Radiation-resistant member and nuclear power generation system using it

The present invention relates to a radiation resistant member useful for use in an environment exposed to radiation such as a nuclear power plant or a spacecraft, and a nuclear power generation system using the radiation resistant member.

Damage to mechanical parts and structures used in radiation environments such as nuclear plants and spacecraft can cause enormous damage. Therefore, the materials constituting them are required to have characteristics such as radiation resistance as well as strength and corrosion resistance.

Radiation-resistant materials using substances having a photocatalytic function in addition to these properties have been proposed (see, for example, Patent Document 1), but conventional substances having a photocatalytic function have durability, heat resistance, and radiation resistance. There was a problem that the photocatalyst function was low.

More specifically, 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). In addition, many studies for practical use of photocatalysts have been carried out in many technical fields.

When producing a photocatalyst product having deodorant, antibacterial, antifogging and antifouling effects by such a photocatalytic function, generally, titanium oxide sol is applied onto a substrate by spray coating, spin coating, dipping or the like. Although a film is formed (see, for example, Patent Documents 2 to 4), the film formed in this way is prone to peeling and abrasion, and thus it is difficult to use the film for a long period of time. Further, a method of forming a photocatalyst film by a sputtering method is also known (see, for example, Patent Documents 5 to 6).

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 an atom such as nitrogen is arranged at the grain boundary of a polycrystalline aggregate of titanium oxide crystals has been proposed (see, for example, Patent Documents 7 to 10). 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. A patent application has been filed that a highly active photocatalyst function can be obtained by growing a titanium oxide crystal from the crystal nuclei so that the crystal shape of the titanium oxide crystal grown from the crystal nuclei forms a columnar crystal (for example). , See Patent Documents 11 to 13). 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.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2001-004789</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 09-241038</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 09-262481</text></patcit><patcit num="4"><text>Japanese Unexamined Patent Publication No. 10-053437</text></patcit><patcit num="5"><text>Japanese Unexamined Patent Publication No. 11-012720</text></patcit><patcit num="6"><text>Japanese Unexamined Patent Publication No. 2001-205105</text></patcit><patcit num="7"><text>JP 2001-205103 (Claims)</text></patcit><patcit num="8"><text>Japanese Patent Application Laid-Open No. 2001-205094 (Claims)</text></patcit><patcit num="9"><text>Japanese Patent Application Laid-Open No. 2002-95976 (Claims)</text></patcit><patcit num="10"><text>International Publication No. 01/10553 Pamphlet (Claims)</text></patcit><patcit num="11"><text>Japanese Unexamined Patent Publication No. 2002-253975</text></patcit><patcit num="12"><text>Japanese Unexamined Patent Publication No. 2002-370027</text></patcit><patcit num="13"><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> In view of the above circumstances, it is an object of the present invention to provide a radiation resistant member having high durability, heat resistance and radiation resistance, and further having a high photocatalytic function, and a nuclear power generation system using the radiation resistant member.</p>

