Titanium material and method for manufacturing titanium material

Abstract

A titanium material according to one aspect of the present invention uses pure titanium or a titanium alloy as a base material. When components that constitute the surface of the titanium material are analyzed by X-ray photoelectron spectroscopy, the maximum value of the Si concentration is 10 atom% to 40 atom% inclusive, the maximum value of the Al concentration is 10 atom% to 40 atom% inclusive, and the minimum value of the O concentration in the range in the depth direction in which either the Si concentration or the Al concentration is 1 atom% or more is 20 atom% to 50 atom% inclusive, in the surface of the material from the outermost surface to the 50 nm position in the depth direction. With respect to the color measurement values of the surface of the titanium material as measured in accordance with JIS Z 8781-4 (2013), L* is 55-75, a* is 1.0-2.0, and b* is 4.0-8.0.

Description

Titanium material and method for manufacturing titanium material

[0001] This application claims priority to Japanese Patent Application No. 2024-001391, filed on January 9, 2024, the contents of which are incorporated herein by reference.

[0002] Titanium materials are broadly divided into uncolored materials, which exhibit the silver color of titanium metal, and colored materials, which exhibit interference colors. Both uncolored and colored materials may discolor when exposed to the atmosphere for a long period of time. It has been revealed that this discoloration is an interference color caused by an oxide film on the surface of the titanium material growing to a thickness of several tens of nanometers or more in an acidic environment with a pH of 4.5 or less, such as acid rain. Such an oxide film of several tens of nanometers does not impair the corrosion resistance of titanium. However, in areas where the appearance is important, such as the walls and roofs of buildings, titanium materials, particularly uncolored materials, that are less likely to exhibit interference colors due to an increase in oxide film thickness are required, and development of such titanium materials is underway.

[0003] For example, Patent Document 1 discloses a titanium material that is resistant to discoloration in an atmospheric environment, characterized in that the average carbon concentration within a range of 100 nm deep from the outermost surface is 14 atomic % or less and that the outermost surface has an oxide film with a thickness of 12 to 40 nm.

[0004] Patent Document 2 discloses a titanium material that is resistant to discoloration and is characterized in that the amount of fluorine in the oxide film on the surface is 7 atomic % or less.

[0005] Patent Document 3 describes a method for forming an oxide film on a titanium surface, in which the composition of the titanium oxide is TiO ｘ where x is in the range of 0.8 to 1.8 and the density of the oxide film is 4.2 g / cm ３ Patent Document 3 discloses a titanium material that is resistant to discoloration in an atmospheric environment and is characterized by the above. The titanium material disclosed in Patent Document 3 is manufactured by treating the titanium surface with a mixed solution of nitric acid and hydrofluoric acid, and then treating it with a nitric acid solution.

[0006] Patent Document 4 discloses a pure titanium material for use as a building material, characterized in that the impurity elements Fe are restricted to 0.08 mass% or less, Nb to 0.02 mass% or less, and Co to 0.02 mass% or less. The pure titanium material disclosed in Patent Document 4 is produced by performing a final pickling process followed by heating in air or in a vacuum at 130 to 280°C for a predetermined period of time.

[0007] Patent Document 5 describes a method for manufacturing a titanium or titanium alloy substrate, in which a base material is titanium or a titanium alloy, a nitrogen-enriched titanium layer having a thickness of 0.2 to 1.5 μm is formed on the surface of the base material, and the nitrogen-enriched titanium layer contains, on average atomic %, 20 to 60 atomic % of nitrogen and 1 to 40 atomic % of oxygen, and the ratio of Ti (average atomic % value) / N (average atomic % value) within a range of 0.1 μm from the outermost layer is in the range of 1.2 to 4.0, and the average carbon concentration within a range of 0.2 μm deep from the surface of the base material toward the inside is 1 atomic % or more and 15 atomic % or less, and the color measurement value L ＊ , a ＊ , b ＊ The titanium material disclosed in Patent Document 5 is manufactured by an ion plating method.

[0008] Japanese Patent Publication No. 2002-12962 Japanese Patent Publication No. 2002-47589 Japanese Patent Publication No. 2005-154882 Japanese Patent Publication No. 2004-300569 Japanese Patent Publication No. 2010-265531

[0009] Non-coloring materials are required to have high resistance to discoloration so that interference colors do not occur. Furthermore, in recent years, there has been a demand for titanium materials that are resistant to discoloration even in even more severe acidic environments of pH 3.0 or less, or in environments where dry and wet cycles are repeated and the pH of the adhesive liquid tends to drop.

[0010] In Patent Documents 1 to 4, discoloration resistance is evaluated as follows: The material is immersed in a sulfuric acid solution of pH 3 or pH 4 at 60°C for several days, and discoloration resistance is evaluated based on the color difference before and after immersion. Specifically, the authors describe a color difference of 3 to 7 or less after immersion in a sulfuric acid solution of pH 3 at 60°C for 7 or 14 days, or a color difference of less than 5 or even less than 1 after immersion in a sulfuric acid solution of pH 4 at 60°C for 3 days. However, the above discoloration resistance evaluation does not adequately reflect use in high-temperature environments. Furthermore, when the titanium materials described in Patent Documents 1 to 4 were immersed in a sulfuric acid solution of pH 4 at 80°C for 4 days, the color difference before and after immersion was approximately 15 or more, indicating that conventional titanium materials do not have sufficient discoloration resistance under higher temperature conditions.

[0011] Furthermore, in the technology described in Patent Document 3, the titanium surface is treated with a mixed solution of nitric acid and hydrofluoric acid, and then treated with a nitric acid solution, which increases production costs and the environmental load.Furthermore, in the technology described in Patent Document 3, titanium material is produced by batch processing of cut plates, which also results in low production efficiency and high production costs.

[0012] The technique described in Patent Document 4 involves heating in the atmosphere or in a vacuum following pickling in the final step, which results in high manufacturing costs.

[0013] The technology described in Patent Document 5 is a batch process for producing titanium material from cut sheets by ion plating, and therefore the production efficiency is not very high and the production costs are high.

[0014] That is, with conventional techniques, it has been difficult to achieve color fastness in a severe acidic environment while taking into consideration production costs and environmental impact.

[0015] The present invention has been made in view of the above circumstances, and aims to provide a titanium material with excellent discoloration resistance that can be produced at low cost and with low environmental impact, and a method for producing the titanium material.

[0016] The present inventors have conducted a detailed study on the relationship between the elements contained in the surface of titanium material and discoloration resistance, and have found that the presence of SiO ２ and Al ２ O３ Furthermore, the present inventors have found that when SiO is contained on the surface of a titanium material, the discoloration resistance may be excellent. ２ and Al ２ O ３ The present inventors have also conducted detailed studies on the method for incorporating the compound, and have come up with the present invention.

