Method for manufacturing a composite having an alloy film formed on a substrate, and the composite

Abstract

To provide a method for simply forming an alloy film excellent in peeling resistance on a base material, and a composite including the alloy film manufactured by the inventive method and high in peeling resistance on a surface.SOLUTION: A method for manufacturing a composite including an alloy film formed on a base material according to the present invention comprises steps of: applying a metal chelate complex solution including a high standard redox potential metal component having an ionization tendency smaller than that of Cd, a low standard redox potential metal component having an ionization tendency equal to or larger than that of Cd and a chelating agent to the base material; and heating a portion of the base material where the metal chelate complex solution is applied. The molar ratio of the high standard redox potential metal component to the low standard redox potential metal component is 4 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for simply forming an alloy film having excellent peeling resistance on a substrate, and to a composite in which an alloy film having excellent peeling resistance is formed on a substrate. [Background technology]

[0002] The technology of forming a metal film on a substrate has been used in various technical fields. For example, a circuit board is manufactured by attaching copper foil to a substrate with an adhesive and then etching the copper foil to form a circuit. However, if the adhesive has low affinity with the substrate or copper foil, the method using the adhesive may result in peeling of the metal film.

[0003] Sputtering is a technique for forming metal films on substrates without using adhesives. Sputtering involves introducing an inert gas such as Ar gas into a vacuum, applying a negative voltage to a target made of the film-forming material to generate a glow discharge, ionizing the inert gas atoms, which collide with the target surface at high speed, violently ejecting particles of the film-forming material that make up the target, which then adhere to the surface of the substrate to form a metal film. However, sputtering is expensive to implement, and because it must be performed in a vacuum, it is difficult to apply to large structures or to perform in situ.

[0004] For example, concrete that makes up port facilities and offshore airport facilities is coated with a titanium film on the surface to protect it from corrosion by seawater and the like, and an anticorrosive current is supplied to the reinforcing steel bars inside (Patent Document 1, etc.). However, it is practically impossible to coat the surface of the huge concrete that makes up the facilities with metal by sputtering. Therefore, to coat concrete building materials with metal, a thermal spraying method is generally used (Patent Document 2, etc.).

[0005] Furthermore, sewage may contain Thiobacillus bacteria, which oxidize hydrogen sulfide, sulfur, and thiosulfate ions to produce sulfuric acid, causing corrosion of concrete sewer pipes and the like. Corrosion-resistant Hume pipes containing inorganic powder carrying antibacterial metal ions have been proposed (Patent Document 3). However, simply mixing antibacterial metal ions into raw cement may not fully exert antibacterial properties, and increasing the proportion of antibacterial metal ions may result in a decrease in strength. Therefore, it is desirable to coat the surfaces of sewer pipes and the like with antibacterial metals.

[0006] Alloys, which are mixtures of two or more metals, are used to improve the physical, chemical, or mechanical properties of pure metals. For example, alloys of copper and zinc are called brass or brass, and have excellent properties such as electrical conductivity, thermal conductivity, corrosion resistance, and workability, making them useful in a wide range of fields. Therefore, composites in which a substrate is coated with an alloy are highly useful. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 4-314880 [Patent Document 2] Japanese Patent Application Publication No. 1-119576 [Patent Document 3] Japanese Patent Application Publication No. 9-60768 Summary of the Invention [Problem to be solved by the invention]

[0008] As mentioned above, thermal spraying is generally used to coat concrete building materials with metal. However, concrete building materials are porous, and the sprayed metal has difficulty penetrating into the pores. Therefore, it must be said that the metal film formed by thermal spraying has low resistance to peeling from concrete building materials. Therefore, an object of the present invention is to provide a method for easily forming an alloy film with excellent peeling resistance on a substrate, and a composite produced by the present invention and having an alloy film with high peeling resistance on its surface. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems. As a result, they have discovered that, although they had expected that a metal oxide film would naturally be formed by applying a solution of a chelate complex of a specific metal component to a substrate and then heat-treating it, the film formed had a metallic luster and, upon analysis, was found to be composed almost entirely of an alloy, leading to the completion of the present invention. The present invention will now be described.

