 and 2 state that a color-developing material with high chroma can be obtained even when an applied voltage is 50 V or higher. However, the technology described in Patent Document 1 is primarily intended for titanium alloys containing Al and Fe, and the technology described in Patent Document 2 requires a special annealing process to form TiN at a predetermined position and within a predetermined range, which increases costs and construction time, leaving room for improvement. Furthermore, the technology described in Patent Document 3 aims to improve discoloration resistance over long-term use, but is unable to achieve high chroma when titanium material is anodized at an applied voltage of 50 V or higher, leaving room for improvement.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a titanium material and a method for producing the titanium material, which can be produced regardless of the composition of the titanium base material, without requiring complex or large-scale equipment, and which can achieve high saturation even when colored by high-voltage anodizing. The term "high-saturation titanium material" as used herein refers to a titanium material that can be produced by immersing it in an acidic aqueous solution of pH 4 or less at room temperature (1 to 40°C), applying a voltage of 50 V or more, and applying a current density of 1.0 to 50.0 mA cm. －２ and the saturation C after anodization with voltage applied for 2 minutes or more ＊ This refers to a titanium material with ab of 20.0 or more.

[0007] The gist of the present invention, which was completed based on the above findings, is as follows: [1] A titanium material according to one aspect of the present invention is a titanium material having a base material of pure titanium or a titanium alloy, and is provided with a surface oxide film having an average thickness of 100.0 to 500.0 nm on the surface of the base material, and when the surface oxide film is measured by depth direction analysis using glow discharge optical emission spectroscopy, the maximum oxygen concentration is 50.0 atomic % or more and the ratio of the maximum carbon concentration to the maximum oxygen concentration is 0.50 or less, and the saturation C of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is ＊ ab is 20.0 or more.

[0008] [2] Another aspect of the present invention provides a titanium material having a base material of pure titanium or a titanium alloy, the base material having a surface oxide film with an average thickness of 5.0 to 50.0 nm on the surface of the base material, and the detection intensity of an ion having an m / z of 49, where m is the molecular weight and z is the valence, obtained when the titanium material is measured by time-of-flight secondary ion mass spectrometry, is expressed as TiH － As the detected intensity of the above TiH － In the depth direction distribution of the detected intensity, TiH － The peak of the detected intensity is within the surface oxide film, and the TiH － The detected intensity of the TiH － The peak detection intensity value of the detection intensity is 5.0 to 100.0.

[0009] [3] Furthermore, a method for producing a titanium material according to yet another aspect of the present invention is a method for producing a titanium material as described in [1] above, which comprises immersing the titanium material as described in [2] above in an acidic aqueous solution at room temperature, pH 4 or less, and applying a voltage of 50 V or more and a current density of 1.0 to 50.0 mA cm －２ and includes an anodization step in which a voltage is applied for 2 minutes or more.

[0010] [4] Furthermore, a method for producing a titanium material according to yet another aspect of the present invention is the method for producing a titanium material according to the above [2], －２ After degassing to a pressure of 0.0 Pa or less, an inert gas containing Group 18 elements having a purity of 99% by volume or more and a dew point of 0 to −50° C. was added in an amount of 5.0×10 －２ [5] The method for producing a titanium material according to [4] above includes an annealing step of annealing the titanium material in a furnace sealed up to a pressure of 1.0 to 6.0 mass % or more. [6] The method for producing a titanium material according to [4] above further includes a pickling step of pickling the titanium material after the annealing step with a solution having a hydrofluoric acid concentration of 1.0 to 6.0 mass % and a nitric acid concentration of 4 to 10 mass %, and pickling the titanium material after the pickling step with a solution having a pH in the range of 4.0 to 7.0 and an electrical conductivity of 6.0 × 10 －５ ~1.0 x 10 －３ S.cm. －１ and the total organic carbon concentration is within 1.0 mg L －１ and a washing step of washing with a washing solution having a temperature of 10 to 60° C. or less.

[0011] According to the above-described aspect of the present invention, production is possible regardless of the composition of the titanium base material, without requiring complex or large-scale equipment, and a titanium material with high saturation can be obtained even when colored by anodizing treatment using high voltage application.

[0012] TiH by TOF-SIMS in Example 1 － 1 is a graph showing the results of quantitative analysis in the depth direction by GDS in Example 2.

[0013] Preferred embodiments of the present invention will be described in detail below. Note that the numerical ranges described below, separated by "to", include the lower and upper limits. Numerical values ​​indicated as "less than" and "greater than" are not included in the numerical range.

[0014] <Coloring Material> A titanium material according to an embodiment of the present invention is a titanium material having a base material of pure titanium or a titanium alloy, and is provided with a surface oxide film having an average thickness of 100.0 to 500.0 nm on the surface of the base material, and when the surface oxide film is measured by depth direction analysis using glow discharge optical emission spectroscopy, the maximum oxygen concentration is 50.0 atomic % or more and the ratio of the maximum carbon concentration to the maximum oxygen concentration is 0.50 or less, and the chroma C of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is 0.001 or less. ＊ The ratio ab is 20.0 or more. The titanium material is a color-developing material. This will be described in detail below. The titanium material according to this embodiment may be referred to as a color-developing titanium material, or simply as a color-developing material.

[0015] The titanium substrate of the color developing material is made of either pure titanium or a titanium alloy, for example, pure titanium or a titanium alloy having a Ti content of 70 mass % or more.

[0016] Pure titanium includes, for example, commercially pure titanium specified by JIS Class 1 to Class 4 and the corresponding ASTM Grades 1 to 4. That is, the commercially pure titanium targeted in this disclosure contains, by mass, C: 0.1% or less, H: 0.015% or less, O: 0.4% or less, N: 0.07% or less, Fe: 0.5% or less, with the balance being Ti and impurities. Note that commercially pure titanium specified by JIS Class 1 or its equivalent ASTM Gr. 1, or equivalent materials, is primarily used in buildings.

[0017] Titanium alloys include α-type titanium alloys, α+β-type titanium alloys, and β-type titanium alloys.

[0018] Examples of α-type titanium alloys include highly corrosion-resistant alloys (titanium alloys specified in JIS standards 11 to 13, 17, 19 to 22, and ASTM standards Grades 7, 11, 13, 14, 17, 30, and 31, as well as titanium alloys containing small amounts of various other elements), Ti-0.5Cu, Ti-1.0Cu, Ti-1.0Cu-0.5Nb, Ti-1.0Cu-1.0Sn-0.3Si-0.25Nb, Ti-0.05Pd, and Ti-0.15Pd.

[0019] Examples of α+β type titanium alloys include Ti-3Al-2.5V, Ti-5Al-1Fe, Ti-5.5Al-1.5Fe-0.2Si, and Ti-6Al-4V.

[0020] Examples of β-type titanium alloys include Ti-11.5Mo-6Zr-4.5Sn, Ti-8V-3Al-6Cr-4Mo-4Zr, Ti-13V-11Cr-3Al, Ti-15V-3Al-3Cr-3Sn, Ti-20V-4Al-1Sn, and Ti-22V-4Al.

[0021] The shape of the color former is not particularly limited and may be a plate, coil, rod, or strip. The color former may also be a processed part such as a plate, coil, rod, or strip. Processed portions of the processed color former, such as pressed portions and crimped portions, also have the characteristics of the color former of the present disclosure. When the color former is a cold-rolled plate, its thickness is, for example, 0.1 mm or more and 5.0 mm or less.