[0017] The gist of the present invention, which was completed based on the above findings, is as follows: [1] A titanium material according to one embodiment of the present invention is a titanium material having a base material of pure titanium or a titanium alloy, and when the components constituting the surface of the titanium material are analyzed by X-ray photoelectron spectroscopy, the maximum Si concentration is 10 atomic % or more and 40 atomic % or less, the maximum Al concentration is 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration is 1 atomic % or more is 20 atomic % or more and 50 atomic % or less, in the material surface from the outermost surface to a position 50 nm in the depth direction, and the color measurement value of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is L ＊ : 55-75, a ＊ :1.0~2.0,b ＊ : 4.0 to 8.0. [2] The titanium material according to [1] above may have a maximum C concentration of 10 atomic % or less when the surface of the material is analyzed by X-ray photoelectron spectroscopy. [3] The titanium material according to [1] or [2] above may have a maximum F concentration of 10 atomic % or less and a maximum N concentration of 0 atomic % or more and 10 atomic % or less when the surface of the material is analyzed by X-ray photoelectron spectroscopy. [4] The titanium material according to any of [1] to [3] above may have a minimum Ti concentration of 1 atomic % or more and 40 atomic % or less when the surface of the material is analyzed by X-ray photoelectron spectroscopy.

[0018] [5] Furthermore, a method for producing a titanium material according to another aspect of the present invention is the method for producing a titanium material according to any one of the above [1] to [4], wherein the surface of the titanium material based on pure titanium or a titanium alloy is coated with SiO ２ and Al ２ O ３ The shot blasting process involves projecting a projectile composed of the above SiO ２The projection material and the Al ２ O ３ The particle size of each projection material is F20 to F100 in accordance with JIS R 6001-1:2017, and the projection amount is 1 to 50 g / m ２ s, the projection speed is 10 m / s or more and 100 m / s or less, and the projection time is 10 s / m ２ [6] 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 any one of [1] to [4] above, and includes an adhesion step of adhering colloidal silica and alumina colloid to the surface of a titanium material having a base material of pure titanium or a titanium alloy, and an annealing step of annealing the titanium material after the adhesion step in air or vacuum at a temperature between 100°C and 500°C for 5 minutes to 10 minutes.

[0019] As described above, according to the present invention, it is possible to provide a titanium material with excellent discoloration resistance that can be produced at low cost and with low environmental impact, and a method for producing the titanium material.

[0020] 1 is a graph showing the results of quantitative analysis in the depth direction by XPS of Examples No. 2 and No. 5 in the Examples. 2 is a graph showing the results of quantitative analysis in the depth direction by XPS of Examples No. 1 and No. 6 in the Examples.

[0021] 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" or "greater than" are not included in the numerical range.

[0022] <Titanium 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 when components constituting the surface of the titanium material are analyzed by X-ray photoelectron spectroscopy (XPS), it is found that, on the material surface from the outermost surface to a position 50 nm in the depth direction, the maximum Si concentration is 10 atomic % or more and 40 atomic % or less, the maximum Al concentration is 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration is 1 atomic % or more is 20 atomic % or more and 50 atomic % or less, and the color measurement value of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is L ＊ : 55-75, a ＊ :1.0~2.0,b ＊ : 4.0 to 8.0, which will be explained in detail below.

[0023] The titanium substrate of the titanium material according to this embodiment 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.

[0024] Pure titanium includes, for example, commercially pure titanium specified by JIS Classes 1 to 4 and the corresponding ASTM Grades 1 to 4. Specifically, the commercially pure titanium targeted in this embodiment contains, by mass, 0.1% or less of C, 0.015% or less of H, 0.4% or less of O, 0.07% or less of N, and 0.5% or less of Fe, with the balance being Ti and impurities. Note that, for buildings, commercially pure titanium specified by JIS Class 1 or its equivalent ASTM Gr. 1, or equivalent materials, is primarily used. The lower limits of the contents of C, H, O, N, and Fe are not particularly limited and may be 0%.

[0025] Examples of titanium alloys include α-type titanium alloys, α+β-type titanium alloys, and β-type titanium alloys.

[0026] 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-0.05Pd, Ti-0.15Pd, Ti-0.5Cu, Ti-1.0Cu, Ti-1.0Cu-0.5Nb, and Ti-1.0Cu-1.0Sn-0.3Si-0.25Nb.

[0027] 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.

[0028] 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.

[0029] The titanium base material may contain, for example, in mass %, Cu: 0% or more and 1.2% or less, Nb: 0% or more and 0.5% or less, Sn: 0% or more and 4.5% or less, Si: 0% or more and 0.5% or less, Al: 0% or more and 7.0% or less, V: 0% or more and 22.5% or less, Fe: 0% or more and 2.5% or less, Mo: 0. % or more and 11.5% or less, Zr: 0% or more and 6.0% or less, Cr: 0% or more and 11.0% or less, Pd: 0% or more and 0.25% or less, Co: 0% or more and 0.80% or less, Ni: 0% or more and 0.80% or less, N: 0% or more and 0.050% or less, C: 0% or more and 0.10% or less, H: 0% or more and 0.015% or less, O: 0% or more and 0.35% or less, and the balance being Ti and impurities.

[0030] Impurities are components present in titanium regardless of their intended addition, but which do not necessarily exist in the resulting titanium material. The term "impurities" encompasses impurities that are mixed in from raw materials or the manufacturing environment during industrial titanium production. Examples of impurities include Cl, Na, Mg, Ca, and B. The upper limits of each impurity element are Cl: 0.1% or less, Na: 0.01% or less, Mg: 0.01% or less, Ca: 0.01% or less, and B: 0.01% or less. The lower limits of the contents of Cl, Na, Mg, Ca, and B are not particularly limited and may be 0%. The total amount of impurities is preferably 0.1% by mass or less.

[0031] The shape of the titanium material according to this embodiment is not particularly limited, and may be a plate, a coil, a strip, or the like.

[0032] When the components constituting the surface of the titanium material according to this embodiment are analyzed by XPS, the maximum Si (silicon) concentration is 10 to 40 atomic % and the maximum Al (aluminum) concentration is 10 to 40 atomic % in the material surface from the outermost surface to a depth of 50 nm, and the minimum O (oxygen) concentration in the depth range from the outermost surface to a depth of 50 nm where either the Si concentration or the Al concentration is 1 atomic % or more is 20 to 50 atomic %. Hereinafter, the range from the outermost surface to a depth of 50 nm will be referred to as the material surface.

[0033] SiO ２ and Al ２ O ３ The present inventors speculate that SiO improves the discoloration resistance of titanium materials due to the following effects: ２ and Al ２ O ３ is inactive in acidic solutions compared to C, TiC, etc. present on the surface of titanium material, and SiO ２ and Al ２ O ３ By covering the surface with SiO, it has the effect of suppressing the elution of titanium ions. ２ and Al ２ O ３ is TiO ２The semiconductor properties are different from those of SiO ２ and Al ２ O ３ The deposition of Al has the effect of preventing electron transfer from the acidic solution (bipolar film effect). ２ O ３ is an amphoteric oxide that reacts with acid to decompose into metal salts and water, which has the effect of raising the pH of the rainwater (acidic solution) that adheres to the material and inhibiting the elution of titanium ions. It is believed that one of the above three effects, or a combination of these effects, inhibits the elution of titanium ions even in a severe acid rain environment, improving the discoloration resistance of titanium materials.

