Rocket part

The first invention relates to a rocket component constituting a rocket, wherein at least the surface layer has a layer made of carbon-doped titanium oxide or titanium alloy oxide, and the carbon is doped in a Ti-C bond state. With respect to rocket parts formed at least in part by. More specifically, it is formed by doping carbon in a Ti-C bond state, has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and is a visible light responsive type. It relates to a rocket component in which at least a part is formed by a member having a layer that functions as a photocatalyst. Further, the second invention relates to a rocket component, and more specifically, a volatile organic compound (VOC) is also easy because it has a large number of protrusions made of titanium oxide or a titanium alloy oxide on at least a part of the surface. Since it has a large surface area and is carbon-doped, it has high activity as a photocatalyst and functions as a visible light responsive photocatalyst. It also has high hardness, and has excellent peel resistance, abrasion resistance, chemical resistance, and heat resistance. With respect to rocket parts formed at least in part by good members.

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

When manufacturing a photocatalyst product that has deodorant, antibacterial, antifogging and antifouling effects by such a photocatalytic function, generally, titanium oxide sol is applied onto the substrate by spray coating, spin coating, dipping or the like. (For example, refer to Patent Documents 1 to 3), but the film formed in this way is prone to peeling and abrasion, so that it is difficult to use it for a long period of time. A method of forming a photocatalyst film by a sputtering method is also known (see, for example, Patent Documents 4 to 5).

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

Further, as the titanium oxide photocatalyst doped with other elements in this way, a titanium compound obtained by substituting the oxygen site of titanium oxide with an atom such as nitrogen, and an atom such as nitrogen being doped between the lattices of the titanium oxide crystal. A photocatalyst composed of a titanium compound or a titanium compound in which atoms such as nitrogen are arranged at the grain boundaries of a multi-crystal aggregate of titanium oxide crystals has been proposed (see, for example, Patent Documents 6 to 9). However, such a photocatalyst is not always satisfactory in terms of durability such as abrasion resistance. Further, for example, n-TiO which is a chemically modified titanium oxide by applying a natural gas combustion flame whose combustion flame temperature is maintained at around 850 ° C by adjusting the flow rate of natural gas and oxygen to a titanium metal.₂It has been reported that -xCx is obtained and that it absorbs light of 535 nm or less (see Non-Patent Document 3).

Further, the crystal nuclei produced by various manufacturing methods such as the CVD method or the PVD method are placed in a sol solution composed of an inorganic metal compound or an organic metal compound, or the sol solution is applied to the crystal nuclei to solidify and heat-treat. It is known that by growing a titanium oxide crystal from the crystal nucleus, a highly active photocatalyst function can be obtained by forming a columnar crystal in the crystal shape of the titanium oxide crystal grown from the crystal nucleus (for example). See Patent Documents 10-12). However, in that case, since the columnar crystals simply grow from the seed crystals placed on the substrate, the formed columnar crystals do not have sufficient adhesion strength to the substrate, and are thus produced. Photocatalysts are not always satisfactory in terms of durability such as abrasion resistance.

The rocket parts constituting the rocket differ depending on the application and installation site, but are formed of, for example, members using carbon fibers having excellent strength and elastic modulus. The rocket parts include the body of the rocket and various parts provided inside.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 09-241038</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 09-262481</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 10-053437</text></patcit><patcit num="4"><text>Japanese Unexamined Patent Publication No. 11-012720</text></patcit><patcit num="5"><text>Japanese Unexamined Patent Publication No. 2001-205105</text></patcit><patcit num="6"><text>JP 2001-205103 (Claims)</text></patcit><patcit num="7"><text>Japanese Patent Application Laid-Open No. 2001-205094 (Claims)</text></patcit><patcit num="8"><text>Japanese Patent Application Laid-Open No. 2002-95976 (Claims)</text></patcit><patcit num="9"><text>International Publication No. 01/10553 Pamphlet (Claims)</text></patcit><patcit num="10"><text>Japanese Unexamined Patent Publication No. 2002-253975</text></patcit><patcit num="11"><text>Japanese Unexamined Patent Publication No. 2002-370027</text></patcit><patcit num="12"><text>JP-A-2002-370034</text></patcit><nplcit num="1"><text>A. Fujishima et al., J. Electrochem. Soc. Vol. 122, No. 11, p. 1487-1489, November 1975</text></nplcit><nplcit num="2"><text>R. Asahi et al., SCIENCE Vol. 293, July 13, 2001, p. 269-271</text></nplcit><nplcit num="3"><text>Shahed UM Khan et al., SCIENCE Vol. 297, September 27, 2002, p. 2243-2245</text></nplcit>

<p> Here, the conventional titanium oxide-based photocatalyst has a problem in durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) in both the ultraviolet responsive type and the visible light responsive type. , It was a bottleneck in terms of practical use.</p><p> On the other hand, since rocket parts are placed in a harsh environment such as temperature, excellent durability is required for the members forming the rocket parts. In addition, rocket parts tend to get dirty depending on the installation site on the rocket and the function of the parts themselves, so it is necessary to prevent dirt from adhering and facilitate cleaning.</p><p> Therefore, the first invention has a carbon-doped titanium oxide layer that has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) as a surface layer and functions as a visible light responsive photocatalyst. It is an object of the present invention to provide a rocket component in which at least a part is formed by a member.</p><p> Further, in the second invention, VOCs can be easily adsorbed, the surface area is large and carbon-doped, so that the activity as a photocatalyst is high and the function functions as a visible light responsive photocatalyst, and peeling resistance, abrasion resistance, and carbon doping resistance. An object of the present invention is to provide a rocket component in which at least a part thereof is formed of a member having excellent chemical properties and heat resistance.</p>