<p> A first aspect of the present invention that achieves the above object is a radiation resistant member characterized in that a multifunctional layer made of carbon-doped titanium oxide or a titanium alloy oxide is provided on at least a part of the surface.</p><p> In the second aspect of the present invention, in the first aspect, the multifunctional layer is integrally formed on the surface of the substrate, and the carbon is doped in a Ti-C bonded state. The radiation-resistant member is characterized in that at least the surface layer of the substrate is titanium, a titanium alloy, a titanium alloy oxide, or titanium oxide.</p><p> In a third aspect of the present invention, in the second aspect, the substrate is composed of a surface forming layer made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, and a core material, and the core material is titanium, a titanium alloy. , A radiation-resistant member characterized by being a material other than titanium oxide and titanium alloy oxide.</p><p> A fourth aspect of the present invention is in the radiation-resistant member according to the second or third aspect, wherein the Vickers hardness of the multifunctional layer is 300 or more.</p><p> A fifth aspect of the present invention is in the radiation resistant member according to the second or third aspect, wherein the Vickers hardness of the multifunctional layer is 1000 or more.</p><p> A sixth aspect 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 of a substrate made of titanium, titanium alloy, titanium alloy oxide or titanium oxide on the surface side at least. The radiation-resistant member is characterized in that a multifunctional layer in which the protrusions are carbon-doped is provided on a part of the surface thereof.</p><p> A seventh aspect of the present invention is the radiation-resistant member according to the sixth aspect, wherein the multifunctional layer is a forest of fine columns and the inside of the fine columns is carbon-doped. is there.</p><p> An eighth aspect of the present invention is in a radiation resistant member characterized in that, in the sixth or seventh aspect, the doped carbon is contained in a Ti-C bonded state.</p><p> A ninth aspect of the present invention is, in any of the sixth to eighth aspects, the substrate comprises a surface forming layer made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, and a core material. Is a radiation resistant member characterized by being made of a material other than titanium, a titanium alloy, and titanium oxide.</p><p> A tenth aspect of the present invention is a radiation-resistant member according to any one of the first to ninth aspects, wherein the radiation-resistant member is a reactor structural material.</p><p> In the eleventh aspect of the present invention, in a nuclear power generation system, at least the inner wall surface of the structural material of the nuclear power generation system is a multifunctional layer containing carbon-doped titanium oxide or titanium alloy oxide, and at least the surface side is titanium or titanium alloy. , Titanium alloy oxide or titanium oxide, which is composed of carbon-doped titanium oxide or titanium alloy oxide integrally formed on the surface of the substrate, and the carbon is doped in a Ti-C bond state. The layer, or at least the surface side, has a large number of protrusions made of titanium oxide or titanium alloy oxide integrally formed on at least a part of the surface of a substrate made of titanium, titanium alloy, titanium alloy oxide or titanium oxide. The nuclear power generation system is characterized in that a multifunctional layer in which the protrusions are carbon-doped is provided, and the multifunctional layer is provided with a light source for irradiating the multifunctional layer with visible light or ultraviolet light.</p>

First, a multifunctional material having a multifunctional layer that can be used in the present invention will be described.

The first multifunctional material used in the present invention uses a combustion flame of a gas containing a hydrocarbon as a main component on the surface of a substrate whose surface layer is made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide at a high temperature. Obtained by heat treatment, carbon is doped in a Ti-C bond state, and it has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance). It has a multifunctional layer composed of a carbon-doped titanium oxide layer that functions as a visible light-responsive photocatalyst as a surface layer.

That is, the first multifunctional material used in the present invention has at least a surface layer made of a carbon-doped titanium oxide layer and the carbon is doped in a Ti-C bond state, and is excellent in durability and visible light responsive type. It is characterized by having a multifunctional layer that functions as a photocatalyst.

The first multifunctional material used in the present invention uses, for example, a combustion flame of a gas containing hydrocarbon as a main component on the surface of a substrate whose surface layer is at least titanium, a titanium alloy, a titanium alloy oxide or titanium oxide. It can be produced by heat treatment at a high temperature. That is, as a result, a structural member in which a carbon-doped titanium oxide layer is integrally formed on the surface of titanium, a titanium alloy, a titanium alloy oxide, or titanium oxide, which is the surface layer of the substrate, and the surface is excellent in durability and visible. It is the first multifunctional material that functions as a photoresponsive photocatalyst. The substrate whose surface layer is at least made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide may be composed entirely of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, or It is composed of a surface forming layer made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, and a core material, and the materials thereof may be different. That is, in this case, a structural member in which a carbon-doped titanium oxide layer is integrally formed on the surface of titanium, a titanium alloy, a titanium alloy oxide, or titanium oxide, which is a surface layer of a substrate of a composite material, is formed on the surface. May be the first multifunctional material having excellent durability and functioning as a visible light responsive photocatalyst.

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.