[0034] SiO ２ and Al ２ O ３ In order to obtain the discoloration resistance effect by the titanium material, SiO ２ and Al ２ O ３ When the surface of a titanium material is analyzed by XPS, if the maximum Si concentration on the material surface is 10 atomic % or more and the maximum Al concentration is 10 atomic % or more, a sufficient discoloration resistance effect can be obtained. On the other hand, when the surface of a titanium material is analyzed by XPS, if the maximum Si concentration and the maximum Al concentration on the material surface are 40 atomic % or less, a sufficient discoloration resistance effect can be obtained while maintaining the metallic color. Furthermore, if the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration is 1 atomic % or more is 20 atomic % or more and 50 atomic % or less, a SiO concentration of 20 atomic % or more and 50 atomic % or less can be obtained to obtain a discoloration resistance effect. ２ and Al ２ O ３ It can be said that a layer of silicon or aluminum is formed. To obtain a more excellent discoloration resistance effect, it is preferable that the maximum Si concentration or the maximum Al concentration on the material surface is 15 atomic % or more. The maximum Si concentration or the maximum Al concentration on the material surface is preferably 35 atomic % or less, and more preferably 30 atomic % or less.

[0035] On the other hand, SiO ２ and Al ２ O ３If a large amount of these elements are present, they may cover the surface of the titanium material, damaging the original silver color of the uncolored material. Therefore, it is preferable that Ti (titanium) is exposed on at least a portion of the surface. Therefore, when analyzing the surface of a titanium material using XPS, it is preferable that the minimum Ti concentration on the surface be 1 atomic % or more. On the other hand, when analyzing the surface of a titanium material using XPS, the titanium present on the surface is present in the form of oxygen, and it is preferable that the minimum Ti concentration on the surface be 40 atomic % or less. When analyzing the surface of a titanium material using XPS, it is more preferable that the minimum Ti concentration on the surface be 5 atomic % or more. Furthermore, when analyzing the surface of a titanium material using XPS, it is more preferable that the minimum Ti concentration on the surface be 35 atomic % or less, more preferably 30 atomic % or less, more preferably 25 atomic % or less, more preferably 20 atomic % or less, and even more preferably 16.0 atomic % or less ... ２ and Al ２ O ３ may be present in the form of islands.

[0036] In the titanium material according to this embodiment, 80% or more of the surface is made of SiO ２ and Al ２ O ３ That is, it is preferable that the surface is covered with SiO ２ and Al ２ O ３ The coverage of the surface of the titanium material by Al is 80% or more. Specifically, when analyzed by Auger Electron Spectroscopy (AES), the area where Al and Si are present at 1 atomic % or more is 80% or more. The coverage may be, for example, 85% or more, or 90% or more. The coverage may also be, for example, 100% or less, or 95% or less. The remainder is at least one of compounds composed of titanium and oxygen, nitrogen, or carbon, and carbon compounds or calcium compounds.

[0037] The coverage is calculated as follows. Specifically, an arbitrary surface of a titanium material is measured at 1 μm intervals over an area of ​​100 μm×100 μm using AES, and the number of points where Al or Si is present at 1 atomic % or more is calculated. Specifically, the acceleration voltage of the electron beam in AES is 10 kV, and the emission current is 10 nA. For sputtering of the surface etching, Ar ＋ Using SiO ２ The components are analyzed every 0.5 nm of sputtering depth in terms of the total number of measurement points. The number of measurements at each measurement point is 10 times per point. The measurement time for each measurement point is constant, but the number of measurements may be changed to improve measurement accuracy. The calculated number of measurement points is converted into a ratio to the total number of measurement points, and the Al ２ O ３ and SiO ２ The surface coverage rate was set at .

[0038] Furthermore, when analyzing the composition of the material surface using XPS, the maximum C (carbon) concentration is preferably 0 atomic % or more and 10 atomic % or less, and the maximum F (fluorine) concentration is preferably 0 atomic % or more and 10 atomic % or less. High C or F concentrations are prone to discoloration. This is because C, F, or their compounds make titanium more likely to dissolve, or because C and F exist as compounds with titanium, which easily dissolve, causing the growth of an oxide film. Note that C and F may exist independently or as compounds with titanium, hydrogen, oxygen, etc. A maximum C concentration of 10 atomic % or less and a maximum F concentration of 10 atomic % or less on the material surface suppresses titanium dissolution and the growth of an oxide film. Therefore, it is preferable that the maximum C concentration be 10 atomic % or less and the maximum F concentration be 10 atomic % or less. More preferably, the C concentration is 8 atomic % or less and the F concentration is 9 atomic % or less. The C and F concentrations on the material surface are preferably low, with both exceeding 0 atomic percent. From a manufacturing perspective, the practical lower limit for both C and F concentrations is 0.1 atomic percent. The C concentration on the material surface may be 0.5 atomic percent or more, preferably 1.0 atomic percent or more, and more preferably 1.1 atomic percent or more. The F concentration on the material surface may be 0.2 atomic percent or more, preferably 0.5 atomic percent or more. C may exist, for example, as TiC. Furthermore, in the production of titanium materials, a pickling process is generally performed in which the titanium material is washed with a mixed acid of hydrofluoric acid and nitric acid. When the pickling process is performed, titanium fluoride may be formed at the interface between the oxide film and the titanium substrate. In this case, F from the titanium fluoride may be detected when the composition of the material surface is analyzed by XPS.

[0039] Furthermore, when the components of the material surface are analyzed by XPS, the maximum N (nitrogen) concentration is preferably 0 atomic % or more and 10 atomic % or less. This is because a high N concentration on the material surface makes it impossible to maintain a dense oxide film, which may cause cracking or peeling of the oxide film, making it impossible to suppress titanium elution. A N concentration of 10 atomic % or less suppresses titanium elution and oxide film growth in the titanium material. Preferably, the N concentration is 8 atomic % or less, more preferably 6 atomic % or less. Even more preferably, the N concentration is 5 atomic % or less. The N concentration on the material surface is controlled during manufacturing and may not be detectable. Therefore, the substantial lower limit is 0 atomic % or more. It may be preferably greater than 0 atomic %, more preferably 0.1 atomic % or more.

[0040] The constituent components of the material surface are determined from the depthwise composition distribution obtained by XPS while sputtering with Ar ions on a titanium material after immersion in acetone and ultrasonic cleaning. The ultrasonic cleaning time may be, for example, 30 seconds or more. After identifying the elements present through qualitative analysis by XPS, quantitative analysis values ​​of each element are obtained to obtain quantitative values ​​of the constituent components of the material surface. The composition analysis in the depthwise direction is performed to obtain SiO ２ Quantitative analysis of each element is performed every 1 nm of sputtering depth, calculated in terms of atomic percent, and the concentrations of Si, Al, O, Ti, C, F, and N are determined from the surface of the titanium material to a depth of 50 nm. Because the C concentration at the outermost surface of the titanium material is affected by the adhesion of organic matter not derived from the titanium material, the value at a depth of 1 nm or more from the outermost surface is taken as the C concentration at the material surface.

[0041] The titanium material according to this embodiment is a silver-colored uncolored material. The color measurement value of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is L ＊ : 55-75, a ＊ :1.0~2.0,b ＊If the IR is between 4.0 and 8.0, the titanium material will be silvery. Color measurements are performed using a Minolta Co., Ltd. color difference meter CR-200b under Illuminant C. Illuminant C refers to the auxiliary illuminant C for colorimetry described in CIE (International Commission on Illumination) 15.3 and JIS Z 8720:2012, and is a light source used to measure the color of objects illuminated by daylight. Illuminant C has a color temperature of 6777K.

[0042] The thickness of the titanium material according to this embodiment is not particularly limited, and is, for example, 0.1 to 5.0 mm.

