JP2015021871A - Deterioration detection method, method of manufacturing sensor, and sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recognize the time to apply a protective paint again, by detecting a degree of deterioration progress of a protective coating film on a steel material at a low cost.SOLUTION: A deterioration detection method for detecting a degree of deterioration progress of a protective paint (for example, a rust inhibiting paint) applied to a steel material S includes at least a step of sticking a sensor 100 comprising a conductor pattern part formed of a metal thin film (for example, an iron foil manufactured by rolling iron) and a base material holding the conductor pattern part, to a surface of the steel material S, a step of applying a protective paint T to the steel material having the sensor 100 stuck thereto, so as to cover the sensor 100, and a step of electrically or magnetically connecting a measuring instrument to the conductor pattern part of the sensor 100 to measure electric characteristics of the conductor pattern part. A degree of deterioration progress of the protective paint T applied to the steel material S is detected on the basis of the measured electric characteristics of the conductor pattern part.

Description

  The present invention relates to a technique for detecting the progress of deterioration of a protective coating applied to a steel material.

  Conventionally, in a structure using a steel material such as an iron bridge or a plant, a protective coating is used so that the steel material does not rust. This protective coating deteriorates over time due to penetration of corrosive factors and ultraviolet rays. For this reason, a method for detecting deterioration by measuring the thickness by fluorescent X-rays and a method for detecting deterioration by connecting a cable to a steel material and measuring a change in electrical characteristics accompanying corrosion have been proposed. . However, the former has a drawback that it is not suitable for on-site measurement and is expensive, and the latter has a disadvantage that the connection portion of the cable can cause a loss of the coating film. For these reasons, these methods are difficult to adopt, and conventionally, peeling of protective paint and inspection for rusting have been performed mainly by visual inspection. However, it is not easy to systematically repaint the protective paint and predict when it should be repainted in the future by the method of simply visual inspection. As a result, conventionally, the entire surface of the structure is regularly repainted with a protective coating.

JP 2013-053916 A JP 2012-208088 A

  However, since the deterioration of the protective coating of the structure does not progress uniformly, even if some deterioration has progressed, there may be places where other repainting is not yet required There is sex. In spite of this, since the entire surface of the structure has been regularly repainted with protective paint, unnecessary costs have been incurred. Since the soundness of steel is managed by the soundness of the protective paint, if it is possible to grasp the time for repainting at various locations in the structure, it is possible to reduce the life cycle cost while ensuring safety. It becomes. On the other hand, since the protective coating applied to the steel material is thin, it is not easy to grasp and manage the deterioration state of the coating.

  The present invention has been made in view of such circumstances, and is a deterioration detection method capable of detecting the progress of deterioration of the protective coating film of steel and detecting the time when the protective coating should be reapplied at low cost. An object of the present invention is to provide a method for manufacturing a sensor and a sensor.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the deterioration detection method of the present invention is a deterioration detection method for detecting the progress of deterioration of a protective coating applied to a steel material, and includes a conductor pattern portion formed of a metal thin film and a substrate that holds the conductor pattern portion. A step of affixing a metal thin film sheet comprising a surface of a steel material, a step of applying a protective coating to the steel material to which the metal thin film sheet is affixed so as to cover the metal thin film sheet, and the metal thin film Connecting a measuring instrument electrically or magnetically to the conductor pattern portion of the sheet and measuring the electrical characteristics of the conductor pattern portion, and based on the measured electrical characteristics of the conductor pattern portion The progress of deterioration of the protective coating applied to the steel material is detected.

  Thus, a metal thin film sheet composed of a conductive pattern portion formed of a metal thin film and a base material holding the conductor pattern portion is pasted on the surface of the steel material, and the metal thin film is applied to the steel material to which the metal thin film sheet is pasted. Since the protective coating is applied so as to cover the sheet, the metal thin film sheet can be installed between the protective coating film having a small thickness and the steel material. Moreover, since it is not necessary to connect a cable to the metal thin film sheet as a sensor, it is possible to detect the progress of deterioration of the protective paint without impairing the protective function of the protective coating film. As a result, it is possible to set an effective and efficient coating cycle, and it is possible to reduce costs.