[0010] [1] A method for producing a composite in which an alloy film is formed on a substrate, comprising: a step of applying a metal chelate complex solution to the substrate, the metal chelate complex solution including a high standard redox potential metal component having an ionization tendency lower than that of Cd, a low standard redox potential metal component having an ionization tendency equal to or higher than that of Cd, and a chelating agent; a step of heat treating the portion of the substrate onto which the metal chelate complex solution is applied, The method according to claim 1, wherein the molar ratio of the high standard redox potential metal component to the low standard redox potential metal component is 4 or greater. [2] The method according to [1] above, wherein the metal chelate complex solution further contains a surfactant. [3] The method according to [1] or 2 above, wherein the substrate is a hardened cement paste. [4] The method according to any one of [1] to [3] above, wherein the low standard oxidation-reduction potential metal component is Cu or Ni. [5] The method according to any one of [1] to [4] above, wherein the high standard redox potential metal component is Zn. [6] The method according to any one of [1] to [5] above, wherein the chelating agent is an aminocarboxylic acid chelating agent. [7] A substrate and an alloy film layer, The substrate is a hardened cement paste, the alloy film layer contains a high standard redox potential metal component having an ionization tendency lower than that of Cd and a low standard redox potential metal component having an ionization tendency equal to or higher than that of Cd, A composite, characterized in that the high standard oxidation-reduction potential metal component and the low standard oxidation-reduction potential metal component are present on the substrate side of the interface between the substrate and the alloy film layer. [Effects of the Invention]

[0011] According to the method of the present invention, it is possible to easily form an alloy film on the surface of a substrate, and it is possible to treat large substrates such as concrete building materials, and in situ treatment is also possible. Furthermore, since the method of the present invention uses a metal chelate complex solution instead of a molten metal as in thermal spraying methods, it is also possible to fill the pores of a porous substrate with metal, and therefore an alloy film with excellent peel resistance can be formed on the surface of a porous substrate. Therefore, the composite of the present invention is extremely useful industrially as a building material with excellent corrosion resistance. [Brief explanation of the drawings]

[0012] [Figure 1] This shows the results of XRD analysis of a metal film obtained by applying a Cu / Zn chelate complex solution to a polycrystalline alumina substrate and heating it with a hydrogen flame. [Figure 2] This shows the results of XRD analysis of a metal film obtained by applying a Cu / Zn chelate complex solution to an aluminum alloy A5052 plate and heating it with a hydrogen flame. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention relates to a method for producing a composite having an alloy film formed on a substrate. The method for producing a composite according to the present invention includes the steps of: applying to the substrate a metal chelate complex solution containing a high standard redox potential metal component having an ionization tendency lower than that of Cd, a low standard redox potential metal component having an ionization tendency equal to or greater than that of Cd, and a chelating agent; and heat-treating the portion of the substrate coated with the metal chelate complex solution. Each step of the method of the present invention will be described below, but the present invention is not limited to the specific examples below.

[0014] 1.Coating process In this process, a metal chelate complex solution containing a high standard oxidation-reduction potential metal component with an ionization tendency lower than that of Cd, a low standard oxidation-reduction potential metal component with an ionization tendency equal to or higher than that of Cd, and a chelating agent is applied to the substrate.

[0015] Ionization tendency is a relative index that primarily indicates the ease with which an element becomes ions in an aqueous solution. The lower the ionization tendency, the higher the standard redox potential E°. Cd has an E° value of −0.4025 V. In the present invention, high standard redox potential metal components with higher E° values ​​and lower ionization tendency, and Cd and low standard redox potential metal components with lower E° values ​​than Cd, higher ionization tendency, are used. Examples of high standard redox potential metal components with low ionization tendency include, in descending order of ionization tendency, Co, Ni, Mo, Sn, Pb, Sb, Bi, Cu, Hg, Ag, Pd, Ir, Pt, and Au. Examples of low standard redox potential metal components with high ionization tendency include, in descending order of ionization tendency, Cd, Fe, Cr, Zn, Mn, Zr, and Al. Note that in the present disclosure, the magnitudes of high standard redox potential metal components and low standard redox potential metal components are purely relative.

