JP4902125B2 - Multifunctional material with mirror surface - Google Patents

Description

1st invention has the layer which consists of a titanium oxide or titanium alloy oxide by which carbon doping was carried out in at least one part of the surface layer, this carbon was doped in the state of a Ti-C bond, and the mirror surface by grinding | polishing to a surface layer Regarding the multifunctional material having a mirror surface that has been processed, more specifically, carbon is doped in a Ti-C bond state, and durability (high hardness, scratch resistance, abrasion resistance, chemical resistance) The present invention relates to a multifunctional material having a layer that is excellent in heat resistance and that functions as a visible light responsive photocatalyst, and that has a mirror surface that is mirror-finished on the surface layer and that has an excellent reflection effect of high-intensity light such as laser.
In addition, the second invention relates to a multifunctional material having a mirror surface, and more specifically, since at least a part of the surface layer has a large number of protrusions made of titanium oxide or titanium alloy oxide, the volatile organic compound (VOC) can also be adsorbed easily, has a large surface area and is carbon-doped, so it has high activity as a photocatalyst and functions as a visible light responsive photocatalyst, and also has high hardness, peeling resistance, abrasion resistance, chemical resistance The present invention relates to a multifunctional material having a mirror surface that is excellent in properties and heat resistance, and has a mirror surface excellent in the reflection effect of high-intensity light such as a laser because the surface layer is mirror-finished.

Conventionally, titanium dioxide TiO ₂ (simply referred to as titanium oxide in the present specification and claims) is known as a substance exhibiting a photocatalytic function. As a method of forming a titanium oxide film on titanium metal, since the 1970s, a method of forming a titanium oxide film on titanium metal by anodic oxidation, thermal titanium oxide on a titanium metal plate in an electric furnace supplied with oxygen A method of forming a film, a method of forming a titanium oxide film on titanium metal by heating a titanium plate in a flame of city gas at 1100 to 1400 ° C. are known (see Non-Patent Document 1).

  When producing photocatalyst products that can provide deodorant, antibacterial, anti-fogging and antifouling effects by such photocatalytic function, titanium oxide sol is generally applied to the substrate by spray coating, spin coating, dipping, etc. (For example, refer to Patent Documents 1 to 3). However, since the film formed in this manner is easily peeled off or worn, it has been difficult to use for a long time. In addition, the method of forming a photocatalyst film | membrane by sputtering method is also known (for example, refer patent documents 4-5).

  In addition, in order to make titanium oxide function as a photocatalyst, ultraviolet rays having a wavelength of 400 nm or less are necessary. However, many studies of titanium oxide photocatalysts that function by visible light by doping various elements have been conducted. For example, comparing titanium oxides doped with F, N, C, S, P, Ni, etc., there is a report that nitrogen-doped titanium oxide is superior as a visible light responsive photocatalyst (see Non-Patent Document 2). .

In addition, titanium oxide photocatalysts doped with other elements in this way include titanium compounds in which the oxygen sites of titanium oxide are replaced with atoms such as nitrogen, and atoms such as nitrogen are doped between the lattices of titanium oxide crystals. There has been proposed a photocatalyst comprising a titanium compound or a titanium compound in which atoms such as nitrogen are arranged at grain boundaries of a polycrystalline aggregate of titanium oxide crystals (see, for example, Patent Documents 6 to 9). However, such a photocatalyst is not always satisfactory in terms of durability such as wear resistance. Further, for example, n-TiO ₂ -xCx, which is a chemically modified titanium oxide, is obtained by applying a natural gas combustion flame in which the temperature of the combustion flame is maintained at around 850 ° C. by adjusting the flow rates of natural gas and oxygen to titanium metal. There is a report that this absorbs light of 535 nm or less (see Non-Patent Document 3).

Furthermore, crystal nuclei prepared by various production methods such as CVD or PVD are put into a sol solution composed of an inorganic metal compound or an organometallic compound, or a sol solution is applied to the crystal nuclei, solidified, and heat-treated. It is known that a highly active photocatalytic function can be obtained by growing a titanium oxide crystal from the crystal nucleus, whereby the crystal shape of the titanium oxide crystal grown from the crystal nucleus forms a columnar crystal (for example, (See Patent Documents 10 to 12). However, in that case, since the columnar crystal is merely grown from the seed crystal placed on the substrate, the formed columnar crystal has insufficient adhesion strength to the substrate, and thus was produced as such. The photocatalyst is not always satisfactory in terms of durability such as wear resistance.
JP 09-2441038 A Japanese Patent Application Laid-Open No. 09-262481 Japanese Patent Laid-Open No. 10-053437 JP-A-11-012720 JP 2001-205105 A JP 2001-205103 A (Claims) JP 2001-205094 A (Claims) JP 2002-95976 A (Claims) WO 01/10553 pamphlet (claims) JP 2002-253975 A JP 2002-370027 A JP 2002-370034 A A. Fujishima et al., J. Electrochem. Soc. Vol. 122, No. 11, p. 1487-1489, November 1975 R. Asahi et al., SCIENCE Vol. 293, July 13, 2001, p. 269-271 Shahed UM Khan et al., SCIENCE Vol. 297, September 27, 2002, p. 2243-2245

  Here, conventional titanium oxide photocatalysts have problems in durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance), both of which are UV responsive and visible light responsive. It became a bottleneck in terms of practical use.

  Therefore, the first invention has a carbon-doped titanium oxide layer that is excellent in durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) as a surface layer and functions as a visible light responsive photocatalyst. In addition, another object is to provide a multifunctional material having a mirror surface suitable for reflection of high-intensity light having a high temperature such as a laser.

  In addition, the second invention can easily adsorb VOC, has a large surface area and is carbon-doped, and therefore has high activity as a photocatalyst and functions as a visible light responsive photocatalyst. The object is to provide a multifunctional material having a mirror surface that is excellent in chemical properties and heat resistance and suitable for reflection of high-intensity light.

The present inventors have results of extensive studies for achieving the above object, the surface of a substrate surface layer is made of titanium or a titanium alloy, heat treatment at a high temperature using a combustion flame of a gas consisting mainly of hydrocarbons In addition, by polishing the surface layer, carbon is doped in a Ti-C bond state, and it has excellent durability (high hardness, scratch resistance, wear resistance, chemical resistance, heat resistance). And having a carbon-doped titanium oxide functioning as a visible light responsive photocatalyst as a surface layer, it is found that a member suitable for reflection of high-intensity light at a high temperature such as a laser (multifunctional material having a mirror surface) can be obtained, The present invention has been completed.

That is, in the multifunctional material having the first mirror surface of the present invention , at least the surface layer is composed of a carbon-doped titanium oxide layer by heat-treating the surface of a substrate made of titanium or a titanium alloy under a predetermined condition. Carbon is doped in a Ti-C bond state, the surface layer is mirror-finished by polishing, has excellent durability and functions as a visible light responsive photocatalyst, and is suitable for the reflection effect of high-intensity light And a multi-functional material (a multi-functional material having a first mirror surface).