[0022] The surface of the substrate is provided with a surface oxide film having an average thickness of 100.0 to 500.0 nm. In conventional titanium materials, the color saturation C ＊ However, the titanium material according to this embodiment has high chroma even when the average thickness of the surface oxide film is 100.0 to 500.0 nm. The average thickness of the surface oxide film may be set to a thickness that produces the desired color within the range of 100.0 to 500.0 nm.

[0023] The average thickness of the surface oxide film is measured by Glow Discharge Spectrometry (GDS) of the surface oxide film. From the results of the depth direction analysis by GDS, the depth position closest to the surface where the oxygen concentration is half of the maximum oxygen concentration using the O concentration profile is defined as the average thickness of the surface oxide film of the color former.

[0024] In the color-developing titanium material according to this embodiment, when the surface oxide film is measured by GDS depth analysis, the maximum oxygen concentration is 50.0 atomic % or more, and the ratio of the maximum carbon concentration to the maximum oxygen concentration is 0.50 or less. Such a surface oxide film results in a titanium material with uniform color development. The inventors speculate as follows about the reason why the surface oxide film according to this embodiment has a maximum oxygen concentration of 50.0 atomic % or more and a ratio of the maximum carbon concentration to the maximum oxygen concentration of 0.50 or less. First, color development occurs when the oxide film thickness is non-uniform on the same surface. Therefore, in order to make the oxide film thickness uniform, the main reaction during anodization, between Ti and O in the solution, is important. ２－ It is effective to slow down the reaction rate of the above. In the production of the color-developing titanium material according to this embodiment, a non-color-developing material (non-color-developing titanium material according to the embodiment of the present invention) described later is used. The surface oxide film of this non-color-developing material contains a larger amount of TiH than conventional non-color-developing materials. ２ According to conventional knowledge, when anodic polarization is performed on a material whose surface is hydrogenated, a reaction occurs in which the titanium hydride on the outermost surface is oxidized (Tsutsui Mitsunori et al., Journal of the Japan Institute of Metals, 39 (1975), 460-466). Therefore, TiH ２ is decomposed during anodization, and Ti and O ２－ In addition, during anodization, a reaction between Ti and the C contained in the solution also occurs on the anode side. ２ It is presumed that an increase in the decomposition reaction of Ti and C inhibits other reactions, slowing down the growth rate of the surface oxide film, keeping the growth rate of the oxide film on the same surface constant, inhibiting the reaction between Ti and C, and reducing the C concentration. If the maximum oxygen concentration is less than 50.0 atomic %, a surface oxide film of uniform thickness is not formed on the same surface, and sufficient saturation cannot be obtained. On the other hand, if the maximum oxygen concentration is 50.0 atomic % or more, a surface oxide film of almost uniform thickness is formed, and high saturation C is obtained. ＊ Although there is no upper limit on the maximum value of the oxygen concentration, the maximum value of the oxygen concentration is preferably less than 100 mass % because Ti oxide must be formed.

[0025] If compounds other than titanium oxides are formed in the surface oxide film, the interference colors will differ between the areas where titanium oxides are formed and the areas where compounds other than titanium oxides are formed, potentially resulting in variations in color development on the same surface. Because the color-developing titanium material according to this embodiment contains a relatively large amount of carbon due to its manufacturing process, it is important to limit the amount of carbon compounds in order to achieve uniform color development. If the ratio of the maximum carbon concentration to the maximum oxygen concentration is 0.50 or less, the amount of carbon compounds formed will be relatively small, resulting in uniform color development. The lower limit of the ratio of the maximum carbon concentration to the maximum oxygen concentration is not particularly limited, and the ratio may be, for example, 0.01 or greater. Therefore, the ratio of the maximum carbon concentration to the maximum oxygen concentration may be 0.01 to 0.50, 0.10 to 0.50, or 0.20 to 0.50. That is, the ratio of the maximum carbon concentration to the maximum oxygen concentration may be 0.01 or greater, 0.10 or greater, or 0.20 or greater. The ratio of the maximum carbon concentration to the maximum oxygen concentration may be 0.45 or less, or 0.40 or less. The lower limit of the maximum carbon concentration is not particularly limited, but the range possible from a manufacturing standpoint is 1.0 atomic % or more. The amount of compounds of elements other than titanium and carbon is smaller than that of carbon compounds.

[0026] Carbon and oxygen concentration analysis using GDS is performed as follows. GDS measurements are performed in constant power mode at 35 W, with an argon gas pressure of 600 Pa and a discharge range of 4 mm in diameter. The measurement pitch is 2 nm. GDS measurements are performed on the surface of the titanium material, analyzing Ti (titanium), O (oxygen), C (carbon), S (sulfur), P (phosphorus), Al (aluminum), N (nitrogen), and Si (silicon). In addition, intentionally or obviously added elements such as alloying elements are also measured, and the sum of all measured element concentrations (atomic %) is calculated as 100 atomic %. The maximum oxygen concentration is calculated at a depth of 5 nm or deeper from the outermost surface to eliminate the influence of organic matter attached to the outermost surface.

[0027] The color-developing titanium material according to this embodiment has high saturation. Specifically, the color-developing titanium material according to this embodiment has a surface saturation C of 0.05, measured in accordance with JIS Z 8781-4:2013. ＊ ab is 20.0 or more. Saturation C ＊ The upper limit of ab is 100, but in the titanium material according to this embodiment, the color is not produced by painting but by the interference of light making use of metallic luster, so the upper limit of saturation is lower, and may be, for example, 80.0 or less. ＊ ab may be 20.0 to 80.0, 20.0 to 70.0, or 20.0 to 50.0. ＊ The ab values ​​are measured using a color difference meter CR-200b manufactured by Minolta Co., Ltd.

[0028] <Uncolored Material> The above-mentioned color-developing material is manufactured using a predetermined uncolored material as a raw material. The uncolored material is a titanium material having a base material of pure titanium or a titanium alloy, and the surface of the base material is provided with a surface oxide film having an average thickness of 5.0 to 50.0 nm. When the titanium material is measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS), the detection intensity of an ion with m / z of 49, where m is the molecular weight and z is the valence, is determined to be TiH － As the detection intensity of TiH － In the depth direction distribution of the detected intensity, TiH － The detected intensity peak of is present in the surface oxide film, and the detected intensity value obtained by standardizing the detected intensity of the peak with the detected intensity at the base material set to 1 is 5.0 to 100.0. In the present disclosure, the ion with m / z 49 is mainly TiH － and is thought to be derived from titanium hydride. The non-coloring material will be described in detail below. The non-coloring material corresponds to the titanium material according to the embodiment of the present invention. Hereinafter, the titanium material according to the embodiment of the present invention may be simply referred to as the non-coloring material.

[0029] The non-color-developing material has a surface oxide film with an average thickness of 5.0 to 50.0 nm on the surface of the substrate. If the average thickness of the surface oxide film is less than 5.0 nm, TiH ２ The effect of suppressing the anodic reaction by the oxide film is reduced, and high saturation cannot be achieved. On the other hand, if the average thickness of the surface oxide film exceeds 50.0 nm, physical defects such as cracks are likely to occur in the surface oxide film, and the anodic reaction is promoted in the vicinity of the physical defects, making it more likely that a uniform surface oxide film will not be formed. The average thickness of the surface oxide film is preferably 5.0 to 30.0 nm, and more preferably 5.0 to 20.0 nm.