[0043] <Method for manufacturing titanium material> Next, an example of a method for manufacturing a titanium material according to an embodiment of the present invention will be described. The method for manufacturing a titanium material according to this embodiment involves forming a SiO ２ and Al ２ O ３ The surface treatment process includes disposing SiO ２ and Al ２ O ３ The method for manufacturing the titanium material is not particularly limited as long as the titanium material can be manufactured by disposing the titanium material on the surface of the titanium material. ２ and Al ２ O ３ or a process in which a colloid made of silica and silica hydrate (colloidal silica) and a colloid made of alumina hydrate (alumina colloid) are adhered to the surface of the titanium material, followed by annealing. Below, a method for manufacturing a titanium material will be described using as an example a case in which the shot blasting process or the adhesion process and annealing process are used as the surface treatment process.

[0044] The surface treatment step is carried out as the final step in the manufacturing process of a titanium material. In the manufacturing method of a titanium material according to this embodiment, for example, the surface treatment step is carried out after the ingot step, hot rolling step, cold rolling step, annealing step, and temper rolling / tensile straightening step are carried out in sequence. Also, for example, if the temper rolling / tensile straightening step is omitted, the surface treatment step is carried out after the annealing step. The above steps other than the surface treatment step can be carried out by known methods.

[0045] (Manufacturing Method Example 1: Shot Blasting Process) When the surface of a titanium material is shot blasted, the shot material is SiO ２ and Al ２ O ３ Shot blasting not only roughens the surface of the titanium material, but also has a surface grinding effect. The finer the particle size of the shot material, the greater the grinding effect, making it possible to strip off impurity elements such as C and N remaining on the surface of the titanium material. Conversely, if the particle size of the shot material is larger, the grinding effect weakens and it may not be possible to sufficiently strip off C and N. The particle size of each shot material is F20 to F100 in accordance with JIS R 6001-1:2017. If the particle size is less than F20, the shot material will remain unevenly, making it impossible to ensure discoloration resistance across the entire surface of the titanium material. Preferably, the particle size of all shot materials is F30 or greater, more preferably F36 or greater. On the other hand, if the particle size is greater than F100, SiO ２ and Al ２ O ３ It is not possible to leave more than the required concentration, and the discoloration resistance cannot be improved. ２ and Al ２ O ３ In order to further enhance the synergistic effect of SiO on discoloration resistance, it is preferable that the difference in particle size number between the two is 70 or less. ２ and Al ２ O ３When a shot blasting material composed of the above is used, the shot blasting may be performed once by mixing the shot blasting materials together, or shot blasting may be performed once using each shot blasting material. The number of shot blasting times is not limited to one, and may be multiple times. In consideration of productivity, the upper limit of the number of shot blasting times is preferably 10 times or less.

[0046] SiO ２ The projection material is composed of SiO as the main component. ２ Contains SiO ２ The projection material is, for example, SiO ２ Contains 50 mass % or more of SiO ２ The projection material may be, for example, glass beads containing 99% or more by mass of soda lime glass. Soda lime glass is, for example, a substance with CAS registration number 65997-17-3, and is a material containing SiO ２ :70-74% by mass, Al ２ O ３ :0 to 2% by mass, CaO: 6 to 12% by mass, MgO: 0 to 4% by mass, Na ２ O: 12 to 16 mass %, and the remainder: including impurities. SiO ２ SiO of the projection material consisting of ２ The content may be 100% by mass or less, 90% by mass or less, or 80% by mass or less.

[0047] Al ２ O ３ The projection material is composed of Al as the main component. ２ O ３ Contains Al ２ O ３ The projection material is, for example, Al ２ O ３ Contains 50 mass % or more of Al. ２ O ３ The projection material is, for example, Al ２ O ３ :95% by mass, SiO ２ : 2% by mass, TiO ２ : 2.5% by mass, and Fe ２ O ３ : Contains 0.5% Al ２ O３ The projection material consists of Al ２ O ３ The content may be 100% by mass or less, 95% by mass or less, or 90% by mass or less.

[0048] The amount of projected material is 1 to 50 g / m ２ s. The projection amount is 1 g / m ２ If the thickness is less than s, SiO ２ and Al ２ O ３ On the other hand, when the projection amount is 50 g / m, the maximum Si concentration cannot be 10 atomic % or more, and the maximum Al concentration cannot be 10 atomic % or more on the material surface. ２ If the concentration exceeds s, the remaining amount will vary depending on the type of projection material, so it is necessary to set the SiO concentration to a level that is effective in improving discoloration resistance. ２ or Al ２ O ３ The amount of projection material is preferably 2 g / m ２ s or more, more preferably 3 g / m ２ The amount of projection material is preferably 40 g / m ２ s or less, more preferably 20 g / m ２ The amount of projection material is preferably 2 to 40 g / m ２ s, more preferably 3 to 20 g / m ２ ・s.

[0049] The projection speed of the projection material is 10 to 100 m / s. If the projection speed is less than 10 m / s, SiO ２ and Al ２ O ３However, if the projection speed exceeds 100 m / s, Si or Al does not remain on the material surface, and the maximum Si concentration cannot be set to 10 atomic % or more, or the maximum Al concentration cannot be set to 10 atomic % or more. If the projection speed exceeds 100 m / s, the material surface will become uneven, and the color will become uneven. ＊ : 55-75, a ＊ :1.0~2.0,b ＊ : 4.0 to 8.0 is not possible. Furthermore, the amount of distortion increases and begins to affect the surface hardness, adversely affecting the processing during product use and the surface design after processing. The projection velocity of the projection material is preferably 20 m / s or more, more preferably 30 m / s or more. Furthermore, the projection velocity of the projection material is preferably 80 m / s or less, more preferably 70 m / s or less. The projection velocity of the projection material is preferably 20 to 80 m / s, more preferably 30 to 70 m / s.

[0050] The projection time of the projection material (shot blast time) is 10 s / m ２ That's all. The projection time is 10 s / m ２ If the thickness is less than 100 nm, SiO ２ or Al ２ O ３ However, the maximum Si concentration on the material surface cannot be set to 10 atomic % or more, and the maximum Al concentration cannot be set to 10 atomic % or more. On the other hand, the maximum projection time is not particularly limited, but from the viewpoint of workability, it is recommended to set it to 120 s / m ２ The projection time of the projection material is preferably 20 s / m or less. ２ More preferably, 30 s / m ２ Furthermore, although not particularly limited, the projection pressure may be, for example, more than 0.1 MPa and not more than 1.5 MPa, and the projection angle may be, for example, more than 40° and not more than 90° (vertical).

[0051] (Production Method Example 2: Adhesion Step and Annealing Step) When colloidal silica and alumina colloid are adhered and annealed, the following may be used as the colloidal silica and alumina colloid. Examples of colloidal silica include OP-S suspension manufactured by Struers and MasterMet2 manufactured by Buehler. Examples of alumina colloid include OP-A suspension manufactured by Struers, AP-D manufactured by Struers, and MasterPrep manufactured by Buehler.