Furthermore, as a result of intensive investigations to achieve the above-mentioned object, the present inventor has determined that specific conditions are obtained by directly applying a combustion flame of unsaturated hydrocarbon, particularly acetylene, to the surface of a substrate having at least a surface layer made of titanium or a titanium alloy. The surface layer is heated in a flue gas atmosphere of unsaturated hydrocarbons, particularly acetylene, under specific conditions, so that titanium oxide or titanium alloy oxide is formed inside the surface layer. A layer in which the fine pillars are erected is formed, and the layer in which the fine pillars are erected is cut in a direction along the surface layer to oxidize the titanium oxide or titanium alloy on at least a part of the substrate. A member in which a layer in which fine pillars made of material are erected is exposed, a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on a thin film, and erections on the protrusions It is possible to obtain a member with an exposed thin column, that is, both of them have a large number of protrusions made of titanium oxide or titanium alloy oxide on at least a part of the surface, both of which are useful. The photocatalytic activity is high and the visible light responsive photocatalyst is a multi-functional material, and the fine column which is a protrusion made of the titanium oxide or titanium alloy oxide and the continuous narrow protrusion are carbon-doped. In addition, it can easily adsorb VOCs, has high hardness, and has a multi-functional material excellent in peeling resistance, abrasion resistance, chemical resistance, and heat resistance, and the surface layer of the multi-functional material It was found that the effect of reflecting high-intensity light such as a laser can be obtained by polishing, and the present invention was completed.

  That is, the multifunctional material having the second mirror surface of the present invention has a large number of protrusions made of titanium oxide or titanium alloy oxide on at least a part of the surface. For example, at least a part of the surface is oxidized. A layer in which fine columns made of titanium or titanium alloy oxide are forested is exposed, or a large number of continuous narrow projections made of titanium oxide or titanium alloy oxide on a thin film, and forested on the projections. A multi-functional material (second multi-material) in which the protrusions, for example, the fine pillars and the narrow protrusions are carbon-doped, and the surface layer is mirror-finished by polishing. Functional material).

  The multifunctional material having the first mirror surface of the present invention has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and functions as a visible light responsive photocatalyst. Not only can it be used as a photoresponsive photocatalyst, it can also be used significantly in various technical fields where hard chrome plating has been used. In addition, it can be expected to be applied to products aimed at reducing the potential of the base material to prevent pitting corrosion, overall corrosion, stress corrosion cracking, and the like. Furthermore, if it is used as a radiation-responsive catalyst that responds to radiation such as γ rays as well as ultraviolet rays, film formation can be facilitated and durability can be improved as compared with other film formation methods. Further, since the surface layer is mirror-finished by polishing, a reflection effect such as a laser can be obtained. This multi-functional material is particularly suitable for use in a high-intensity light reflector having a high temperature because of its high heat resistance.

  The multifunctional material having the second mirror surface of the present invention has high photocatalytic activity, functions as a visible light responsive photocatalyst, can easily adsorb VOC, has high hardness, peel resistance, abrasion resistance, chemical resistance In addition, it is possible to obtain a reflection effect of high intensity light such as a laser.

The multi-functional material having a mirror surface of the present invention hardly corrodes even when used in seawater or chemicals due to its durability, and also when used in the sea due to organic decomposition, Adhesion is reduced.
Furthermore, even if the multifunctional material having a mirror surface of the present invention is used in a place with high humidity, the antifogging effect due to the photohydrophilic property is exhibited and there is an effect that it is difficult to fog.

  Note that the first multifunctional material is preferably used if importance is attached to the durability, and the second multifunctional material is preferably used if importance is attached to the high photocatalytic activity.

  Hereinafter, the best mode for carrying out the present invention will be described.

The multifunctional material having the first mirror surface of the present invention heat-treats at least the surface of a substrate whose surface layer is made of titanium or a titanium alloy at a high temperature using, for example, a combustion flame of a gas containing hydrocarbon as a main component. can be produced by a substrate at least the surface layer is made of titanium or titanium alloy is composed in its entirety substrate it is composed of titanium or titanium alloy, or a surface portion forming layer and the core And their materials may be different. In addition, regarding the shape of the substrate, the final product shape (flat or three-dimensional) where durability such as high hardness, scratch resistance, abrasion resistance, chemical resistance, and heat resistance is desired, or visible light on the surface It may be a final product shape that is desired to have a responsive photocatalytic function.

If at least the surface layer is made of titanium or a titanium alloy and the surface portion forming layer and the core material are made of different materials, the thickness of the surface portion forming layer is the carbon-doped oxidation formed. It may be the same as the thickness of the titanium layer (that is, the entire surface portion forming layer becomes a carbon-doped titanium oxide layer) or may be thick (that is, a portion of the surface portion forming layer in the thickness direction is carbon-doped oxidized. It becomes a titanium layer and a part remains as it is). The material of the core material is not particularly limited as long as it does not burn, melt or deform during the heat treatment in the manufacturing method of the first invention. For example, iron, iron alloy, non-ferrous alloy, ceramics, other ceramics, high temperature heat resistant glass, etc. can be used as the core material. As a substrate composed of such a thin film surface layer and a core material, for example, a film made of titanium or a titanium alloy on the surface of the core material by a method such as sputtering, vapor deposition or thermal spraying, or a commercially available one The titanium oxide sol may be applied to the surface of the core material by spray coating, spin coating or dipping to form a film.

The multifunctional material having the first mirror surface is composed of a layer made of carbon-doped titanium oxide or titanium alloy oxide, an intermediate layer, and a core material, and the intermediate layer is titanium or a titanium alloy. The core material may be made of a material other than titanium or a titanium alloy.

  Various known titanium alloys can be used as the titanium alloy, and are not particularly limited. For example, Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo, Ti-10V-2Fe-3Al, Ti-7Al-4Mo, Ti-5Al-2.5Sn, Ti- 6Al-5Zr-0.5Mo-0.2Si, Ti-5.5Al-3.5Sn-3Zr-0.3Mo-1Nb-0.3Si, Ti-8Al-1Mo-1V, Ti-6Al-2Sn-4Zr- 2Mo, Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-11.5Mo-6Zr-4.5Sn, Ti-15V-3Cr-3Al-3Sn, Ti-15Mo-5Zr-3Al, Ti-15Mo-5Zr, Ti-13V-11Cr-3Al or the like can be used.

  In the production of the multifunctional material having the first mirror surface, a gas combustion flame mainly composed of hydrocarbons, particularly acetylene, can be used, and it is particularly desirable to use a reducing flame. In the production of the multifunctional material having the first mirror surface, the hydrocarbon-based gas means a gas containing at least 50% by volume of hydrocarbon, for example, containing at least 50% by volume of acetylene. It means a gas mixed with air, hydrogen, oxygen and the like. In the production of the multifunctional material having this mirror surface, the gas containing hydrocarbon as a main component preferably contains 50% by volume or more of acetylene, and the hydrocarbon is most preferably 100% of acetylene. When unsaturated hydrocarbons, especially acetylene having a triple bond, are used, in the process of combustion, especially in the reducing flame part, the unsaturated bond part decomposes to form an intermediate radical substance. It is considered that carbon doping is likely to occur because of its high activity.

  In the production of the multifunctional material having the first mirror surface, when the surface layer of the substrate to be heat-treated is titanium or a titanium alloy, oxygen that oxidizes the titanium or titanium alloy is necessary, and air or It needs to contain oxygen.

In the production of the multifunctional material having the first mirror surface, the surface of the substrate whose surface layer is made of titanium or a titanium alloy is heated at a high temperature using a combustion flame of a gas mainly composed of hydrocarbon. In this case, even if a combustion flame of a gas containing hydrocarbon as a main component is directly applied to the surface of the substrate and heat-treated at a high temperature, the surface of such a substrate is in a combustion gas atmosphere of a gas containing hydrocarbon as a main component. The heat treatment may be carried out at a high temperature, and this heat treatment can be carried out, for example, in a furnace. When heat treatment is performed at a high temperature by directly applying a combustion flame, the above-described fuel gas may be burned in a furnace and the combustion flame may be applied to the surface of the substrate. When heat treatment is performed in a combustion gas atmosphere at a high temperature, the above fuel gas is burned in a furnace and the high-temperature combustion gas atmosphere is used.