[0030] The average thickness of the surface oxide film of the uncolored material is measured by TOF-SIMS. From the results of depth direction analysis by TOF-SIMS, ions with m / z 64 were identified as TiO － As TiO － Using the profile of the detected intensity in the depth direction, － The average thickness of the surface oxide film is determined as the depth closest to the surface where the peak intensity of the detected intensity is half of the maximum intensity. Depth direction analysis in TOF-SIMS is performed as follows. The primary ion species is Bi １＋ The acceleration voltage of the primary ions is 30 kV, the measurement range is 50 μm square, and the sputter ion species is Cs － The acceleration voltage of the sputter ions is set to 1 kV. In order to eliminate the influence of organic matter on the outermost surface, TiO － The peak intensity of the detected intensity is used.

[0031] In the case of uncolored materials, the ion with m / z 49, which is an indicator of the presence of titanium hydride, obtained by TOF-SIMS measurement, was identified as TiH － In the depth direction distribution of the detected intensity, TiH － The peak of TiH in the substrate is within the surface oxide film. － The detection intensity of TiH is set to 1. － The normalized detection intensity values ​​of the peaks are 5.0 to 100.0.

[0032] In order to obtain good color development, TiH２ It is important that TiH exists in the oxide film. ２ The oxidation reaction of O in the solution, which is the main reaction, increases. ２－ The inventors speculate that this is because the reaction rate of the reaction between Ti and C and the side reaction between C and Ti is reduced, the growth rate of the surface oxide film on the same plane is kept constant, and the impurity concentration in the oxide film is reduced, resulting in improved saturation after color development. ２ TiH, which is an indicator of the presence of － It is important that the peak of the detected intensity is detected within the thickness of the surface oxide film and is higher than the detected intensity at the substrate.

[0033] TiH － If the detected intensity value of the peak is less than 5.0, the effect of improving the color development property cannot be obtained sufficiently. － When the detected intensity value of the peak exceeds 100.0, TiH in the surface oxide film ２ Because the concentration is too high, the anodic reaction that oxidizes titanium does not occur sufficiently, and a coloring material cannot be obtained. － The detected intensity value of the peak is 5.0 to 100.0. In order to more reliably obtain a color former with excellent color development, it is preferable to use TiH － The detected intensity value of the peak is 5.0 to 50.0, and more preferably TiH － The detected intensity value of the peak is 10.0 to 50.0.

[0034] Here, TiH in the substrate － The detection intensity is the detection intensity of hydride at a depth of 100 nm from the outermost surface of the uncolored material.

[0035] The above-mentioned non-color-forming material is immersed in an acidic aqueous solution of pH 4 or less at room temperature, and the applied voltage is 50 V or more and the current density is 1.0 to 50.0 mA cm －２ When voltage is applied for 2 minutes or more under the condition, the saturation C ＊ The ab is 20.0 or more. The titanium material in Patent Document 3 is a non-coloring material, and therefore is not a target for coloring material to be anodized. Even if the titanium material is anodized with an applied voltage of 50 V or more, TiH２ Since the amount of is different from that of the present disclosure, high saturation cannot be obtained.

[0036] Furthermore, the non-colored material according to this embodiment has significantly lower wettability than conventional titanium materials, with a water contact angle of 15° or greater when evaluated according to a method conforming to JIS Z0305:1998. The surface of conventional titanium materials typically has high wettability, resulting in a contact angle of 15° or less when moisture such as rainwater or sweat adheres to it. When moisture remains on the surface, the optical path length changes, resulting in a visually perceived difference from the original color. Furthermore, high wettability makes it easy for dirt such as sand and dust to accumulate or adhere, resulting in color changes. However, since the titanium material according to this embodiment has a contact angle of 15° or greater, changes in optical path length and color changes are less likely to occur, making it easier to maintain its appearance.

[0037] The shape of the uncolored material is not particularly limited and may be a plate, coil, rod, or strip. The uncolored material may also be a processed part such as a plate, coil, rod, or strip. Processed parts such as press-processed parts and crimped parts that the processed uncolored material may have also have the characteristics of the uncolored material of the present disclosure. When the uncolored material is a cold-rolled plate, its thickness is, for example, 0.1 mm or more and 5.0 mm or less.

[0038] <Method for manufacturing non-colored material> A method for manufacturing the non-colored material described above will be described. The method for manufacturing the non-colored material described below is one of methods for manufacturing a titanium material according to an embodiment of the present invention. ―２ After degassing to a pressure of 0.0 Pa or less, 5.0 × 10 inert gas containing Group 18 elements having a purity of 99% or more and a dew point of 0 to −50° C. was added. ―２ This process includes an annealing step in which titanium material is annealed in a furnace filled to a pressure of 100 Pa or higher.

[0039] In the method for producing the uncolored material, for example, an ingot process, a hot rolling process, and a cold rolling process are sequentially performed, followed by an annealing process. The above processes other than the annealing process can be performed by known methods.

[0040] In the ingot casting process, a pure titanium or titanium alloy ingot having the above-mentioned components is produced using raw materials such as titanium sponge or a master alloy for adding alloying elements, by various melting methods, including hearth melting methods such as vacuum arc melting, electron beam melting, or plasma melting. The obtained ingot is then bloomed and hot forged as necessary to produce an ingot.

[0041] In the hot rolling process, for example, the ingot may be heated to 600 to 850°C and rolled at a temperature below the transformation point. The rolling reduction may be determined depending on the characteristics of the final product. The heating temperature is preferably 700 to 850°C. From the viewpoint of deformation resistance, the lower limit of the heating temperature is preferably 700°C or higher. The upper limit of the heating temperature is preferably 850°C or lower, because this allows the thickness of the oxide film on the titanium material after hot rolling to be thin and enables descaling after hot rolling to be carried out under mild conditions.

[0042] In the cold rolling step, the hot-rolled titanium material may be rolled under conditions that result in the desired thickness and properties. If multiple cold rolling passes are performed, the titanium material may be annealed at least between cold rolling passes and / or after the final cold rolling pass.

[0043] In the annealing process, 2.0 × 10 ―２ After degassing to a pressure of 0.0 Pa or less, 5.0 × 10 inert gas containing Group 18 elements having a purity of 99% by volume or more and a dew point of 0 to −50° C. is added. ―２ The titanium material is annealed for 10 hours or more at a temperature in the range of 650°C to 850°C in a furnace filled to a pressure of 100 Pa or higher. There is no particular upper limit to the annealing time, but from the viewpoint of productivity, it is preferably 40 hours or less.

[0044] The pressure inside the furnace before the inert gas was sealed was 2.0 × 10 ―２ If the pressure exceeds 2.0 × 10 Pa, the titanium material will be oxidized due to the influence of oxygen remaining in the furnace, and the required properties and design will not be obtained. Therefore, the pressure inside the furnace before the inert gas is sealed is set to 2.0 × 10 ―２ On the other hand, the lower limit of the pressure inside the furnace before the inert gas is sealed is not particularly limited, and is, for example, 1.0 × 10 ―３From the viewpoint of heating efficiency by heat circulation, the pressure inside the furnace before the inert gas is sealed therein is preferably 1.0×10 Pa or more. ―３ ~2.0 x 10 ―２ Pa, and more preferably 1.0×10 ―３ ~1.0 x 10 ―２ MPa.