[0016] The alloy film formed on the surface of the substrate can be used as an electrode. For example, if an alloy film is formed on the surface of a hardened cement body and a voltage is applied, the alloy film acts as a corrosion-resistant coating. Furthermore, the metal elements can be selected based on their usefulness. Only one high standard redox potential metal component and one low standard redox potential metal component may be selected, or two or more may be selected and combined.

[0017] Examples of alloys include Krupp steel (Ni-Cr), Permalloy (Ni-Fe), chromium molybdenum steel (Fe-Cr-Mo), manganese molybdenum steel (Fe-Mn-Mo), stainless steel (Fe-Ni-Cr), maraging steel (Fe-18 - 30Ni(Co,Mo)), 42 Alloy (Fe-42Ni), Invar (Fe-36Ni), Kovar (Fe-29Ni-17Co), Permendur (Fe-Co), brass (Cu-Zn), nickel silver (Cu-27Zn-18Ni), Nordic Gold (89Cu-5Al-5Zn-1Sn), Kunife (60Cu-20Ni-20Fe), duralumin (Al-Cu), Hastelloy (50Ni-Mo-Cr-Fe), Inconel (72Ni-15Cr-Fe), Nichrome (80Ni-20Cr), Sun Platinum (85Ni-11Cr-3Ag), shape memory alloy (Ni-Ti), and Stellite (Co-30Cr-10W).

[0018] In the present invention, the molar ratio of the high standard redox potential metal component to the low standard redox potential metal component (number of moles of high standard redox potential metal component / number of moles of low standard redox potential metal component) is set to 4 or more. If the molar ratio is less than 4, the amount of metal oxide contained in the alloy film will be excessively large. The molar ratio is preferably 5 or more or 6 or more, more preferably 8 or more or 10 or more, and even more preferably 15 or more. There is no particular upper limit to the molar ratio, but if the molar ratio is too high, the properties of the low standard redox potential metal component may not be utilized, so it is preferably 50 or less.

[0019] The chelating agent is not particularly limited as long as it can form a chelate with a metal component to improve its solubility, and examples thereof include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminediacetic acid, 1,2-diaminopropanetetraacetic acid, 1,3-diaminopropanetetraacetic acid, hexamethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, diaminopropanoltetraacetic acid, hydroxyethylenediaminetriacetic acid, glycol ether diaminetetraacetic acid, ethylenediaminedi(o-hydroxyphenyl)acetic acid, iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, methylglycinediacetic acid, and ethylenediaminediproacetic acid. Aminocarboxylic acid chelating agents such as pionic acid, nitrilotripropionic acid, ethylenediaminedisuccinic acid, 1,3-diaminopropanedisuccinic acid, glutamic acid-N,N-diacetic acid, and aspartic acid-N,N-diacetic acid; phosphonic acid chelating agents such as hydroxyethylidene diphosphonic acid, nitrilotrismethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, 2-phosphono-1,2,4-butanetricarboxylic acid, phosphonohydroxyacetic acid, and hydroxyethyldimethylenephosphonic acid; and hydroxycarboxylic acid chelating agents such as gluconic acid, citric acid, tartaric acid, and malic acid can be used.

[0020] The chelating agent is preferably water-soluble. The chelating agent may be used alone or in combination of two or more. Among these, it is preferable to use an aminocarboxylic acid chelating agent because it is easily thermally decomposed in the subsequent heat treatment step. Preferred aminocarboxylic acid chelating agents include one or more selected from ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, and nitrilotriacetic acid, with ethylenediaminetetraacetic acid being more preferred. These chelating agents are inexpensive and easily available, and metal chelate complex solutions formed from these chelating agents stably dissolve metal components, allowing clear metal chelate complex solutions to be easily prepared.

[0021] From the viewpoints of cost and ease of handling, the solvent for the metal chelate complex solution is preferably water or a mixed solvent of a water-miscible organic solvent and water. Examples of water-miscible organic solvents include alcoholic solvents such as methanol, ethanol, and isopropanol. The solvent for the metal chelate complex solution preferably contains at least water, and for example, the concentration of water in the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more or 95% by mass or more. From the viewpoint of low environmental impact, it is particularly preferable to use substantially only water as the solvent, and therefore the metal chelate complex solution is preferably an aqueous chelate complex solution.