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. When a fuel with a low hydrocarbon content is used, the amount of carbon doping may be insufficient or none at all, resulting in insufficient hardness and insufficient photocatalytic activity under visible light. It becomes. In the production of the first multifunctional material used in the present invention, the gas containing at least 50% by volume of this hydrocarbon 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 in which air, hydrogen, oxygen, etc. are mixed as appropriate. In the production of the first multifunctional material used in the present invention, it is preferable that the gas containing 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 of the present invention, 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 the amount thereof is required. Must contain oxygen.

In the production of the first multifunctional material used in the present invention, a combustion flame of a gas containing a hydrocarbon as a main component is used on the surface of a substrate whose surface layer is made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide. In this case, even if the surface of the substrate is directly exposed to a combustion flame of a gas containing hydrocarbon as a main component and heat-treated at a high temperature, the surface of such a substrate is mainly composed of hydrocarbons. The heat treatment may be performed at a high temperature in the combustion gas atmosphere of the gas as a component, 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. When at least the surface layer is a powdery substrate made of titanium, titanium alloy, titanium alloy oxide or titanium oxide, such powder is introduced into a flame and allowed to stay in the flame for a predetermined time for heating. The entire particle is made into carbon-doped titanium oxide doped with carbon in a Ti-C bond state by treating or maintaining such a powder in a fluidized high temperature combustion gas for a predetermined time in a fluidized bed state. Alternatively, it can be a powder having a carbon-doped titanium oxide layer doped with carbon in a Ti-C bonded state.

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 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 an important function of the first multifunctional material, cannot be obtained, it is necessary to cool it after heat treatment. It is necessary that the time is such that peeling does not occur on the surface of the substrate. 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 used in the present invention, 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 doped carbon-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 the first 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 and scratch resistance. It is more preferably 50 nm or more in order to achieve resistance and 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 used in the present invention contains conventional chemically modified titanium oxide and the conventionally proposed titanium compound Ti-OX doped with various atoms or anions X. Unlike titanium oxide, 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 used in the present invention 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 of the present invention can be significantly used in various technical fields in which hard chrome plating has been conventionally used.

The carbon-doped titanium oxide layer, which is the multifunctional layer of the first multifunctional material used in the present invention, responds not only to ultraviolet rays but also to visible light having a wavelength of 400 nm or more, and effectively acts as a photocatalyst. Therefore, the first multifunctional material used in the present invention can be used as a visible light responsive photocatalyst, and exhibits a photocatalytic function not only outdoors but also indoors. Further, the carbon-doped titanium oxide layer of the first multifunctional material used in the present invention exhibits superhydrophilicity with a contact angle of 3 ° or less.

The carbon-doped titanium oxide layer of the first multifunctional material used in the present invention 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 and abrasion resistance. When the photocurrent 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.

Further, the carbon-doped titanium oxide layer of the first multifunctional material used in the present invention can also be used as a catalyst that responds to radiation such as γ-rays. That is, the present inventors have previously invented that a sprayed film such as titanium oxide suppresses stress corrosion cracking and scale adhesion of reactor structural members in response to radiation, but the first invention used in the present invention. Similarly, when the carbon-doped titanium oxide layer of the multifunctional material 1 is used as such a radiation-responsive catalyst, the potential of the base material can be lowered to suppress pitting corrosion, total corrosion, and stress corrosion cracking. It has the effect of being able to decompose scale and dirt by the oxidizing power. It is simpler than other radiation catalyst film forming methods, and is also excellent in terms of durability such as chemical resistance and wear resistance.