[0045] The gas sealed in the furnace is an inert gas consisting of Group 18 elements with a purity of 99% by volume or more and a dew point of 0 to -50°C. The inert gas is, for example, Ar gas. Since Ar gas is inert, TiH ２ The effect of the gas on the formation of titanium can be limited to the dew point, making it easier to control. Any gas can be used as long as it is inert to titanium, and other inert gases made from Group 18 elements such as He, Ne, and Kr can also be used.

[0046] The purity of the inert gas is 99% by volume or more. If the purity of the inert gas is less than 99% by volume, the impurity elements react with the titanium surface, resulting in the formation of the target compound, TiH. ２ It is not possible to generate only Ti. The upper limit of the purity of the inert gas is not particularly limited, and the purity of the inert gas may be 100% by volume. However, trace amounts of water vapor, oxygen, and hydrogen may be contained to adjust the dew point. Therefore, the purity of the inert gas is, for example, 99.5 to 100% by volume, preferably 99.9 to 100% by volume, and more preferably 99.9 to 99.99% by volume. Furthermore, the gas sealed in the furnace may contain nitrogen, but as described above, it is an inert gas consisting of Group 18 elements with a dew point of 0 to -50°C, and its purity is 99% by volume or more. Therefore, the non-coloring material according to this embodiment includes Ti. ２ It is presumed that titanium nitrides such as N and TiN are not present.

[0047] The dew point of the inert gas sealed in the furnace is 0 to -50°C. If an inert gas with a dew point higher than 0°C is used, TiH ２ Furthermore, if an inert gas with a dew point of less than -50°C is used, the amount of TiH produced will increase, and good color development will not be achieved. ２The dew point of the inert gas sealed in the furnace is preferably −10 to −50°C, more preferably −10 to −40°C. The dew point of an inert gas whose dew point is not adjusted is usually −60°C or lower. Therefore, in an inert gas whose dew point is not adjusted, TiH ２ is not generated, and good color development cannot be obtained.

[0048] The pressure inside the furnace after the inert gas was sealed was 5.0 × 10 －２ The pressure inside the furnace after the inert gas is sealed is 5.0 × 10 Pa or more. －２ If the pressure is less than Pa, the TiH ２ In addition to insufficient formation, the heat circulation in the furnace becomes poor, and uneven heating occurs in the coil. The upper limit of the pressure in the furnace after the inert gas is sealed is not particularly limited as long as it is equal to or lower than atmospheric pressure. －１ Therefore, the pressure inside the furnace after the inert gas is sealed therein may be, for example, 5.0×10 －２ ~1.0 x 10 －１ The pressure inside the furnace after the inert gas is sealed is preferably 5.0 × 10 Pa from the viewpoint of manufacturing cost and productivity. －２ ~9.0 x 10 －２ Pa, and more preferably 6.0 × 10 －２ ~9.0 x 10 －２ It is Pa.

[0049] The annealing step is preferably carried out after removing impurities such as lubricating oil that have adhered during the cold rolling step in an alkali washing line. Alternatively, the titanium material after the cold rolling step may be subjected to air annealing, salt bath descaling, and pickling in that order before the annealing step.

[0050] By carrying out the above-mentioned annealing step, the surface of the substrate is provided with a surface oxide film having an average thickness of 5.0 to 50.0 nm, and when the titanium material is measured by TOF-SIMS, TiH ２ TiH with m / z 49, which is indicative of the presence of －In the depth direction distribution of the detected intensity, there is a peak within the surface oxide film, and the detected intensity value of the peak detected intensity, normalized to the detected intensity at the base material of 1, is 5.0 to 100.0.

[0051] After the annealing step, the titanium material after the annealing step is further subjected to a pickling step in which the titanium material after the annealing step is pickled with a pickling solution having a hydrofluoric acid concentration of 1.0 to 6.0 mass % and a nitric acid concentration of 4 to 10 mass %; and the titanium material after the pickling step is subjected to a pickling step in which the titanium material after the pickling step is pickled with a pickling solution having a pH in the range of 4.0 to 7.0 and an electrical conductivity of 6.0 × 10 －５ ~1.0 x 10 －３ S.cm. －１ and the total organic carbon concentration is within 1.0 mg L －１ By carrying out the pickling step and the cleaning step, TiH formed in the surface oxide film can be removed. ２ increases.

[0052] In the pickling process, the titanium material after the annealing process is pickled with a pickling solution having a hydrofluoric acid concentration of 1.0 to 6.0 mass % and a nitric acid concentration of 4 to 10 mass %. By using the above pickling solution, TiH is formed on the titanium surface with a minimum amount of thinning. ２ The concentration of hydrofluoric acid is preferably 1.0 to 5.0 mass %, more preferably 2.0 to 4.0 mass %, and the concentration of nitric acid is preferably 5 to 10 mass %, more preferably 6 to 10 mass %.

[0053] The temperature of the pickling solution is 40 to 60°C. By keeping the temperature of the solution at 40 to 60°C, the reaction between the acid and the titanium surface is activated, and TiH ２ The temperature of the pickling solution is preferably 45 to 60°C, more preferably 50 to 60°C.

[0054] The pickling method may be any known method, for example, the titanium material may be immersed in the pickling solution, or the pickling solution may be sprayed onto the titanium material.

[0055] In the cleaning process, the titanium material after the pickling process is washed with a solution having a pH in the range of 4.0 to 7.0 and an electrical conductivity of 6.0 × 10 －５ ~1.0 x 10 －３ S.cm.－１ and the total organic carbon concentration is within 1.0 mg L －１ The temperature is 10 to 60°C and the cleaning solution is used.

[0056] The pH of the cleaning solution is 4.0 to 7.0. If the pH of the cleaning solution is less than 4.0, TiH ２ When the pH of the cleaning solution exceeds 7.0, the formation of Ti(OH) becomes dominant, and the oxide film cannot be stably formed. ４ Compounds such as TiH ２ The pH of the washing liquid is preferably 4.5 to 7.0, more preferably 4.5 to 6.7.

[0057] The electrical conductivity of the cleaning solution is 6.0 x 10 －５ ~1.0 x 10 －３ S.cm. －１ The electrical conductivity of the cleaning solution is 6.0 × 10 －５ S.cm. －１ If the electrical conductivity of the cleaning solution is less than 1.0 × 10, it is not used in industrial products because of the high manufacturing costs and labor required. －３ S.cm. －１ In the case of ultra-high temperature, the amount of impurity elements contained in the cleaning water is large, and TiH ２ The amount of formation or adhesion of compounds other than the above increases, which adversely affects color development. －５ ~8.0 x 10 －４ S.cm. －１ and more preferably 1.0 × 10 －４ ~5.0 x 10 －４ S.cm. －１ is.