[0022] The content of the metal component in the metal chelate complex solution is preferably adjusted so that it is sufficiently dissolved by the chelating agent. For example, it can be 0.1% by mass or more and 15% by mass or less, and preferably 10% by mass or less. The content of the chelating agent in the metal chelate complex solution is preferably equal to or greater than the theoretical amount required for chelate coordination with the metal component, and is preferably 0.8 to 1.5 times the molar amount per mole of metal ions in the metal component. The molar ratio is preferably 0.9 times or more, more preferably 0.95 times or more, and preferably 1.2 times or less, and more preferably 1.1 times or less. The concentration of the metal chelate complex in the metal chelate complex solution can be, for example, 1% by mass or more and 60% by mass or less, and preferably 10% by mass or more and 40% by mass or less. The metal chelate complex solution may contain additives in addition to the metal element and the chelating agent, including, but not limited to, surfactants and viscosity modifiers.

[0023] The surfactant reduces the surface tension of the metal chelate complex solution. For example, if the substrate is porous and the metal chelate complex solution contains a surfactant, the metal chelate complex solution can more easily penetrate into the pores, resulting in the alloy being present in the pores and increasing the peel resistance of the alloy film from the substrate.

[0024] As the surfactant, nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used without particular limitation, but nonionic surfactants are preferred because of their affinity to porous substrates such as hardened cement bodies. Nonionic surfactants are not particularly limited, but examples thereof include acetylene-based surfactants, polyalkylene glycol-based nonionic surfactants, and silicone-based surfactants.

[0025] The viscosity adjuster is mainly used to increase the viscosity of the metal chelate complex solution to prevent dripping, and examples thereof include polysaccharides, polymers such as polyethylene glycol and acrylic polymers, and amides.

[0026] The amount of additive used may be adjusted appropriately within a range in which the effects of each component are sufficiently obtained. For example, in the case of a surfactant, the concentration in the metal chelate complex solution may be 0.01% by mass or more and 1% by mass or less. The concentration is preferably 0.05% by mass or more, and preferably 0.5% by mass or less, more preferably 0.2% by mass or less. The concentration of the viscosity modifier may be adjusted according to the desired viscosity of the metal chelate complex solution.

[0027] The metal chelate complex solution can be prepared by dissolving at least a metal compound containing a high standard redox potential metal component, a metal compound containing a low standard redox potential metal component, and a chelating agent in a solvent. Alternatively, the metal chelate complex solution may be prepared by dissolving a chelate complex of a metal element in a solvent.

[0028] Examples of metal compounds containing high standard redox potential metal components and / or low standard redox potential metal components include oxides, hydroxides, halide salts such as chlorides and bromides, carbonates, nitrates, sulfates, phosphates, borates, and silicates. Among these, metal oxides, metal hydroxides, metal carbonates, and metal nitrates are preferred. By preparing a metal chelate complex solution using these metal compounds, it is possible to prevent unwanted elements from being mixed into the alloy film formed by the coating and heat treatment processes.

[0029] The chelating agent used in preparing the metal chelate complex solution may be the free acid type or a salt of the chelating agent described above. The salt of the chelating agent is preferably an ammonium salt or an amine salt. The use of such a chelating agent facilitates decomposition of the ammonium ion or amine component during the heat treatment process, thereby preventing unwanted elements from being mixed into the alloy film.

[0030] When the valence of the chelating agent is not equal to the valence of the metal ion to be chelated, a cation or anion may be added to make the metal chelate complex electrically neutral. Examples of the cation include ammonium ions and quaternary ammonium cations. Examples of the anion include nitrate ions and halide ions such as chloride ions and bromide ions, but nitrate ions are preferred because they are less likely to remain in the alloy film.

[0031] The temperature at which the metal chelate complex solution is prepared is not particularly limited as long as it is equal to or higher than the melting point and equal to or lower than the boiling point of the solvent, but is preferably 20° C. or higher, more preferably 35° C. or higher, even more preferably 50° C. or higher, and is preferably 80° C. or lower, more preferably 70° C. or lower. If the chelating agent or metal chelate complex does not dissolve completely, it is preferable to add ammonia, an amine, or the like to completely dissolve them.