<p>As a result of diligent studies to achieve the above object, the present inventor has obtained a combustion flame of a gas containing a hydrocarbon as a main component on the surface of a substrate whose surface layer is titanium, a titanium alloy, a titanium alloy oxide or titanium oxide. By heat-treating at high temperature using, carbon is doped in the state of Ti-C bond, and it has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance). We have found that a member (hereinafter referred to as "multifunctional material") useful for applying a carbon-doped titanium oxide that functions as a visible light-responsive photocatalyst as a surface layer to a rocket component can be obtained, and complete the present invention. It came to.</p><p> That is, in the first rocket component of the present invention, at least the surface layer is composed of a carbon-doped titanium oxide layer, and the carbon is doped in a Ti-C bond state, and as a highly durable and visible light responsive photocatalyst. It is characterized in that it is formed of a functional multifunctional material (first multifunctional material).</p><p> Furthermore, as a result of diligent studies to achieve the above object, the present inventor burns unsaturated hydrocarbons, especially acetylene, on the surface of a substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide. The inside of the surface layer is heat-treated under specific conditions by directly applying a flame, or by heat-treating the surface of the substrate under specific conditions in the atmosphere of combustion exhaust gas of unsaturated hydrocarbons, especially acetylene. A layer in which fine columns made of titanium oxide or titanium alloy oxide are standing is formed, and a layer in which the fine columns are standing is cut along the surface layer to at least a part of the substrate. A member in which a layer in which fine columns made of titanium oxide or titanium alloy oxide stand is exposed, and a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide and the protrusions on the thin film. It is possible to obtain a member in which fine columns standing on the part are exposed, 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. The photocatalytic activity is increased by the fact that both of them are useful multifunctional materials, and that the fine columns, which are protrusions made of titanium oxide or titanium alloy oxide, and the continuous narrow protrusions are carbon-doped. We found that a multifunctional material that is high, functions as a visible light responsive photocatalyst, can easily adsorb VOC, has high hardness, and has excellent peel resistance, abrasion resistance, chemical resistance, and heat resistance can be obtained. The present invention has been completed.</p><p> That is, the second rocket component 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, titanium oxide or titanium alloy on at least a part of the surface. A layer of fine pillars made of oxide is exposed, or a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide are formed on the thin film, and fine pillars are made of fine pillars. Is exposed, and the protrusions, for example, the fine columns, and the narrow protrusions are formed of a carbon-doped multifunction material (second multifunction material).</p><p> In the present invention, at least a part of various rocket parts is formed of a first multifunctional material or a second multifunctional material.</p>

<p> The first multifunctional material is used as a visible light responsive photocatalyst because it has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and functions as a visible light responsive photocatalyst. Not only that, it can be significantly used for various rocket parts in which hard chrome plating has been conventionally used. Further, it can be expected to be applied to rocket parts for the purpose of preventing pitting corrosion, total corrosion, stress corrosion cracking, etc. by lowering the potential of the base material. Furthermore, by using it as a radiation-responsive catalyst that responds to radiation such as γ-rays as well as ultraviolet rays to suppress stress corrosion cracking and scale adhesion of rocket parts, it is easier to compare with other film formation methods. A film can be formed and the durability can be improved.</p><p> The second multifunctional material has high photocatalytic activity, functions as a visible light responsive photocatalyst, can easily adsorb VOCs, has high hardness, and has excellent peel resistance, abrasion resistance, chemical resistance, and heat resistance. ing.</p><p> Therefore, by forming the rocket parts with the first multifunctional material or the second multifunctional material, not only the weight can be reduced, but also the rocket parts have excellent durability such as high hardness and visible light. It is possible to provide a rocket component having an excellent effect of a responsive photocatalyst. In addition, the effect of avoiding the adhesion of ice to rocket parts can be expected.</p><p> If durability is important, it is preferable to use the first multifunctional material, and if high photocatalytic activity is important, it is preferable to use the second multifunctional material.</p>

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

The rocket component of the present embodiment is characterized in that a predetermined multifunctional material is used for at least a part of the members. Therefore, in the following, first, this multifunctional material will be described in detail, and then rocket parts using this multifunctional material will be described.

[About multifunctional materials]

The first multifunctional material used in the rocket component of the present invention has at least the surface of a substrate whose surface layer is titanium, titanium alloy, titanium alloy oxide or titanium oxide, for example, a gas containing hydrocarbon as a main component. It can be produced by heat treatment at a high temperature using the combustion flame of Titanium, but the substrate whose surface layer is at least titanium, titanium alloy, titanium alloy oxide or titanium oxide is entirely titanium, titanium. It may be composed of either an alloy, a titanium alloy oxide or titanium oxide, or may be composed of a surface forming layer and a core material, and the materials thereof may be different. Regarding the shape of the substrate, the final product shape (flat plate or three-dimensional shape) where durability such as high hardness, scratch resistance, abrasion resistance, chemical resistance, and heat resistance is desired, and visible light on the surface. It may be a final product shape that is desired to have a responsive photocatalytic function.

If at least a substrate whose surface layer is made of titanium, titanium alloy, titanium alloy oxide or titanium oxide is composed of a surface cambium and a core material and their materials are different, the thickness of the surface cambium The thickness may be the same as the thickness of the carbon-doped titanium oxide layer formed (ie, the entire surface cambium is the carbon-doped titanium oxide layer) or thicker (ie, the thickness of the surface cambium). A part of the direction becomes a carbon-doped titanium oxide layer, and a part remains as it is). 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 method of the first invention. For example, iron, iron alloy, non-ferrous alloy, ceramics, other ceramics, high temperature heat resistant glass and the like can be used as the core material. As a substrate composed of such a thin film-like surface layer and a core material, for example, a method such as sputtering, vapor deposition, or thermal spraying of a film made of titanium, a titanium alloy, a titanium alloy oxide, or titanium oxide on the surface of the core material. Or a commercially available titanium oxide sol formed by spray coating, spin coating or dipping on the surface of the core material to form a film.

The first multifunctional material 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, titanium alloy, titanium alloy oxide, or It is titanium oxide, and the core material may be made of a material other than titanium, a titanium alloy, and titanium oxide.

Various known titanium alloys can be used as the above-mentioned titanium alloy, and there is no particular limitation. 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, etc. Can be used.

