WO2023170979A1 - Matériau de titane - Google Patents

Matériau de titane Download PDF

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Publication number
WO2023170979A1
WO2023170979A1 PCT/JP2022/011131 JP2022011131W WO2023170979A1 WO 2023170979 A1 WO2023170979 A1 WO 2023170979A1 JP 2022011131 W JP2022011131 W JP 2022011131W WO 2023170979 A1 WO2023170979 A1 WO 2023170979A1
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Prior art keywords
titanium
less
oxide film
concentration
base material
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PCT/JP2022/011131
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English (en)
Japanese (ja)
Inventor
実菜美 松本
一浩 ▲高▼橋
遼太郎 三好
道郎 金子
昌宏 山本
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日本製鉄株式会社
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Priority to PCT/JP2022/011131 priority Critical patent/WO2023170979A1/fr
Priority to TW112108617A priority patent/TW202342776A/zh
Publication of WO2023170979A1 publication Critical patent/WO2023170979A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon

Definitions

  • the present invention relates to titanium materials.
  • Titanium materials exhibit extremely high corrosion resistance in atmospheric environments, and are therefore used for building materials such as building roofs and exterior walls. However, titanium materials that have been used for a long period of time may become discolored. Discoloration of titanium materials may pose a problem from a design standpoint. Therefore, titanium materials that suppress discoloration and have excellent discoloration resistance have been proposed.
  • Patent Document 1 discloses that an oxide film with a thickness of 100 ⁇ or less is present on the surface of the substrate, the amount of C in the surface oxide film is 30 atomic % or less, and the carbon content in the surface layer of the substrate under the oxide film is A titanium material or titanium alloy material with excellent discoloration resistance characterized by an amount of 30 atomic % or less is disclosed.
  • Patent Document 2 describes that in an atmospheric environment, the average carbon concentration in the depth range of 100 nm from the surface is 14 at% or less, and the outermost surface has an oxide film with a thickness of 12 to 40 nm. Titanium is disclosed that is resistant to discoloration.
  • Patent Document 3 discloses a titanium material that does not easily cause discoloration and is characterized in that the amount of fluorine in the oxide film on the surface is 7 at% or less.
  • Patent Document 4 states that in order to efficiently produce a titanium or titanium alloy plate with little discoloration under an environment where it is irradiated with light, the amount of carbon in the carbon-enriched layer on the surface layer of the titanium plate after cold rolling is A titanium plate is cold-rolled using a lubricant with a concentration of 150 mg/m2 or less , then annealed in an oxidizing atmosphere, and then descaled by immersion in molten salt and pickling with an aqueous nitric-hydrofluoric acid solution. A method for manufacturing a titanium plate is disclosed.
  • Patent Document 5 discloses that the average carbon concentration in the depth range of 100 nm from the surface is 14 at% or less, the surface has an oxide film with a thickness of 12 nm or more and 30 nm or less, and the arithmetic mean height of the titanium surface ( Titanium or a titanium alloy is disclosed which is characterized by having a Ra) of 0.035 ⁇ m or less and is less likely to discolor in an atmospheric environment.
  • Patent Documents 1 to 5 say that deterioration of the color fastness of titanium material is suppressed by reducing the carbon concentration on the surface. Further, conventional evaluation of the color fastness of titanium materials is, for example, as described in Patent Document 5, based on the color difference after being immersed in sulfuric acid of pH 3 at a temperature of 60° C. for 14 days. However, in recent years, there has been a demand for titanium materials that have even better discoloration resistance than conventional titanium materials.
  • the present invention was made in view of the above problems, and an object of the present invention is to provide a titanium material with excellent discoloration resistance that can suppress discoloration for a longer period of time than conventional titanium materials. It is.
  • the present invention aims to provide a titanium material that does not discolor even when immersed for a longer period of time than the evaluations described in Patent Documents 1 to 5, for example.
  • the gist of the present invention which was completed based on the above findings, is as follows.
  • the titanium material according to one aspect of the present invention has an average of the range from the surface to a position where the oxygen concentration measured in the thickness direction from the surface by glow discharge spectrometry is 1/3 of the maximum value.
  • Nitrogen concentration and average carbon concentration are each 14.0 atom % or less, and the average hydrogen concentration is 30.0 atom % or less,
  • the c-axis lattice constant of ⁇ -phase Ti determined by X-ray diffraction measurement using the parallel beam method with an incident angle of 0.3 degrees on the surface, and ⁇ determined by X-ray diffraction measurement using the concentrated method at the center of the plate thickness.
  • the difference from the c-axis lattice constant of Ti in the phase is 0.015 ⁇ or less.
  • the titanium material described in [1] above may include an oxide film having a thickness of 30.0 nm or less.
  • the titanium material according to [1] or [2] above has a titanium base material and an oxide film disposed on the surface of the titanium base material, and the titanium material according to the above [1] or [2] has a titanium base material and an oxide film disposed on the surface of the titanium base material, and the titanium material according to X-ray photoelectron spectroscopy on the oxide film.
  • the maximum value of the nitrogen concentration derived from the nitride when analyzed is 2.0 to 10.0 at.
  • the nitride-derived material exists within a range of 2 to 10 nm from the surface of the oxide film and exists within a range of 20 nm from the position where the oxygen concentration is 1/2 of the maximum value to the titanium base material side when converted in terms of speed.
  • the concentration of nitrogen is less than the maximum value of the nitrogen concentration derived from the nitride in the oxide film and 7 atomic % or less, and the maximum value of the nitrogen concentration derived from the nitride in the oxide film is lower than the maximum value of the nitrogen concentration derived from the nitride in the oxide film.
  • the concentration of nitrogen derived from nitride may be higher than or equal to the carbon concentration derived from carbide at the position where the nitrogen concentration derived from nitride becomes maximum.
  • the titanium material described in [1] or [2] above has Ra/, which is the ratio of the arithmetic mean roughness Ra to the element length RSm, in the roughness curve in the direction in which the arithmetic mean roughness Ra is maximum.
  • the titanium base material has a RSm of 0.006 to 0.015 and a root mean square slope R ⁇ q of 0.150 to 0.280, the titanium base material has a kurtosis Rku of more than 3, and the titanium The skewness Rsk of the base material may be greater than -0.5.
  • the titanium material according to [3] above has Ra, which is the ratio of the arithmetic mean roughness Ra to the element length RSm, in the roughness curve in the direction in which the arithmetic mean roughness Ra of the titanium base material is maximum.
  • /RSm is 0.006 to 0.015
  • the root mean square slope R ⁇ q is 0.150 to 0.280
  • the kurtosis Rku of the titanium base material is greater than 3
  • the skewness of the titanium base material is Rsk may be greater than ⁇ 0.5.
  • the present invention it is possible to provide a titanium material with excellent discoloration resistance that can suppress discoloration for a longer period of time than conventional titanium materials.
  • FIG. 1 is a schematic enlarged cross-sectional view showing a layered structure of a titanium material according to an embodiment of the present invention. It is a figure which shows an example of the change of the spectrum in the depth direction by X-ray photoelectron spectroscopy of the titanium material based on the same embodiment.
  • FIG. 3 is a diagram showing an example of a change in the depth direction of a spectrum obtained by X-ray photoelectron spectroscopy of a general titanium material. It is a figure which shows an example of the element concentration distribution of the depth direction by X-ray photoelectron spectroscopy of the titanium material based on the same embodiment, and a general titanium material.
  • FIG. 1 is a schematic enlarged cross-sectional view showing a layered structure of a titanium material according to an embodiment of the present invention. It is a figure which shows an example of the change of the spectrum in the depth direction by X-ray photoelectron spectroscopy of the titanium material based on the same embodiment.
  • FIG. 3 is a diagram showing the relationship between the maximum concentration of nitrogen derived from titanium nitride in an oxide film and the color difference ⁇ E * ab before and after a discoloration test. It is a figure which shows the relationship between Ra/RSm which is a ratio of arithmetic mean roughness Ra and average length RSm of a contour curve element, root-mean-square slope R ⁇ q of a roughness curve element, and color fastness. It is a schematic diagram for explaining kurtosis Rku.
  • Titanium materials have a structure in which an oxide film is disposed on the surface of a titanium base material, and the discoloration of titanium materials is thought to be due to an increase in the thickness of the oxide film due to acid rain or the like. Since the carbon concentration near the surface of a titanium material affects the increase in the thickness of the oxide film, the carbon concentration on the surface of conventional titanium materials aimed at improving discoloration resistance is limited. The present inventors conducted studies in order to obtain a titanium material with excellent discoloration resistance that suppresses discoloration for a longer period of time than conventional ones.
  • the present inventors used glow discharge spectroscopy (hereinafter referred to as "GDS") to determine the oxygen concentration, carbon The concentration and nitrogen concentration were measured.
  • GDS glow discharge spectroscopy
  • the titanium material has an oxide film, and the position where the oxygen concentration measured by GDS is 1/3 of the maximum value is located on the titanium base material side near the interface between the oxide film and the titanium base material. I found out that it does.
  • the range from the surface of the titanium material to the position where the oxygen concentration measured in the thickness direction by GDS is 1/3 of the maximum value will be referred to as the surface layer portion of the titanium material.
  • the present inventors immersed the titanium material in an aqueous sulfuric acid solution at pH 3 and 60° C. for 4 weeks, and evaluated the color fastness based on the color difference before and after immersion. Comparing the titanium material with obvious discoloration and the titanium material with almost no discoloration before and after this immersion, it was found that there was a difference in the carbon concentration and nitrogen concentration measured by GDS in the titanium material before immersion. Ta. Specifically, in the case of a titanium material that clearly discolored when immersed in an aqueous sulfuric acid solution at pH 3 and 60°C for 4 weeks, the inside of the oxide film and the oxide film and base material of the titanium material before immersion were It was found that nitrogen and carbon exist near the interface on the base material side from the interface with.