Further, in the second multifunctional material, a combustion flame of unsaturated hydrocarbons, particularly acetylene, is directly applied to the surface of a substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide, and under specific conditions. The surface of the substrate is made of titanium oxide or a titanium alloy oxide by heat-treating the surface of the substrate under specific conditions in the atmosphere of combustion exhaust gas of unsaturated hydrocarbons, particularly acetylene. The formation of a layer in which fine columns are standing, and the titanium oxide or titanium alloy oxide being formed on at least a part of the substrate by cutting the layer in which the fine columns are standing in the direction along the surface layer. A member with an exposed layer of fine pillars made of titanium oxide, a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide on a thin film, and fine pillars standing on the protrusions. It is possible to obtain a member in which is 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, both of which are useful multifunctional functions. It has high photocatalytic activity and functions as a visible light responsive photocatalyst because it is a material and the fine columns and continuous narrow protrusions, which are protrusions made of titanium oxide or titanium alloy oxide, are carbon-doped. In addition, VOC can be easily adsorbed, the hardness is high, and the material has excellent peel resistance, abrasion resistance, chemical resistance, and heat resistance.

That is, the second multifunctional material used in the present invention has a large number of protrusions made of titanium oxide or a titanium alloy oxide on at least a part of the surface, for example, titanium oxide or at least a part of the surface. A layer of fine pillars made of titanium alloy oxide is exposed, or a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide are standing on the thin film and on the protrusions. The fine pillars are exposed, and the protrusions, for example, the fine pillars and the narrow protrusions are carbon-doped.

In the second multifunctional material used in the present invention, the surface of a substrate whose surface layer is at least titanium, titanium oxide, titanium alloy or titanium alloy oxide is heat-treated with a combustion flame of, for example, unsaturated hydrocarbons, especially acetylene. A layer of fine columns made of titanium oxide or titanium alloy oxide is formed inside the surface layer, and then, for example, thermal stress, shear stress, and tensile force are applied to the fine columns. A layer in which the layer is cut along the surface layer and at least a part of the substrate, usually a large part of the substrate, is lined with fine columns made of the titanium oxide or titanium alloy oxide. By obtaining an exposed member and a member in which a large number of continuous narrow protrusions made of titanium oxide or titanium alloy oxide and fine columns standing on the protrusions are exposed on the thin film. It is a multifunctional material that can be manufactured, 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, and both of them are the second multifunctional materials used in the present invention. It is a material.

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.

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 used in the present invention. For example, iron, iron alloy, non-ferrous alloy, glass, ceramics 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, titanium oxide, a titanium alloy, or a titanium alloy 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 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 above-mentioned titanium alloy, and the same as the first multifunctional material can be used without particular limitation.

In the production of the second multifunctional material used in the present invention, for example, it is desirable to use an unsaturated hydrocarbon, particularly a combustion flame of a gas containing acetylene as a main component, and particularly a reducing flame. In the production of the multifunctional material of the present invention, it is possible to use 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. preferable. In the production of the second multifunctional material used in the present invention, 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 used in the present invention, 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, or the substrate is heat-treated. The surface of the titanium is heat-treated in the atmosphere of combustion exhaust gas, 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 of fine columns made of titanium oxide or titanium alloy oxide 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 pillars standing on the protrusions. It is necessary to adjust the heating temperature and the heat treatment time so that the exposed member 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. It is possible to obtain a protrusion and a member in which fine pillars standing on the protrusion are exposed.

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 can easily adsorb VOCs and has a large surface area, so it has high activity as a photocatalyst, and also has high film hardness, and is also excellent in peeling resistance, abrasion resistance, chemical resistance, and heat resistance. It is a functional material.

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, there are cases where a large number of continuous narrow protrusions are exposed with almost no fine pillars by cutting the layer in which the fine pillars stand in the direction along the surface layer. 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 used in the present invention, 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. Therefore, it responds not only to ultraviolet rays but also to visible light having 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. ..

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 used in the present invention stands is determined from the micrographs of FIGS. 10 and 13. Pyramid, columnar, pyramidal, conical, inverted pyramid, inverted cone, etc., extending straight in the direction perpendicular to or inclined from the surface of the substrate, while bending or bending. There are those that are elongated, those that are branched and extended in a branch shape, and those that are in the form of a complex thereof. 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 and fine pillars standing on the protrusions are exposed on the thin film, which is the second multifunctional material used in the present invention. As can be seen from the photomicrograph of FIG. 12, the members can be seen as having a large number of continuous narrow protrusions on the outside of the walnut shell, on the appearance of pumice, and on each continuation. It can be seen that the narrow protrusions are bent with a walnut-like pattern. 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.