In the production of the first multifunctional material, a combustion flame of a gas containing hydrocarbons, particularly acetylene as a main component, can be used, and it is particularly desirable to use a reducing flame. In the production of the first multifunctional material, the gas containing at least 50% by volume of this hydrocarbon as a main component means a gas containing at least 50% by volume of hydrocarbon, for example, air containing at least 50% by volume of acetylene, as appropriate. It means a gas in which hydrogen, oxygen, etc. are mixed. In the production of this multifunctional material, it is preferable that the gas containing a hydrocarbon as a main component contains 50% by volume or more of acetylene, and most preferably the hydrocarbon is 100% acetylene. When unsaturated hydrocarbons, especially acetylene having a triple bond, are used, the unsaturated bond portion is decomposed to form an intermediate radical substance in the process of combustion, especially in the reducing flame portion, and this radical substance is formed. Since is highly active, it is considered that carbon doping is likely to occur.

In the production of the first multifunctional material, when the surface layer of the substrate to be heat-treated is titanium or a titanium alloy, oxygen for oxidizing the titanium or the titanium alloy is required, and air or oxygen is contained accordingly. You need to be.

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

For heat treatment, the surface temperature of the substrate is 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 so as to be. In the case of heat treatment in which the surface temperature of the substrate is less than 900 ° C, the durability of the obtained substrate having the carbon-doped titanium oxide layer becomes insufficient, and the photocatalytic activity under visible light becomes 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) aimed at in the first invention is achieved. , Scratch resistance, abrasion resistance, chemical resistance, heat resistance) cannot be obtained. Further, even in the case of heat treatment in which the surface temperature of the substrate is in the range of 900 to 1500 ° C, if the heat treatment time is long, the ultrathin film peels 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) aimed at in the first invention cannot be obtained, the surface of the substrate is exposed to cooling after heat treatment. The time should be such that it does not cause peeling. That is, the heat treatment time is sufficient for the surface layer to be a carbon-doped titanium oxide layer doped with carbon in a Ti-C bond state, but the electrode from the surface of the substrate during cooling after heating. It should be a time that does not cause the thin film to peel off. This heat treatment time correlates with the heating temperature, but is preferably about 400 seconds or less.

In the production of the first multifunctional material, carbon containing 0.3 to 15 at%, preferably 1 to 10 at% of carbon is doped in a Ti-C bond state by adjusting the heating temperature and the heat treatment time. A doped titanium oxide layer can be obtained relatively easily. When the carbon doping amount is small, the carbon-doped titanium oxide layer becomes 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 the transparent plate-shaped core material, it is excellent in durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and visible light response. A transparent plate that functions as a type photocatalyst can be obtained, and durability (high hardness, scratch resistance, abrasion resistance) is obtained by forming a transparent carbon-doped titanium oxide layer on a plate having a colored pattern on the surface. , Chemical resistance, heat resistance), and a decorative plate that functions as a visible light responsive photocatalyst can be obtained. When at least the surface layer is made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, and the substrate is composed of a surface forming layer and a core material, and the thickness of the surface forming layer is 500 nm or less. When heated to near the melting point of the surface cambium, many islet-like undulations floating in the sea are generated on the surface and become translucent.

In a multifunctional material having a carbon-doped titanium oxide layer in which carbon is doped 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, scratch resistance, and scratch resistance. It is more preferably 50 nm or more in order to achieve abrasion resistance. When the thickness of the carbon-doped titanium oxide layer is less than 10 nm, the durability of the obtained multifunctional material having the carbon-doped titanium oxide layer tends to be insufficient. The upper limit of the thickness of the carbon-doped titanium oxide layer needs to be considered in consideration of cost and the effect to be achieved, but is not particularly limited.

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

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

The carbon-doped titanium oxide layer of the first multifunctional material responds not only to ultraviolet rays but also to visible light having a wavelength of 400 nm or more, and acts effectively as a photocatalyst. Therefore, the first multifunctional material 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 first multifunctional material exhibits superhydrophilicity with a contact angle of 3 ° or less. The carbon-doped titanium oxide layer also avoids the adhesion of ice to its surface.

Furthermore, the carbon-doped titanium oxide layer of the first multifunctional material is also excellent in chemical resistance, and after being immersed in each aqueous solution of 1M sulfuric acid and 1M sodium hydroxide for one week, the film hardness, abrasion resistance and light When the current density was measured and compared with the measured value before the treatment, no significant change was observed. Incidentally, with respect to a commercially available titanium oxide film, the binder generally dissolves in an acid or an alkali depending on the type of the binder, so that the film peels off and there is almost no acid resistance or alkali resistance.

The second multifunctional material used in the rocket component of the present invention has a combustion flame of, for example, an unsaturated hydrocarbon, particularly acetylene, on the surface of a substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide. The surface layer is heat-treated to form a layer in which fine columns made of titanium oxide or titanium alloy oxide are standing, and then, for example, thermal stress, shear stress, and tensile force are applied to the fine columns. The layer in which the forest is standing is cut along the surface layer, and fine columns made of the titanium oxide or titanium alloy oxide are forested in at least a part of the substrate, usually most of the substrate. A member with an exposed layer, a number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on the thin film, and a member with exposed fine columns standing on the protrusions. Can be manufactured by obtaining.

The substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide may be entirely composed of titanium, titanium oxide, titanium alloy or titanium alloy oxide. Alternatively, it may be composed of a surface forming layer made of titanium, titanium oxide, a titanium alloy or a titanium alloy oxide, and a core material made of another material. Further, the shape of the substrate may be any final product shape (flat plate shape or three-dimensional shape) for which photocatalytic activity and / or superhydrophilicity is desired.

A substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide is composed of a surface forming layer made of titanium, titanium oxide, titanium alloy or titanium alloy oxide and a core material made of other materials. If so, the thickness (amount) of the surface forming layer is comparable to the amount of the layer in which fine columns made of titanium oxide or titanium alloy oxide are formed. That is, the entire surface forming layer may be a layer in which fine columns made of titanium oxide or titanium alloy oxide stand in a forest), or may be thicker than that (that is, a part of the surface forming layer in the thickness direction). It becomes a layer of fine columns made of titanium oxide or titanium alloy oxide, 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 second multifunctional material. For example, iron, iron alloys, non-ferrous alloys, 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 the core material, the same ones as 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.

As the titanium alloy, various known titanium alloys can be used, and the same as the first multifunctional material is used without particular limitation.

In the production of the second multifunctional material, for example, it is desirable to use a combustion flame of a gas containing unsaturated hydrocarbons, particularly acetylene as a main component, and particularly a reducing flame. In the production of the second multifunctional material, 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 and the like may be used. preferable. In the production of the second multifunctional material, it is most preferable that the fuel component is 100% acetylene. When unsaturated hydrocarbons, especially acetylene having a triple bond, are used, the unsaturated bond portion is decomposed to form an intermediate radical substance in the process of combustion, especially in the reducing flame portion, and this radical substance is formed. Since is highly active, carbon doping is likely to occur, and the doped carbon is contained in a Ti-C bonded state. When carbon dope is generated in the fine columns in this way, the hardness of the fine columns is increased, and as a result, the hardness of the multifunctional material, the mechanical strength such as abrasion resistance, and the heat resistance are also improved.

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

For heat treatment, at least the surface layer is made of titanium, titanium oxide, titanium alloy or titanium alloy oxide, and a layer in which fine columns made of titanium oxide or titanium alloy oxide are standing is formed inside the surface layer, and then a layer is formed. For example, by applying thermal stress, shear stress, and tensile force, the layer in which the fine columns stand is cut in the direction along the surface layer, and at least a part of the substrate is covered with the titanium oxide or titanium alloy oxide. A member in which a layer of fine pillars consisting of is exposed, a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on a thin film, and fine protrusions standing on the protrusions. It is necessary to adjust the heating temperature and the heat treatment time so that the members with the exposed columns can be obtained. This heat treatment is preferably carried out at a temperature of 600 ° C. or higher.

By 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 on it is about 0.1 to 10 μm, and the average of the fine pillars is about 0.1 to 10 μm. An intermediate having a thickness of about 0.2 to 3 μm is formed. After that, for example, thermal stress, shear stress, and tensile force are applied to cut the layer in which the fine columns stand in the direction along the surface layer, so that at least a part of the substrate is covered with the titanium oxide or the titanium oxide. Members with exposed layers of titanium alloy oxide fine columns (ie, all or most of the thin film that was present on the layers of fine columns on the substrate are exfoliated. However, some of the thin films that existed on the layer of forested microcolumns may remain without peeling), and a large number of continuous narrow widths of titanium oxide or titanium alloy oxides on the thin films. A protrusion and a member in which fine pillars standing on the protrusion are exposed are obtained.

When applying thermal stress to cut a layer in which fine columns stand in a direction along the surface layer, for example, the surface of the substrate is cooled or heated by either the front surface or the back surface of the substrate. Provide a temperature difference between the back surface and the back surface. As this cooling method, for example, either the front surface or the back surface of the hot intermediate is brought into contact with a cooling object, for example, a stainless steel block, or cold air (air at room temperature) is applied to either the front surface or the back surface of the hot intermediate. Spray. Thermal stress is generated even if the above hot intermediate is allowed to cool, but the degree is low.

When a shear stress is applied to cut a layer in which fine columns stand in a direction along a surface layer, for example, a force in a relatively opposite direction is applied to the front surface and the back surface of the above-mentioned intermediate by a frictional force. Further, when a tensile force is applied to cut a layer in which fine columns are standing in a direction along the surface layer, for example, a vacuum suction plate or the like is used to cut the front surface and the back surface of the above intermediate body of those surfaces. Pull in the vertical and reverse directions. When only the member in which the layer in which the fine columns made of titanium oxide or the titanium alloy oxide are standing is exposed on at least a part of the substrate, it is oxidized on the thin film of the above intermediate. It is also possible to remove a large number of continuous narrow protrusions made of titanium or a titanium alloy oxide and a portion corresponding to a member in which fine columns standing on the protrusions are exposed by polishing, sputtering or the like.

In the member in which the layer in which fine pillars made of titanium oxide or titanium alloy oxide are standing is exposed at least partly on the substrate obtained as described above, the layer in which fine pillars are standing is used. The height of the layer where the fine pillars are standing changes depending on the height position of the fine pillars cut along the surface layer, but the height of the layer where the fine pillars are standing is generally 1 ~ It is about 20 μm, and the average thickness of the fine columns is about 0.5 to 3 μm. This member is a multifunctional material that can easily adsorb VOCs, has a large surface area, has high activity as a photocatalyst, has high film hardness, and has excellent peel resistance, abrasion resistance, chemical resistance, and heat resistance. is there.

On the other hand, a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide and fine pillars standing on the protrusions are exposed on the thin film obtained as described above. The height of the protrusions on each small piece is about 2 to 12 μm, and the height of the fine pillars is the height of the fine pillars obtained by cutting the layer in which the fine pillars stand in the direction along the surface layer. Although it 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 stand in the direction along the surface layer, there are cases where there are almost no fine columns and a large number of continuous narrow protrusions are exposed. This member can also adsorb VOCs and has a large surface area, so that it is highly active as a photocatalyst. Further, this member can be used as it is or pulverized, and the pulverized product can easily adsorb VOCs and has a large surface area, so that it has high activity as a photocatalyst.

In the second multifunctional material, fine columns made of titanium oxide or titanium alloy oxide, a large number of continuous narrow protrusions, and fine columns standing on the protrusions are carbon-doped, so that ultraviolet rays are emitted. Of course, it also responds to visible light with a wavelength of 400 nm or more, acts particularly effectively as a photocatalyst, can be used as a visible light responsive photocatalyst, and exhibits a photocatalytic function not only outdoors but also indoors.