[0058] The total organic carbon concentration in the cleaning solution was 1.0 mg / L. －１ Total organic carbon concentration is 1.0 mg L or less. －１ If the total organic carbon concentration is more than 1.0×10, the amount of carbides such as TiC formed by the reaction of carbon in the cleaning solution with the titanium surface increases, which affects color development. －２ mg.L －１Therefore, the total organic carbon concentration in the cleaning solution may be, for example, 1.0 × 10 －２ ~1 mg / L －１ From the viewpoint of productivity of the cleaning solution preparation process, the total organic carbon concentration contained in the cleaning solution is preferably 1.0 × 10 －２ ~5.0 x 10 －１ mg.L －１ and more preferably 5.0 × 10 －２ ~5.0 x 10 －１ mg.L －１ The cleaning liquid may be, for example, pure water, H ２ CO ３ , H ２ O ２ , HNO ３ , HCl, H ２ SO ４ , H ３ P.O. ４ or a mixture thereof.

[0059] The total organic carbon concentration in the cleaning solution is measured by a combustion oxidation method conforming to JIS K 0551: 1994. As combustion oxidation measurement methods, the standard lists combustion oxidation-infrared TOC (total organic carbon) automatic measurement method and combustion oxidation-infrared TOC analysis method, and either method may be applied to measure the total organic carbon concentration in the cleaning solution.

[0060] The temperature of the cleaning solution is 10 to 60° C. If the temperature of the cleaning solution is less than 10° C., the desired amount of TiH ２ Furthermore, even if the temperature of the cleaning solution exceeds 60°C, the reaction to form TiH ２ The temperature of the cleaning solution is preferably 20 to 60°C, more preferably 30 to 60°C.

[0061] The cleaning method is not particularly limited as long as it allows the cleaning solution to be uniformly dispersed on the surface of the titanium material and the pickling solution to be washed away. For example, the titanium material may be immersed in the cleaning solution, or the cleaning solution may be sprayed onto the titanium material.

[0062] The pickling time and immersion time are not particularly limited as long as they can remove surface dirt and oxide films, and may be, for example, 1 minute or more and 10 minutes or less, or 2 minutes or 3 minutes or less, respectively. From the viewpoint of equipment and production costs, the pickling time and immersion time are preferably 5 minutes or less in total.

[0063] The produced uncolored material may be subjected to a temper rolling and stretch straightening process by a known method.

[0064] <Method for producing color former> A method for producing the above-mentioned color former will be described. The method for producing the color former described below is one of methods for producing a titanium material according to an embodiment of the present invention. The method for producing the color former involves immersing the above-mentioned uncolored material in an acidic aqueous solution at room temperature, pH 4 or less, and applying a voltage of 50 V or more and a current density of 1.0 to 50.0 mA cm. －２ and includes an anodization step in which a voltage is applied for 2 minutes or more.

[0065] Even if a conventional uncolored material is anodized under the above conditions, it is not possible to obtain high saturation. On the other hand, by anodizing the uncolored material according to the embodiment of the present invention under the above conditions, high saturation can be obtained. Furthermore, by anodizing the uncolored material according to the embodiment of the present invention under the above conditions, a colored material can be obtained that has a surface oxide film on the surface of the substrate with an average thickness of 100.0 to 500.0 nm, and that, when the surface oxide film is measured by depth profile analysis using glow discharge optical emission spectroscopy, has a maximum oxygen concentration of 50.0 atomic % or more and a maximum carbon concentration of 0.50 or less compared to the maximum oxygen concentration.

[0066] The lower limit of the pH of the acidic aqueous solution is not particularly limited, and may be, for example, 0 or higher. In order to suppress surface reactions other than the anodic oxidation reaction, the pH is preferably 0.5 or higher, more preferably 1.0 or higher. In addition, in order to promote the anodic oxidation reaction, the pH is preferably 3.5 or lower, more preferably 3.0 or lower.

[0067] The saturation improvement effect of the present invention can be obtained if the applied voltage is 50 V or higher. The applied voltage is preferably 55 V or higher, and more preferably 60 V or higher. In order to obtain the interference color of the oxide film formed by anodic oxidation, the applied voltage is preferably 200 V or lower, and more preferably 150 V or lower.

[0068] If the current density is too low, the anodic oxidation reaction may not occur locally, whereas if the current density is too high, the anodic oxidation reaction may be locally accelerated, which may result in uneven color. Therefore, the current density is preferably 2.5 mA cm －２ More preferably, 5.0 mA cm －２ The current density is preferably 50 mA cm －２ and more preferably 40 mA cm －２ The following is the result.

[0069] To sufficiently grow an oxide film at the above-mentioned applied voltage, the voltage application time is preferably 1 minute or more, more preferably 2 minutes or more. Furthermore, since no current flows even if the voltage is continued to be applied after the oxide film growth is completed, there is no particular upper limit to the voltage application time. The voltage application time may be 5 minutes or less, or may be 4 minutes or less.

[0070] Furthermore, according to the above-described manufacturing method, the color former can be manufactured regardless of the composition of the titanium substrate, and without requiring complex or large-scale equipment.

[0071] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples. Note that the examples shown below are merely examples of the present invention, and the present invention is not limited to the examples below.

[0072] (Example 1) A cold-rolled sheet of pure titanium equivalent to JIS Class 1 was manufactured, and the grade was designated CP1. Multiple samples measuring 70 mm in length (length in the rolling direction) × 70 mm in width (length in the direction perpendicular to the rolling direction on the rolled surface) × 0.3 mm in thickness were cut out from the cold-rolled sheet, and uncolored materials were manufactured under the following conditions 1 to 4.

[0073] Under condition 1, the following steps were performed on the sample: the initial furnace gas pressure was 5.0 × 10 －３ Ar gas with a purity of 99.99% by volume and a dew point of −30° C. was sealed in a furnace at a pressure of 9.0×10 Pa. －２ An annealing step was performed in which the samples cut out at 700°C were annealed. The annealing temperature was 700°C and the annealing time was 40 hours. The samples after the annealing step were pickled for 2 minutes in a pickling solution having a hydrofluoric acid concentration of 2 mass% and a nitric acid concentration of 10 mass% at a temperature of 60°C, and a pH of 4.7 and an electrical conductivity of 1.0 × 10 －４ S.cm. －１ and the total organic carbon concentration is 1.0 × 10 －２ mg.L －１ and H at 60°C ２ O ２ A cleaning process was performed in which the steel sheet was immersed in an aqueous solution for 2 minutes. In condition 2, the annealing process and the pickling process were performed under the same conditions as in condition 1, and the pH was 6.7 and the electrical conductivity was 2.5×10 －４ S.cm. －１ and the total organic carbon concentration is 1.0 × 10 －２ mg.L －１ and H at 25°C ２ CO ３ A cleaning step was performed in which the steel sheet was immersed in an aqueous solution for 2 minutes. In condition 3, the annealing step was performed under the same conditions as in condition 1, and the pickling step and the cleaning step were not performed. In condition 4, none of the annealing step, the pickling step, and the cleaning step were performed. The total organic carbon concentration in the cleaning solution was measured by a combustion oxidation method in accordance with JIS K 0551:1994.