[0052] It is important that the colloidal concentration (concentration of the dispersed phase) of each of the colloidal silica and the alumina colloid is 1% by mass or more and less than 50% by mass. When the colloidal concentrations of both the colloidal silica and the alumina colloid are 1% by mass or more, a discoloration resistance effect is obtained. When the colloidal concentrations of each of the colloidal silica and the alumina colloid are less than 50% by mass, there is no significant difference in the proportion of these colloids adhering to the material surface, and a discoloration resistance effect is obtained while maintaining the metallic color. The colloidal concentration of each of the colloidal silica and the alumina colloid may be 45% by mass or less. The colloidal concentration of each of the colloidal silica and the alumina colloid is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. The colloidal silica and the alumina colloid are preferably SiO ２ or Al ２ O ３ is dispersed in water, alcohol, etc. Colloidal silica is, for example, SiO ２ : 5 to 10 mass %, 1,3 butanediol: 5 to 20 mass %, and the remainder: water. ２ O ３The dispersion medium may be 10 to 30% by mass, with the remainder being water. 1,3-butanediol is readily soluble in water and ethanol and has a boiling point of approximately 200°C, so it is removed by washing with water or ethanol, or by drying by heating. Therefore, 1,3-butanediol does not remain on the surface of the titanium material. Organic solvents that are easily soluble in water or have a relatively low boiling point are removed by washing with water or ethanol, or by drying by heating, just like 1,3-butanediol. Therefore, carbon derived from the dispersion medium does not remain on the surface of the titanium material. Furthermore, since ethanol also has a boiling point of approximately 80°C, it is completely removed by drying at 100°C or higher, so carbon derived from ethanol does not remain on the surface of the titanium material.

[0053] The amount of colloidal silica and alumina colloid attached to the titanium material may be, when analyzed by XPS, such that the maximum Si concentration on the surface of the titanium material of the final product is 10 atomic % or more and 40 atomic % or less, the maximum Al concentration is 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction within a range where either the Si concentration or the Al concentration is 1 atomic % or more is 20 atomic % or more and 50 atomic % or less, for example, 0.01 to 10 g / m ２ That's fine.

[0054] The method for applying the colloidal silica and alumina colloid is not particularly limited, and the titanium material may be immersed in each solution, or each solution may be sprayed or coated. The order in which the colloidal silica and alumina colloid are applied is also not particularly limited. A mixed solution of colloidal silica and alumina colloid may also be used.

[0055] After immersion in colloidal silica and alumina colloid, the titanium material surface is preferably washed with alcohol or hydrofluoric acid. This washing step is optional. Furthermore, washing with alcohol allows for selective washing away of organic components other than the colloid while leaving the colloidal oxide particles adsorbed on the surface. The alcohol used to wash the titanium material surface may be, for example, ethanol, 1-propanol, 2-propanol, or butanol. The alcohol used is heated and dried after washing, so carbon does not remain on the titanium material surface. Washing with alcohol can reduce the maximum carbon concentration to 10 atomic % or less when the material surface is analyzed by X-ray photoelectron spectroscopy. Furthermore, washing with alcohol can reduce the maximum fluorine and nitrogen concentrations to 10 atomic % or less when the material surface is analyzed by X-ray photoelectron spectroscopy.

[0056] The annealing conditions are heating in air or vacuum at a holding temperature of 100°C to 500°C for 5 to 10 minutes. Heating for a long period of time strengthens the adsorption of colloidal oxide particles, but also causes the growth of an oxide film, resulting in the loss of the silver-white metallic color. Therefore, heating is performed for 10 minutes or less. The heating atmosphere is air or vacuum. Furthermore, if the holding temperature is less than 100°C, the adsorption of colloidal oxide particles becomes insufficient, and the effect of improving discoloration resistance is not fully achieved. On the other hand, if the holding temperature exceeds 500°C, the oxide film grows rapidly, resulting in the loss of the silver-white metallic color. The holding temperature may be 200°C or higher. Alternatively, the holding temperature may be 400°C or lower. The holding time may be 6 minutes or longer. Alternatively, the holding time may be 9 minutes or shorter.

[0057] The above steps other than the surface treatment step can be carried out by known methods. For example, in the ingot casting step, a pure titanium or titanium alloy ingot having the above-mentioned components is produced using sponge titanium or a master alloy for adding alloying elements as a raw material by various melting methods, such as a vacuum arc melting method, an electron beam melting method, or a hearth melting method such as a plasma melting method. The obtained ingot is then bloomed and hot forged as necessary to produce an ingot.

[0058] 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.

[0059] In the cold rolling process, the hot-rolled titanium material is rolled under conditions that result in the desired thickness and properties. If multiple cold rolling passes are performed, the titanium material may be annealed between cold rolling passes.

[0060] In the annealing step after the cold rolling step, for example, impurities such as lubricating oil adhered during the cold rolling step may be removed in an alkali washing line, and then the titanium material may be annealed in an inert atmosphere.Furthermore, for example, the titanium material after the cold rolling step may be subjected to salt bath descaling and pickling in this order after the annealing step.

[0061] Furthermore, an annealing step may be carried out before the surface treatment step, in which the titanium material is annealed. The annealing step may be carried out, for example, in an inert atmosphere, at an annealing temperature of 350 to 700°C for an annealing time of 1 to 40 hours. The annealing temperature may be 400°C or higher. The annealing time may be 10 hours or longer. This annealing step can remove C, if present on the surface of the titanium material. Note that if the annealing step is carried out in an air annealing atmosphere, the oxide film will become thick, the metallic color will be lost, and the color measurement results will not be satisfied.

[0062] The temper rolling and tensile straightening process may be carried out as appropriate, for example, for the purpose of straightening the shape of the titanium material after the annealing process.

[0063] According to the above-described manufacturing method, when analyzed by XPS, the maximum Si concentration at the surface of the material is 10 atomic % or more and 40 atomic % or less, the maximum Al concentration is 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration is 1 atomic % or more is 20 atomic % or more and 50 atomic % or less, and the color measurement value of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 is L ＊ : 55-75, a ＊ :1.0~2.0,b ＊ It is possible to produce a titanium material having a viscosity of 4.0 to 8.0. Furthermore, since the above-mentioned production method allows for continuous processing of long titanium material such as strips, it is possible to suppress increases in production costs compared to batch processing. Furthermore, since titanium material with excellent discoloration resistance can be obtained without performing a pickling process, it is possible to suppress the use of chemicals that have a large environmental impact, such as nitric acid and hydrofluoric acid, and therefore it is possible to suppress an increase in the environmental impact.

[0064] 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.

[0065] Example 1 Titanium cold-rolled sheets (titanium substrates) of the types shown in Tables 1 to 3 were manufactured, and multiple samples measuring 70 mm in length (length in the rolling direction) x 70 mm in width (length in the direction perpendicular to the rolling direction on the rolled surface) x 0.3 mm in thickness were cut out from the titanium cold-rolled sheets, and subjected to an annealing process under the conditions shown in Tables 1 to 3. Subsequently, a shot blasting process or a surface treatment process consisting of an adhesion process and an annealing process was carried out. CP1 listed under the titanium material type heading in Tables 1 to 3 indicates commercially pure titanium JIS class 1, CP2 indicates commercially pure titanium JIS class 2, and CP3 indicates commercially pure titanium JIS class 3. Ti-1Cu, Ti-3Al-2.5V, Ti-5Al-1Fe, Ti-0.05Pd, Ti-0.15Pd, and Ti-20V-4Al-1Sn are symbols indicating the content (mass%) of contained elements and the type of contained element (element symbol) after a hyphen, respectively, and indicate the nominal composition of the titanium material. In Tables 1 to 3, "-" indicates that no experiment was performed. The underlined parts in Tables 1 to 3 indicate that the experiment is outside the scope of the present invention.