  As for the heat treatment, the surface temperature of the substrate becomes 900 to 1500 ° C., preferably 1000 to 1200 ° C., and a carbon-doped titanium oxide layer doped with carbon in a Ti—C bond state is formed as the surface layer of the substrate. It is necessary to heat-treat. In the case of the heat treatment in which the surface temperature of the substrate ends below 900 ° C., the durability of the substrate having the carbon-doped titanium oxide layer obtained is insufficient and the photocatalytic activity under visible light is also insufficient. On the other hand, in the case of heat treatment in which the surface temperature of the substrate exceeds 1500 ° C., the ultrathin film peels off from the surface of the substrate during cooling after the heat treatment, and the durability (high hardness, (Scratch resistance, abrasion resistance, chemical resistance, heat resistance) effect cannot be obtained. Moreover, even in the case of the heat treatment in which the surface temperature of the substrate is in the range of 900 to 1500 ° C., if the heat treatment time becomes long, the ultrathin film is peeled off from the surface of the substrate during cooling after the heat treatment, Since the effect of durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance), which is the object of the first invention, cannot be obtained, the surface of the substrate is peeled off during cooling after heat treatment. It is necessary to have a time that does not bring about That is, the heat treatment time is sufficient to make the surface layer a carbon-doped titanium oxide layer doped with carbon in a Ti-C bond state. It must be a time that does not result in peeling of the thin film. This heat treatment time is correlated with the heating temperature, but is preferably about 400 seconds or less.

  In the production of the multifunctional material having the first mirror surface, the carbon containing 0.3 to 15 at%, preferably 1 to 10 at% of carbon is in a Ti-C bond state by adjusting the heating temperature and the heat treatment time. A carbon-doped titanium oxide layer doped with can be obtained relatively easily. When the carbon doping amount is small, the carbon-doped titanium oxide layer is transparent, and as the carbon doping amount increases, the carbon-doped titanium oxide layer becomes translucent and opaque. Therefore, by forming a transparent carbon-doped titanium oxide layer on a transparent plate-shaped core material, it has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and visible light response A transparent plate that functions as a mold photocatalyst can be obtained, and durability (high hardness, scratch resistance, abrasion resistance) can be obtained by forming a transparent carbon-doped titanium oxide layer on a plate having a colored pattern on the surface. , A decorative plate that is excellent in chemical resistance and heat resistance) and functions as a visible light responsive photocatalyst.

  In the multifunctional material having a mirror surface having a carbon-doped titanium oxide layer doped with carbon in a Ti-C bond state, the thickness of the carbon-doped titanium oxide layer is preferably 10 nm or more, and has high hardness and scratch resistance. In order to achieve the properties and wear resistance, the thickness is more preferably 50 nm or more. When the thickness of the carbon-doped titanium oxide layer is less than 10 nm, the durability of the multifunctional material having a mirror surface having the obtained carbon-doped titanium oxide layer tends to be insufficient. The upper limit of the thickness of the carbon-doped titanium oxide layer is not particularly limited, although it is necessary to consider the cost and the effect achieved.

  The carbon-doped titanium oxide layer of the multifunctional material having the first mirror surface is doped with chemically modified titanium oxide as described in Non-Patent Document 3 described above and various atoms or anions X that have been proposed conventionally. Unlike titanium oxide containing the titanium compound Ti—O—X, the carbon is contained in a relatively large amount, and doped carbon is contained in a Ti—C bond state. As a result, it is considered that mechanical strength such as scratch resistance and abrasion resistance is improved, and the Vickers hardness is remarkably increased. Moreover, heat resistance is also improved.

  The carbon-doped titanium oxide layer of the multifunctional material having the first mirror surface has a Vickers hardness of 300 or more, preferably 500 or more, more preferably 700 or more, and most preferably 1000 or more. A Vickers hardness of 1000 or more is harder than that of hard chrome plating. Therefore, the multifunctional material having the first mirror surface can be significantly used in various technical fields in which hard chrome plating has been conventionally used.

  The multifunctional carbon-doped titanium oxide layer having the first mirror surface effectively responds to visible light having a wavelength of 400 nm or more as well as ultraviolet rays, and functions effectively as a photocatalyst. Therefore, the multifunctional material having the first mirror surface can be used as a visible light responsive photocatalyst and exhibits a photocatalytic function not only outdoors but also indoors. In addition, the carbon-doped titanium oxide layer of the multifunctional material having the first mirror surface exhibits super hydrophilicity with a contact angle of 3 ° or less.

  Furthermore, the carbon-doped titanium oxide layer of the multifunctional material having the first mirror surface has excellent chemical resistance, and after being immersed in an aqueous solution of 1M sulfuric acid and 1M sodium hydroxide for one week, the film hardness and abrasion resistance When the property and the photocurrent density were measured and compared with the measured values before the treatment, no significant change was observed. Incidentally, with respect to commercially available titanium oxide films, generally, the binder dissolves in acid or alkali depending on the kind thereof, so that the film peels off, and there is almost no acid resistance and alkali resistance.

  Further, the multifunctional carbon-doped titanium oxide layer having the first mirror surface of the present invention can be used as a catalyst that also responds to radiation such as γ rays. That is, the present inventors have invented that a sprayed film such as titanium oxide suppresses stress corrosion cracking, scale adhesion, and the like of a nuclear reactor structural member in response to radiation. Similarly, the multi-functional carbon-doped titanium oxide layer with a mirror surface can also reduce pitting corrosion, overall corrosion, and stress corrosion cracking by lowering the substrate potential when used as such a radiation-responsive catalyst. In addition, the effect of being able to decompose scale, dirt and the like by the oxidizing power is achieved. It is simpler than other radiocatalyst film-forming methods, and is excellent from the viewpoint of durability such as chemical resistance and wear resistance.

  In the production of the multifunctional material having the first mirror surface of the present invention, after the heat treatment described above is performed, a polishing process for mirroring the surface of the multifunctional material is performed. The mirror surface is formed by a polishing method such as electrolytic polishing or buffing when the surface of the multifunctional material is smoothed. “Electrolytic polishing” is a polishing method in which the surface of a multifunctional material is smoothed by passing a direct current through the electrolytic solution between the surface layer and the counter electrode of the multifunctional material used as the positive electrode. When the surface of the multifunctional material is smoothed by electropolishing, the surface becomes a glossy mirror surface. That is, the surface of the multifunctional material is mirror-finished, and light such as laser light incident on the surface of the multifunctional material having a mirror surface is reflected. As described above, the mirror surface processing by the electrolytic polishing process is performed, so that a reflection effect of high-intensity light such as a laser can be obtained.

  In the multifunctional material having a mirror surface that has been subjected to the polishing treatment, the above-described various effects obtained in the state prior to the polishing treatment are maintained as they are.

  Incidentally, since the multifunctional material having a mirror surface of the present invention absorbs visible light or ultraviolet light having a short wavelength, there may be a problem when this is used as a mirror. However, in that case, a method of bringing the reducing flame, which is desirable in the heat treatment, close to a neutral flame, or a method of oxidizing in a gas atmosphere having high oxidizing power such as oxygen or carbon monoxide gas after film formation By one or both of the methods, the amount of carbon dope can be reduced, whereby the absorption wavelength band can be shortened to 410 nm of rutile.