As can be judged from the micrographs of FIGS. 10 and 13, the shape of each of the fine pillars in the layer in which the fine pillars made of titanium oxide or titanium alloy oxide constituting the second multifunctional material are standing is determined. , Pyramid, Cylindrical, Pyramid, Conical, Inverted Pyramid or Inverted Cone, etc., extending straight in the direction perpendicular to or inclined from the surface of the substrate, extending while bending or bending , Branched and extended, and their complex. Further, the overall shape can be represented by various expressions such as a frost column, a brushed carpet, a coral, a column, and a column assembled of building blocks. In addition, the thickness and height of these fine pillars, the size of the base (bottom surface) of the fine pillars, and the like vary depending on the heating conditions and the like.

A large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide in the form of a thin film and a member in which fine columns standing on the protrusions are exposed can be judged from the micrograph of FIG. In addition, the numerous continuous narrow protrusions can be seen as having the appearance of the outside of the walnut shell, the appearance of pumice stones, and each continuous narrow protrusion has a hot water or tiny shape. It can be seen that the pattern is bent. Further, the shape of the fine pillars standing on the protrusions is the same as the shape of each fine pillar in the layer in which the fine pillars on the substrate are standing, but the joint portion between the fine pillars and the thin film. Since many of them are cut by, the density of the fine pillars standing on the protrusions is generally smaller than the density of the fine pillars in the layer in which the fine pillars on the substrate are standing.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples.

[Examples 1 to 3]

By heat-treating a titanium plate with a thickness of 0.3 mm to a surface temperature of about 1100 ° C using a combustion flame of acetylene, carbon is doped in a state of Ti-C bond as a surface layer. A titanium plate having a titanium oxide layer was formed. The amount of carbon-doped and the thickness of the carbon-doped titanium oxide layer were adjusted by adjusting the heat treatment time at 1100 ° C to 5 seconds (Example 1), 3 seconds (Example 2), and 1 second (Example 3), respectively. Formed a titanium plate with different carbon-doped titanium oxide layers.

The carbon content of 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 determined by a fluorescent X-ray analyzer. TiO based on its carbon content_2-Assuming the molecular structure of xCx, for Example 1, the carbon content is 8 at%, TiO_{1. 76}C_0.24For Example 2, the carbon content is about 3.3 at%, TiO_1.90C_0.10, Example 3 has a carbon content of 1.7 at%, TiO_1.95C_0.05Met. 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 heated to form a titanium plate having a titanium oxide film having improved adhesion.

[Comparative example 2]

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

Test Example 1 (Vickers hardness) Nanohard nestester (NHT) (manufactured by CSM Instruments in Switzerland) was used for the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti-C bond state and the titanium oxide film of Comparative Example 1. ), The film hardness was measured under the conditions of indenter: Vickers hardness type, test load: 2 mN, load unloading rate: 4 mN / min. The doped titanium oxide layer had a high Vickers hardness 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. 1. For reference, the document values of Vickers hardness of the hard chrome plating layer and the nickel plating layer (cited from Tomono, "Practical Plating Manual", Chapter 6, Ohmsha (1971)) are also shown. It is clear that the carbon-doped titanium oxide layer in which the carbon of Example 1 is doped in a Ti-C bond state has a higher hardness than the nickel-plated layer and the hard chrome-plated layer.

Test Example 2 (Scratch resistance) Microscratch tester (MST) (CSM Instruments in Switzerland) for the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti-C bond state and the titanium oxide film of Comparative Example 1. Indenter: Rockwell (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 scratch property test was conducted. The "peeling start" load in which a small film peels off in the scratch mark and the "whole surface peeling" load in which the film peels off in the entire scratch mark are determined. The results are as shown in Table 1.<tables num="1"><img file="JP2006240333A_D0001.tif" /></tables>

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

Test Example 3 (Abrasion resistance) The high temperature tribometer (HT-TRM) (Switzerland) was used for the carbon-doped titanium oxide layer in which the carbon of Example 1 was doped in a Ti-C bond state and the titanium oxide film of Comparative Example 1. By CSM Instruments), test temperature: room temperature and 470 ° C, ball: SiC ball with diameter 12.4mm, load: 1N, sliding speed: 20mm / sec, radius of gyration: 1mm, test rotation speed: 1000 rotations A wear test was carried out at.

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

Test Example 4 (Chemical resistance) A titanium plate having a carbon-doped titanium oxide layer in which carbon of Example 1 was doped in a Ti-C bond state was immersed in a 1 M aqueous sulfuric acid solution and a 1 M aqueous sodium hydroxide solution at room temperature for 1 week, respectively. After that, the film hardness, abrasion resistance, and photocurrent density described later were measured. As a result, 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) X-ray photoelectrons of the carbon-doped titanium oxide layer doped with carbon in a Ti-C bond state in Example 1 The analysis was started by performing Ar ion sputtering for 2700 seconds with an acceleration voltage of 10 kV and a target of Al using a spectroanalyzer (XPS). This sputtering rate is SiO₂At 0.64 Å / s, which is equivalent to a film, the depth is about 173 nm. The results of the XPS analysis are shown in Fig. 2. The highest peak appears when the binding energy is 284.6 eV. This is determined to be the CH (C) binding commonly found in Cls analysis. The next highest peak is seen when the binding energy is 281.7 eV. Since the binding 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 near 281.6 eV at all points.

A Ti-C bond was also confirmed at the boundary between the carbon-doped titanium oxide layer and the substrate. Therefore, the hardness is increased by the Ti-C bond in the carbon-doped titanium oxide layer, and the film peeling strength is significantly increased by the Ti-C bond at the boundary between the carbon-doped titanium oxide layer and the substrate. Is expected.