  • the oxide film and the nitrogen present in the vicinity of the interface on the base material side from the interface between the oxide film and the base material affect the discoloration of titanium materials.
  • the oxide film and nitrogen present in its vicinity also act as a starting point for the growth of the oxide film, similar to carbon.
  • the nitrogen concentration in the oxide film and its vicinity also affects the discoloration resistance of titanium materials in the same way as the carbon concentration, and the discoloration resistance is improved by limiting the nitrogen concentration. was gotten. Furthermore, in the range from the surface of the titanium material to the position where the oxygen concentration measured in the thickness direction by GDS is 1/3 of the maximum value, the average nitrogen concentration and the average carbon concentration are each 14.0 at% or less. It has been found that the color fastness of titanium materials is improved compared to conventional methods.
  • the average carbon concentration in the surface layer of the titanium material can be lowered by increasing the annealing temperature or by lengthening the annealing time.
  • the average nitrogen concentration can be lowered by increasing the degree of vacuum during heat treatment.
  • the present inventors focused on the hydrogen concentration in the surface layer of the titanium material and investigated the influence of the hydrogen concentration in the surface layer of the titanium material on the discoloration resistance of the titanium material. As a result, it was found that the discoloration resistance was further improved when the average hydrogen concentration in the surface layer of the titanium material was 30.0 at % or less. Titanium hydride is thermodynamically unstable compared to titanium oxide in atmospheric acid rain environments. If the production of titanium oxide is promoted due to an increase in the hydrogen concentration in the titanium material, the discoloration resistance may decrease. However, if the average hydrogen concentration in the surface layer portion of the titanium material is 30.0 at.
  • the present inventors focused on changes in the crystal structure of Ti on the surface of the titanium material.
  • the present inventors have discovered that a change in the c-axis of ⁇ -phase Ti, which is a close-packed hexagonal system, affects the discoloration resistance of a titanium material.
  • the penetration level of X-rays differs depending on the X-ray diffraction energy, but by performing the above X-ray diffraction measurement on the surface of the titanium material and the center of the thickness of the titanium material, it is possible to detect Ti in each ⁇ phase.
  • the c-axis lattice constant can be measured.
  • the increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer is defined as follows.
  • the c-axis lattice constant of ⁇ -phase Ti determined by X-ray diffraction measurement using the parallel beam method with an incident angle of 0.3 degrees on the surface of the titanium material and the X-ray diffraction measurement using the concentrated method at the center of the plate thickness.
  • the difference between the c-axis lattice constant of ⁇ -phase Ti and the c-axis lattice constant of ⁇ -phase Ti determined by is referred to as an increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer.
  • the measurement depth in X-ray diffraction measurement using the parallel beam method with an incident angle of 0.3 degrees does not exactly match the thickness range of the surface layer measured by GDS, but it is approximately the same as the depth of the surface layer measured by GDS.
  • the increase in the c-axis lattice constant of ⁇ -phase Ti can be measured. It is thought that oxygen is involved in the increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer of the titanium material. When oxygen is dissolved in ⁇ -phase Ti in the surface layer of the titanium material, the c-axis lattice constant becomes large.
  • the c-axis lattice constant of ⁇ -phase Ti existing on the surface of the titanium material is larger than the c-axis lattice constant of ⁇ -phase Ti existing at the center of the thickness, acid rain will cause oxidation with a high defect concentration. It is presumed that titanium is generated, oxide film grows easily, and discoloration resistance deteriorates.
  • the crystal structure of ⁇ -phase Ti in the surface layer of the titanium material is affected by the temperature, time, and degree of vacuum of the heat treatment. By increasing the degree of vacuum in the heat treatment atmosphere, the amount of oxygen dissolved in ⁇ -phase Ti in the surface layer of the titanium material decreases, and the c-axis lattice constant of ⁇ -phase Ti in the surface layer of the titanium material decreases. Increase will be suppressed. Up to this point, new findings obtained through studies by the present inventors have been explained.
  • FIG. 1 is a schematic enlarged cross-sectional view showing the layer structure of the titanium material according to the present embodiment.
  • the titanium material according to the present embodiment has an average nitrogen concentration and an average carbon concentration in a range from the surface to a position where the oxygen concentration measured in the thickness direction from the surface by glow discharge spectroscopy is 1/3 of the maximum value.
  • ⁇ -phase Ti determined by X-ray diffraction measurement using a parallel beam method with a concentration of 14.0 atomic % or less, an average hydrogen concentration of 30.0 atomic % or less, and an incident angle of 0.3 degrees on the surface.
  • the difference between the c-axis lattice constant of the ⁇ -phase Ti and the c-axis lattice constant of ⁇ -phase Ti determined by X-ray diffraction measurement using the focusing method at the center of the plate thickness is 0.015 ⁇ or less.
  • the titanium material 1 is a titanium material in which an oxide film 20 is formed on the surface of a titanium base material 10, as shown in FIG.
  • the titanium material 1 has a titanium base material 10 and an oxide film 20 formed on the surface of the titanium base material 10.
  • the surface layer portion 30 is a region from the surface of the titanium material 1 (in other words, the surface of the oxide film 20) to the position where the oxygen concentration measured by GDS is 1/3 of the maximum value in the thickness direction, Contains a part of the titanium base material 10.
  • the titanium base material 10 of the titanium material 1 is pure titanium, industrially pure titanium, or a titanium alloy.
  • the titanium base material 10 is, for example, pure titanium, industrially pure titanium, or a titanium alloy with a Ti content of 70% by mass or more. Below, these may be collectively referred to as "titanium".
  • the crystal structure of pure titanium is a close-packed hexagonal ⁇ phase and does not include a body-centered cubic structure ⁇ phase.
  • Industrially pure titanium mainly consists of an ⁇ phase, and may also contain a ⁇ phase depending on its chemical composition.
  • the titanium alloy may be an ⁇ -type alloy having only an ⁇ -phase, or an ⁇ + ⁇ -type alloy containing a ⁇ -phase with a body-centered cubic structure.
  • the titanium base material 10 may be, for example, industrial titanium.
  • industrial titanium used for the titanium base material 10 include various industrial titanium plates and strips described in JIS H 4600:2012, and various industrial titanium rods described in JIS H 4650:2016. Can be mentioned.
  • industrially pure titanium of JIS Class 1 for example, JIS H 4600:2012
  • JIS H 4600:2012 with reduced impurities
  • industrially pure titanium of JIS Class 2 to Class 4 can be applied to the titanium base material 10.
  • titanium alloys include JIS types 11 to 23, which contain trace amounts of precious metal elements such as palladium, platinum, and ruthenium, and JIS 60 types, which contain relatively many elements, to improve corrosion resistance. Examples include Ti-6Al-4V alloy, 60E type, 61 type, and 61F type.
  • JIS type 1 or equivalent ASTM Gr Industrially pure titanium specified in 1 or its equivalent material is mainly used.
  • titanium alloys mainly containing ⁇ -phase include highly corrosion-resistant alloys (JIS standard grades 11 to 13, 17, 19 to 22, and ASTM grades 7, 11, 13, 14, 17, 30, Ti-0.5Cu, Ti-1.0Cu, Ti-1.0Cu-0.5Nb , Ti-1.0Cu-1.0Sn-0.35Si-0.25Nb, etc. Mm indicates misch metal.
  • Examples of ⁇ + ⁇ type titanium alloys include Ti-3Al-2.5V, Ti-5Al-1Fe, and Ti-6Al-4V.
  • the titanium base material 10 contains aluminum, such as a Ti-6Al-4V alloy, corrosion resistance may deteriorate and discoloration resistance may be adversely affected. Therefore, when forming the oxide film 20 on the surface of the titanium alloy as the titanium base material 10, the influence of alloy elements on the application is investigated in advance, and the composition and thickness of each layer are adjusted as appropriate depending on the titanium base material 10. It is recommended that you do so.
  • the titanium base material 10 is, for example, mass%, Co: 0% or more and 1.0% or less, Cr: 0% or more and 0.5% or less, Ni: 0% or more and 1.00% or less, Ta: 0% or more and 6.00% or less, Al: 0% or more and 7.0% or less, V: 0% or more and 5.0% or less, S: 0% or more and 0.3% or less, Cu: 0% or more and 1.50% or less, Nb: 0% or more and 0.70% or less, Sn: 0% or more and 1.40% or less, Si: 0% or more and 0.55% or less, Mo: 0% or more and 0.5% or less, W: 0% or more and 0.5% or less, Pd: 0% or more 0.25%, Ru: 0% or more and 0.15% or less, Rh: 0% or more and 0.15% or less, Os: 0% or more and 0.15% or less, Ir: 0% or more and 0.15% or less, Pt: 0% or more and 0.15% or less
  • REM is a rare earth element, specifically Sc, Y, light rare earth elements (La, Ce, Pr, Nd, Pm, Sm, Eu) and heavy rare earth elements (Gd, Tb, Dy, Ho). , Er, Tm, Yb, Lu).
  • the titanium base material 10 is, for example, in mass %, C: 0% or more and 0.10% or less, H: 0% or more and 0.015% or less, O: 0% or more and 0.40% or less, N: 0% or more and 0.05% or less, and Fe: 0% or more and 0.50% or less, It is industrially pure titanium with the remainder consisting of Ti and impurities.