In the multifunctional material having the second mirror surface of the present invention, at least the surface layer of the substrate made of titanium or a titanium alloy is heat-treated with, for example, a combustion flame of unsaturated hydrocarbon, particularly acetylene, and the inside of the surface layer is formed. A layer in which fine columns made of titanium oxide or titanium alloy oxide are erected is formed, and then a layer in which the fine columns are erected is applied to the surface layer by applying, for example, thermal stress, shear stress, or tensile force. A member that is cut in a direction along the substrate and exposes a layer in which fine columns made of the titanium oxide or titanium alloy oxide are forested on at least a part of the substrate, usually a large part of the substrate; In addition, it can be produced by obtaining a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on a thin film and a member in which fine columns standing on the protrusions are exposed.

The substrate whose at least surface layer is made of titanium or a titanium alloy may be composed entirely of titanium or a titanium alloy, or a surface portion forming layer made of titanium or a titanium alloy and a core material made of other materials. It may be comprised. Further, the shape of the substrate may be any final product shape (flat plate shape or three-dimensional shape) where photocatalytic activity and / or super hydrophilicity is desired.

In the case where at least the substrate whose surface layer is made of titanium or a titanium alloy is composed of a surface portion forming layer made of titanium or a titanium alloy and a core material made of another material, the thickness (amount) of the surface portion forming layer ) Even if the thickness is comparable to the amount of layers in which fine columns made of titanium oxide or titanium alloy oxide are formed (that is, the entire surface layer forming layer is made of titanium oxide or titanium alloy oxide). The fine pillars become forested layers) and may be thicker (that is, the fine pillars in which part of the surface portion forming layer in the thickness direction is made of titanium oxide or titanium alloy oxide are forested. Layer, and the rest remains unchanged). Further, the material of the core material is not particularly limited as long as it does not burn, melt or deform during the heat treatment in the production of the multifunctional material having the second mirror surface. For example, iron, iron alloy, non-ferrous alloy, glass, ceramics, and other ceramics can be used as the core material. As the substrate composed of such a thin film-like surface layer and a core material, those similar to those described in the first invention can be used. The thickness of this surface layer is preferably 0.5 μm or more, more preferably 4 μm or more.

  Various known titanium alloys can be used as the titanium alloy, and there is no particular limitation, and the same multi-functional material having the first mirror surface is used.

  In the production of the multifunctional material having the second mirror surface, for example, it is desirable to use a combustion flame of a gas mainly containing an unsaturated hydrocarbon, particularly acetylene, and particularly to use a reducing flame. In the production of the multifunctional material having the second mirror surface, a gas containing at least 50% by volume of unsaturated hydrocarbon, for example, a gas containing at least 50% by volume of acetylene and appropriately mixed with air, hydrogen, oxygen, etc. It is preferable to use it. In the production of the multifunctional material having the second mirror surface, the fuel component is most preferably 100% acetylene. When unsaturated hydrocarbons, especially acetylene having a triple bond, are used, in the process of combustion, especially in the reducing flame part, the unsaturated bond part decomposes to form an intermediate radical substance. Has a strong activity, and carbon doping is likely to occur, and doped carbon is contained in a Ti-C bond state. Thus, when carbon dope arises in a fine pillar, the hardness of a fine pillar will become high, and as a result, mechanical strength, such as hardness of a multifunctional material which has a mirror surface, and abrasion resistance will improve, and heat resistance will also improve.

In the production of the multifunctional material having the second mirror surface, the surface layer is heated by directly applying a combustion flame to the surface of the substrate made of titanium or a titanium alloy, or the surface of the substrate is heated in a combustion exhaust gas atmosphere. The heat treatment can be carried out, for example, with a gas burner or in a furnace. When the combustion flame is directly applied and heat treatment is performed at a high temperature, the combustion flame may be applied to the surface of the substrate by a gas burner. When heat treatment is performed in a combustion exhaust gas atmosphere at a high temperature, the above fuel gas may be burned in a furnace and an atmosphere containing the high-temperature combustion exhaust gas may be used.

For the heat treatment, at least the surface layer is made of titanium or a titanium alloy, a layer in which fine columns made of titanium oxide or a titanium alloy oxide are formed is formed inside the surface layer, and then, for example, thermal stress, shear stress, By applying a tensile force, the layer in which the fine columns are erected is cut in a direction along the surface layer, and at least a part of the titanium oxide or titanium alloy oxide is erected in at least a part of the substrate. A member in which a layer is exposed, and a member in which a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on a thin film and fine columns standing on the protrusions are exposed Therefore, it is necessary to adjust the heating temperature and the heat treatment time. This heat treatment is preferably performed at a temperature of 600 ° C. or higher.

  By performing the heat treatment under such conditions, the height of the layer in which the fine pillars stand is about 1 to 20 μm, and the thickness of the thin film thereon is about 0.1 to 10 μm. Intermediates having an average thickness of about 0.2 to 3 μm are formed. Thereafter, for example, by applying a thermal stress, a shear stress, or a tensile force to cut the layer in which the fine pillars are erected in a direction along the surface layer, at least a part of the titanium oxide or the substrate is formed on the substrate. A member in which a layer with fine columns made of titanium alloy oxide is exposed (that is, all or most of the thin film existing on the layer with fine columns on the substrate is peeled off) However, a part of the thin film existing on the layer where the fine pillars are erected may remain without being peeled) and a large number of continuous narrow widths made of titanium oxide or titanium alloy oxide on the thin film A protrusion and a member in which a fine pillar standing on the protrusion is exposed are obtained.

  In the case of cutting a layer in which fine columns are erected by applying thermal stress in a direction along the surface layer, for example, either the surface or the back surface of the substrate is cooled or heated to heat the surface of the substrate. A temperature difference is provided between the back surface and the back surface. As this cooling method, for example, either the surface or the back surface of the hot intermediate is brought into contact with a cooling object, such as a stainless steel block, or cold air (room temperature air) is applied to either the surface or the back surface of the hot intermediate. Spray. Even if the hot intermediate is allowed to cool, thermal stress is generated, but the degree is low.

  When shearing stress is applied and the layer in which the fine pillars are erected is cut in a direction along the surface layer, for example, a relatively reverse force is applied to the front and back surfaces of the intermediate by frictional force. In addition, when a layer in which fine columns are erected is cut in a direction along the surface layer by applying a tensile force, for example, the surface and the back surface of the above intermediate body are removed from those surfaces using a vacuum suction disk or the like. Pull in the opposite direction in the vertical direction. When using only a member in which a layer in which fine columns made of titanium oxide or titanium alloy oxide are forested is exposed on at least a part of the substrate, oxidation is performed on the intermediate thin film. A portion corresponding to a member in which a large number of continuous narrow protrusions made of titanium or a titanium alloy oxide and fine columns standing on the protrusions are exposed can be removed by polishing, sputtering, or the like.

  In a member in which a layer with fine columns made of titanium oxide or titanium alloy oxide is exposed on at least a part of the substrate obtained as described above, the layer with fine columns is set Although the height of the layer in which the fine column stands is changed depending on the height position of the fine column cut in the direction along the surface layer, the height of the layer in which the fine column stands is generally 1 to The average thickness of the fine columns is about 0.5 to 3 μm. This member can easily adsorb VOCs, has a large surface area, has high activity as a photocatalyst, and also has high film hardness, and has a mirror surface with excellent peel resistance, wear resistance, chemical resistance, and heat resistance. It is a functional material.