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

The results are shown in Fig. 3. 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 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 amount of carbon doping increases. Was recognized. Although not shown here, it was found that the current density tends to decrease when the carbon doping amount exceeds 10 at%, and that tendency becomes remarkable when the carbon doping amount exceeds 15 at%. Therefore, it was confirmed that the optimum value is in the carbon doping amount of about 1 to 10 at%. On the other hand, in the titanium oxide films of Comparative Examples 1 and 2, it was found that the photocurrent density was extremely small and the wavelength absorption end was about 410 nm.

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

As is clear from FIG. 4, the light energy conversion efficiency of the carbon-doped titanium oxide layer in which the carbons of Examples 1 to 3 are doped in a Ti-C bond state is extremely high, and the conversion efficiency near a wavelength of 450 nm is a comparative example. It was found that the conversion efficiency of the titanium oxide film 1 and 2 in the ultraviolet region (200 to 380 nm) was superior. Further, the water splitting 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 of more than 10% can be obtained at a wavelength of 350 nm or less. I understood.

Test Example 8 (Deodorant Test) A deodorant test was carried out 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, acetaldehyde, which is generally used in deodorization tests, is sealed in a 1000 ml glass container together with a substrate having a carbon-doped titanium oxide layer, and the effect of concentration reduction due to initial adsorption can be ignored. Visible light was irradiated with a fluorescent lamp equipped with a UV cut filter, and the acetaldehyde concentration was measured by gas chromatography at predetermined irradiation times. The surface area of each film is 8.0 cm.²And said.

The result is shown in Fig. 5. 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 layer of Examples 1 and 2 is about twice as high as the acetaldehyde decomposition rate of the titanium oxide film of Comparative Example 1, and the amount of carbon-doped is large, so that light It was found that the carbon-doped titanium oxide layer of Example 1 having high energy conversion efficiency had a higher decomposition rate than the carbon-doped titanium oxide layer of Example 2.

Test Example 9 (Anti-fouling 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 film was installed in a smoking room in the Central Research Institute of Electric Power Industry, and the surface stains were observed 145 days later. There is no direct sunlight incident into this smoking room.

A photograph showing this result is shown in FIG. Fat adhered to the surface of the titanium oxide film of Comparative Example 1 and exhibited a pale yellow color, but the surface of the carbon-doped titanium oxide layer of Example 1 did not show any particular change and was kept clean. It was confirmed that the antifouling effect was fully exhibited.

[Examples 4 to 7]

Using the combustion flame of acetylene as in Examples 1 to 3, a titanium plate having a thickness of 0.3 mm was heat-treated at the surface temperature shown in Table 2 for the time shown in Table 2 to form carbon as a surface layer. A titanium plate having a doped titanium oxide layer was formed.

[Comparative example 3]

Using a natural gas combustion flame, a titanium plate having a thickness of 0.3 mm 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 layer 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. The carbon-doped titanium oxide layers formed in Examples 4 to 11 were superhydrophilic with a contact angle of about 2 ° with water droplets.<tables num="2"><img file="JP2006240333A_D0002.tif" /></tables>

As is clear from the data shown in Table 2, when heat treatment was performed with natural gas combustion gas so that the surface temperature was 850 ° C, only a film with a Vickers hardness of 160 was obtained, but the surface temperature was 1000. In the cases of Examples 4 to 7 which were heat-treated with the combustion gas of acetylene so as to have a temperature of ° C or higher, a carbon-doped titanium oxide layer having a Vickers hardness of 1200 was obtained.

Test Example 11 For the carbon-doped titanium oxide layer of Examples 4 to 7 and the titanium oxide film of Comparative Examples 1 and 3, a voltage of 0.3 V was applied between the carbon-doped titanium oxide film and the counter electrode in a 0.05 M sodium sulfate aqueous solution in the same manner as in Test Example 6. Then, the light current density was measured by irradiating with light of 300 nm to 520 nm. The results are shown in Fig. 7. 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-treating the surface temperature to 1000 to 1200 ° C using acetylene combustion gas have a relatively large photocurrent density and are excellent. I understood. 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 photocurrent density was relatively small.

[Example 8]

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

[Example 9]

A titanium thin film having a film 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-treating the surface temperature of the acetylene combustion flame to about 900 ° C. The heat treatment time at 900 ° C was set to 15 seconds. The carbon-doped titanium oxide layer thus formed is superhydrophilic with a contact angle of about 2 ° with water droplets, and exhibits the same photocatalytic activity as the carbon-doped titanium oxide layer obtained in Example 4. It was.

[Example 10]

Titanium oxide powder with a particle size of 20 μm is supplied into the combustion flame of acetylene, retained in the combustion flame for a predetermined time, and heat-treated so that its surface temperature becomes about 1000 ° C. A titanium powder having a titanium layer was formed. The heat treatment time at 1000 ° C was set to 4 seconds. The titanium powder having the carbon-doped titanium oxide layer thus formed exhibited the same photocatalytic activity as the carbon-doped titanium oxide layer obtained in Example 4.

[Examples 11 to 12]

A titanium thin film having a film thickness of about 100 nm was formed on the surface of a glass plate (Pyrex (registered trademark)) having a thickness of 1 mm by sputtering. Glass having a carbon-doped titanium oxide layer as a surface layer by heat-treating using a combustion flame of acetylene so that its surface temperature becomes 1100 ° C (Example 11) or 1500 ° C (Example 12). A plate was formed. The heat treatment time at 1100 ° C or 1500 ° C was set to 10 seconds. The carbon-doped titanium oxide layer thus formed was transparent as shown in the photograph in Fig. 8 (a) when the surface temperature was 1100 ° C, but when the surface temperature was 1500 ° C, it was transparent. As shown in Fig. 9, many islet-like undulations floating in the sea occurred on the surface, and it became translucent as shown in Fig. 8 (b).