[0074] For each uncolored material, measurements of titanium oxide and titanium hydride were carried out from the surface to the depth direction by TOF-SIMS under the following conditions. The average thickness of the surface oxide film and TiH － The peak position and peak intensity were measured. Apparatus: IONTOF TOF. SIMS5 Primary ion species: Bi １＋ Primary ion acceleration voltage: 30 keV Measurement range: 50 μm□ Sputter ion species: Cs －Sputter ion acceleration voltage: 1 keV

[0075] From the outermost surface, TiO － The depth up to which the peak intensity of the surface oxide film reaches half of its maximum intensity was defined as the average thickness of the surface oxide film. － The detected intensity of the peak was standardized to calculate the detected intensity value, with the detected intensity of the peak being set to 1. － The detected intensity was the intensity at a position 100 nm deep from the surface of the uncolored material. Figure 1 is a graph showing the results of quantitative analysis in the depth direction by TOF-SIMS for the uncolored material under conditions 1 to 4. The sputtering depth was measured using SiO ２ This is the depth of the conversion.

[0076] The average thickness of the surface oxide film of the non-colored material under condition 1 was 8.7 nm, the average thickness of the surface oxide film of the non-colored material under condition 2 was 11.3 nm, the average thickness of the surface oxide film of the non-colored material under condition 3 was 5.3 nm, and the average thickness of the surface oxide film of the non-colored material under condition 4 was 10.5 nm. － The peaks of the TiH2O4 particles were 6.1 nm, 8.4 nm, and 4.7 nm, respectively, and all of them were within the surface oxide film, and the detected intensity values ​​were within the range of 5.0 to 100.0. － The peak was at 9.0 nm and was located within the surface oxide film, but the detected intensity value was less than 5.0.

[0077] (Example 2) Samples measuring 50 mmL x 25 mmW x 0.3 mmT were cut out from the uncolored materials under conditions 1 and 4 in Example 1, and anodized to produce colored materials. Specifically, the surface of each sample was immersed in acetone and ultrasonically cleaned for at least 5 minutes, after which the surface of the test piece was wiped with a cloth soaked in ethanol and dried. After drying, each sample was anodized under the following conditions: the sample was immersed in a 5% by mass phosphoric acid aqueous solution with a pH of about 1 at room temperature (25°C), with an applied voltage of 80 V and a current density of 2.5 mA cm －２ The voltage application time was 2 minutes. A pure titanium JIS Class 1 plate having the same area as the sample was used as the counter electrode (cathode).

[0078] Quantitative composition analysis in the depth direction was carried out for each color former by GDS. Apparatus: GD-Profiler 2 manufactured by HORIBA, LTD. (JOBIN YVON) Discharge conditions: 35 W (constant power mode) Ar pressure: 600 Pa Discharge range: 4 mmφ Measurement pitch: 2 nm

[0079] The measurement depth was confirmed by measuring the depth of the discharge mark after measurement using a surface roughness meter. Furthermore, using the O concentration profile obtained in this measurement, the surface oxide film of the color former was determined to be the depth position from the outermost surface of the color former to the position where the maximum oxygen concentration was 1 / 2. Figure 2 is a graph showing the results of depth direction quantitative analysis by GDS for the color formers under conditions 1 and 4.

[0080] The average thickness of the surface oxide film of the color former under condition 1 was 125.9 nm, and the average thickness of the surface oxide film of the color former under condition 4 was 187.8 nm. Furthermore, as shown in Figure 2, the color former under condition 1 had a maximum oxygen concentration of 50.0 atomic % or more and a ratio of the maximum carbon concentration to the maximum oxygen concentration of 0.50 or less. On the other hand, the color former under condition 4 had a maximum oxygen concentration of less than 50.0 atomic % and a ratio of the maximum carbon concentration to the maximum oxygen concentration of more than 0.50.

[0081] Example 3 Cold-rolled annealed sheets of the types shown in Table 1A were produced, and multiple samples measuring 70 mm in length (in the rolling direction) × 70 mm in width (in the direction perpendicular to the rolling direction on the rolling surface) × 0.3 mm in thickness were cut from the cold-rolled annealed sheets. Uncolored materials were produced using each sample under the conditions shown in Table 1A. CP1 to CP4 listed for the titanium material types in Table 1 indicate that materials equivalent to JIS pure titanium types 1 to 4 were used. Ti-1Cu, Ti-3Al-2.5V, Ti-5Al-1Fe, Ti-0.05Pd, and Ti-0.15Pd are symbols indicating the content (mass %) of contained elements and the contained element type (element symbol) after a hyphen, respectively, and indicate the nominal composition of the titanium material. The total organic carbon concentration in the cleaning solution was measured using a combustion oxidation method in accordance with JIS K 0551:1994.

[0082]

[0083] Furthermore, a sample measuring 50 mmL x 25 mmW x 0.3 mmT was cut from each uncolored material and anodized to produce a colored material. Specifically, the surface of each sample was immersed in acetone and ultrasonically cleaned for at least 5 minutes, and then the surface of the test piece was wiped with a cloth soaked in ethanol and dried. After drying, each sample was anodized under the conditions listed in Table 1B. A pure titanium JIS Class 1 plate with the same area as the sample was used as the counter electrode (cathode).

[0084]

[0085] For each uncolored material, the titanium oxide and titanium hydride were measured from the surface to the depth direction by TOF-SIMS under the same conditions as in Example 1, and the average thickness of the surface oxide film and TiH － The detection intensity value was calculated.

[0086] For each color former, quantitative composition analysis in the depth direction was carried out by GDS under the same conditions as in Example 2.

[0087] In addition, the wettability of the uncolored material was evaluated. Specifically, the contact angle of water was measured in accordance with JIS Z0305:1998. From the viewpoint of maintaining the appearance, a small wettability (large contact angle) is preferable, and a large wettability (small contact angle) is unpreferable. When the contact angle is 15° or more, the wettability is determined as preferable (A), and when it is less than 15°, the wettability is determined as unpreferable (B).

[0088] In addition, the coloring material L ＊ , a ＊ , b ＊ The color was measured in accordance with JIS Z 8781-4:2013. A Minolta Co., Ltd. color difference meter CR-200b was used to measure the color, and the light source was the auxiliary illuminant C for color measurement (illuminant C) described in JIS Z 8720:2012 and CIE15.3. Measurements were performed at five points on each side of the length x width of the color former, one at the center and four at the corners of the surface, and on two surfaces, the front and back, for a total of 10 points. ＊ and b ＊ Measure the measured a ＊ and b ＊ From this, the saturation C＊ ab was calculated and the average value was calculated. ＊ ab = {(a ＊ ) ２ +(b ＊ ) ２} １／２ …(1) formula

[0089] Generally, chroma C ＊ When ab is 20 or more, the color is visually recognized as vivid, so 20 is set as the threshold for determining whether or not the color is highly saturated. ＊ When ab is 20.0 or more, the color development is judged to be good (B), and the saturation C ＊ When ab is less than 20.0, the color development is judged to be poor (C). ＊ When ab is 35.0 or more, it is judged that the color development property is even more excellent (A). Note that the underlined conditions in Tables 1 and 2 indicate conditions outside the range of the present invention.

[0090]

[0091] Example No. 1 is an example in which an anodizing process was carried out on an uncolored material that had not been subjected to any of the annealing process, pickling process, and cleaning process. In the anodizing process, the titanium material was immersed in a phosphoric acid aqueous solution with a pH of 1 at a temperature of 25°C, and the applied voltage was 80 V and the current density was 2.5 mA cm. －２ In this example, the average thickness of the oxide film on the surface of the non-color-forming material was 10.5 nm, and the TiH － The detected peak intensity was 1.5, the maximum oxygen concentration (maximum oxygen intensity) of the color former was 42.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 1.19, and the evaluation result of color development was C. In addition, the wettability of the uncolor former was B.