  On the other hand, on the thin film obtained as described above, a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide and members with exposed fine columns standing on the protrusions are small. The height of the protrusion on each small piece is about 2 to 12 μm, and the height of the fine column is the height of the fine column obtained by cutting the layer in which the fine column stands in the direction along the surface layer. Although the height varies depending on the position, the height of the layer in which the fine pillars stand is generally about 1 to 5 μm, and the average thickness of the fine pillars is about 0.2 to 0.5 μm. However, depending on the conditions for cutting the layer in which the fine columns are erected in the direction along the surface layer, there are cases where a large number of continuous narrow protrusions are exposed without the presence of the fine columns. This member can also adsorb VOCs and has a large surface area, so it has high activity as a photocatalyst. Further, this member can be used as it is or after being pulverized, and the pulverized product can easily adsorb VOC and has a large surface area, so it has high activity as a photocatalyst.

  In the multifunctional material having the second mirror surface, fine columns made of titanium oxide or titanium alloy oxide, a large number of continuous narrow projections, and fine columns standing on the projections are carbon-doped. Therefore, it responds not only to ultraviolet rays but also visible light having a wavelength of 400 nm or more, works particularly effectively as a photocatalyst, and can be used as a visible light responsive photocatalyst, and exhibits a photocatalytic function not only outdoors but indoors.

  The shape of each fine column of the layer in which fine columns made of titanium oxide or titanium alloy oxide constituting the multifunctional material having the second mirror surface are erected is determined from the micrographs of FIGS. 10 and 13. As shown in the figure, a prismatic shape, a cylindrical shape, a pyramid shape, a conical shape, an inverted pyramid shape or an inverted conical shape, etc., which extends straightly in a direction perpendicular to or inclined from the surface of the substrate, extends while being bent or bent. , Branched and extended, and composites thereof. Moreover, as the whole shape, it can show by various expressions, such as a frost column shape, a raising carpet shape, a basket shape, a row column shape, and the column shape assembled with blocks. In addition, the thickness and height of the fine columns, the size of the base (bottom surface), and the like vary depending on heating conditions and the like.

  A member in which a large number of continuous narrow protrusions made of titanium oxide or a titanium alloy oxide in a thin film form and fine columns standing on the protrusions are exposed is judged from the micrograph in FIG. In addition, it can be seen that the many continuous narrow protrusions look like the outside of the walnut shell and the appearance of pumice. It can be seen that the pattern is bent. In addition, the shape of the fine column standing on the protrusion is the same as the shape of each fine column in the layer where the fine column on the base is standing, but the junction between the fine column and the thin film Therefore, the density of the fine columns standing on the protrusion is generally smaller than the density of the fine columns in the layer where the fine columns on the base are standing.

  Hereinafter, the present invention will be described in more detail based on examples and comparative examples.

[Examples 1 to 3]
Carbon dope in which carbon is doped in a Ti—C bond state as a surface layer by heat-treating a titanium plate having a thickness of 0.3 mm using an acetylene combustion flame so that its surface temperature is about 1100 ° C. A titanium plate having a titanium oxide layer was formed. By adjusting the heat treatment time at 1100 ° C. to 5 seconds (Example 1), 3 seconds (Example 2), and 1 second (Example 3), respectively, the amount of carbon doping and the thickness of the carbon-doped titanium oxide layer were reduced. Titanium plates with different carbon doped titanium oxide layers were formed.

The carbon content was calculated | required with the fluorescent-X-ray-analysis apparatus about the carbon dope titanium oxide layer with which the carbon formed in this Example 1-3 was doped in the state of Ti-C bond. Assuming a molecular structure of TiO _2-x C x based on the carbon content, carbon content 8at% for Example 1, TiO _{1. 76} C _0.24, carbon content of about 3.3At% for Examples 2, TiO _1.90 C _0.10 and Example 3 had a carbon content of 1.7 at% and TiO _1.95 C _0.05 . In addition, the carbon-doped titanium oxide layer in which the carbon formed in Examples 1 to 3 was doped in a Ti—C bond state was superhydrophilic with a contact angle of about 2 ° with water droplets.

[Comparative Example 1]
A commercially available titanium oxide sol (STS-01 manufactured by Ishihara Sangyo Co., Ltd.) was spin-coated on a titanium plate having a thickness of 0.3 mm, and then a titanium plate having a titanium oxide film whose adhesion was improved by heating was formed.

[Comparative Example 2]
A commercially available product in which titanium oxide was spray-coated on a SUS plate was used as the substrate having the titanium oxide film of Comparative Example 2.

Test Example 1 (Vickers hardness)
The carbon-doped titanium oxide layer doped with the carbon of Example 1 in a Ti—C bond state and the titanium oxide film of Comparative Example 1 were subjected to indenter: Belkovic using a nanohard nesting tester (NHT) (manufactured by CSM Instruments, Switzerland). When the film hardness was measured under the conditions of type, test load: 2 mN, load unloading speed: 4 mN / min, the carbon-doped titanium oxide layer doped with carbon in the state of Ti-C bond in Example 1 had a Vickers hardness. Was a high value of 1340. On the other hand, the Vickers hardness of the titanium oxide film of Comparative Example 1 was 160.

  These results are shown in FIG. For reference, the literature values of Vickers hardness of hard chrome plating layer and nickel plating layer (Tomono, “Practical Plating Manual”, Chapter 6, Ohmsha (1971)) are also shown. It is obvious that the carbon-doped titanium oxide layer in which the carbon of Example 1 is doped in a Ti—C bond state has higher hardness than the nickel plating layer and the hard chromium plating layer.

Test Example 2 (Scratch resistance)
For the carbon-doped titanium oxide layer doped with the carbon of Example 1 in a Ti—C bond state and the titanium oxide film of Comparative Example 1, a microscratch tester (MST) (manufactured by CSM Instruments, Switzerland) was used as an indenter: Rockwell. The scratch resistance test was performed under the conditions of (diamond), tip radius 200 μm, initial load: 0 N, final load: 30 N, load speed: 50 N / min, scratch length: 6 mm, stage speed: 10.5 mm / min. A “peeling start” load at which a small film peels off within the scratch mark and an “overall peel” load at which the film peels across the scratch mark were determined. The results were as shown in Table 1.

  As is apparent from this table, it can be seen that the carbon-doped titanium oxide layer of Example A is superior to the titanium oxide film of Comparative Example 1 in scratch resistance.

Test Example 3 (Abrasion resistance)
The carbon-doped titanium oxide layer doped with the carbon of Example 1 in a Ti—C bond state and the titanium oxide film of Comparative Example 1 were tested at a test temperature using a high-temperature tribometer (HT-TRM) (manufactured by CSM Instruments, Switzerland). A wear test was performed under the conditions of: room temperature and 470 ° C., ball: SiC sphere having a diameter of 12.4 mm, load: 1 N, sliding speed: 20 mm / sec, rotation radius: 1 mm, test rotation speed: 1000 rotations.

  As a result, for the titanium oxide film of Comparative Example 1, peeling occurred at both room temperature and 470 ° C., but for the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti—C bond state, No significant trace wear was detected under both room temperature and 470 ° C conditions.

Test Example 4 (Chemical resistance)
After immersing the titanium plate having the carbon-doped titanium oxide layer doped with the carbon of Example 1 in a Ti—C bond state in a 1M sulfuric acid aqueous solution and a 1M sodium hydroxide aqueous solution for 1 week at room temperature, When the wear resistance and the photocurrent density described below were measured, no significant difference was observed in the results before and after immersion. That is, it was confirmed that the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti—C bond state had high chemical resistance.