[0066]

[0067]

[0068]

[0069] After the surface treatment process, the test piece was immersed in acetone and ultrasonically cleaned for 5 minutes or more, and then the surface of the test piece was wiped with a cloth soaked in ethanol and dried. Qualitative analysis, quantitative analysis, and depth direction analysis were performed by XPS on the range from the outermost surface of the annealed test piece to a position 50 nm in the depth direction. The XPS analysis conditions were as follows: Apparatus: VersaProbe III manufactured by ULVAC-PHI X-ray source: mono-AlKα (hν: 1486.6 eV) Beam diameter: 200 μmφ (≒ analysis area) Sputtering conditions: Ar ＋ , sputtering rate 2.0 nm / min. (SiO ２ Conversion value) SiO ２ The converted value is the SiO thickness measured in advance using an ellipsometer. ２The sputtering rate was determined using a film under the same measurement conditions. The O concentrations in Tables 4 to 6 indicate the minimum O concentration in the depth range from the outermost surface of the test piece to a depth position of 50 nm, where either the Si concentration or the Al concentration is 1 atomic % or more. Regarding carbon, whose concentration decreases almost monotonically with respect to the depth direction, the outermost surface is affected by the adhesion of organic matter. Therefore, the maximum C concentration from 1 nm depth from the outermost surface onward was taken as the maximum C concentration on the material surface. Furthermore, "-" in Tables 4 to 6 indicates that the concentration was below the detection limit.

[0070] Furthermore, test pieces measuring 50 mm in length, 25 mm in width, and 0.3 mm in thickness were cut out from the samples after the surface treatment process and subjected to a discoloration acceleration test. The discoloration acceleration test simulated a tropical environment with acid rain, and involved immersion in a sulfuric acid solution with a pH of 3 at 80°C for 4 days. The color L of the titanium material surface before and after the discoloration acceleration test was ＊ , a ＊ , b ＊ was measured in accordance with JIS Z 8781-4:2013. The color was measured using a Minolta Co., Ltd. color difference meter CR-200b under light source C. Measurements were made on each test piece before and after the accelerated discoloration test at five points on one side of the length x width of the test piece, one point at the center and four points at the corners of the surface, and two points on the front and back surfaces, for a total of ten points. All ten color measurement points on the titanium material surface before the accelerated discoloration test were L ＊ : 55-75, a ＊ :1.0~2.0,b ＊ If the color measurement result was within the range of 4.0 to 8.0, the evaluation result was rated as GOOD (pass), and if it was outside the range, it was rated as BAD (fail). In addition, examples that were not evaluated are marked with "-" in the evaluation result section in the table. Tables 4 to 6 also list the maximum and minimum values ​​at each measurement point.

[0071] In addition, the L before and after the discoloration acceleration test was measured. ＊ , a ＊ , b ＊ From the above, the color difference ΔE before and after the discoloration acceleration test ＊ The color difference was calculated by the difference in brightness L before and after the accelerated discoloration test at each measurement point. ＊ and chromaticity a ＊ , b ＊The difference ΔL between the values ​​before and after the accelerated discoloration test at each measurement point was used. ＊ , Δa ＊ , Δb ＊ From this, the color difference ΔE ＊ ab = [(ΔL ＊ ) ２ + (Δa ＊ ) ２ + (Δb ＊ ) ２ ] １／２ The color difference ΔE was calculated according to the following formula. ＊ The ab values ​​were calculated for each measurement point and evaluated at all 10 points. Tables 4 to 6 show the maximum values ​​at each measurement point. Color difference ΔE, which is the difference in color that is recognized visually ＊ Since the threshold value of ab is 8.0, the color difference ΔE ＊ When the maximum value of ab is less than 8.0, the discoloration resistance is judged to be A (excellent), and the color difference ΔE before and after the discoloration acceleration test is ＊ When the maximum value of ab is 8.0 or more and less than 10.0, the discoloration resistance is judged to be B (good), and the color difference ΔE before and after the discoloration acceleration test is ＊ When the maximum value of ab was 10.0 or more, the discoloration resistance was judged to be C (poor). In addition, examples that were not evaluated are marked with "-" in the evaluation result column in the tables. Note that the underlined conditions in Tables 4 to 6 indicate conditions outside the scope of the present invention.

[0072]

[0073]

[0074]

[0075] Example No. 1 is an example in which the surface treatment process was not performed. In this example, Si and Al were not detected on the material surface, the minimum O concentration was 1.0 atomic %, and the discoloration resistance was poor.

[0076] In the example of No. 2, SiO with a particle size of F36 was used for the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F36. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0077] In the example of No. 3, SiO with a particle size of F36 was used for the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F100. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0078] In the example of No. 4, SiO with a particle size of F100 was used for the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F36. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0079] In the example of No. 5, the first shot blasting treatment was performed using Al with a grain size of F36. ２ O ３ The second shot blasting treatment was performed using SiO2 with a particle size of F36. ２ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0080] Example No. 6 is an example in which a colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed for 2 minutes in a colloidal solution with a concentration of 20 mass% each and a temperature of 50°C. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 200°C for 5 minutes. In this example, the maximum Si concentration on the material surface was 10 atomic % to 40 atomic %, the maximum Al concentration was 10 atomic % to 40 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % to 50 atomic %, the color measurement evaluation result was pass, and the evaluation result for color resistance was excellent.

[0081] Example No. 7 is also an example in which colloid immersion treatment was performed. ２ concentration and Al ２ O ３This is an example in which the concentrations of each were 10 mass %, and the other conditions were the same as in Example No. 6. In this example, at the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0082] Example No. 8 is also an example in which colloid immersion treatment was performed. ２ concentration and Al ２ O ３ This example was performed under the same conditions as Example No. 6, with the concentrations of each being 40 mass %, and other conditions being the same as Example No. 6. In this example, at the material surface, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0083] In the example of No. 9, SiO2 with a particle size of F20 was used for the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F20. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, at the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, and discoloration resistance was good. This is thought to be because the diameter of the shot material was relatively large and the shot material remained unevenly, resulting in the formation of parts where discoloration resistance could not be ensured.

[0084] In the example of No. 10, SiO with a particle size of F30 was used for the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F30. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0085] In the example of No. 11, the first shot blasting treatment was performed using Al with a grain size of F36. ２ O ３ Projection material and SiO ２ This is an example using a projection material. ２ O ３ Projection material and SiO ２ The proportions of the projection material were 50% by mass and 50% by mass, respectively. The projection amount of the projection material was 5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0086] In the example of No. 12, the first shot blasting treatment was performed using Al with a grain size of F36. ２ O ３ The second shot blasting treatment was performed using SiO2 with a particle size of F36. ２ This is an example using a projectile. The projectile amount in each shot blasting process was 50 g / m ２s, the projection speed is 10 m / s, and the projection time is 15 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0087] In the example of No. 13, Al of grain size F36 was used for the first shot blasting treatment. ２ O ３ The second shot blasting treatment was performed using SiO2 with a particle size of F36. ２ This is an example using a projectile. The amount of projectile in each shot blasting process was 1 g / m ２ s, the projection speed is 100 m / s, and the projection time is 60 s / m ２ In this example, on the surface of the material, the maximum Si concentration was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation result of the color measurement was pass, and the evaluation result of the discoloration resistance was excellent.