[0032] When the metal chelate complex is used as a raw material for a metal chelate complex solution, the metal chelate complex may be precipitated as a solid from the metal chelate complex solution prepared as described above, and the precipitated metal chelate complex may be used as a raw material for the metal chelate complex solution. The precipitation of the metal chelate complex may be carried out by adding a poor solvent to the metal chelate complex solution, or by heating, concentrating, or cooling the metal chelate complex solution, and may be further treated, if necessary, by filtration, drying, washing, recrystallization, or the like.

[0033] The substrate to which the metal chelate complex solution is applied is not particularly limited as long as it has sufficient heat resistance to prevent deterioration or deformation even when heated in the subsequent heat treatment step, and is preferably composed mainly of an inorganic material. From this perspective, hardened cement paste, minerals, ceramics, and metals are preferably used as the substrate. The substrate may be real estate such as a structure, or may be a clay pipe or building material. Examples of real estate substrates include the walls and ceilings of structures such as tunnels, underground shopping malls, and ports, the walls and ceilings of buildings such as buildings, roads, bridges, and cliffs.

[0034] Cement is primarily composed of calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3), and iron(III) oxide (Fe2O3). Portland cement contains tricalcium silicate (alite, 3CaO·SiO2), dicalcium silicate (belite, 2CaO·SiO2), calcium aluminate (aluminate, 3CaO·Al2O3), calcium aluminoferrite (ferrite, 4CaO·Al2O3·Fe2O3), and calcium sulfate (gypsum, CaSO3·2H2O). Cement hardens through chemical reactions in which calcium oxide becomes calcium hydroxide and other components become hydrated. In addition to Portland cement, there are blended cements, which are made by mixing Portland cement with blast furnace slag, fly ash, or silica-based admixtures. Mortar is made by mixing sand, which is a fine aggregate, with cement and water and then hardening it, while concrete is a hardened product made by solidifying sand, gravel, water, etc. with cement. As mentioned above, cement hardens through a hydration reaction, and the water that is not involved in the reaction evaporates, so typical hardened cement products are porous.

[0035] As described above, hardened cement bodies are hardened by hydration and therefore tend to be deteriorated by water, particularly seawater, and also tend to be deteriorated by acids because they contain calcium hydroxide. However, the method of the present invention can coat part or all of the surface of the hardened cement body substrate with an alloy film, thereby improving the durability of the hardened cement body.

[0036] Examples of minerals include limestone such as marble, silica, and Oya stone. Examples of ceramics include metal oxides such as alumina, zirconia, barium titanate, and silica; metal hydroxides such as hydroxyapatite; metal carbides such as silicon carbide; and metal nitrides such as silicon nitride. Examples of metals constituting the substrate include metals other than those that form alloy films. Examples include iron; iron alloys such as carbon steel, stainless steel, chromium-molybdenum steel, and manganese-molybdenum steel; aluminum alloys such as duralumin; and nickel alloys such as Hastelloy and Monel.

[0037] The method for applying the metal chelate complex solution to the substrate is not particularly limited, and can be, for example, application using a brush or roller as in the case of painting with paint, spray application, etc. Depending on the size of the substrate, application by a dipping method or spin coating method is also possible.

[0038] The metal chelate complex solution may be applied to the entire surface of the substrate, or to only a portion of the surface. Two or more metal chelate complex solutions may be applied to different areas to enhance the design of the applied areas. Furthermore, depending on the desired thickness of the alloy film, the thickness of the metal chelate complex coating can be increased by repeating the application and drying of the metal chelate complex solution multiple times, or by applying a thicker layer of a highly viscous metal chelate complex solution.

[0039] The drying conditions after applying the metal chelate complex solution to the substrate surface may be adjusted appropriately depending mainly on the solvent of the metal complex chelate solution. For example, the substrate may be heated at a temperature of 40°C or higher and 80°C or lower for 5 minutes to 1 hour. Alternatively, the substrate may be left at room temperature until the coating film dries.

[0040] 2.Heat treatment process In this process, the portion of the substrate coated with the metal chelate complex solution is heat-treated to form an alloy film. More specifically, by heating the portion coated with the metal chelate complex solution, organic components such as chelating agents and surfactants are thermally decomposed and removed. Furthermore, it is believed that, due to the use of a high standard oxidation-reduction potential metal component with a relatively low ionization tendency in the present invention, a film of the high standard oxidation-reduction potential metal is formed rather than a metal oxide, and all or most of the low standard oxidation-reduction potential metal component with a relatively high ionization tendency also forms a metal film rather than a metal oxide.