Test Example 5 (Structure of carbon-doped titanium oxide layer doped with carbon in a Ti-C bond state)
For the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti—C bond state, the acceleration voltage was 10 kV, the target was Al, and Ar ion sputtering was performed for 2700 seconds using an X-ray photoelectron spectrometer (XPS). Done and started the analysis. If this sputtering rate is 0.64 Å / s corresponding to the SiO ₂ film, the depth is about 173 nm. The result of the XPS analysis is shown in FIG. The highest peak appears when the binding energy is 284.6 eV. This is judged to be a C—H (C) bond commonly found in Cls analysis. The next highest peak is seen when the binding energy is 281.7 eV. Since the bond energy of the Ti—C bond is 281.6 eV, it is determined that C is doped as a Ti—C bond in the carbon-doped titanium oxide layer of Example 1. As a result of XPS analysis at 11 points at different positions in the depth direction of the carbon-doped titanium oxide layer, similar peaks appeared in the vicinity of 281.6 eV at all points.

  Ti-C bonds were also confirmed at the boundary between the carbon-doped titanium oxide layer and the substrate. Accordingly, the hardness is increased due to the Ti—C bond in the carbon-doped titanium oxide layer, and the film peeling strength is significantly increased due to the Ti—C bond at the boundary between the carbon-doped titanium oxide layer and the substrate. Is expected.

Test Example 6 (wavelength response)
The wavelength responsiveness of the carbon-doped titanium oxide layer in which the carbons of Examples 1 to 3 were doped in a Ti—C bond state and the titanium oxide films of Comparative Examples 1 and 2 were measured using an Oriel monochromator. Specifically, a voltage of 0.3 V was applied to each layer and film between the counter electrode in a 0.05 M aqueous sodium sulfate solution, and the photocurrent density was measured.

  The result is shown in FIG. FIG. 3 shows the obtained photocurrent density jp with respect to the irradiation wavelength. The wavelength absorption edge of the carbon-doped titanium oxide layer in which the carbons of Examples 1 to 3 are doped in a Ti—C bond state extends to 490 nm, and the photocurrent density increases as the carbon doping amount increases. Was recognized. Although not shown here, it has been found that when the carbon doping amount exceeds 10 at%, the current density tends to decrease, and when the carbon doping amount exceeds 15 at%, the tendency becomes remarkable. Therefore, it was recognized that the carbon doping amount has an optimum value of about 1 to 10 at%. On the other hand, in the titanium oxide films of Comparative Examples 1 and 2, it was confirmed that the photocurrent density was extremely small and the wavelength absorption edge was about 410 nm.

Test example 7 (light energy conversion efficiency)
For the carbon-doped titanium oxide layer in which the carbons of Examples 1 to 3 are doped in a Ti—C bond state and the titanium oxide films of Comparative Examples 1 and 2, the formula η = jp (Ews−Eapp) / I
The light energy conversion efficiency η defined by Here, Ews is the theoretical decomposition voltage of water (= 1.23 V), Eapp is the applied voltage (= 0.3 V), and I is the irradiation light intensity. The result is shown in FIG. FIG. 4 shows the light energy conversion efficiency η with respect to the irradiation light wavelength.

  As is clear from FIG. 4, the carbon-doped titanium oxide layer in which the carbons of Examples 1 to 3 are doped in a Ti—C bond state has extremely high light energy conversion efficiency, and the conversion efficiency in the vicinity of a wavelength of 450 nm is a comparative example. It was recognized that the conversion efficiency in the ultraviolet region (200 to 380 nm) of the 1 and 2 titanium oxide films was superior. Further, the water decomposition efficiency of the carbon-doped titanium oxide layer in which the carbon of Example 1 is doped in a Ti—C bond state is about 8% at a wavelength of 370 nm, and an efficiency exceeding 10% can be obtained at 350 nm or less. I understood.

Test Example 8 (Deodorization test)
A deodorizing test was performed on the carbon-doped titanium oxide layer in which the carbons of Examples 1 and 2 were doped in a Ti-C bond state and the titanium oxide film of Comparative Example 1. Specifically, after acetaldehyde generally used in deodorization tests is enclosed in a 1000 ml glass container together with a substrate having a carbon-doped titanium oxide layer, the influence of concentration reduction due to initial adsorption can be ignored. Visible light was irradiated with a fluorescent lamp with a UV cut filter, and the acetaldehyde concentration was measured by gas chromatography at every predetermined irradiation time. The surface area of each film was 8.0 cm ² .

  The result is shown in FIG. FIG. 5 shows the acetaldehyde concentration with respect to the elapsed time after irradiation with visible light. The acetaldehyde decomposition rate of the carbon-doped titanium oxide layers of Examples 1 and 2 is higher than the acetaldehyde decomposition rate of the titanium oxide film of Comparative Example 1, and the carbon doping amount is large. It was found that the carbon-doped titanium oxide layer of Example 1 having a higher energy conversion efficiency has a higher decomposition rate than the carbon-doped titanium oxide layer of Example 2.

Test example 9 (antifouling test)
An antifouling test was carried out on the carbon-doped titanium oxide layer of Example 1 and the titanium oxide film of Comparative Example 1. Each coating was placed in a smoking room in the Central Research Institute of Electric Power Co., Ltd., and surface contamination after 145 days was observed. There is no direct incidence of sunlight in the smoking room.

  A photograph showing the results is shown in FIG. Fat was attached to the surface of the titanium oxide film of Comparative Example 1 and had a pale yellow color, but the surface of the carbon-doped titanium oxide layer of Example 1 was not particularly changed and was kept clean. It was confirmed that the antifouling effect was sufficiently exhibited.

[Examples 4 to 7]
By using an acetylene combustion flame in the same manner as in Examples 1 to 3, a titanium plate having a thickness of 0.3 mm was heated at the surface temperature shown in Table 2 for the time shown in Table 2, thereby forming a surface layer. A titanium plate having a carbon-doped titanium oxide layer was formed.

[Comparative Example 3]
Using a natural gas combustion flame, a 0.3 mm thick titanium plate was heat-treated at the surface temperature shown in Table 2 for the time shown in Table 2.

Test Example 10
The Vickers hardness (HV) of the carbon-doped titanium oxide layers of Examples 4 to 7 and the film of Comparative Example 3 was measured in the same manner as in Test Example 1 above. The results are shown in Table 2. Moreover, the carbon dope titanium oxide layer formed in Examples 4-11 was super hydrophilicity whose contact angle with a water droplet was about 2 degrees.

  As is apparent from the data shown in Table 2, when the heat treatment was performed with the combustion gas of natural gas so that the surface temperature became 850 ° C., only a film having a Vickers hardness of 160 was obtained, but the surface temperature was 1000 ° C. In Examples 4 to 7 where heat treatment was performed using acetylene combustion gas as described above, a carbon-doped titanium oxide layer having a Vickers hardness of 1200 was obtained.

Test Example 11
For the carbon-doped titanium oxide layers of Examples 4 to 7 and the titanium oxide films of Comparative Examples 1 and 3, as in Test Example 6, a voltage of 0.3 V was applied between the counter electrode in a 0.05 M sodium sulfate aqueous solution. The photocurrent density was measured by irradiating with light of 300 nm to 520 nm. The result is shown in FIG. FIG. 7 shows the obtained photocurrent density jp with respect to the potential ECP (V vs. SSE).

  The carbon-doped titanium oxide layers of Examples 4 to 6 obtained by heat treatment using an acetylene combustion gas so that the surface temperature becomes 1000 to 1200 ° C. have relatively high photocurrent density and are excellent. all right. On the other hand, the titanium oxide of Comparative Example 3 obtained by heat treatment so that the surface temperature becomes 850 ° C. and the carbon-doped titanium oxide layer of Example 7 obtained by heat treatment so that the surface temperature becomes 1500 ° C. It was found that the current density was relatively small.