[0092] In the example of No. 2, the initial furnace gas pressure was 5.0 × 10 －３ Ar gas with a purity of 99.99% by volume and a dew point of −30° C. was sealed in a furnace at a pressure of 9.0×10 Pa. －２The titanium material after the annealing process was subjected to an annealing step in which the material was annealed at 700°C for 40 hours. The titanium material after the annealing process was subjected to a pickling step in which the material was pickled for 2 minutes in a pickling solution having a hydrofluoric acid concentration of 2.0 mass% and a nitric acid concentration of 10 mass% at a temperature of 60°C, and a pH of 4.7 and an electrical conductivity of 1.0 × 10 －４ S.cm. －１ and the total organic carbon concentration is 1.0 × 10 －２ mg.L －１ and H at 60°C ２ O ２ This example shows a non-colored material produced by a cleaning process in which the material was immersed in an aqueous solution for 2 minutes, and then an anodizing process was carried out on the non-colored material under the same conditions as in Example No. 1. In this example, the average thickness of the surface oxide film of the non-colored material was 8.7 nm, and the TiH － The peak was at a position 6.1 nm from the surface, the detected intensity value of the peak was 20.2, the average thickness of the surface oxide film of the color former was 125.9 nm, the maximum oxygen concentration was 76.8 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.29, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0093] Example No. 3 is the same as Example No. 2 except that the cleaning solution in the cleaning step has a pH of 6.7 and an electrical conductivity of 2.5 × 10 －４ S.cm. －１ and the total organic carbon concentration is 1.0 × 10 －２ mg.L －１ and H at 25°C ２ CO ３ This example was carried out under the same conditions as in Example No. 2, except that the solution was changed to an aqueous solution. In this example, the average thickness of the oxide film on the surface of the non-color-forming material was 11.3 nm, and the average thickness of the oxide film on the surface of the non-color-forming material was 11.3 nm. － The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 146.9 nm, the maximum oxygen concentration was 72.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.23, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0094] Example No. 4 is an example in which the annealing step was carried out under the same conditions as Example No. 2, but the pickling step and the cleaning step were not carried out. In this example, the average thickness of the surface oxide film of the uncolored material was 5.3 nm, and TiH － The peak was at a position 4.7 nm from the surface, the detected intensity value of the peak was 6.3, the average thickness of the surface oxide film of the color former was 131.4 nm, the maximum oxygen concentration was 67.3 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.29, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0095] Example No. 5 is the same as Example No. 4 except that the initial furnace gas pressure in the annealing process is 2.0 × 10 －２ The pressure in the furnace was changed to 5.5 × 10 Pa, and Ar gas with a purity of 99.99% by volume and a dew point of −30° C. was sealed in the furnace. －２ In this example, the average thickness of the oxide film on the surface of the uncolored material is 6.4 nm, and the average thickness of the oxide film on the surface of the uncolored material is 6.4 nm. － The peak was at a position 4.8 nm from the surface, the detected intensity value of the peak was 16.8, the average thickness of the surface oxide film of the color former was 134.5 nm, the maximum oxygen concentration was 69.8 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.27, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0096] Example No. 6 is an example in which the inert gas in the annealing process in Example No. 4 was changed to He gas with a purity of 99.99% by volume and a dew point of −30° C. In this example, the average thickness of the surface oxide film of the uncolored material was 5.4 nm, and the TiH － The peak was at a position 4.6 nm from the surface, the detected intensity value of the peak was 7.2, the average thickness of the surface oxide film of the color former was 132.7 nm, the maximum oxygen concentration was 68.1 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.27, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0097] In Example No. 7, the nitric acid concentration of the pickling solution in the pickling step was changed from Example No. 3 to 4 mass % and the hydrofluoric acid concentration was changed to 1.0 mass %, and the cleaning solution in the cleaning step had a pH of 6.9 and an electrical conductivity of 6.0 × 10 －５ S.cm. －１ and the total organic carbon concentration is 8.0 × 10 －３ mg.L －１ and the temperature is 15°C. ２ CO ３ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 10.9 nm, and the TiH － The peak was at a position 7.8 nm from the surface, the detected intensity value of the peak was 23.8, the average thickness of the surface oxide film of the color former was 145.8 nm, the maximum oxygen concentration was 73.4 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.25, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0098] In Example No. 8, the hydrofluoric acid concentration of the pickling solution in the pickling step was changed to 6.0 mass % from Example No. 3, and the cleaning solution in the cleaning step had a pH of 6.1 and an electrical conductivity of 1.0 × 10 －３ S.cm. －１ and the total organic carbon concentration was 0.9 mg L －１ and the temperature is 15°C. ２ CO ３ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 12.8 nm, and the TiH － The peak was at a position 9.3 nm from the surface, the detected intensity value of the peak was 27.8, the average thickness of the surface oxide film of the color former was 147.2 nm, the maximum oxygen concentration was 75.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.23, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0099] Example No. 9 differs from Example No. 3 in that the temperature of the phosphoric acid aqueous solution in the anodizing step was changed by 1°C and the current density was changed to 50 mA cm －２In Example No. 9, the current density of the anodizing treatment was higher than that of the other examples (Nos. 1 to 8, 11 to 22). The applied voltage during anodizing treatment affects the thickness of the surface oxide film, while the current density affects the growth rate of the surface oxide film. That is, changing the applied voltage changes the thickness of the surface oxide film, while changing the current density while keeping the applied voltage constant changes the growth rate of the surface oxide film but not the thickness of the surface oxide film. Once a surface oxide film of a thickness corresponding to a certain applied voltage is formed, the substrate is insulated by the surface oxide film, so almost no current flows between the solution and the substrate. At this time, it is necessary to continue applying the voltage for a predetermined time. This allows for the formation of an oxide film with fewer defects and voids. In this example, the average thickness of the surface oxide film on the uncolored material is 11.3 nm, and the TiH － The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 140.2 nm, the maximum oxygen concentration was 69.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.23, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0100] Example No. 10 is the same as Example No. 3 except that the temperature of the phosphoric acid aqueous solution in the anodizing step was changed to 40°C, the pH to 4, the applied voltage to 60 V, and the current density to 50 mA cm －２ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 11.3 nm, and TiH － The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 130.2 nm, the maximum oxygen concentration was 76.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.25, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0101] Example No. 11 is the same as Example No. 3 except that the cleaning solution in the cleaning step has a pH of 2.5 and an electrical conductivity of 3.7 × 10 －２ S.cm. －１ and the total organic carbon concentration is 1.0 × 10－２ mg.L －１ and HNO at 25°C. ３ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 11.2 nm, and the TiH － The peak was at a position 8.1 nm from the surface, the detected intensity value of the peak was 98.2, the average thickness of the surface oxide film of the color former was 150.7 nm, the maximum oxygen concentration was 55.3 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.45, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0102] Example No. 12 is an example in which the annealing temperature in the annealing step was changed to 650°C and the annealing time to 10 hours in Example No. 3. In this example, the average thickness of the surface oxide film of the uncolored material was 10.3 nm, and the TiH － The peak was at a position 7.9 nm from the surface, the detected intensity value of the peak was 26.4, the average thickness of the surface oxide film of the color former was 148.9 nm, the maximum oxygen concentration was 69.8 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.26, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0103] Example No. 13 is an example in which the annealing temperature in the annealing step was changed to 850°C and the annealing time to 40 hours in Example No. 3. In this example, the average thickness of the surface oxide film of the uncolored material was 10.5 nm, and the TiH － The peak was at a position 8.3 nm from the surface, the detected intensity value of the peak was 27.2, the average thickness of the surface oxide film of the color former was 150.1 nm, the maximum oxygen concentration was 70.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.25, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0104] Example No. 14 is the same as Example No. 3 except that the applied voltage in the anodizing step was 50 V and the current density was 1.0 mA cm －２ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 11.3 nm, and TiH －The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 111.5 nm, the maximum oxygen concentration was 75.9 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.19, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0105] Example No. 15 differs from Example No. 3 in that the applied voltage in the anodizing process was 150 V and the current density was 5.0 mA cm －２ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 11.3 nm, and TiH － The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 352.3 nm, the maximum oxygen concentration was 65.8 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.29, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