[0041] The temperature of this process is adjusted within a range in which the organic components are thermally decomposed. For example, it can be set to 1000°C or higher and 3500°C or lower. The temperature is preferably 1200°C or higher, more preferably 1300°C or higher. For heating, a flame obtained by burning a combustible gas can be used. The combustible gas is not particularly limited, and examples include hydrogen, acetylene, propane, and butane. The inventors initially believed that heating with a reducing hydrogen flame was necessary to form an alloy film. However, according to the method of the present invention, an alloy film can also be formed using an acetylene or butane flame. The heat treatment time should also be adjusted appropriately. For example, if the formation of an alloy film is observed, the heat treatment should be stopped to prevent oxidation to metal oxide. The formation of an alloy film can be confirmed by discoloration from metal ions or the appearance of a metallic luster.

[0042] The heat treatment may be performed using a laser instead of a flame. A laser is a light that is directional (linear), monochromatic, and coherent, and by irradiating a target object with a laser, the surface temperature of the target object can be rapidly increased, making processing possible. In the present invention, the reaction is caused to proceed by irradiating the area coated with the metal chelate complex solution with laser light and adjusting the surface temperature to the above range. The laser to be used may be selected appropriately within the range that allows the formation of an alloy film, and for example, a YAG laser or a CO2 laser, which are commonly used for laser processing, can be used.

[0043] The laser irradiation conditions may be adjusted so long as an alloy film is formed on the coated area of ​​the metal chelate complex solution. For example, the higher the energy of the irradiated laser, the shorter the heat treatment time. However, it is not desirable to use a laser with such high energy that it damages the formed alloy film. Specifically, it is preferable to use a laser with a relatively long wavelength, such as 1.06 μm or 10.6 μm, and a relatively low energy of approximately 0.01 msec or more and 1 msec or less, with a pulse rate of approximately 1 pps or more and 100 pps or less. The laser irradiation time may be such that the coated surface acquires a metallic luster.

[0044] The substrate is preferably placed in the flame or at the end of the flame. The distance from the burner that generates the flame to the substrate may be adjusted, for example, within a range of 30 mm or more and 300 mm or less. In the heat treatment process, the substrate is preferably heated by the flame while the substrate and / or burner are moved at a relative speed (relative to each other) of 10 mm / sec or more and 200 mm / sec or less. This prevents damage or deterioration of the substrate and facilitates the formation of an alloy film on the substrate surface. When the substrate and / or burner are moved in this manner, the substrate may be heated by the flame only once or multiple times. In the latter case, it is convenient to heat the substrate by the flame while moving the substrate and / or burner back and forth, for example. When a laser is used, it is preferable to adjust the distance between the focusing system of the laser processing machine and the coating surface so that the amount of energy and the irradiation area applied to the coating surface are appropriate.

[0045] As described above, a composite having an alloy film formed on a substrate can be obtained. According to the manufacturing method of the present invention, an alloy film can be easily formed on a substrate by applying a metal chelate complex solution to the substrate and then heat-treating it with a flame or laser. That is, the composite of the present invention refers to a composite comprising a substrate and an alloy film layer, with at least a portion of the substrate being coated with the alloy film layer. The alloy film thus formed can be formed in a thin film form, thereby reducing the costs associated with applying and forming metal. The thickness of the alloy film is not particularly limited, but can be, for example, 0.5 μm or more and 100 μm or less. Furthermore, according to the manufacturing method of the present invention, an alloy film can be easily formed in situ on a substrate, even if the substrate is one that cannot be easily moved, such as a civil engineering structure or building.

[0046] As mentioned above, hardened cement pastes are generally porous because they are hardened by chemical reactions such as hydration and contain relatively large-particle sand or gravel to enhance strength. Examples of hardened cement pastes include hardened cement itself, mortar, which is a hardened mixture of cement and sand, and concrete, which is a hardened mixture containing relatively large-particle gravel. All of these are porous. In contrast, thermal spraying methods using molten metal, for example, are unable to fill the pores of hardened cement pastes with metal, resulting in poor peeling resistance of the formed alloy film. However, the method of the present invention uses a liquid metal chelate complex solution, which allows the metal chelate complex solution to penetrate into the pores, resulting in the formation of an alloy film with excellent peeling resistance. A metal chelate complex solution containing a surfactant and reduced surface tension allows the solution to penetrate even smaller pores more easily.