[Example 8]
A titanium alloy whose surface layer contains carbon-doped titanium oxide by heat treatment of a Ti-6Al-4V alloy plate having a thickness of 0.3 mm using an acetylene combustion flame so that its surface temperature is about 1100 ° C. An alloy plate made of The heat treatment time at 1100 ° C. was 60 seconds. The layer containing carbon-doped titanium oxide thus formed is superhydrophilic with a contact angle with water droplets of about 2 °, and has the same photocatalytic activity as that of the carbon-doped titanium oxide layer obtained in Example 4. showed that.

[Example 9]
A titanium thin film having a thickness of about 500 nm was formed on the surface of a stainless steel plate (SUS316) having a thickness of 0.3 mm by sputtering. A stainless steel sheet having a carbon-doped titanium oxide layer as a surface layer was formed by heat treatment using an acetylene combustion flame so that the surface temperature was about 900 ° C. The heat treatment time at 900 ° C. was 15 seconds. The carbon-doped titanium oxide layer thus formed is superhydrophilic with a contact angle with water droplets of about 2 °, and exhibits the same photocatalytic activity as the carbon-doped titanium oxide layer obtained in Example 4. It was.

[Example 10]
A titanium oxide powder having a particle size of 20 μm is supplied into an acetylene combustion flame, and is retained in the combustion flame for a predetermined time, and heat-treated so that the surface temperature is about 1000 ° C. A titanium powder having a layer was formed. The heat treatment time at 1000 ° C. was 4 seconds. The titanium powder having the carbon-doped titanium oxide layer formed as described above showed the same photocatalytic activity as that of the carbon-doped titanium oxide layer obtained in Example 4.

[Examples 11 to 12]
A titanium thin film having a thickness of about 100 nm was formed by sputtering on the surface of a 1 mm thick glass plate (Pyrex (registered trademark)). A glass plate having a carbon-doped titanium oxide layer as a surface layer is obtained by heat treatment using an acetylene combustion flame so that the surface temperature is 1100 ° C. (Example 11) or 1500 ° C. (Example 12). Formed. The heat treatment time at 1100 ° C. or 1500 ° C. was 10 seconds. The carbon-doped titanium oxide layer thus formed was transparent as shown in the photograph in FIG. 8A when the surface temperature was 1100 ° C., but when the surface temperature was 1500 ° C., FIG. As shown in FIG. 8, many small island-like undulations floating in the sea are generated on the surface, and it became translucent as shown in FIG.

[Examples 13 to 16]
The surface of the titanium plate having a thickness of 0.3 mm was subjected to heat treatment with an acetylene combustion flame at the surface layer temperature shown in Table 3 for the time shown in Table 3. After that, when the surface to which the flame is applied is brought into contact with a flat surface of a stainless steel block having a thickness of 30 mm and cooled, a layer in which fine columns made of white titanium oxide stand on the most part of the titanium plate surface is exposed. And a small piece member in which a large number of continuous narrow protrusions made of white titanium oxide on the thin film and fine columns standing on the protrusions are exposed. That is, the layer in which the fine columns made of titanium oxide formed in the surface layer by heat treatment are erected is cut in the direction along the surface layer by the subsequent cooling. In this way, Examples 13 to 16 were obtained.

  FIG. 10 is a photomicrograph of the member obtained in Example 13, in which a layer 2 in which fine columns made of white titanium oxide are forested is exposed on the titanium plate surface 1, and a white color is formed on the thin film. A state is shown in which a small piece member 3 in which a large number of continuous narrow protrusion portions made of titanium oxide and fine columns standing on the protrusion portions are exposed remains on a part of the layer 2. . In addition, in the manufacturing method of Examples 13-16, although the titanium plate surface 1 is not exposed, the micrograph of FIG. 10 has shown the state which removed a part of layer 2 in which the fine pillar stands. FIG. 11 is a photomicrograph showing the state of the surface on the thin film side of the small piece member 3 in which a large number of continuous narrow protrusions made of white titanium oxide and thin columns standing on the protrusions are exposed on the thin film. FIG. 12 shows a number of continuous narrow widths of small piece members 3 in which a large number of continuous narrow-width projections made of white titanium oxide are exposed on a thin film and fine columns standing on the projections are exposed. FIG. 13 is a photomicrograph showing the state of the protrusion and the surface on the side where the fine pillar standing on the protrusion is exposed, and FIG. 13 is the state of the layer 2 where the fine pillar made of white titanium oxide is standing FIG.

[Example 17]
The surface of a Ti-6Al-4V alloy plate having a thickness of 0.3 mm was heat-treated with an acetylene combustion flame at the surface layer temperature shown in Table 3 for the time shown in Table 3. After that, when the surface to which the flame is applied is brought into contact with a flat surface of a stainless steel block having a thickness of 30 mm and cooled, a layer in which fine columns made of titanium alloy oxide stand on most of the surface of the titanium alloy plate is exposed. And a small piece member in which a number of continuous narrow protrusions made of titanium alloy oxide on the thin film and fine columns standing on the protrusions are exposed.

[Example 18]
A titanium thin film having a thickness of about 3 μm was formed on the surface of a stainless steel plate (SUS316) having a thickness of 0.3 mm by electron beam evaporation. The surface of the thin film was heat-treated with an acetylene combustion flame at the surface layer temperature shown in Table 3 for the time shown in Table 3. After that, when the surface to which the combustion flame is applied is brought into contact with a flat surface of a 30 mm thick stainless steel block and cooled, a layer in which fine columns made of white titanium oxide are forested is exposed on the majority of the surface of the stainless steel plate. And a small piece member in which a large number of continuous narrow protrusions made of white titanium oxide on the thin film and fine columns standing on the protrusions are exposed.

[Comparative Example 4]
A commercially available titanium oxide sol (STS-01 manufactured by Ishihara Sangyo Co., Ltd.) was spin-coated on a titanium plate having a thickness of 0.3 mm, and then a titanium plate having a titanium oxide film whose adhesion was improved by heating was formed.

Test Example 12 (Scratch hardness test: pencil method)
Mitsubishi Pencil Co., Ltd., based on JIS K 5600-5-4 (1999), on the surface of the fine column side of the member in which the layer in which the fine column is grown is exposed on the substrate surface obtained in Examples 13 to 18 A pencil scratch hardness test was carried out using Uni 1H-9H pencils. The results were as shown in Table 3. That is, no damage was observed when a 9H pencil was used for all the test pieces.

Test Example 13 (Chemical resistance test)
The members having exposed layers with fine pillars exposed on the substrate surfaces obtained in Examples 13 to 18 were immersed in 1M sulfuric acid aqueous solution and 1M sodium hydroxide aqueous solution for 1 week at room temperature, washed with water and dried. Then, the above scratch hardness test: the pencil method was carried out. The results were as shown in Table 3. That is, even when a 9H pencil was used for all the test pieces, no damage was observed, and it was confirmed that the test pieces had high chemical resistance.

Test example 14 (heat resistance test)
A member in which a layer in which fine columns are erected is exposed on the surface of the substrate obtained in Examples 13 to 18 is placed in a tubular furnace, and the temperature is raised from room temperature to 500 ° C. in an air atmosphere over 1 hour. After holding at a constant temperature of 500 ° C. for 2 hours and further allowing to cool to room temperature over 1 hour, the above-described scratch hardness test: pencil method was performed. The results were as shown in Table 3. That is, no damage was observed even when a 9H pencil was used for all the test pieces, and it was confirmed that the specimen had high heat resistance.