  • the titanium base material 10 is, for example, in mass %, Co: 0% or more and 0.80% or less, Pd: 0% or more and 0.25% or less, Cr: 0% or more and 0.2% or less, Ru: 0% or more and 0.06% or less, Ni: 0% or more and 0.60% or less, Ta: 0% or more and 6.0% or less, N: 0% or more and 0.05% or less, C: 0% or more and 0.08% or less, H: 0% or more and 0.015% or less, O: 0% or more and 0.35% or less, and Fe: 0% or more and 0.30% or less, It is a titanium alloy with the remainder consisting of Ti and impurities.
  • the titanium base material 10 is, for example, in mass %, Al: 2.0% or more and 7.0% or less, V: 1.0% up to 5.0%, S: 0% or more and 0.3% or less, REM: 0% or more and 0.08% or less, N: 0% or more and 0.05% 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 Fe: 0% or more and 2.5% or less, It is a titanium alloy with the remainder consisting of Ti and impurities.
  • the titanium base material 10 is, for example, in mass %, Cu: 0.3% or more and 1.50% or less, Nb: 0% or more and 0.70% or less, Sn: 0% or more and 1.40% or less, Si: 0% or more and 0.55% or less, N: 0% or more and 0.05% 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 0.15% or less, and Fe: 0% or more and 0.10% or less, It is a titanium alloy with the remainder consisting of Ti and impurities.
  • the titanium base material 10 is, for example, in mass %, V: 0% or more and 0.5% or less, Ni: 0% or more and 1.00% or less, Cr: 0% or more and 0.5% or less, Co: 0% or more and 1.0% or less, Mo: 0% or more and 0.5% or less, W: 0% or more and 0.5% or less, Pd: 0% or more and 0.15% or less, Ru: 0% or more and 0.15% or less, Rh: 0% or more and 0.15% or less, Os: 0% or more and 0.15% or less, Ir: 0% or more and 0.15% or less, Pt: 0% or more and 0.15% or less, REM: 0.001% or more and 0.10% or less, N: 0% or more and 0.03% or less, C: 0% or more and 0.18% or less, H: 0% or more and 0.015% or less, O: 0% or more and 0.35% or less, Fe: 0% or more and 0.30% or less, and the
  • the term "impurity” is a concept that includes impurities that are mixed in from raw materials or the manufacturing environment when titanium is industrially manufactured. Examples of impurities include Cl, Na, Mg, Ca, and B.
  • the content of each impurity element is preferably 0.1% by mass or less, and the total amount is preferably 0.4% by mass or less.
  • the titanium base material 10 is usually a plate, strip, tube, wire rod, or a shape obtained by appropriately processing these.
  • the titanium base material 10 may have any shape, for example, a spherical shape or a rectangular parallelepiped shape.
  • the thickness of the oxide film 20 is not particularly limited, but if it exceeds 30.0 nm, the coloring of the titanium material 1 may be affected due to light interference. Therefore, the thickness of the oxide film 20 is preferably 30.0 nm or less.
  • the thickness of the oxide film 20 is more preferably 25.0 nm or less, and even more preferably 20.0 nm or less, from the viewpoint of suppressing color development due to light interference.
  • the thickness of the oxide film 20 is more than 0 nm, but may be, for example, 10.0 nm or more.
  • the color fastness of the titanium material is improved by ensuring the thickness of the oxide film 20. Therefore, from the viewpoint of improving color fastness, the thickness of the oxide film 20 on the surface of the titanium material 1 is more preferably 12.0 nm or more.
  • the thickness of the oxide film 20 is measured by GDS. Measurement by GDS is performed in the following manner. GDS measurements are performed using JOBIN YVON GD-Profiler 2 manufactured by Horiba Ltd. in a constant power mode of 35 W, with an argon gas pressure of 600 Pa and a discharge range of 4 mm in diameter. The measurement pitch in GDS measurement is 0.5 nm. In the GDS measurement, O (oxygen), N (nitrogen), C (carbon), H (hydrogen), and Ti are analyzed from the surface of the titanium material 1. The concentration (atomic %) of each of the above elements is calculated with the total of the above elements as 100 atomic %. The thickness of the oxide film 20 is determined from the oxygen concentration measured by GDS.
  • the distance in the thickness direction from the surface to the position where the oxygen concentration is half of the maximum value is the thickness of the oxide film 20.
  • the average nitrogen concentration, average carbon concentration, and average hydrogen concentration are the arithmetic average values of the nitrogen concentration, carbon concentration, and hydrogen concentration values at each measurement point.
  • the concentration of nitrogen derived from nitride near the interface with the oxide film 20 in the titanium base material 10 is preferably less than the maximum value of the nitrogen concentration in the oxide film 20 measured by XPS and 7 atomic % or less.
  • Nitride is formed in the oxide film 20 by the method for manufacturing the titanium material 1 according to the present embodiment, which will be described later. is non-existent or in very small amounts.
  • the nitrogen content of the base material, which is the titanium base material 10 is about 0.05 to 0.07% by mass, and at most about 0.20 atomic%, which is at the impurity level, according to the value obtained by chemical analysis. Since this content is below the solid solubility limit of nitrogen in titanium, no nitride is formed.
  • the concentration of nitrogen derived from nitride near the interface with the oxide film 20 in the titanium base material 10 is preferably less than the maximum value of the nitrogen concentration in the oxide film 20 measured by XPS and 7 atomic % or less.
  • the titanium material 1 is The growth of an oxide film when exposed to an acid rain environment is suppressed, and discoloration is suppressed.
  • the concentration of nitrogen derived from nitride near the interface with the oxide film 20 in the titanium base material 10 is more preferably less than the maximum value of the nitrogen concentration in the oxide film 20 and 3.0 atomic % or less.
  • the lower limit of the nitrogen concentration derived from nitride near the interface with the oxide film 20 in the titanium base material 10 is not limited.
  • the lower limit of the concentration of nitrogen derived from nitrides near the interface with the oxide film 20 in the titanium base material 10 is 0 at.
  • the amount may be about 0.5 at.%.
  • the vicinity of the interface between the titanium base material 10 and the oxide film 20 refers to a range of 20 nm from the interface to the titanium base material side when measured by XPS.
  • a diagram for example, FIG. 4 measured by XPS, which will be described later
  • the position where the oxygen concentration measured by XPS is 1/2 of the maximum value is defined as the interface. Therefore, a 20 nm range from the position where the oxygen concentration measured by XPS becomes 1/2 of the maximum value to the titanium base material side is defined as the vicinity of the interface with the oxide film 21 in the titanium base material 10.
  • the vicinity of the interface with the oxide film 20 in the titanium base material 10 is a region different from the surface layer portion 30.
  • the oxide film 20 can be identified by GDS or XPS, but the thickness of the oxide film obtained by each measurement method often does not exactly match because the measurement methods are different. However, in each measurement method, the definition of an oxide film is the same in that the position where the oxygen concentration is 1/2 of the maximum value is defined as an oxide film. In this application, when measuring the nitrogen concentration derived from nitride near the interface with the oxide film 20 in the titanium base material 10, the oxide film is measured by XPS.
  • the oxide film 20 contains nitrogen derived from nitride. Nitrogen derived from nitride in the oxide film 20 is measured by X-ray Photoelectron Spectroscopy (XPS).
  • FIG. 2 is a diagram showing an example of a change in the spectrum in the depth direction by X-ray photoelectron spectroscopy of the titanium material 1 according to the present embodiment.
  • FIG. 3 is a diagram showing an example of a change in the spectrum in the depth direction of a general titanium material by X-ray photoelectron spectroscopy.
  • FIGS. 2(D) and 3(D) show changes in the Ti2p spectrum in the depth direction.
  • FIG. 2C in the titanium material 1 according to this embodiment, a clear peak derived from nitrides may be observed at a depth corresponding to the oxide film 20.
  • FIG. 3(C) in general titanium materials, the peak derived from nitrides is extremely small.
  • the titanium material 1 according to the present embodiment contains a predetermined amount of nitrogen derived from nitride in the oxide film 20.
  • nitrogen derived from nitride in the oxide film 20 will be explained in detail.
  • the intensity of the peak related to TiN in FIG. 2(A) also increases. Since the nitride in FIG. 2(C) increases, it is considered that the nitride in FIG. 2(C) is derived from titanium nitride.
  • the nitrogen content (maximum value of nitrogen concentration) derived from nitride in the oxide film 20 is preferably 2.0 to 10.0 at.%.
  • the nitride-derived nitrogen content in the oxide film 20 refers to the maximum concentration of nitride-derived nitrogen in the oxide film 20 measured by XPS.
  • the oxide film 20 contains 2.0 atomic % or more of nitrogen derived from nitride using a non-coloring material, the discoloration resistance is further improved. The reason for this is not necessarily clear, but when nitride exists in the oxide film 20, the atomic arrangement is disturbed and the strain distribution in the oxide film 20 changes, or the conductivity changes and the potential reaches a nanometer level.
  • the function of blocking ion transmission (shielding function) in the oxide film 20 has changed due to a change in distribution or the like.
  • the nitrogen content derived from nitride in the oxide film 20 is 2.0 atomic % or more, the shielding function can be improved more reliably, and the effect of improving color fastness can be more reliably obtained.
  • the nitrogen content derived from nitride in the oxide film 20 is more preferably 4.0 atomic % or more in consideration of manufacturing stability.
  • the nitrogen content derived from nitride in the oxide film 20 exceeds 10.0 atomic %, the shielding function may deteriorate and the effect of improving color fastness may not be obtained.
  • the nitrogen content derived from nitrogen is 10.0 at % or less, the shielding function is maintained and a higher effect of improving color fastness can be obtained.
  • the nitrogen content derived from nitride in the oxide film 20 is more preferably 8.0 atomic % or less in consideration of manufacturing stability.