  (2) Moreover, the deterioration detection method of the present invention is characterized in that a plurality of types of metal thin film sheets having different base material thicknesses are attached to the surface of a steel material.

  As described above, since a plurality of types of metal thin film sheets having different base material thicknesses are attached to the surface of the steel material, the thickness of the protective coating on the metal thin film sheet can be accurately changed step by step. . Thereby, it becomes possible to detect the progress of deterioration of the protective coating in stages. Furthermore, it is possible to grasp the protective performance of the protective paint at the site where the steel structure is installed.

  (3) Further, in the deterioration detection method of the present invention, before the metal thin film sheet is applied to the surface of the steel material, at least one thickness adjustment seal is applied to the back surface of the metal thin film sheet or the surface of the steel material. Including a step of attaching the metal thin film sheet having the thickness adjustment seal attached to the back surface to the surface of the steel material, or attaching the metal thin film sheet to the thickness adjustment seal attached to the surface of the steel material It is characterized by that.

  As described above, before the metal thin film sheet is applied to the surface of the steel material, at least one thickness adjusting seal is applied to the back surface of the metal thin film sheet or the surface of the steel material. And since the metal thin film sheet with the thickness adjustment seal stuck on the back surface is stuck on the surface of the steel material, or the metal thin film sheet is stuck on the thickness adjustment seal stuck on the surface of the steel material, the metal thin film sheet It becomes possible to change the thickness of the upper protective coating film accurately in a stepwise manner. Thereby, it becomes possible to detect the progress of deterioration of the protective coating in stages. Furthermore, it is possible to grasp the protective performance of the protective paint at the site where the steel structure is installed.

  (4) Further, in the deterioration detection method of the present invention, the metal thin film sheet includes a marking portion formed of a material having a specific heat different from that of the metal, and the heat radiation characteristics and / or the heat receiving characteristics of the marking section are infrared rays. The method further includes the step of specifying the position of the metal thin film sheet coated with the protective paint by nondestructive detection using thermography.

  In this way, the position of the metal thin film sheet covered with the protective coating is specified by detecting the marking portion nondestructively using infrared thermography, so the position of the metal thin film sheet embedded in the protective coating is determined. It can be easily detected.

  (5) Moreover, the deterioration detection method of this invention connects the detection circuit for measuring the change of the electrical property of a conductor pattern part to the conductor pattern part of the metal thin film sheet of said (1) description, The said detection Connecting a control IC chip to the circuit, connecting an antenna pattern for wireless communication to the IC chip, and forming a measurement unit; and detecting the measurement unit non-destructively using radio waves The method further includes a step of specifying a position and an electric signal of the metal thin film sheet coated with the protective paint.

  Thus, by detecting the measurement unit nondestructively using radio waves, the position and electrical signal of the metal thin film sheet covered with the protective coating can be easily specified.

  (6) Moreover, the manufacturing method of the sensor of this invention is a manufacturing method of the sensor which detects the deterioration progress state of the protective coating applied to steel materials, Comprising: A metal thin film and a base material are integrated, and a metal thin film sheet A step of forming a resist film of a circuit pattern on the metal thin film of the metal thin film sheet, a step of etching the metal thin film sheet on which the resist film is formed, and the metal thin film sheet after the etching And a step of masking a part of the circuit pattern of the metal thin film sheet and covering the other part with a noble metal or a noble metal and a buffer metal.

  In this way, a metal thin film and a base material are integrated to produce a metal thin film sheet, and a very thin conductor pattern part is formed, so a sensor to be installed between a thin protective coating and a steel material is produced. It becomes possible to do. Further, according to this method, it is possible to form a pattern having a two-dimensionally complicated shape. Thereby, the degree of freedom of the shape of the entire sensor is increased, and the area of the conductor pattern portion can be increased. As a result, the sensitivity of the sensor can be improved. In addition, since the circuit portion can be formed simultaneously with the conductor pattern portion, the manufacturing process can be simplified and mass production can be achieved.