[0047] Specifically, in the composite of the present invention, in which the substrate is a hardened cement paste, the metal component is present closer to the substrate than to the interface between the substrate and the alloy film, and therefore the peeling resistance of the alloy film is high. The interface between the substrate and the metal film refers to, for example, the average line in a reference length of 100 μm when the composite is cut in a direction perpendicular to the planar direction of the alloy film and the cross section is observed at a magnification of 1000 times or more and 10,000 times or less using a scanning electron microscope or the like. The average line here refers to the line obtained by converting a filtered waviness curve for a roughness curve into a straight line using the least squares method (JIS B 0601-1994). [Example]

[0048] The present invention will be described in more detail below by showing examples, but the scope of the present invention is not limited to these examples.

[0049] Example 1: Formation of Cu-Zn alloy film on polycrystalline alumina plate (1) Preparation of metal chelate complex aqueous solution Ethylenediaminetetraacetic acid (150.7 g, 0.516 mol) was placed in a 500 mL beaker and distilled water was added to bring the total volume to 350 g. 25% aqueous ammonia (70.2 g) and copper(II) oxide (41.1 g, 0.516 mol) were then added and stirred at 90°C for 4 hours until completely dissolved. The mixture was then diluted with distilled water to obtain a 40% by mass aqueous solution of EDTA·Cu·(NH4)2. Similarly, ethylenediaminetetraacetic acid (150.0 g, 0.514 mol) was placed in a 500 mL beaker and distilled water was added to bring the total volume to 350 g. 25% aqueous ammonia (69.9 g) and zinc oxide (41.3 g, 0.514 mol) were then added and stirred at 80°C for 3 hours until completely dissolved. Distilled water was then added to dilute the mixture, yielding a 40% by mass aqueous solution of EDTA·Zn·(NH4)2. The resulting solutions were mixed to a molar ratio of Cu:Zn = 0.61:0.39, 0.71:0.29, 0.80:0.20, 0.90:0.10, or 0.95:0.05, and then a nonionic surfactant ("Olfine") was added. (R)EXP.4300 (manufactured by Nissin Chemical Industry Co., Ltd.) was added to a concentration of 0.1% by mass.

[0050] (2) Formation of Cu-Zn alloy film 0.012 g / cm per unit area on a 5 cm x 2.5 cm polycrystalline alumina substrate 2 The aqueous solution of each metal chelate complex was applied in an amount of 1000 ppm and dried at 65° C. for 20 minutes. Next, a spray gun ("6P-II" manufactured by Sulzer Metco) was used to supply hydrogen at a rate of 32.5 L / min and oxygen at a rate of 43.0 L / min, and the spray gun was moved at a speed of 50 mm / s from a distance of 13 cm, scanning the front of the substrate three times to heat the coating. The resulting coating was analyzed by X-ray diffraction using an X-ray diffractometer (Ultima IV, manufactured by Rigaku). The results are shown in Figure 1. In Figure 1, (a) to (e) indicate the Cu:Zn (molar ratio). Specifically, the Cu:Zn ratios were 0.61:0.39 (a), 0.71:0.29 (b), 0.80:0.20 (c), 0.90:0.10 (d), and 0.95:0.05 (e).