  • FIG. 4 is a diagram showing an example of the element concentration distribution in the depth direction of the titanium material 1 according to the present embodiment (example of the present invention) and a general titanium material (example of the prior art) measured by X-ray photoelectron spectroscopy.
  • the sputtering depth on the horizontal axis in FIG. 4 is the depth converted by the SiO 2 sputtering rate.
  • the example of the present invention shown in FIG. 4 is an element concentration distribution for the titanium material according to the present embodiment shown in FIG.
  • the conventional example shown in FIG. 4 is an element concentration distribution for the general titanium material (industrial pure titanium type 1) shown in FIG.
  • the nitrogen concentration derived from nitrides is maximum at a position where the sputtering depth is 2 to 10 nm when converted to the SiO 2 sputtering rate.
  • the nitrogen concentration is extremely low. Therefore, the depth at which the concentration of nitrogen derived from nitride in the oxide film 20 is maximum is preferably 2 to 10 nm when converted to the sputtering rate of SiO 2 .
  • the upper limit of the sputtering depth is preferably 30 nm or more, including the area near the interface with the oxide film 20 described above. Further, it may be changed depending on the thickness of the oxide film 20, and is preferably about three times or more the thickness of the oxide film 20.
  • FIG. 5 is a diagram showing the relationship between the maximum concentration of nitrogen derived from nitride in the oxide film 20 and the color difference ⁇ E * ab before and after the discoloration test.
  • the nitrogen concentration at the depth where the nitrogen concentration derived from nitride in the oxide film 20 is maximum is less than 2.0 at%, the shielding property is not sufficiently increased and the color difference exceeds 8. There was a case.
  • the concentration of nitrogen derived from nitride exceeds 10.0 atomic %, the shielding performance decreases, and the color difference may exceed 8.
  • the color tone may be golden or yellowish. When the color tone becomes golden or yellowish, the color tone changes, so it may not be suitable for applications where the silver color of titanium itself is required. This change in color is presumed to be due to the material color of titanium nitride becoming apparent. Therefore, the nitrogen concentration at the depth where the nitride-derived nitrogen concentration in the oxide film 20 is maximum is 2.0 to 10.0 at.%.
  • the nitrogen concentration at the depth where the nitride-derived nitrogen concentration in the oxide film 20 is maximum is less than the carbide-derived carbon concentration at the same depth, the color difference may exceed 8. there were. As described above, this is also considered to be due to the fact that the strain distribution within the oxide film 20 is affected, the conductivity changes, and the potential distribution at the nanometer level is affected. Therefore, the nitrogen concentration at the depth where the nitride-derived nitrogen concentration in the oxide film 20 is maximum is equal to or higher than the carbide-derived carbon concentration at the position where the nitride-derived nitrogen concentration in the oxide film 20 is maximum. preferable.
  • the concentrations of N, C, O, and Ti derived from nitrides, carbides, and oxides in the titanium base material 10 and the oxide film 20 are calculated by using X-ray photoelectron spectroscopy and Ar ion sputtering on the surface of the titanium material. This can be done with In detail, the analysis conditions are: Ar + and a sputtering rate of 4.3 nm/min. (SiO 2 equivalent value).
  • the SiO 2 equivalent value is a sputtering rate determined under the same measurement conditions using an SiO 2 film whose thickness was measured in advance using an ellipsometer.
  • a peak appearing at a position where the binding energy is approximately 393 to 408 eV is measured as the N1s peak, and N derived from organic matter is separated as approximately 399 to 401 eV, and N derived from nitride is determined to be approximately 397 ⁇ 1 eV.
  • a peak appearing at a position where the binding energy is approximately 280 to 395 eV is measured as a C1s peak, and organic matter-derived C is determined to be approximately 284 to 289 eV, and carbide-derived C is determined to be approximately 281.5 ⁇ 1 eV.
  • a peak appearing at a position where the binding energy is approximately 525 to 540 eV is measured as the O1s peak, and O derived from organic matter is approximately 399 to 401 eV, and O derived from metal oxide is approximately 529.5 to 530.5 eV.
  • a peak appearing at a position with binding energy of 450 to 470 eV is measured as a Ti2p peak.
  • the binding energy of the above-mentioned substances is a general value, and may change depending on the charging of the measurement sample, etc.
  • a method of correction based on the peak position of the C--C bond in C derived from an organic substance can be applied.
  • the concentration of the above elements can be determined by calculating the peak area of each element detected by XPS, including all peaks related to that element (without separating them), and then adding the sensitivity coefficient for each element to this peak area. It is calculated as a percentage. Up to this point, the content of nitrogen derived from nitrides in the oxide film 20 has been described in detail.
  • the color fastness of the titanium material 1 is improved by decreasing the average nitrogen concentration and average carbon concentration of the surface layer portion 30.
  • the average nitrogen concentration and average carbon concentration of the surface layer portion 30 measured from the surface of the titanium material 1 in the thickness direction by GDS using the above method are each 14.0 atomic % or less from the viewpoint of discoloration resistance.
  • the average nitrogen concentration in the surface layer portion 30 of the titanium material 1 is preferably 12.0 atom % or less, more preferably 10.0 atom % or less.
  • the average carbon concentration of the surface layer portion 30 of the titanium material 1 is preferably 13.0 atom % or less, more preferably 12.0 atom % or less, still more preferably 10.0 atom % or less.
  • the average nitrogen concentration in the surface layer portion 30 of the titanium material 1 may be 0 atomic % or more than 1.0 atomic %.
  • the average carbon concentration of the surface layer portion 30 of the titanium material 1 may be 0 atomic % or more than 1.0 atomic %.
  • the color fastness of the titanium material 1 is further improved by reducing the average hydrogen concentration in the surface layer 30.
  • the hydrogen concentration in the surface layer portion 30 of the titanium material 1 is 30.0 atom % or less, preferably 25.0 atom % or less, more preferably 20.0 atom % or less.
  • Titanium is a metal that has a high affinity for hydrogen, and the hydrogen concentration in the surface layer portion 30 may be 10.0 atomic % or more.
  • the crystal structure of ⁇ -phase Ti in the surface layer 30 of the titanium material 1 affects the color fastness. Specifically, when the c-axis lattice constant of ⁇ -phase Ti in the surface layer 30 of the titanium material 1 increases, the color fastness deteriorates.
  • the increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer 30 of the titanium material 1 is ⁇ determined by X-ray diffraction measurement using the parallel beam method at an incident angle of 0.3 degrees on the surface of the titanium material 1.
  • the increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer 30 of the titanium material 1 is 0.015 ⁇ or less, preferably 0.010 ⁇ or less, from the viewpoint of discoloration resistance.
  • the increase in the c-axis lattice constant of ⁇ -phase Ti on the surface of the titanium material 1 is preferably as small as possible, and may be 0 ⁇ . If this increment becomes a negative value, the cause is a measurement error, and the increment is considered to be 0 ⁇ .
  • the c-axis lattice constant of ⁇ -phase Ti in the surface layer 30 of the titanium material 1 is determined by X-ray diffraction measurement using the parallel beam method on the surface of the titanium material.
  • a W/Si multilayer mirror was used on the X-ray incident side.
  • the X-ray source load power (tube voltage/tube current) is 5.4 kW (40 kV/135 mA), respectively.
  • the angle of incidence of the X-rays on the sample is 0.3 degrees, and the diffraction angle 2 ⁇ is scanned.
  • a sample cut out from a titanium material into a size of 25 mm (vertical) x 50 mm (horizontal) by machining is used.
  • a beam is irradiated centering on a 12.5 mm (vertical) x 25 mm (horizontal) area of the sample, and measurement is performed on the surface of the sample.
  • the cut sample may have dirt attached to the surface to be measured, so clean it with acetone or ethanol.
  • the crystal structure of ⁇ -phase Ti at the center of the thickness of the titanium material is measured by X-ray diffraction using the concentration method.
  • the sample used to analyze the crystal structure of ⁇ -phase Ti at the center of the thickness of the titanium material is finished by mechanical polishing and electrolytic polishing so that the center of the thickness of the titanium material becomes the measurement surface for X-ray diffraction measurements. .
  • an X-ray diffraction apparatus used for X-ray diffraction measurements using the parallel beam method which includes an X-ray source, a K ⁇ ray removal filter, and an X-ray source.
  • the load power may also be the same as the conditions for the parallel beam method. Since the crystal structure of Ti is uniform at the center of the plate thickness, samples may be prepared from any point in the width of the plate or in the rolling direction. Here, a sample was prepared from the center of the board from about a quarter of the width, and the test was conducted.
  • the c-axis lattice constant of ⁇ -phase Ti on the surface of the titanium material and at the center of the plate thickness is calculated from the diffraction peak of the (0002) plane using software (Expert High Score Plus) manufactured by Spectris Co., Ltd. . Even when the titanium base material is an ⁇ + ⁇ type, the c-axis lattice constant of ⁇ -phase Ti is calculated from the diffraction peak of ⁇ -phase Ti.
  • the arithmetic mean roughness Ra, the average length RSm of the contour curve element, and the root mean square slope R ⁇ q of the roughness curve element can be measured by a method compliant with JIS B 0601:2013. Note that kurtosis Rku and skewness Rsk, which will be described later, can also be measured by a method based on JIS B 0601:2013.
  • the arithmetic mean roughness Ra of this embodiment is the arithmetic mean roughness Ra defined in JIS B 0601:2013, and is the average of the absolute values of the total coordinate values Zj in the reference length.
  • the reference length of the roughness curve is set to be equal to the cutoff wavelength ⁇ c, that is, 0.8 mm.
  • ⁇ c is a filter that defines the boundary between the roughness component and the waviness component.