The third multifunctional material used in the present invention is provided with a multifunctional layer containing carbon-doped titanium oxide or titanium alloy oxidation powder (hereinafter referred to as carbon-doped titanium oxide powder) on the surface of the substrate by a method such as coating. It is a thing. The multifunctional layer in this case is formed by a coating agent containing carbon-doped titanium oxide and an inorganic binder. Here, examples of the inorganic binder include alkoxysilanes such as ethyl silicate, partial condensates of alkoxysilanes, and silica sol.

The carbon-doped titanium oxide powder used in such a third multifunctional material uses titanium powder as a substrate, and is a gas containing a hydrocarbon, particularly acetylene, as a main component, similar to the method for producing the first multifunctional material. It can be formed by heat treatment using a combustion flame or the like. In this case, when the particle size of the powder is small, the entire particle can be made into carbon-doped titanium oxide by the above heat treatment, but in this application, only the surface layer needs to be made of carbon-doped titanium oxide. Yes, and therefore there are no restrictions on the particle size of the powder. However, considering the ease of heat treatment and the ease of production, it is preferably 15 nm or more.

Further, the carbon-doped titanium oxide powder can be obtained by pulverizing a second multifunctional material having fine columns or a thin film having fine columns.

In any case, the carbon-doped titanium oxide powder is particularly preferably one in which carbon is doped in a Ti-C bond state, and the effect is as described above.

Hereinafter, the functions of the multifunctional material used in the present invention will be described in more detail based on Examples and Comparative Examples.

Examples 1 to 3 (First multifunctional material) Carbon as a surface layer 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. Formed a titanium plate with a carbon-doped titanium oxide layer doped in a Ti-C bonded state. 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 content₂Assuming the molecular structure of -xCx, for Example 1, the carbon content is 8 at%, TiO_1.76C_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 chromium-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.

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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 (1st multifunctional material) Using the combustion flame of acetylene as in Examples 1 to 3, a titanium plate with a thickness of 0.3 mm is shown in Table 2 at the surface temperature shown in Table 2. By heat-treating for a period of time, a titanium plate having a carbon-doped titanium oxide layer as a surface 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 7 were superhydrophilic with a contact angle of about 2 ° with water droplets.

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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 (First multifunctional material) A surface of a 0.3 mm-thick Ti-6Al-4V alloy plate is heat-treated to a surface temperature of about 1100 ° C using a combustion flame of acetylene. An alloy plate was formed in which the layer was made of a titanium alloy containing carbon-doped titanium oxide. 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 (First multifunctional material) 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 (First multifunctional material) Titanium oxide powder having a particle size of 20 μm is supplied into a combustion flame of acetylene, and is retained in the combustion flame for a predetermined time to be heated so that its surface temperature becomes about 1000 ° C. By the treatment, a titanium powder having a carbon-doped titanium oxide layer as a surface 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 (first multifunctional material) 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 (second multifunctional material) 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, the second multifunctional materials of Examples 13 to 16 were obtained.

FIG. 10 is a photomicrograph of the second multifunctional material obtained in Example 13, and the layer 2 in which fine columns made of white titanium oxide stand on the surface 1 of the titanium plate is exposed. A state in which a large number of continuous narrow protrusions made of white titanium oxide on the thin film and a small piece member 3 in which fine columns standing on the protrusions are exposed remain in a part on the layer 2. Is shown. 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 of the exposed side of the fine pillars standing on the protrusion, and FIG. 13 shows the layer 2 in which the fine pillars made of white titanium oxide are standing. It is a micrograph showing the state.