[0088] Example No. 14 is an example in which a colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed for 2 minutes in a colloidal solution with a concentration of 20 mass% each and a temperature of 50°C. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 500°C for 5 minutes. In this example, the maximum Si concentration on the material surface was 10 atomic % to 40 atomic %, the maximum Al concentration was 10 atomic % to 40 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % to 50 atomic %, the color measurement evaluation result was pass, and the evaluation result for color resistance was excellent.

[0089] Example No. 15 is an example in which a colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed in a colloidal solution with a concentration of 20 mass% each at 50°C for 2 minutes. The surface of the sample removed from the colloidal solution was washed with ethanol and then annealed in a vacuum at 200°C for 5 minutes. In this example, the maximum Si concentration on the material surface was 10 atomic % to 40 atomic %, the maximum Al concentration was 10 atomic % to 40 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % to 50 atomic %, the color measurement evaluation result was pass, and the evaluation result for color resistance was excellent.

[0090] Examples No. 16 to 23 were performed using a different titanium material from Example No. 2, with the other conditions being the same as those of Example No. 2. In these examples, when measured by XPS, the maximum Si concentration at the material surface was 10 atomic % or more and 40 atomic % or less, the maximum Al concentration was 10 atomic % or more and 40 atomic % or less, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was 20 atomic % or more and 50 atomic % or less, the evaluation results for color measurement were pass, and the evaluation results for discoloration resistance were excellent.

[0091] Example No. 24 is SiO with particle size F36 ２ In this example, no Al was detected on the surface of the material, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20%, resulting in a poor evaluation of discoloration resistance.

[0092] Example No. 25 is Al with a particle size of F36. ２ O ３ In this example, no Si was detected on the surface of the material, and the minimum O concentration in the depth direction where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20%, resulting in a poor evaluation of discoloration resistance.

[0093] Example No. 26 is an example in which the particle size of the shot material used in each shot blasting treatment was changed to F120 from Example No. 2, and the other conditions were the same as those of Example No. 2. In this example, at the material surface, the maximum Si concentration was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result for discoloration resistance was poor.

[0094] Example No. 27 is an example in which the particle size of the shot material used in each shot blasting treatment in Example No. 2 was changed to F14, and other conditions were the same as those in Example No. 2. In this example, at the material surface, the maximum Si concentration was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result for discoloration resistance was poor.

[0095] Example No. 28 is an example in which the projection speed in Example No. 2 was changed from 40 m / s to 5 m / s, and the other conditions were the same as those in Example No. 2. In this example, at the material surface, the maximum Si concentration was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result for discoloration resistance was poor.

[0096] Example No. 29 is an example in which the projection speed in Example No. 2 was changed from 40 m / s to 150 m / s, and the other conditions were the same as those in Example No. 2. In this example, at the material surface, the maximum Si concentration was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the results of the color measurement and the evaluation of discoloration resistance were poor.

[0097] Example No. 30 is the same as Example No. 2 except that the projection time is 60 s / m ２ to 5 s / m ２This is an example in which the test conditions were changed to Example No. 1, with the other conditions being the same as in Example No. 2. In this example, at the surface of the material, the maximum Si concentration was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result for discoloration resistance was poor.

[0098] In the example of No. 31, SiO with a particle size of F36 was used in the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F36. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 0.5 g / m ２ s, the projection speed is 40 m / s, and the projection time is 60 s / m ２ In this example, the maximum Si concentration on the surface of the material was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result of discoloration resistance was poor.

[0099] In the example of No. 32, SiO with a particle size of F36 was used in the first shot blasting treatment. ２ The second shot blasting treatment was performed using a projectile of Al with a particle size of F36. ２ O ３ This is an example using a projectile. The projectile amount in each shot blasting process was 60 g / m ２ s, the projection speed is 10 m / s, and the projection time is 60 s / m ２ In this example, the maximum Si concentration on the surface of the material was less than 10 atomic %, and the evaluation result of discoloration resistance was poor.

[0100] In the example of No. 33, the annealing atmosphere in the annealing step was air, and the atmospheric gas pressure was 1.0 × 10 ５ This example was performed under the same conditions as Example No. 2, except that the annealing temperature was changed to 1 Pa and the annealing time was changed to 1 hour. In this example, the oxide film became thick because annealing was performed in the air, and the evaluation result of the color measurement was unacceptable.

[0101] Example No. 34 is an example in which the annealing temperature in the annealing step was changed to 350°C, and the other conditions were the same as those of Example No. 2. In this example, the annealing temperature was low, so C remained on the surface of the titanium material, the maximum C concentration on the material surface exceeded 10 atomic %, and the evaluation result for discoloration resistance was good.

[0102] Example No. 35 is an example in which the annealing time in the annealing step was changed to 1 hour, and the other conditions were the same as those of Example No. 2. In this example, the annealing time was short, C remained on the surface of the titanium material, the maximum C concentration on the material surface exceeded 10 atomic %, and the evaluation result for discoloration resistance was good.

[0103] Example No. 36 is an example in which colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed in a colloidal solution with a concentration of 20% by mass and a temperature of 50°C for 2 minutes. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 550°C for 5 minutes. ＊ 51, a ＊ The evaluation result of the color measurement was poor.

[0104] Example No. 37 is an example in which a colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed for 2 minutes in a colloidal solution with a concentration of 20 mass % and a temperature of 50°C. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 50°C for 5 minutes. In this example, the maximum Si concentration on the material surface was less than 10 atomic %, the maximum Al concentration was less than 10 atomic %, and the minimum O concentration in the depth direction range where either the Si concentration or the Al concentration was 1 atomic % or more was less than 20 atomic %, and the evaluation result for discoloration resistance was poor.

[0105] Example No. 38 is an example in which colloid immersion treatment was performed. ２ concentration and Al ２ O３ The samples were immersed for 2 minutes in colloidal solutions each having a concentration of 20% by mass and heated to 50°C. The surfaces of the samples removed from the colloidal solutions were washed with ethanol, and then annealed in an air atmosphere at 200°C for 12 minutes. In this example, the annealing time in an air atmosphere during the colloidal immersion step was too long, causing an oxide film to grow, resulting in a loss of the silvery-white metallic color and a failure in the evaluation results of the color measurement.

[0106] Example No. 39 is an example in which colloid immersion treatment was performed. ２ The concentration is 50% by mass, and Al ２ O ３ A sample was immersed in a colloidal solution with a concentration of 0 mass % at a temperature of 50°C for 2 minutes. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 200°C for 5 minutes. In this example, the colloidal solution did not contain alumina colloid but contained colloidal silica at a high concentration, which resulted in aggregation of the colloidal silica. As a result, the maximum Si concentration was over 40 atomic % and the maximum Al concentration was less than 10 atomic %, resulting in a failing evaluation result in the color measurement and a poor evaluation result in discoloration resistance.