  • ⁇ s is a filter that defines the boundary between the roughness component and the shorter wavelength component.
  • n is the number of measurement points
  • Zj is the height of the jth measurement point on the roughness curve.
  • the average length RSm of the contour curve element is calculated from the following formula (2).
  • m is the number of measurement points
  • Xsi is the length of the contour curve element at the reference length
  • the root mean square slope R ⁇ q of the roughness curve element is calculated from the following formula (3).
  • N is the number of measurement points.
  • (dZj/dXj) is the local slope at the j-th measurement point in the roughness curve, and is defined by the following equation (4).
  • ⁇ X is the measurement interval.
  • the measurement interval ⁇ X may be determined as follows.
  • the measurement interval ⁇ X is a value set by the surface roughness profile measuring machine, and if numerical data is obtained at N points when measuring the measurement length L, the measurement interval ⁇ X is on average L/( N-1).
  • SURFCOM 1900DX manufactured by Tokyo Seimitsu, software TIMS Ver.
  • ⁇ X becomes 5 mm/25,600 points, which is about 0.195 ⁇ m on average.
  • the root mean square slope R ⁇ q of the roughness curve element is a parameter that defines the slope angle (local slope dZ/dX) of the minute range formed by the surface unevenness with respect to the reference length X of the roughness curve.
  • FIG. 6 is a diagram showing the relationship between Ra/RSm, which is the ratio of the arithmetic mean roughness Ra of the titanium base material to the average length RSm of the contour curve element, the root mean square slope R ⁇ q of the roughness curve element, and color fastness. It is.
  • color fastness can be evaluated by color difference ⁇ E * ab and appearance observation.
  • L * a * b * for evaluating the color difference ⁇ E * ab
  • light is irradiated from a daylight light source provided directly above the titanium plate. Therefore, the actual appearance may differ.
  • a titanium plate with a large R ⁇ q may appear discolored when visually observed under sunlight even if the color difference ⁇ E * ab is small. Therefore, visual observation under sunlight is also important for evaluating color fastness.
  • ⁇ indicates a condition in which the color difference ⁇ E * ab was 5 or less and the proportion of people who said that the discoloration was not noticeable in visual sensory evaluation was 80% or more
  • x indicates the color difference ⁇ E * Conditions are shown in which, although the ab is 5 or less, the proportion of people who said that the discoloration was not noticeable in visual sensory evaluation was less than 80%.
  • this sensory evaluation by visual observation was carried out by arranging the titanium material that had not been subjected to the previous main discoloration acceleration test and the titanium material after the main discoloration acceleration test on a flat plate, and having 10 evaluators examine the titanium material under sunlight under various conditions. We compared the results from different angles to determine whether there were any angles where the discoloration was noticeable. We compared the proportion of people who said their discoloration was not noticeable. Note that this visual observation is performed under conditions that assume the roof and walls of an actual building, and the evaluation assumes that the color tone changes depending on the viewing angle.
  • the titanium material according to the present embodiment has a surface with Ra/RSm, which is the ratio of the arithmetic mean roughness Ra to the average length RSm of the contour curve elements, of 0.006 to 0.015. It has been found that when the roughness curve element has a root mean square slope R ⁇ q of 0.150 to 0.280, the color fastness is excellent even at higher temperatures and in an acidic environment. Such titanium materials have excellent discoloration resistance even under high temperature and acidic environments, and can further suppress discoloration over a long period of time.
  • Ra/RSm is the ratio of the arithmetic mean roughness Ra to the average length RSm of the contour curve elements
  • Ra/RSm When Ra/RSm is less than 0.006, the irregularities on the surface of the titanium base material are small and the intervals between the irregularities are wide.
  • the surface of the titanium material When Ra/RSm is less than 0.006, the surface of the titanium material is relatively smooth, and due to the optical path difference between the light reflected on the surface of the oxide film and the light reflected on the titanium base material surface, In some cases, the color of the light that is enhanced by the light may be recognized. That is, the titanium material may change color. If Ra/RSm is 0.006 to 0.015, the optical path difference between the light reflected on the surface of the oxide film and the light reflected on the surface of the titanium base material becomes small due to the relatively large slope of the titanium material surface.
  • the upper limit of Ra/RSm is preferably 0.015 so that the effects of the present invention can be clearly obtained.
  • Ra/RSm is 0.006 to 0.015 and the root mean square slope R ⁇ q of the roughness curve element is 0.150 to 0.280, the above effects are obtained by superimposing the titanium material. discoloration is further suppressed. Furthermore, even if a titanium material having the above-mentioned surface condition grows an oxide film of several tens of nanometers on its surface, a change in color tone, that is, discoloration, is suppressed. Therefore, for the titanium base material, in the roughness curve in the direction where the arithmetic mean roughness Ra is maximum, Ra/RSm, which is the ratio of the arithmetic mean roughness Ra to the element length RSm, is 0.006 to 0.015.
  • R ⁇ q is preferably 0.150 to 0.280.
  • the lower limit of Ra/RSm is more preferably 0.007.
  • R ⁇ q is more preferably 0.190 or more. When R ⁇ q is 0.190 to 0.0280, the color difference in the discoloration acceleration test becomes 6 or less, and even higher effects can be obtained.
  • Ra/RSm is preferably 0.006 to 0.015 as described above, but the arithmetic mean roughness Ra is 0.700 to 3.0 ⁇ m.
  • the average length RSm of the contour curve elements is more preferably 60 to 300 ⁇ m. Setting the arithmetic mean roughness Ra to 0.700 to 3.0 ⁇ m and setting the average length RSm of the contour curve elements to 60 to 300 ⁇ m can be achieved industrially relatively easily using the manufacturing method described below. can.
  • Kurtosis Rku is an index representing the sharpness of the amplitude distribution curve.
  • FIG. 7 is a diagram for explaining kurtosis Rku. Furthermore, Figure 7 is based on Tsutomu Miyashita, "Surface roughness that I would like to review again," Journal of the Japan Society for Precision Engineering, Japan Society for Precision Engineering, Vol. 73, No. 2, 2007, p. This is a diagram published in 205.
  • the kurtosis Rku represents the fourth root mean of Zj in a dimensionless reference length determined by the fourth power of the root mean square height Rq.
  • Zj is the height of the jth measurement point on the roughness curve.
  • Rq is the root mean square height and is expressed by the following formula (6).
  • Kurtosis Rku is an index indicating the sharpness of the height distribution, and when Kurtosis Rku is 3, the height distribution is a normal distribution as shown in FIG. 7, and when Kurtosis Rku is less than 3, the value becomes small. As the kurtosis Sku increases beyond 3, the surface becomes flat, and as the value of the kurtosis Sku increases beyond 3, sharp peaks and valleys increase on the surface of the titanium material.
  • the kurtosis Rku of the titanium base material is greater than 3.
  • the surface of the titanium base material has sharp irregularities, and on a surface with sharp irregularities, the specular reflection component in which interference colors become apparent in the light reflected on the surface of the titanium base material is further suppressed. It will be done. As a result, even if the oxide film thickness increases, the interference color becomes even less noticeable, and the discoloration of the titanium material is further suppressed.
  • the skewness Rsk is also called the degree of distortion and is an index representing the sharpness of surface irregularities.
  • the skewness Rsk represents the root mean cube of Z(x) at the reference length, which is made dimensionless by the cube of the root mean square height Rq, and is expressed by the following formula (7).
  • N is the number of measurement points
  • Zj is the height of the jth measurement point on the roughness curve.
  • the skewness Rsk when the valley length is greater than the peak length, the skewness Rsk is greater than 0. In other words, when the skewness Rsk is greater than 0, the proportion of concave portions in the average line of the roughness curve is high. That is, the tips of the peaks (convex portions) in the roughness curve are sharply pointed, and the ends of the valleys (concave portions) are wide.
  • the average line of the roughness curve refers to a curve representing the long wavelength component cut off by the cutoff wavelength ⁇ c.
  • the valley length is smaller than the peak length, the skewness Rsk is smaller than zero.
  • the skewness Rsk when the skewness Rsk is smaller than 0, the proportion of concave portions in the average line of the roughness curve is high. That is, the tips of the peaks (convex portions) in the roughness curve are wide, and the ends of the valleys (concave portions) are sharply pointed.
  • the skewness Rsk When the skewness Rsk is 0, the shape of the unevenness in the roughness curve is symmetrical with respect to the average surface.
  • the skewness Rsk of the titanium base material is preferably greater than -0.5.
  • the tips of the peaks (convex parts) in the roughness curve become sharp, and the light reflected on the titanium base material surface becomes more sharp on the side closer to the light source, that is, at the peaks (protrusions). It becomes more easily scattered and discoloration is further suppressed.
  • the area far from the light source, that is, the valley (convex part) is estimated to be less affected than the peak (convex part) because the shadow effect caused by the peak (convex part) makes it difficult to see the interference color that causes discoloration. be done.
  • the thickness of the titanium material according to this embodiment may be, for example, 0.2 mm or more, or 0.3 mm or more. Further, the thickness of the titanium material according to this embodiment is not particularly limited, and may be, for example, 5.0 mm or less, 3.0 mm or less, or 2.0 mm or less.
  • the average nitrogen concentration and the average carbon concentration in the range from the surface to the position where the oxygen concentration measured in the thickness direction from the surface by glow discharge spectrometry is 1/3 of the maximum value.
  • ⁇ -phase Ti determined by X-ray diffraction measurement using a parallel beam method with a concentration of 14.0 atomic % or less, an average hydrogen concentration of 30.0 atomic % or less, and an incident angle of 0.3 degrees on the surface.