Example 17 (Second multifunctional material) The surface of a 0.3 mm thick Ti-6Al-4V alloy plate is heat-treated with a combustion flame of acetylene at the surface layer temperature shown in Table 3 for the time shown in Table 3. did. 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 (Second multifunctional material) 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.

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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 4²A deodorant 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 12 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 bonded state) X-ray diffraction (XRD) was performed on a sample obtained from the fine pillars of a member in which a layer in which 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.

As described above, the first multifunctional material has excellent durability (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and functions as a visible light responsive photocatalyst, and is therefore visible. Not only can it be used as a photocatalyst, but it can also be significantly used in various technical fields in which hard chrome plating has been conventionally used. Further, it can be expected to be applied to products 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 in reactor structures, etc., it is compared with other film formation methods. It is possible to easily form a film and improve the durability.

In addition, the second multifunctional material has high photocatalytic activity, functions as a visible light responsive photocatalyst, can easily adsorb VOCs, has high hardness, and has peel resistance, abrasion resistance, chemical resistance, and heat resistance. Is excellent.

Further, the third multifunctional material has high photocatalytic activity and functions as a visible light responsive photocatalyst.

Hereinafter, the radiation-resistant member of the present invention to which the above-mentioned multifunctional material is applied and the nuclear power generation system using the same will be described.

(Embodiment 1) FIG. 16 shows a schematic view of the nuclear power generation system of the first embodiment, which is an example of the radiation-resistant member of the present invention.

As shown in FIG. 16, in the nuclear power generation system 100, the reactor pressure vessel 110 containing nuclear fuel and water and the recirculation paths 120a and 120b for recirculating the water contained in the reactor pressure vessel 110 are recirculated. A water supply path 130 that discharges water vapor and supplies water, and a reactor containment vessel 140 that accommodates the reactor pressure vessel 110 to prevent radioactive materials from leaving the power plant even in the event of an accident. And are equipped. The recirculation paths 120a and 120b are located below the water surface 111 of the water contained in the reactor pressure vessel 110 and are above the recirculation drainage ports 121a and 121b and the recirculation drainage ports 121a and 121b for discharging the water. It is a route connecting the recirculation water supply ports 122a and 122b that supply water, and is a recirculation pump 123a that recirculates water between the recirculation drainage ports 121a and 121b and the recirculation water supply ports 122a and 122b. , 123b is provided. The water supply path 130 is located below the water surface 111 of the water contained in the reactor pressure vessel 110 and is located above the water supply port 132 for supplying water and above the water surface 111 of the water contained in the reactor pressure vessel 110. It is a route connecting the exhaust port 131 that discharges water vapor located at, and is connected to the turbine 133 and the turbine 133 located on the water supply port 132 side of the turbine 133 between the water supply port 132 and the exhaust port 131. A condenser 134 and a water supply pump 135 located on the water supply port 132 side of the condenser 134 are provided. The reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the inner surface of the reactor containment vessel 140 are provided with a multifunctional layer provided with the above-mentioned multifunctional material. The multifunctional layer may be provided on all of their inner surfaces or a part of the inner surface, and the recirculation pumps 123a and 123b provided in the recirculation paths 120a and 120b and the water supply path 130. , Turbine 133, condenser 134, water supply pump 135, all or part of the inner surface.

As a first method of providing such a multifunctional layer, a structure serving as a reactor pressure vessel 110, a recirculation path 120a and 120b, a water supply path 130, and a reactor containment vessel 140 is provided on the surface of titanium, titanium. It is composed of a metal member having a surface forming layer of an alloy, a titanium alloy oxide or titanium oxide, or a member made of titanium, a titanium alloy, a titanium alloy oxide or titanium oxide, and this has been described as a first multifunctional material. As described above, a method of heat-treating at a high temperature using a combustion flame of a gas containing a hydrocarbon as a main component can be mentioned.

As a result, carbon is doped in a Ti-C bond state on the surfaces of the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140, which is durable. It is possible to form a multifunctional layer made of a carbon-doped titanium oxide layer having excellent properties (high hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance) and functioning as a visible light responsive photocatalyst.