[0051] As shown in Figure 1, the smaller the relative molar ratio of Zn to Cu, the smaller the ZnO peak intensity. At Cu:Zn = 0.80:0.20 (c), a ZnO peak was detected analytically, but was not visible to the naked eye. According to the powder X-ray diffraction database published by the International Centre for Diffraction Data (ICDD), the diffraction peak angles (2θ) of Cu(111) and Cu(200) (ICDD-00-050-1333) were 43.2970° and 50.4330°, respectively, and Cu 0.951 Zn 0.049 The diffraction peak angles (2θ) of (111) and (200) (ICDD-00-050-1333) are 43.2690° and 50.3930°, respectively. 0.75 Zn 0.25 The diffraction peak angles (2θ) of (111) and (200) (ICDD-01-071-7924) are 42.6735° and 49.6865°, respectively.0.64 Zn 0.36 The diffraction peak angles (2θ) of (111) and (200) (ICDD-00-050-1333) are 42.4350° and 49.2751°, respectively. The diffraction peak angles of Cu-Zn alloys tend to shift to lower angles as the Zn content increases. In the measurement results of this example, the diffraction peak angles (2θ) of (111) for Cu:Zn = 0.95:0.05 (e) and 0.90:0.10 (d) were 43.14°, and for Cu:Zn = 0.80:0.20 (c) to 0.61 The diffraction peak angle (2θ) of Cu:Zn=0.95:0.05(200) was 43.12°, that of Cu:Zn=0.90:0.10(200) was 50.26°, and that of Cu:Zn=0.80:0.20-0.61:0.39(200) was 50.24°. Similarly, the diffraction peak angle tended to shift to lower angles as the Zn content increased. This indicates that Cu-Zn alloy films are well formed, especially when the molar ratio of Zn to Cu is 4 or higher.

[0052] Example 2: Formation of Cu-Zn alloy film on aluminum alloy plate A Cu—Zn alloy film was formed on an aluminum alloy plate in the same manner as in Example 1, except that the Cu:Zn (molar ratio) in the metal chelate complex aqueous solution was 0.61:0.39, 0.71:0.29, 0.90:0.10, or 0.95:0.05. The resulting coating was analyzed by X-ray diffraction using an X-ray diffractometer (Ultima IV, manufactured by Rigaku). The results are shown in Figure 2. In Figure 2, (a) to (d) indicate the Cu:Zn (molar ratio). Specifically, the Cu:Zn ratios were 0.61:0.39 (a), 0.71:0.29 (b), 0.90:0.10 (c), and 0.95:0.05 (d).

[0053] As shown in the results in Figure 2, the diffraction peak of ZnO was observed only at Cu:Zn = 0.61:0.39 (a). Furthermore, although the diffraction peak angles (2θ) of (111) and (200) tend to be higher for Cu:Zn = 0.71:0.29 (b) and 0.61:0.39 (a), the diffraction peak angle (2θ) of Cu:Zn = 0.95:0.05 (d) (111) is 42.80°, the diffraction peak angle (2θ) of Cu:Zn = 0.90:0.10 (c) (111) is 42.74°, the diffraction peak angle (2θ) of Cu:Zn = 0.95:0.05 (d) (200) is 49.96°, and the diffraction peak angle (2θ) of Cu:Zn = 0.90:0.10 (c) (200) is 49.90°. Therefore, it was considered that a Cu-Zn alloy film was formed well when the molar ratio of Zn to Cu was 4 or more. [Industrial Applicability]

[0054] According to the method of the present invention, it is possible to simply produce an alloy film-coated composite having excellent corrosion resistance and antibacterial properties that can be used as concrete building materials in tunnels, underground shopping malls, ports, etc., where deterioration due to moisture and seawater is a concern, and as sewer pipes, etc., where deterioration due to moisture as well as acids produced by microorganisms is a concern.

Claims

1. A method for producing a composite having an alloy film formed on a substrate, comprising: applying a metal chelate complex solution containing Cu, Zn, a chelating agent, and a surfactant to the substrate; and a step of heat treating the portion of the substrate onto which the metal chelate complex solution is applied, The method according to claim 1, wherein the molar ratio of Cu to Zn is 4 or greater.

2. The method of claim 1, wherein the substrate is a hardened cement paste.

3. 3. The method according to claim 1, wherein the molar ratio of Cu to Zn (moles of Cu / moles of Zn) is 4 or more and 50 or less.

4. 4. The method according to claim 1, wherein the metal chelate complex solution contains, as a solvent, water or a mixed solvent of water and a water-miscible organic solvent.

5. 5. The method according to claim 1, wherein the content of Cu and Zn in the metal chelate complex solution is 0.1% by mass or more and 15% by mass or less.

6. The method according to any one of claims 1 to 5, wherein the chelating agent is an aminocarboxylic acid-based chelating agent.

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