  • the difference between the c-axis lattice constant of the ⁇ -phase Ti and the c-axis lattice constant of ⁇ -phase Ti determined by X-ray diffraction measurement using the focusing method at the center of the plate thickness is 0.015 ⁇ or less.
  • the maximum value of the nitrogen concentration derived from nitrides when analyzed by X-ray photoelectron spectroscopy in the oxide film is 2.0 to 10.0 at%, and the maximum value of the nitrogen concentration derived from the nitrides in the oxide film is 2.0 to 10.0 at%.
  • the nitride is present in a range of 2 to 10 nm from the surface of the oxide film, and the nitride is present in the vicinity of the interface with the oxide film in the titanium base material, when converted to the SiO 2 sputtering rate.
  • the concentration of nitrogen derived from the nitride in the oxide film is less than the maximum value of the nitrogen concentration derived from the nitride and 7.0 atomic % or less, and the maximum value of the nitrogen concentration derived from the nitride in the oxide film is If the concentration of nitrogen derived from the nitride in the oxide film is equal to or higher than the carbon concentration derived from the carbide at the maximum position, the color fastness is excellent even under high temperature and acidic environments. Titanium material, which has excellent discoloration resistance even under high temperature and acidic environments, can further suppress discoloration over a long period of time.
  • Method for manufacturing titanium material An example of a method for manufacturing a titanium material according to this embodiment will be described.
  • the titanium material according to this embodiment is not limited to that manufactured by the manufacturing method described below.
  • pure titanium and titanium alloys used for building materials such as exterior materials are often plate-shaped, an example of a method for producing plate-shaped titanium materials will be described below.
  • a titanium material is manufactured by cold rolling a raw material of pure titanium or a titanium alloy, and then subjecting it to an annealing treatment and a cooling treatment.
  • the titanium material to be subjected to cold rolling may be produced by a known method. For example, using sponge titanium or a master alloy for adding alloying elements as a raw material, a pure material containing the above components is produced by various melting methods such as vacuum arc melting, electron beam melting, or Haas melting such as plasma melting. A titanium or titanium alloy ingot is produced. Next, the obtained ingot is bloomed and hot forged to form a slab, if necessary. Thereafter, the slab is hot rolled into a hot rolled coil of pure titanium or titanium alloy having the above composition. Note that the slab may be subjected to pretreatment such as cleaning treatment and cutting as necessary. Further, when the rectangular shape can be hot rolled by the hearth melting method, hot rolling may be performed without performing hot forging or the like.
  • the hot rolled coil is subjected to cold rolling.
  • Lubricating oil is used in cold rolling, but the lubricating oil used may cause an increase in the carbon concentration on the surface of the titanium material during annealing. Therefore, before annealing, oil present on the surface of the titanium material is preferably removed by alkaline degreasing, dull rolling using dull rolls, coil grinder, polishing, or the like. Note that when lubricating oil is applied to the surface of a titanium material and cold rolling is performed, carbon is contained on the surface of the titanium material due to a mechanochemical reaction.
  • the cold titanium material to be subjected to the final annealing treatment may be pickled or annealed as appropriate.
  • a final annealing treatment is performed on the titanium material after cold rolling or the titanium material after oil removal treatment.
  • the final annealing treatment is generally a process of reducing the strain introduced into the titanium material, pure titanium or titanium alloy, by cold rolling and softening the titanium material.
  • the final annealing treatment and the subsequent cooling treatment include the average nitrogen concentration, average carbon concentration, and average hydrogen concentration in the surface layer of the titanium material, and the ⁇ -phase Ti in the surface layer of the titanium material. This process aims to control the c-axis lattice constant and the thickness of the oxide film.
  • the final sintering treatment is performed in an inert gas (excluding nitrogen gas) atmosphere after creating a vacuum atmosphere, or directly in a vacuum.
  • the inert gas refers to a gas that is inert to titanium, and includes argon, helium, and neon.
  • the heating temperature (annealing temperature) of the final annealing treatment is 630° C. or higher from the viewpoint of reducing the average nitrogen concentration and average carbon concentration in the surface layer portion of the titanium material.
  • the annealing temperature is preferably 650° C. or higher from the viewpoint of reducing the average carbon concentration in the surface layer of the titanium material. Although there is no particular upper limit to the annealing temperature, it is preferably 750° C. or lower from the viewpoint of manufacturing costs.
  • the annealing temperature referred to here is the temperature inside the heating furnace used for annealing treatment, and is measured using a thermocouple installed in the heating furnace.
  • the annealing time is preferably 5 hours or more from the viewpoint of reducing the average nitrogen concentration and average carbon concentration in the surface layer portion of the titanium material.
  • the annealing time is more preferably 10 hours or more.
  • the annealing time may be 3 hours or more because the as-cold rolled titanium material can be annealed.
  • the annealing time is preferably 48 hours or less.
  • the annealing time is preferably 10 hours or less.
  • the annealing time referred to here is the time during which the temperature in the heating furnace containing the titanium material is maintained at the annealing temperature.
  • the final annealing treatment is performed in a vacuum atmosphere, an inert gas atmosphere (excluding nitrogen gas), or an inert gas atmosphere in which an inert gas excluding nitrogen is introduced after creating a vacuum atmosphere.
  • the degree of vacuum of the vacuum atmosphere is, for example, 1.0 ⁇ 10 ⁇ 2 Pa or less.
  • the inert gas atmosphere is preferably a rare gas atmosphere, more preferably an Ar atmosphere.
  • the degree of vacuum before creating an inert gas atmosphere in the final annealing treatment is to suppress the increase in the c-axis lattice constant of ⁇ -phase Ti in the surface layer of the titanium material, and to suppress the average hydrogen concentration and average nitrogen concentration in the surface layer of the titanium material.
  • the inert gas atmosphere in the heating furnace may be, for example, an atmosphere containing 99.99% by volume or more of Ar.
  • the inert atmosphere may be an atmosphere containing 99.99% by volume or more of He (helium).
  • the inside of the heating furnace may be made into a vacuum atmosphere before the start of heating for the final annealing treatment, and then an inert gas atmosphere may be created. In the meantime, the inside of the heating furnace may be changed from a vacuum atmosphere to an inert gas atmosphere.
  • titanium materials can be At the surface, conditions with low levels of oxygen, nitrogen, carbon, and hydrogen are formed.
  • the surface of the titanium material By making the surface of the titanium material highly clean in the final annealing treatment, it can be exposed to the atmosphere, a nitrogen gas atmosphere, or an inert gas atmosphere containing 10% or more nitrogen gas during the subsequent cooling treatment.
  • a predetermined amount of nitride can be generated in the oxide film by the nitrogen contained in these atmospheres.
  • the desired nitride cannot be generated in the oxide film.
  • the nitrogen concentration in the annealing atmosphere is an inert gas of 0.005% by volume or less. Note that in general industrial pure gas, nitrogen accounts for less than half of the impurities, so the purity is sufficient as the atmosphere for the annealing process in this embodiment using the above-mentioned inert gas.
  • the atmosphere for the final annealing treatment is maintained at a temperature below which temper color does not form on the titanium material after the annealing treatment, for example, at a temperature below 300°C.
  • the annealing atmosphere may be maintained until it is cooled to room temperature, or the inside of the heating furnace may be opened to the atmosphere at a temperature of 300° C. or lower.
  • the cooling atmosphere is, for example, an atmosphere similar to the annealing atmosphere at the beginning of cooling, and when the temperature in the heating furnace is below 300°C, an atmosphere consisting of nitrogen gas, or a mixture of argon or helium containing 10% by volume or more of nitrogen. Any atmosphere or air may be used.
  • the cooling rate after the final annealing treatment is not particularly limited. However, at a temperature below 300° C. where the temperature is open, in order to keep the amount of nitrogen derived from nitrides present in the oxide film within a predetermined range, it is preferable to use the conditions described below.
  • the cooling rate until opening is preferably 50°C/min or less, more preferably 30°C/min or less. Furthermore, when cooling a large titanium material weighing 1 ton or more, 1° C./min is preferable.
  • nitrogen gas is introduced into the heating furnace or the inside of the heating furnace is opened to the atmosphere, and the inside of the heating furnace is heated to 10 vol. It is preferable to use a nitrogen atmosphere containing % or more of nitrogen.
  • the amount of nitrogen derived from nitrides present in the oxide film varies depending on the temperature and atmosphere as well as the cleanliness of the titanium material surface. This is because the trace amounts of carbon, oxygen, hydrogen, and nitrogen that exist on the surface of the titanium material compete and react on the surface of the titanium material, but the amount of reaction between nitrogen and titanium depends on which reaction occurs preferentially. This is thought to be because the amount of nitrides produced changes accordingly.
  • the temperature when changing the atmosphere is 300° C. or lower, the reaction between titanium and nitrogen will occur sufficiently, and nitrides will not be produced in excess. Therefore, by cooling treatment subsequent to annealing treatment, the maximum concentration of nitrogen derived from nitrides present in the oxide film can be set to 2.0 to 10.0 at.%.
  • the temperature when changing the atmosphere is less than 200° C., the nitrogen content derived from nitrides in the oxide film will be less than 2.0 at %. This is because the reaction between nitrogen and titanium becomes slower at lower temperatures.
  • the above temperature is preferably 250°C or higher, more preferably 280°C or higher.
  • the cooling time until reaching 200° C. is preferably 1.5 hours or more, and more preferably 2.0 hours or more.
  • the maximum concentration of nitrogen derived from nitrides when analyzed by X-ray photoelectron spectroscopy in the oxide film is reduced. value is 2.0 to 10.0 atomic %, and the position where the nitrogen concentration derived from the nitride in the oxide film has the maximum value is the surface of the oxide film when converted by the sputtering rate of SiO 2 It exists in the range of 2 to 10 nm from .