In addition, as a second method, a structure serving as a reactor pressure vessel 110, a recirculation path 120a and 120b, a water supply path 130, and a reactor storage vessel 140 is provided on the surface of titanium, a titanium alloy, and a titanium alloy oxide. Alternatively, the surface is formed of, for example, a metal member having a surface forming layer of titanium oxide, or a member made of titanium, a titanium alloy, a titanium alloy oxide, or titanium oxide, and as described as the second multifunctional material described above. It is heat-treated with a combustion flame of unsaturated hydrocarbons, especially acetylene, to form a layer in which fine columns made of titanium oxide or titanium alloy oxide stand inside the surface layer, and then, for example, thermal stress, shear stress. , Titanium oxide or titanium alloy is applied to the surface on the substrate, usually most of the substrate, by cutting the layer in which the fine columns stand along the surface layer. A method of exposing a layer in which fine columns made of oxide are standing can be mentioned. As a result, the multifunctional layer provided by the second multifunctional material, that is, has high photocatalytic activity, functions as a visible light responsive photocatalyst, can easily adsorb VOCs, has high hardness, and has high peeling resistance and abrasion resistance. A multifunctional layer having excellent properties, chemical resistance, and heat resistance can be easily provided on the surfaces of the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140.

Here, the metal member having a surface forming layer of titanium, titanium alloy, titanium alloy oxide or titanium oxide on the surface used in the first method and the second method is, for example, iron, iron alloy, stainless steel or the like. A film made of titanium, titanium alloy, titanium alloy oxide or titanium oxide is formed on the surface of the core material by a method such as sputtering, vapor deposition or spraying, or a commercially available titanium oxide sol is formed by spray coating, spin coating or dipping. Can be mentioned. Further, in the embodiment, although the metal member is illustrated, ceramics and other ceramics can be applied as the core material.

Since the heat treatment method in the first method and the second method has been described in detail in the method for producing the first multifunctional material and the second multifunctional material, the description thereof is omitted here.

Further, as a third method of providing the multifunctional layer, the above-mentioned first method is performed on the surface of the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140. A method of attaching a panel made of the above-mentioned multifunctional material or the second multifunctional material can be mentioned. As a result, the conventionally manufactured reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140 are directly used as the reactor pressure vessel 110 having the multifunctional layer of the present invention. It can be a recirculation path 120a, 120b, a water supply path 130, and a reactor containment vessel 140.

Further, as the fourth method, as described in the third multifunctional material described above, the structure comprises the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140. This is a method of providing a multifunctional layer containing carbon-doped titanium oxide powder on the surface of the body by a method such as coating. In this case, although the durability is inferior to that of the first to third methods described above, it is very easy to provide a multifunctional layer having high photocatalytic activity and functioning as a visible light responsive photocatalyst. There is an advantage that it can be done. Of course, the third multifunctional material may be attached to the surfaces of the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor containment vessel 140 to form a multifunctional layer.

In the nuclear power generation system 100 provided with the multifunctional layer described above, in particular, in the case where the first multifunctional member is applied by the first method or the third method, the first multifunctional material has durability ( High hardness, scratch resistance, abrasion resistance, chemical resistance, heat resistance), excellent peel resistance of the multifunctional layer, and functioning as a visible light responsive photocatalyst, so it has excellent durability and its surface. It has the effect of being extremely excellent as something that can be kept clean. That is, even if a metallic brush is used when cleaning the nuclear power generation system 100, it will not be damaged and has excellent durability, and after cleaning, the surface thereof is exposed to visible light or preferably ultraviolet light. Can be kept clean. Further, inside the reactor pressure vessel 110, the surface can be kept clean by the Cherenkov light emitted during the operation of the reactor without irradiating with visible light or preferably ultraviolet light. Further, since the nuclear power generation system 100 provided with this multifunctional layer is excellent in durability and photocatalytic action, it has an effect that the maintenance cycle of the nuclear power generation system 100 can be extended. Further, since the nuclear power generation system 100 provided with this multifunctional layer has high strength and excellent heat resistance, it is possible to construct a nuclear power generation system that operates at a higher temperature and higher pressure than before. When a multifunctional layer is provided on the inner surfaces of the recirculation paths 120a and 120b and the water supply path 130, it is difficult for direct light to hit the inner surface of the water supply path 130. Must be inserted inside recirculation paths 120a, 120b, water supply path 130