[0107] Example No. 40 is an example in which a colloid immersion treatment was performed. Example No. 39 is an example in which SiO ２ The concentration is 0 mass %, and Al ２ O ３ A sample was immersed in a colloidal solution with a concentration of 50% by mass at a temperature of 50°C for 2 minutes. The surface of the sample removed from the colloidal solution was washed with ethanol, and then annealed in an air atmosphere at 200°C for 5 minutes. In this example, the colloidal solution did not contain alumina colloid but contained colloidal silica at a high concentration, which resulted in aggregation of the alumina colloid. As a result, the maximum Al concentration was greater than 40 atomic % and the maximum Si concentration was less than 10 atomic %, resulting in a failing evaluation result in the color measurement and a poor evaluation result in discoloration resistance.

[0108] Example No. 41 is an example in which colloid immersion treatment was performed. ２concentration and Al ２ O ３ The samples were immersed for 2 minutes in colloidal solutions each having a concentration of 20% by mass and heated to 50°C. The surfaces of the samples removed from the colloidal solutions were washed with 1% by mass of hydrofluoric acid, and then annealed in air at 200°C for 5 minutes. In this example, the evaluation results for color measurement were pass, and the evaluation results for color fastness were good.

[0109] Example No. 42 is an example in which colloid immersion treatment was performed. ２ concentration and Al ２ O ３ The sample was immersed for 2 minutes in a colloidal solution having a concentration of 20% by mass and a temperature of 50° C. After removing the sample from the colloidal solution, it was annealed in an air atmosphere at 200° C. for 5 minutes. In this example, the evaluation result of the color measurement was pass, and the evaluation result of the color fastness was good.

[0110] In the example of No. 43, the cut sample was annealed in the air at an atmospheric gas pressure of 1.0 × 10 ５ This is an example where the sample was annealed for 40 hours under the conditions of 0.1 Pa and 0.25 Pa. In this example, the sample was significantly oxidized and the sheet shape could not be maintained. Therefore, the surface treatment step was not carried out, and the color measurement value and evaluation of discoloration resistance were not carried out.

[0111] FIG. 1 shows the results of quantitative depth analysis by XPS for Examples No. 2 and No. 5, and FIG. 2 shows the results of quantitative depth analysis by XPS for Examples No. 1 and No. 6. As shown in FIG. 1, it was found that Si and Al were present on the material surface in Examples No. 2, 5, and 6. Furthermore, when their bond energies were examined, it was found that Si had a peak at 103.3 eV and Al had a peak at 74.8 eV, and both had bond energies derived from oxides. Furthermore, since a certain amount of oxygen was present in the presence of these elements, it was also found that Si was derived from SiO ２ Al exists in the state of Al ２ O ３ In this way, it can be inferred that SiO exists on the surface of the material. ２ and Al ２ O３ Furthermore, in Examples No. 2, 5, and 6, in addition to Ti and O, F, N, and C were detected on the material surface, and the maximum F concentration and maximum N concentration on the material surface were both 10 atomic % or less, and the maximum C concentration in the range excluding the influence of attached organic matter was 10 atomic % or less.

[0112] Example 2 The thickness of the oxide film was measured for Example No. 14 and Example No. 15 in Example 1. Specifically, the thickness of the oxide film was determined by XPS from the outermost surface to the depth position where the O concentration was half of its maximum value. Table 7 shows the thickness and color measurement values ​​of the oxide film for each example.

[0113]

[0114] For example, Non-Patent Document 1 (Hidetoshi Yamaguchi, Hiroshi Sato, Surface Technology, 40(1), 64-65 (1992)) shows a graph of color measurements using the voltage required to form an oxide film as a reference value, and Non-Patent Document 2 (Hiroshi Sato, Surface Technology, 43(11), 1014-1019 (1992)) shows a graph of oxide film thickness measurements using the voltage required to form an oxide film as a reference value. These graphs show that the thickness of an oxide film affects the color measurements. Table 7 shows the relationship between the color measurements and oxide film thickness of titanium materials manufactured using colloidal silica and alumina colloid. The oxide films listed in Table 7 were obtained by observing cross sections of oxide films processed using a focused ion beam method using a field emission transmission electron microscope (FE-TEM). The thickness of the oxide film was estimated from bright-field images obtained at 10 different locations on the same substrate, and the average value was used as the oxide film thickness for each substrate. The oxide film thickness is very thin, less than 50 nm, and is therefore considered to satisfy the color measurement criteria of the present application. It has been confirmed that the oxide film thickness of titanium materials manufactured using colloidal silica and colloidal alumina is 5 to 50 nm. Furthermore, accurate detection of the oxide film is difficult for titanium materials manufactured using a shot blasting process because the oxide film is embedded in the titanium material due to the shot blasting. However, since the color values ​​in Example 1 described above indicate a certain range, it is considered that this titanium material also has an oxide film of a similar thickness to titanium materials manufactured using colloidal silica and colloidal alumina. If the thickness of the oxide film is defined as the depth from the outermost surface to the position where the O concentration is half of its maximum value in XPS, the thickness of the oxide film on titanium materials manufactured using a shot blasting process is approximately 500 nm to 1 μm, while the thickness of the oxide film on titanium materials manufactured using colloidal silica and colloidal alumina is approximately 10 nm to 1 μm.

[0115] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

Claims

1. A titanium material having a pure titanium or titanium alloy as a base material, when analyzing the components constituting the surface of the titanium material by X-ray photoelectron spectroscopy, on the material surface from the outermost surface to a depth of 50 nm in the depth direction, the maximum value of the Si concentration is 10 atomic% or more and 40 atomic% or less, the maximum value of the Al concentration is 10 atomic% or more and 40 atomic% or less, the minimum value of the O concentration in the depth direction range where either the Si concentration or the Al concentration is 1 atomic% or more is 20 atomic% or more and 50 atomic% or less, and the color measurement values of the surface of the titanium material measured in accordance with JIS Z 8781-4:2013 are L*: 55 to 75, a*: 1.0 to 2.0, b*: 4.0 to 8.0, a titanium material.

2. When analyzing the material surface by X-ray photoelectron spectroscopy, the maximum value of the C concentration is 10 atomic% or less, the titanium material according to claim 1.

3. When analyzing the material surface by X-ray photoelectron spectroscopy, the maximum value of the F concentration is 10 atomic% or less, and the maximum value of the N concentration is 0 atomic% or more and 10 atomic% or less, the titanium material according to claim 1 or 2.

4. When analyzing the material surface by X-ray photoelectron spectroscopy, the minimum value of the Ti concentration is 1 atomic% or more and 40 atomic% or less, the titanium material according to claim 1.

5. The method for manufacturing a titanium material according to claim 1, wherein on the surface of a titanium material having pure titanium or a titanium alloy as a base material, SiO ２ projectile composed of and Al ２ O ３ including a shot blasting step of projecting a projectile composed of, and the SiO ２ projectile composed of and the Al ２ O ３ each particle size of the projectile composed of is F20 to F100 in accordance with JIS R 6001-1:2017, the projection amount is 1 to 50 g / m ２ ·s, the projection speed is 10 m / s or more and 100 m / s or less, and the projection time is 10 s / m ２ or more, a method for manufacturing a titanium material.

6. A method for manufacturing the titanium material according to claim 1, including an adhesion step of adhering colloidal silica and alumina colloid to the surface of a titanium material having a pure titanium or titanium alloy as a base material, and an annealing step of annealing the titanium material after the adhesion step at 100°C to 500°C for 5 minutes or more and 10 minutes or less in air or in vacuum, a method for manufacturing a titanium material.

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