Test Example 15 (Anti-fouling test)
As a sample, a titanium plate surface area 8 cm ² having a titanium oxide film obtained in member and Comparative Example 4 of surface area 8 cm ² of the layer minute columns the resulting substrate surface in Example 16 is bristled is exposed An antifouling test was conducted using Specifically, each of these samples was immersed in 80 mL of an aqueous methylene blue solution adjusted to a concentration of about 10 μmol / L, and the influence of the decrease in concentration due to initial adsorption became negligible. Matsushita Electric Industrial Co., Ltd. Visible light was irradiated with a fluorescent lamp with a UV cut filter manufactured, and the absorbance of the methylene blue aqueous solution at a wavelength of 660 nm was measured with a water quality inspection apparatus DR / 2400 manufactured by HACH at every predetermined irradiation time. The result was as shown in FIG.

  From FIG. 14, the member in which the layer with the fine pillars exposed on the surface of the substrate obtained in Example 16 is exposed to methylene blue as compared with the titanium plate having the titanium oxide film obtained in Comparative Example 4. It can be seen that the decomposition speed of is high and the antifouling effect is high.

Test Example 16 (Crystal structure and bonding state)
As a result of performing X-ray analysis (XRD) on the sample obtained from the fine column of the member in which the layer with the fine column grown on the substrate surface obtained in Example 15 is exposed, it has a rutile crystal structure. It has been found.

Further, with respect to the fine column portion of the member in which the layer with the fine columns grown on the surface of the substrate obtained in Example 15 is exposed, an X-ray photoelectron spectrometer (XPS) is used to accelerate voltage: 10 kV, target: Al was used for Ar sputtering for 2700 seconds, and analysis was started. If this sputtering rate is 0.64 Å / s corresponding to the SiO ₂ film, the depth is about 173 nm. The result of the XPS analysis was as shown in FIG. The highest peak appears when the binding energy is 284.6 eV. This is judged to be a C—H (C) bond commonly found in Cls analysis. The next highest peak is seen when the binding energy is 281.6 eV. Since the bond energy of the Ti—C bond is 281.6 eV, it is determined that C is doped as a Ti—C bond in the fine column of Example 15. As a result of XPS analysis at 14 points at different heights of the fine columns, similar peaks appeared in the vicinity of 281.6 eV at all points.

[Example 19]
A disc having a diameter of 32 mm and a thickness of 0.3 mm was used as a test piece, and the surface thereof was heated by an acetylene combustion flame so that the surface temperature was maintained at about 1150 ° C. About the 1st test piece, the heating was stopped at the time of the heating time of 120 seconds, and it stood to cool. About the 2nd test piece, the heating was stopped at the time of 180 second and it stood to cool. The third test piece was heated for 480 seconds, and immediately the surface to which the flame was applied was brought into contact with the flat surface of a 30 mm thick stainless steel block and cooled. By this cooling, a thin film was peeled off from the surface of the titanium plate, and a member in which a layer in which fine columns made of white titanium oxide were erected was exposed. With respect to these three test pieces, a hole of 3 μm × 12 μm and a depth of 10 μm was dug on the surface of the test piece using a FIB-SEM apparatus SMI8400SE manufactured by Seiko Instruments Inc., and the side and bottom surfaces thereof were observed with a SEM apparatus VE7800 manufactured by Keyence Corporation. Went. The SEM photograph of the test piece after 120 seconds is FIG. 16, the SEM photograph of the test piece after 180 seconds is FIG. 17, and the SEM photograph of the test piece after 480 seconds is FIG. In FIG. 17 after 180 seconds, signs of a fine column structure begin to appear in the lower part of the film, and it is considered that by continuing the flame treatment, the fine column is elongated and a fine column structure as intended in the present invention is formed. .

It is a figure which shows the result of the film hardness test of Test Example 1. 10 is a diagram showing the results of XPS analysis in Test Example 5. FIG. It is a figure which shows the wavelength response of the photocurrent density of Test Example 6. It is a figure which shows the test result of the light energy conversion efficiency of Test Example 7. It is a figure which shows the result of the deodorizing test of Test Example 8. 10 is a photograph showing the results of an antifouling test in Test Example 9. It is a figure which shows the result of Test Example 11. It is a photograph which shows the light transmission state of the carbon dope titanium oxide layer obtained in Example 11 and 12. 6 is a photograph showing the surface state of the carbon-doped titanium oxide layer obtained in Example 11. FIG. It is a microscope picture which shows the state of the multifunctional material which has the mirror surface obtained in Example 13. FIG. It is a microscope picture which shows the state of the thin film side surface of the small piece member 3 which has exposed many fine narrow protrusions which consist of white titanium oxide on a thin film, and the fine pillar standing on a protrusion part. A large number of continuous narrow-width projections made of white titanium oxide on the thin film and a large number of continuous narrow-width projections of the small piece member 3 in which fine columns standing on the projection are exposed, and the projections It is the microscope picture which shows the state of the surface of the side where the fine pillar which stands in the side is exposed. It is a microscope picture which shows the state of the layer 2 in which the micro pillar which consists of white titanium oxide stands. It is a graph which shows the result of Test Example 15 (antifouling test). It is a graph which shows the result of Test Example 16 (crystal structure and bonding state). It is a SEM photograph after a heating time of 120 seconds in Example 19. It is a SEM photograph after a heating time of 180 seconds in Example 19. It is a SEM photograph after the heating time of 480 seconds in Example 19.

1 Surface of substrate 2 Fine column 3 Thin film

Claims (5)

The surface of the substrate made of titanium or titanium alloy is heat-treated at a high temperature using a combustion flame of a gas containing hydrocarbon as a main component, or is heated at a high temperature in a combustion gas atmosphere of a gas containing hydrocarbon as a main component. by, at least a portion of the surface layer, carbon and carbon-doped titanium oxide layer composed of the doped titanium oxide or titanium alloy oxide in the state of Ti-C bonds, mirror by polishing the carbon-doped titanium oxide layer machining becomes provide Reinforced, multifunctional material having a mirror surface, characterized in that. The surface of the substrate made of titanium or titanium alloy is heat-treated at a high temperature using a combustion flame of a gas containing hydrocarbon as a main component, or is heated at a high temperature in a combustion gas atmosphere of a gas containing hydrocarbon as a main component. by, at least a portion of the surface layer, carbon and carbon-doped titanium oxide layer having a plurality of projections consisting of oxide doped with titanium or a titanium alloy oxide in the state of Ti-C bonds, the carbon-doped oxide formed by facilities mirror-finished by polishing the titanium layer, multi-functional material having a mirror surface, characterized in that. The surface of the substrate made of titanium or titanium alloy is heat-treated at a high temperature using a combustion flame of a gas containing hydrocarbon as a main component, or is heated at a high temperature in a combustion gas atmosphere of a gas containing hydrocarbon as a main component. by, at least a portion of the surface layer is exposed a layer of carbon is doped titanium oxide or titanium alloy oxide in the state of Ti-C bonds minute columns is bristled, fine Hosohashira There is a layer that is bristled, formed by facilities mirror-finished by polishing the carbon-doped titanium oxide layer, multi-functional material having a mirror surface, characterized in that. The layer having a mirror surface according to any one of claims 1 to 3 , wherein the layer made of carbon-doped titanium oxide or titanium alloy oxide contains 0.3 to 15 at% carbon. Functional material. The multifunctional material having a mirror surface according to any one of claims 1 to 4 , wherein the mirror surface processing is performed by electrolytic polishing or buffing.