Further, the structure itself that becomes the reactor pressure vessel 110, the recirculation paths 120a and 120b, the water supply path 130, and the reactor storage vessel 140 by the first method or the second method is oxidized with titanium, a titanium alloy, or a titanium alloy. When composed of a material or a member made of titanium oxide, the reactor pressure vessel 110 of the nuclear power generation system 100, the recirculation paths 120a and 120b, the water supply path 130, and the reactor storage vessel 140 are made of titanium, titanium alloy, etc. It is composed of a member having a multifunctional layer on the surface of a substrate made of titanium alloy oxide or titanium oxide, that is, a titanium-based laminated member having a multifunctional layer on the surface, which is lightweight and has high rigidity. It will have the effect.

The various functions of the multifunctional layer of the nuclear power generation system 100 described above are as proved in the above-mentioned explanations of the first to third multifunctional materials, and the details are omitted.

As described above, the nuclear power generation system 100 has been described as an example of using the radiation-resistant member according to the present invention, but it is not limited to this, for example, a particle accelerator, a radiation detector, an X-ray X-ray apparatus, and the like. It may be an X-ray CT device, a radiotherapy device, a non-destructive inspection device, or the like.

<figref num="1">FIG. 1 is a diagram showing the results of the film hardness test of Test Example 1.</figref><figref num="2">FIG. 2 is a diagram showing the results of XPS analysis of Test Example 5.</figref><figref num="3">FIG. 3 is a diagram showing the wavelength responsiveness of the photocurrent density of Test Example 6.</figref><figref num="4">FIG. 4 is a diagram showing the test results of the light energy conversion efficiency of Test Example 7.</figref><figref num="5">FIG. 5 is a diagram showing the results of the deodorant test of Test Example 8.</figref><figref num="6">FIG. 6 is a photograph showing the results of the antifouling test of Test Example 9.</figref><figref num="7">FIG. 7 is a diagram showing the results of Test Example 11.</figref><figref num="8">FIG. 8 is a photograph showing the light transmission state of the carbon-doped titanium oxide layer obtained in Examples 11 and 12.</figref><figref num="9">FIG. 9 is a photograph showing the surface state of the carbon-doped titanium oxide layer obtained in Example 12.</figref><figref num="10">FIG. 10 is a photomicrograph showing the state of the multifunctional material obtained in Example 13.</figref><figref num="11">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. is there.</figref><figref num="12">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 fine columns standing on the protrusions are exposed. It is a micrograph which shows the state of the surface on the side where the fine pillars standing on the protrusion are exposed.</figref><figref num="13">FIG. 13 is a photomicrograph showing the state of layer 2 in which fine columns made of white titanium oxide stand.</figref><figref num="14">FIG. 14 is a graph showing the results of Test Example 15 (antifouling test).</figref><figref num="15">FIG. 15 is a graph showing the results of Test Example 16 (crystal structure and bonding state).</figref><figref num="16">FIG. 16 is a schematic view of the nuclear power generation system of the first embodiment, which is an example of the radiation resistant member of the present invention.</figref>

Code description

100 Nuclear power system 110 Reactor pressure vessel 111 Water surface 120a, 120b Recirculation path 121a, 121b Recirculation drainage port 122a, 122b Recirculation water supply port 123a, 123b Recirculation pump 130 Water supply path 131 Exhaust port 132 Water supply port 133 Turbine 134 Condenser Water vessel 135 Water supply pump 140 Reactor containment vessel