[0106] Example No. 16 is an example in which the purity of the Ar gas used in the annealing process in Example No. 4 was changed to Ar gas with a dew point of -3°C. In this example, the average thickness of the surface oxide film of the uncolored material was 45.9 nm, and the TiH － The peak was at a position 7.8 nm from the surface, the detected intensity value of the peak was 43.6, the average thickness of the surface oxide film of the color former was 142.9 nm, the maximum oxygen concentration was 69.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.18, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0107] Example No. 17 is an example in which the purity of the Ar gas used in the annealing process in Example No. 4 was changed to Ar gas with a dew point of -45°C and an average thickness of the oxide film on the surface of the uncolored material was 9.8 nm, and the TiH －The peak was at a position 4.5 nm from the surface, the detected intensity value of the peak was 5.5, the average thickness of the surface oxide film of the color former was 135.6 nm, the maximum oxygen concentration was 65.4 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.24, and the evaluation result of the color former was B. In addition, the wettability of the uncolor former was A.

[0108] Example No. 18 is an example in which the purity of the Ar gas used in the annealing process in Example No. 4 was changed to Ar gas with a dew point of -60°C and an average thickness of the oxide film on the surface of the uncolored material was 5.6 nm, and the TiH － The peak was at a position 4.8 nm from the surface, the detected intensity value of the peak was 3.3, the average thickness of the surface oxide film of the color former was 177.4 nm, the maximum oxygen concentration was 49.6 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.77, and the evaluation result of the color former was C. In addition, the wettability of the uncolor former was B.

[0109] Example No. 19 is the same as Example No. 4 except that the initial furnace gas pressure in the annealing process is 1.0 × 10 －２ Pa, the gas pressure inside the furnace after the inert gas was sealed was 1.0 × 10 －２ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 13.3 nm, and the average thickness of the oxide film on the surface of the non-coloring material was 13.3 nm. － The peak was at a position 9.2 nm from the surface, the detected intensity value of the peak was 4.7, the average thickness of the surface oxide film of the color former was 177.2 nm, the maximum oxygen concentration was 48.2 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.88, and the evaluation result of the color former was C. In addition, the wettability of the uncolor former was B.

[0110] Example No. 20 is an example in which the temperature of the phosphoric acid aqueous solution in the anodizing step was changed to 50°C and the voltage application time was changed to 1 minute from Example No. 3. In this example, the average thickness of the surface oxide film of the non-coloring material was 11.3 nm, and the TiH －The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 128.9 nm, the maximum oxygen concentration was 47.1 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.61, and the evaluation result of the color former was C. In addition, the wettability of the uncolor former was B.

[0111] In Example No. 21, the pH of the phosphoric acid aqueous solution in the anodizing step was changed from Example No. 3 to 5, and the applied voltage was 40 V and the current density was 0.5 mA cm －２ In this example, the average thickness of the oxide film on the surface of the non-coloring material was 11.3 nm, and TiH － The peak was at a position 8.4 nm from the surface, the detected intensity value of the peak was 25.9, the average thickness of the surface oxide film of the color former was 98.2 nm, the maximum oxygen concentration was 45.3 atomic %, the ratio of the maximum carbon concentration to the maximum oxygen concentration was 0.40, and the evaluation result of the color former was C. In addition, the wettability of the uncolor former was B.

[0112] Examples No. 22 to No. 28 are examples in which the titanium material was changed from Example No. 3. In these examples, the average thickness of the surface oxide film of the uncolored material was 5.0 to 50.0 nm, and TiH － The peak was within the surface oxide film, the detected intensity was 5.0 or more, the average thickness of the surface oxide film of the color former was 100.0 to 500.0 nm, the maximum oxygen concentration was 50.0 atomic % or more, the maximum carbon concentration relative to the maximum oxygen concentration was 0.50 or less, and the evaluation result of the color former was A. In addition, the wettability of the uncolor former was A.

Claims

1. A titanium material having a base material of pure titanium or a titanium alloy, wherein the surface of the base material has a surface oxide film having an average thickness of 100.0 to 500.0 nm, and when the surface oxide film is measured by depth direction analysis using glow discharge optical emission spectroscopy, the maximum oxygen concentration is 50.0 atomic % or more, and the ratio of the maximum carbon concentration to the maximum oxygen concentration is 0.50 or less, and the saturation C of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 ＊ A titanium material having ab of 20.0 or more.

2. A titanium material having a base material of pure titanium or a titanium alloy, the surface of the base material having a surface oxide film with an average thickness of 5.0 to 50.0 nm, and when the titanium material is measured by time-of-flight secondary ion mass spectrometry, the detection intensity of an ion with m / z of 49, where m is the molecular weight and z is the valence, is determined as TiH － The detected intensity is － In the depth direction distribution of the detected intensity, TiH － the peak of the detected intensity is within the surface oxide film, and － The detected intensity of the TiH － The titanium material has a peak detection intensity value of 5.0 to 100.

0.

3. A method for producing a titanium material according to claim 1, comprising immersing the titanium material according to claim 2 in an acidic aqueous solution at room temperature and pH 4 or less, applying a voltage of 50 V or more, and applying a current density of 1.0 to 50.0 mA cm －２ The method for manufacturing a titanium material includes an anodizing step of applying a voltage for 2 minutes or more.

4. The method for producing a titanium material according to claim 2, －２ After degassing to a pressure of 0.0 Pa or less, an inert gas containing Group 18 elements having a purity of 99% by volume or more and a dew point of 0 to −50° C. was added in an amount of 5.0×10 －２ A method for manufacturing titanium material, comprising an annealing step of annealing titanium material in a furnace filled to 100 Pa or higher.

5. A pickling process in which the titanium material after the annealing process is pickled with a solution having a hydrofluoric acid concentration of 1.0 to 6.0 mass % and a nitric acid concentration of 4 to 10 mass %; and －５ ~1.0 x 10 －３ S.cm. －１ and the total organic carbon concentration is within 1.0 mg L －１ and a cleaning step of cleaning the titanium material with a cleaning solution having a temperature of 10 to 60°C, wherein the temperature is:

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