[Examples 13 to 16]

The surface of a titanium plate having a thickness of 0.3 mm was heat-treated with a combustion flame of acetylene at the surface layer temperature shown in Table 3 for the time shown in Table 3. After that, when the surface exposed to the combustion flame was brought into contact with the flat surface of a 30 mm thick stainless steel block and cooled, a layer of white titanium oxide fine columns was exposed on most of the surface of the titanium plate. The member was separated into a large number of continuous narrow protrusions made of white titanium oxide on the thin film and a small piece member in which fine columns standing on the protrusions were exposed. That is, the layer in which the fine pillars made of titanium oxide formed inside the surface layer by the heat treatment are standing 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 stand on the surface 1 of the titanium plate is exposed, and a white layer 2 is exposed on the thin film. It shows a state in which a large number of continuous narrow protrusions made of titanium oxide and a small piece member 3 in which fine columns standing on the protrusions are exposed remain in a part on the layer 2. .. Although the titanium plate surface 1 is not exposed in the manufacturing methods of Examples 13 to 16, the micrograph of FIG. 10 shows a state in which a part of the layer 2 in which fine columns stand is removed. FIG. 11 is a photomicrograph showing the state of the thin film side surface of the small piece member 3 in which a large number of continuous narrow protrusions made of white titanium oxide and fine columns standing on the protrusions are exposed on the thin film. FIG. 12 shows a large number of continuous narrow protrusions made of white titanium oxide on the thin film and a large number of continuous narrow protrusions of the small piece member 3 in which the fine columns standing on the protrusions are exposed. It is a photomicrograph showing the state of the protrusion and the surface on the exposed side of the fine pillars standing on the protrusion, and FIG. 13 shows the state of the layer 2 in which the fine pillars made of white titanium oxide are standing. It is a micrograph showing.

[Example 17]

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

[Example 18]

A titanium thin film having a film 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 deposition. The surface of the thin film was heat-treated with a combustion flame of acetylene at the surface layer temperature shown in Table 3 for the time shown in Table 3. After that, when the surface exposed to the combustion flame was brought into contact with the flat surface of a stainless steel block having a thickness of 30 mm and cooled, a layer of white titanium oxide fine columns was exposed on most of the surface of the stainless steel plate. The member was separated into a large number of continuous narrow protrusions made of white titanium oxide on the thin film and a small piece member in which fine columns standing on the protrusions were 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 heated to form a titanium plate having a titanium oxide film having improved adhesion.

Test Example 12 (Scratch hardness test: Pencil method) JIS K 5600-5- Based on 4 (1999), a pencil scratch hardness test was conducted using Uni 1H-9H pencils manufactured by Mitsubishi Pencil Co., Ltd. The results are shown in Table 3. That is, no damage was observed even when a 9H pencil was used for all the test pieces.

Test Example 13 (Chemical resistance test) The members obtained in Examples 13 to 18 with exposed layers of fine columns on the surface of the substrate were placed in 1 M aqueous sulfuric acid solution and 1 M aqueous sodium hydroxide solution at room temperature, respectively. After soaking for a week, washing with water and drying, the above scratch hardness test: pencil method was performed. The results are 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 they had high chemical resistance.

Test Example 14 (Heat resistance test) The members obtained in Examples 13 to 18 with exposed layers of fine columns on the surface of the substrate were placed in a tube furnace, and it took 1 hour from room temperature in an air atmosphere. The temperature was raised to 500 ° C., the temperature was kept at a constant temperature of 500 ° C. for 2 hours, and the mixture was allowed to cool to room temperature for 1 hour, and then the above scratch hardness test: pencil method was performed. The results are 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 they had high heat resistance.<tables num="3"><img file="JP2006240333A_D0003.tif" /></tables>

Test Example 15 (Anti-fouling test) As a sample, the surface area of the substrate obtained in Example 16 is 8 cm, in which a layer of fine columns is exposed.²Surface area 8 cm with the member of No. 4 and the titanium oxide film obtained in Comparative Example 4²An antifouling test was carried out using the titanium plate of. Specifically, each of these samples was immersed in 80 mL of a methylene blue aqueous solution adjusted to a concentration of about 10 μmol / L, and after the effect of the concentration decrease due to initial adsorption became negligible, Matsushita Electric Industrial Co., Ltd. Visible light was irradiated with a fluorescent lamp equipped with a UV cut filter manufactured by HACH, and the absorbance of the methylene blue aqueous solution at a wavelength of 660 nm was measured with a water quality inspection device DR / 2400 manufactured by HACH Co., Ltd. at predetermined irradiation times. The results are as shown in FIG.

From FIG. 14, the member in which the layer in which fine columns stand on the surface of the substrate obtained in Example 16 is exposed is 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 rate of titanium is fast and the antifouling effect is high.

Test Example 16 (Crystal structure and bonding state) X-ray analysis (XRD) was performed on the sample obtained from the fine pillars of the member in which the layer in which the fine pillars stand on the surface of the substrate obtained in Example 15 is exposed. As a result, it was found to have a rutile-type crystal structure.

Further, regarding the fine pillar portion of the member obtained in Example 15 in which the layer in which fine pillars stand on the surface of the substrate is exposed, the acceleration voltage: 10 kV, target: with an X-ray photoelectron spectroscopy analyzer (XPS). Al was used, and Ar ion sputtering was performed for 2700 seconds to start the analysis. This sputtering rate is SiO₂At 0.64 Å / s, which is equivalent to a film, the depth is about 173 nm. The results of the XPS analysis are as shown in Fig. 15. The highest peak appears when the binding energy is 284.6 eV. This is determined to be the CH (C) binding commonly found in Cls analysis. The next highest peak is seen when the binding energy is 281.6 eV. Since the binding energy of the Ti-C bond is 281.6 eV, it is determined that C is doped as a Ti-C bond in the microcolumns of Example 15. As a result of XPS analysis at 14 points with different height positions of the fine columns, similar peaks appeared near 281.6 eV at all points.