  • the characteristics of the titanium material according to the present embodiment are maintained.
  • the method for manufacturing a titanium material according to the present embodiment includes a polishing step of polishing the surface of the titanium material using abrasive fine powder having a particle size distribution of #320 or less in accordance with JIS R 6001-2:2017, and It is preferable to include a dull rolling step in which the titanium material is rolled down using a rolling roll having an Ra of 0.5 ⁇ m or more so that the total rolling reduction is 0.10% or more.
  • the polishing step is performed before the final annealing treatment, and the dull rolling step is performed after the final annealing treatment.
  • the Ra/RSm of the titanium base material surface becomes 0.006 to 0.015, and the root mean square slope R ⁇ q of the roughness curve element becomes 0.150 to 0.280. .
  • the polishing process and dull rolling process will be explained.
  • the surface of the titanium material is polished using abrasive fine powder having a particle size distribution of #320 or less in accordance with JIS R 6001-2:2017.
  • the means for polishing the surface of the titanium material is not particularly limited, and for example, known means such as a brush roll or a coil grinder can be used.
  • the surface of a plate coil-shaped titanium material is polished by the following method.
  • the titanium material is polished using a coil line polishing machine using a polishing belt with a count of #320 or less, for example, #320, #240, #100, #80, etc.
  • the abrasive fine powder used in the abrasive belt preferably has a count of #100 or less.
  • polishing may be performed multiple times with the same or different grits.
  • the titanium material used in the polishing process may be manufactured by a known method. For example, using sponge titanium or a master alloy for adding alloying elements as a raw material, a pure material containing the above components is produced by various melting methods such as vacuum arc melting, electron beam melting, or Haas melting such as plasma melting. A titanium or titanium alloy ingot is produced. Next, the obtained ingot is bloomed and hot forged to form a slab, if necessary. Thereafter, the slab is hot rolled into a hot rolled coil of pure titanium or titanium alloy having the above composition. This hot-rolled coil may be cold-rolled, and the titanium material after cold-rolling may be subjected to a polishing process.
  • a pure material containing the above components is produced by various melting methods such as vacuum arc melting, electron beam melting, or Haas melting such as plasma melting.
  • a titanium or titanium alloy ingot is produced. Next, the obtained ingot is bloomed and hot forged to form a slab, if necessary. Thereafter, the slab is hot rolled into
  • the cold-rolled titanium material to be subjected to the polishing step may be appropriately annealed.
  • the slab may be subjected to pretreatment such as polishing and cutting as necessary.
  • hot rolling may be performed without performing blooming, hot forging, or the like.
  • Cold rolling conditions are also not particularly limited, and may be carried out under conditions that allow desired thickness, properties, etc. to be obtained as appropriate.
  • the titanium material is rolled down using a rolling work roll (hereinafter referred to as rolling roll) whose surface has an arithmetic mean roughness Ra of 0.5 ⁇ m or more.
  • rolling roll a rolling work roll
  • the total rolling reduction ratio is 0.10% or more
  • more locally inclined unevenness is imparted to the surface of the titanium material.
  • the arithmetic mean roughness Ra of the surface of the roll is too large, the uneven shape provided in advance by the polishing process may change significantly, so the arithmetic mean roughness Ra of the surface of the roll is preferably 2.0 ⁇ m. It is as follows.
  • the surface roughness of the rolling roll can be adjusted by polishing or shot blasting.
  • the total rolling reduction ratio is preferably 0.10% or more in order to provide locally sloped unevenness, and preferably 0.2% or more in view of the stability of the surface build-up over the entire length of the coil.
  • the surface roughness is 1.5% or less so that the surface roughness formed by polishing in the previous step is not crushed by cold rolling and the necessary uneven shape disappears.
  • one pass of cold rolling is sufficient to obtain the surface characteristics of the present invention, two or more passes of cold rolling are necessary to finish the surface as uniformly as possible over the entire length using a long coil. It may be performed multiple times.
  • the total rolling reduction rate is determined in consideration of this point, and in the case of multiple passes, the total rolling reduction rate is determined from the difference between the initial and finished plate thicknesses.
  • Example 1 The titanium materials shown in Table 1 were cold rolled to a thickness of 0.4 mm, and then degreased using an alkali or organic solvent to remove oil on the surface of the titanium materials.
  • JIS Class 1 pure titanium (equivalent to ASTM Gr. 1)
  • JIS Class 2 pure titanium (equivalent to ASTM Gr. 2)
  • JIS Class 3 pure titanium (equivalent to ASTM Gr. 3)
  • JIS 4 are used in accordance with JIS H 4600:2012.
  • Seed pure titanium (equivalent to ASTM Gr.4), JIS class 11 titanium alloy (equivalent to ASTM Gr.11, Ti-0.15Pd), JIS class 21 titanium alloy (equivalent to ASTM Gr.13, Ti-0.5Ni-0.05Ru) , JIS 17 grade titanium alloy (equivalent to ASTM Gr. 7, Ti-0.05Pd), Ti-Ru-Mm, Ti-3Al-2.5V, Ti-5Al-1Fe, and JIS 60 grade titanium alloy (equivalent to ASTM Gr. 5) , Ti-6Al-4V) was used.
  • Mm in Ti-Ru-Mm represents misch metal.
  • each titanium material was annealed under the conditions shown in Table 1.
  • the opening temperature shown in Table 1 is the temperature when the inside of the furnace is opened in the cooling process after holding each annealing time at each annealing temperature.
  • the temperature at this time is the temperature inside the furnace measured using a thermocouple.
  • heating was started in the vacuum atmosphere shown in "Degree of Vacuum" in Table 1, and until the start of cooling, the temperature in the annealing furnace was 99. Ar gas of 99% by volume or more was introduced.
  • each annealing atmosphere is maintained up to the opening temperature shown in Table 1, and when the temperature in the furnace has decreased to the opening temperature.
  • Example 14 and 15 of the present invention heating was started in an Ar atmosphere, and the Ar atmosphere was maintained until the inside of the furnace was opened.
  • Examples 16 to 18 of the present invention heating was started under the vacuum atmosphere shown in "Degree of Vacuum" in Table 1, and the degree of vacuum was maintained until the inside of the furnace was opened.
  • Comparative Example 4 and Comparative Example 5 the titanium materials shown in Table 1 were cold rolled to a thickness of 0.4 mm, degreased using an alkali or organic solvent, etc., and then subjected to no final annealing treatment. , nitric-hydrofluoric acid pickling finish was performed.
  • the average nitrogen concentration, average carbon concentration, and average hydrogen concentration in the surface layer were determined by the following method. Analysis of O, N, C, H, and Ti was performed using GDS. For the measurement, JOBIN YVON GD-Profiler 2 manufactured by Horiba, Ltd. was used. The measurement conditions were a constant power mode of 35 W, an argon gas pressure of 600 Pa, and a discharge range of 4 mm in diameter. In the measurement by GDS, the measurement pitch was 0.5 nm. The concentration (atomic %) of each of the above elements was calculated with the total of the above elements being 100 atomic %.
  • the range from the surface of the titanium material to the position where the oxygen concentration measured in the thickness direction by GDS was 1/3 of the maximum value was defined as the surface layer portion of the titanium material.
  • the average nitrogen concentration, average carbon concentration, and average hydrogen concentration were the arithmetic average values of the nitrogen concentration, carbon concentration, and hydrogen concentration values at each measurement point.
  • the c-axis lattice constant of ⁇ -phase Ti on the surface of the titanium material was determined by X-ray diffraction measurement using the parallel beam method.
  • a W/Si multilayer mirror was used on the X-ray incident side.
  • the X-ray source load power (tube voltage/tube current) was 5.4 kW (40 kV/135 mA), respectively.
  • the incident angle of the X-rays on the sample was 0.3 degrees, and the diffraction angle 2 ⁇ was scanned.
  • a titanium material with a thickness of 0.4 mm was machined and cut into a size of 25 mm (vertical) x 50 mm (horizontal). Measurements were performed by irradiating a beam centered on a position of 25 mm (vertical) x 25 mm (horizontal). Note that the cut sample was cleaned using acetone because there was a possibility that dirt was attached to the surface to be measured.
  • the c-axis lattice constant of ⁇ -phase Ti at the center of the thickness of the titanium material was measured by X-ray diffraction using the concentration method.
  • the sample used to analyze the crystal structure of ⁇ -phase Ti at the center of the thickness of the titanium material is finished by mechanical polishing and electrolytic polishing so that the center of the thickness of the titanium material becomes the measurement surface for X-ray diffraction measurements.
  • Ta For X-ray diffraction measurements using the focused method, the X-ray diffraction device used for X-ray diffraction measurements using the parallel beam method is used, and the X-ray source, K ⁇ ray removal filter, and X-ray source load power are The conditions were also the same as those for the parallel beam method above.
  • the c-axis lattice constant of ⁇ -phase Ti on the surface of the titanium material and at the center of the plate thickness was calculated from the diffraction peak of the (0002) plane.
  • the difference in the c-axis lattice constant of ⁇ -phase Ti on the surface of the titanium material was determined from the difference between the lattice constant calculated on the surface of the titanium material and the lattice constant calculated at the center of the plate thickness.
  • the thickness of the oxide film was determined by the oxygen concentration measured using the above method using GDS. Specifically, the distance in the thickness direction from the surface to the position where the oxygen concentration was half of the maximum value was defined as the thickness of the oxide film.
  • the content of nitrogen derived from nitrides contained in the oxide film was measured by the following method. That is, from the distribution of nitride-derived nitrogen concentration in the depth direction measured by the following method, the maximum value in the oxide film was taken as the content of nitride-derived nitrogen contained in the oxide film.
  • the concentration of nitrogen derived from nitrides was measured by the following method. That is, using XPS, the surface of the titanium material was sputtered with Ar ions to measure the concentration distribution in the depth direction, and the state of each element at each peak position of N1s, C1s, O1s and Ti2p was analyzed, and nitrides, carbides, etc. , the concentrations of N, C, O, and Ti derived from oxides were calculated. The details were calculated using the procedure described above.
  • the analysis conditions for XPS were as follows. Equipment: Quantera SXM manufactured by ULVAC-PHI X-ray source: mono-AlK ⁇ (h ⁇ :1486.6eV) Beam diameter: 200 ⁇ m ⁇ ( ⁇ analysis area) Detection depth: several nm Intake angle: 45° Sputtering conditions: Ar + , sputtering rate 4.3 nm/min. (SiO 2 equivalent value) The SiO 2 equivalent value is a sputtering rate determined under the same measurement conditions using an SiO 2 film whose thickness was measured in advance using an ellipsometer.
  • Each parameter of the surface roughness of the manufactured titanium material was determined according to JIS B 0601: 2013, and was measured under the following conditions.
  • Equipment Surface roughness profile measuring machine (SURFCOM 1900DX manufactured by Tokyo Seimitsu Co., Ltd., analysis software: TiMS Ver. 9.0.3)
  • Measuring head Shape measuring head manufactured by Tokyo Seimitsu Co., Ltd.
  • Each of the manufactured titanium materials was immersed in an aqueous sulfuric acid solution at pH 3 and 60° C. for 4 weeks, the color difference before and after immersion was calculated, and the color fastness was evaluated based on the color difference value.
  • the color difference ⁇ E is 0 or more and 5 or less, the color fastness is extremely good (A), when it is more than 5 and 10 or less, the color fastness is good (B), and when it is more than 10, it is considered poor ( It was determined that C).
  • L*1, a*1, b*1 are the color measurement results before the color change test
  • L*2, a*2, b*2 are the color measurement results after the color change test
  • the color difference measurement was carried out using CR400 manufactured by Konica Minolta Co., Ltd. under the conditions of a measurement area with a diameter of 8 mm and a D65 light source.
  • the average nitrogen concentration and average carbon concentration in the surface layer portion are both 14.0 at% or less, the average hydrogen concentration is 30.0 at% or less, and the surface and plate thickness of the titanium material are
  • the difference in the c-axis lattice constant of Ti in the central ⁇ phase was 0.015 ⁇ or less, the color difference evaluation results were B or higher, and the visual sensory evaluation results were B or higher.
  • the degree of vacuum during the annealing treatment was as low as 1.0 ⁇ 10 ⁇ 1 Pa, so the average nitrogen concentration in the surface layer portion was high. As a result, both the color difference evaluation result and the visual sensory evaluation result of the titanium material of Comparative Example 1 failed.
  • Comparative Example 2 had a low annealing temperature and a high average carbon concentration in the surface layer. As a result, both the color difference evaluation result and the visual sensory evaluation result of the titanium material of Comparative Example 2 failed.
  • the degree of vacuum during the annealing treatment was as low as 8.0 ⁇ 10 -2 Pa, so the oxygen concentration in the surface layer of the titanium material increased, and the c-axis lattice constant of ⁇ -phase Ti in the surface layer decreased. It is presumed that the difference in lattice constants has become larger. As a result, both the color difference evaluation result and the visual sensory evaluation result of the titanium material of Comparative Example 3 failed. In Comparative Examples 4 and 5, the average hydrogen concentration in the surface layer portion was high, and both the color difference evaluation result and the visual sensory evaluation result of the titanium material of Comparative Example 3 failed.
  • the titanium material according to the present embodiment had excellent discoloration resistance for a long period of time even in a pH 3 sulfuric acid aqueous solution simulating severe acid rain.
  • the present invention is particularly effective for applications in outdoor environments such as roof or wall panels, and its industrial value can be said to be extremely high.
  • Example 2 The titanium materials shown in Table 4 were cold rolled to a thickness of 0.4 mm, and then degreased using an alkali or organic solvent to remove oil on the surface of the titanium materials. Thereafter, each titanium material was annealed under the conditions shown in Table 4.
  • the opening temperature shown in Table 4 is the temperature when the inside of the furnace is opened in the cooling process after holding each annealing time at each annealing temperature. The temperature at this time is the temperature inside the furnace measured using a thermocouple.
  • Example 2 The same evaluation as in Example 1 was performed on each manufactured titanium material. The results are shown in Tables 5 and 6.
  • the maximum concentration of nitrogen derived from nitrides when analyzed by X-ray photoelectron spectroscopy in the oxide film was 2.0 to 10.0 at%.
  • the position where the nitrogen concentration derived from nitride in the oxide film shows the maximum value exists in a range of 2 to 10 nm from the surface of the oxide film when converted to the sputtering rate of SiO 2 , and the oxide film on the titanium base material
  • the concentration of nitrogen derived from nitrides existing near the interface with The concentration of nitrogen derived from nitride in the oxide film was higher than the carbon concentration derived from carbide at the maximum position.
  • the color difference evaluation results were A, and the visual sensory evaluation results were all A++, indicating excellent color fastness.
  • Example 3 After cold rolling the titanium materials shown in Table 7 to a thickness of 0.4 mm, a polishing step, cleaning, annealing treatment, and dull rolling step were performed in this order under the conditions shown in Tables 7 and 8.
  • the "number of polishing passes" shown in Table 7 indicates the number of times the titanium material was passed through the line of a coil grinder consisting of three polishing stands on which polishing belts were arranged.
  • each titanium material was subjected to final annealing treatment under the conditions shown in Table 8.
  • the opening temperatures shown in Table 8 are the temperatures when the inside of the furnace was opened in the cooling process after each annealing time was maintained at each annealing temperature.
  • the temperature at this time is the temperature inside the furnace measured using a thermocouple.
  • heating was started under the vacuum atmosphere shown in "Degree of Vacuum" in Table 8, and until the start of cooling, 99.99% by volume or more of Ar was present in the annealing furnace. gas was introduced.
  • each annealing atmosphere is maintained up to the opening temperature shown in Table 8, and when the temperature in the furnace has decreased to the opening temperature. The inside of the furnace was opened.
  • Inventive Example 62 heating was started under the vacuum atmosphere shown in "Degree of Vacuum" in Table 8, and the vacuum degree was maintained until the inside of the furnace was opened.
  • Comparative Example 6 a titanium material was cold rolled to a thickness of 0.4 mm, degreased using an alkali or organic solvent, and then finished by pickling with nitric hydrofluoric acid without performing a final annealing treatment. I was disappointed.
  • Example 9 The same evaluation as in Example 1 was performed on each manufactured titanium material. The results are shown in Tables 9 and 10. The underline in Table 9 indicates that it is outside the scope of the present invention.
  • the arithmetic mean roughness Ra and element length will change in the roughness curve in the direction where the arithmetic mean roughness Ra is maximum.
  • the ratio of RSm, Ra/RSm is 0.006 to 0.015
  • the root mean square slope R ⁇ q is 0.150 to 0.280
  • the kurtosis Rku of the titanium base material is more than 3
  • the titanium base material has a kurtosis Rku of more than 3. It was found that the skewness Rsk of the base material could be made to exceed -0.5, and the evaluation results were even more excellent.
  • both the average nitrogen concentration and the average carbon concentration in the surface layer portion are 14.0 atomic % or less, the average hydrogen concentration is 30.0 atomic % or less, and the surface layer of the titanium material and The difference in the c-axis lattice constant of Ti in the ⁇ phase at the center of the plate thickness is less than 0.015 ⁇ , and the maximum concentration of nitrogen derived from nitrides when analyzed by X-ray photoelectron spectroscopy in the oxide film is 2.0.
  • the position where the nitrogen concentration derived from nitride in the oxide film shows the maximum value exists within a range of 2 to 10 nm from the surface of the oxide film when converted to the sputtering rate of SiO 2
  • the concentration of nitride-derived nitrogen present near the interface with the oxide film in the titanium base material is less than the maximum value of the nitride-derived nitrogen concentration in the oxide film and 7 at% or less, and the nitride in the oxide film
  • the maximum value of the nitrogen concentration derived from the carbide was higher than the carbon concentration derived from the carbide at the position where the nitrogen concentration derived from the nitride in the oxide film was the maximum.
  • the color difference evaluation result was A
  • the visual sensory evaluation result was A+++, indicating that the color fastness was extremely excellent.
  • Titanium material 10 Titanium base material 20 Oxide film 30 Surface layer part

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Abstract

Le matériau de titane est conçu de sorte que dans une plage allant de la surface à une position à laquelle la concentration en oxygène mesurée dans le sens de l'épaisseur depuis la surface par un procédé d'analyse spectroscopique à décharge luminescente corresponde à 1/3 de la valeur maximale, la concentration moyenne en azote et la concentration moyenne en carbone sont toutes deux inférieures ou égales à 14,0 % atomique, et la concentration moyenne en hydrogène est inférieure ou égale à 30,0 % atomique ; et la différence entre la constante de réseau d'axe c de Ti en phase α, telle que déterminée par mesure de diffraction des rayons X par un procédé à faisceau parallèle dans lequel l'angle d'incidence sur la surface est de 0,3 degré, et la constante de réseau d'axe c de Ti en phase α, telle que déterminée par mesure de diffraction des rayons X par un procédé intensif, au centre d'épaisseur de plaque est inférieure ou égale à 0,015 Å.
PCT/JP2022/011131 2022-03-11 2022-03-11 Matériau de titane WO2023170979A1 (fr)

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