[Example 19]

A disk having a diameter of 32 mm and a thickness of 0.3 mm was used as a test piece, and its surface was heated by a combustion flame of acetylene so that the surface temperature was maintained at about 1150 ° C. The first test piece was allowed to cool after stopping heating when the heating time was 120 seconds. The second test piece was allowed to cool after stopping heating at 180 seconds. The third test piece was heated for 480 seconds and immediately cooled by bringing the surface exposed to the combustion flame into contact with the flat surface of a 30 mm thick stainless steel block. By this cooling, a thin film was peeled off from the surface of the titanium plate, and a member was obtained in which a layer in which white titanium oxide fine columns were standing was exposed from below. For 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 the FIB-SEM device SMI8400SE manufactured by Seiko Instruments, and the side surface and bottom surface were observed by the SEM device VE7800 manufactured by KEYENCE. Was done. 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 pillar structure began to appear at the bottom of the film, and it is considered that the fine pillar structure is formed as intended by the present invention by further extending the fine pillars by continuing the flame treatment. ..

[Concrete example]

Hereinafter, specific examples of the rocket parts formed as the first invention and the second invention will be described.

FIG. 19 is a cross-sectional view showing an example of the internal configuration of a rocket on which various rocket parts are mounted. The rocket 10 shown in FIG. 19 is a three-stage rocket, and is configured to include a first-stage and second-stage liquid rocket and a third-stage solid rocket. Although not shown, for example, several solid rockets (for example, nine) are mounted on the first stage.

As shown in FIG. 19, the rocket 10 includes the satellite fairing 11, the satellite separation unit 12, the third stage solid motor 13, the spin table 14, the guidance section 15, and the fuel tanks 16, 19 as rocket parts. , The oxidizer tanks 17, 21 and the second stage engine 18, the center body section 20, and the first stage engine 22.

The satellite fairing 11 is a rocket component that constitutes the tip of the rocket 10, and contains the satellite 30 and the like. The satellite 30 mounted in the satellite fairing 11 is separated from the main body of the rocket 10 by the satellite separation unit 12 in outer space, and is put into a predetermined satellite orbit.

The fuel tanks 16 and 19 are containers for storing fuel for propelling the rocket 10. Fuel such as liquid hydrogen is stored in the fuel tank 16. In addition, fuel such as kerosene is stored in the fuel tank 19.

Oxidizing agent tanks 17, 21 and a container for storing the oxidizing agent for generating oxygen. Oxidizing agents such as liquid oxygen are stored in the oxidizing agent tanks 17 and 21.

In this example, at least a portion of the rocket component as described above has at least a layer of carbon-doped titanium oxide or titanium alloy oxide on the surface, and the carbon is doped in a Ti-C bonded state. It is formed by a member. Then, when necessary (when the ket parts are installed in a part that does not receive sufficient ultraviolet rays), install an ultraviolet irradiation device and irradiate the rocket parts with a sufficient amount of ultraviolet rays. Just do it.

Alternatively, at least a part of the rocket component as described above has a large number of protrusions made of titanium oxide or a titanium alloy oxide on at least a part of the surface, and the protrusions are formed by a carbon-doped member. Has been done. In this case as well, if necessary, an ultraviolet irradiation device may be installed to irradiate the rocket parts with a sufficient amount of ultraviolet rays.

With such a configuration, the rocket parts can be made excellent in durability, and in particular, rocket parts having an antifouling effect and rocket parts having a significantly extended life can be provided. Can be done.

For example, when the housings (outer wall, inner wall, or both) of the fuel tanks 16, 19 and the oxidant tanks 17, 21 are formed of the above members, the durability of the fuel tanks 16, 19 and the oxidizer tanks 17, 21 is durable. The properties can be made excellent, an antifouling effect can be obtained, and the service life thereof can be significantly extended.

The rocket parts of the present invention are not limited to those listed above, and may be other parts such as wings such as tail blades and moving blades, and various actuators. Various rocket parts are used depending on the model and application of the rocket (whether it is for unmanned flight or manned flight, etc.), but any part may be used as long as it is a part that requires durability.

<figref num="1">It is a figure which shows the result of the film hardness test of Test Example 1.</figref><figref num="2">It is a figure which shows the result of the XPS analysis of Test Example 5.</figref><figref num="3">It is a figure which shows the wavelength responsiveness of the photocurrent density of Test Example 6.</figref><figref num="4">It is a figure which shows the test result of the light energy conversion efficiency of Test Example 7.</figref><figref num="5">It is a figure which shows the result of the deodorant test of Test Example 8.</figref><figref num="6">It is a photograph which shows the result of the antifouling test of Test Example 9.</figref><figref num="7">It is a figure which shows the result of Test Example 11.</figref><figref num="8">It is a photograph which shows the light transmission state of the carbon-doped titanium oxide layer obtained in Examples 11 and 12.</figref><figref num="9">It is a photograph which shows the surface state of the carbon-doped titanium oxide layer obtained in Example 11.</figref><figref num="10">It is a micrograph which shows the state of the rocket parts obtained in Example 13.</figref><figref num="11">It is a micrograph which shows the state of the thin film side surface of the small piece member 3 which has a large number of continuous narrow protrusions made of white titanium oxide on a thin film, and the fine pillars which stand on the protrusions are exposed.</figref><figref num="12">A large number of continuous narrow protrusions made of white titanium oxide on the thin film and a large number of continuous narrow protrusions of the small piece member 3 in which fine columns standing on the protrusions are exposed and on the protrusions. It is a micrograph showing the state of the surface on the exposed side of the fine pillars standing in the forest.</figref><figref num="13">It is a micrograph which shows the state of the layer 2 in which fine columns made of white titanium oxide stand.</figref><figref num="14">It is a graph which shows the result of Test Example 15 (antifouling test).</figref><figref num="15">It is a graph which shows the result of Test Example 16 (crystal structure and bonding state).</figref><figref num="16">6 is an SEM photograph after a heating time of 120 seconds in Example 19.</figref><figref num="17">6 is an SEM photograph after a heating time of 180 seconds in Example 19.</figref><figref num="18">6 is an SEM photograph after a heating time of 480 seconds in Example 19.</figref><figref num="19">It is sectional drawing which shows the internal structure example of the rocket on which a rocket component is mounted.</figref>

Code description

1 Surface of substrate 2 Fine pillars 3 Thin film