  (7) Moreover, the manufacturing method of the sensor of this invention is a manufacturing method of the sensor which detects the deterioration progress of the protective coating applied to steel materials, Comprising: In locations other than the pattern part formed on the base material A step of masking, and a step of forming a conductor pattern portion on the substrate by forming a thin film by any one of vapor deposition, sputtering, or ion plating on the pattern portion, It is characterized by including at least.

  As described above, when the metal thin film used for the conductor pattern portion is made of a metal to which a forming technique such as vapor deposition, sputtering, or ion plating can be applied, the conductor pattern portion is used as a base material by using the forming technique described above. You can also create directly on top of. As a result, the metal thin film and the base material are integrated to produce a metal thin film sheet, and a very thin conductive pattern portion is formed. Therefore, a sensor to be installed between a protective coating film having a thin thickness and a steel material is produced. It becomes possible. Further, according to this method, it is possible to form a pattern having a two-dimensionally complicated shape. Thereby, the degree of freedom of the shape of the entire sensor is increased, and the area of the conductor pattern portion can be increased. As a result, the sensitivity of the sensor can be improved. In addition, since the circuit portion can be formed simultaneously with the conductor pattern portion, the manufacturing process can be simplified and mass production can be achieved.

  (8) Moreover, the manufacturing method of the sensor of this invention further includes the process of forming the said base material with the material from which specific heat differs with respect to a metal.

  In this way, since the base material is formed of a material having a specific heat different from that of the metal, it is embedded in the protective coating by non-destructively detecting the heat dissipation characteristics and / or heat receiving characteristics of the base material using infrared thermography. It is possible to easily detect the formed metal thin film sheet.

  (9) Moreover, the manufacturing method of the sensor of this invention is characterized by further including the process of forming a marking part in the said base material with the material from which specific heat differs with respect to a metal.

  As described above, since the marking portion is formed on the base material with a material having a specific heat different from that of the metal, the protective coating is detected by non-destructively detecting the heat radiation characteristic and / or the heat receiving characteristic of the marking portion using infrared thermography. It becomes possible to easily detect the metal thin film sheet embedded in the film.

  (10) Further, the sensor of the present invention is a sensor for detecting the progress of deterioration of the protective coating applied to the steel material, and a conductor pattern portion formed of a metal thin film and a base material for holding the conductor pattern portion. And a thin film portion formed of a noble metal and provided in a part of the conductor pattern portion, and a marking portion formed of a material having a specific heat different from that of the metal, and is attached to a steel material and covered with a protective coating The electrical characteristics of the conductor pattern portion change depending on the state.

  Thus, since the conductor pattern part is formed of a metal thin film, the thickness can be made very thin, and the time until disconnection can be shortened. As a result, it is possible to increase the sensitivity as a sensor. In addition, since it has a thin film part made of noble metal provided in a part of the conductor pattern part made of metal thin film, corrosion of the metal thin film and thin film part made of noble metal starts at the same time A battery is formed, and the detection sensitivity of the sensor is improved. In addition, it is not necessary to newly provide a cathode portion, and wiring between the detection portion and the cathode portion is not necessary, so that work efficiency can be improved. In addition, it can be installed at a site where it is difficult to attach the cathode. Furthermore, since a buffer metal is provided between the conductor pattern portion and the thin film portion, the adhesion of each layer is improved by using a metal thin film and a metal having high adhesion to the noble metal, and a thin film cathode is formed on the sensor. Is possible.

  (11) Moreover, the sensor of this invention is a sensor which detects the deterioration progress of the protective coating applied to steel materials, Comprising: The base material which hold | maintains the conductor pattern part formed with the metal thin film, and the said conductor pattern part And a thin film portion formed of a noble metal and provided in a part of the conductor pattern portion, and at least one thickness adjustment seal provided on the back surface of the base material, and applied to a steel material as a protective coating The electrical characteristics of the conductor pattern portion change in the coated state.

  Thus, since the conductor pattern part is formed of a metal thin film, the thickness can be made very thin, and the time until disconnection can be shortened. As a result, it is possible to increase the sensitivity as a sensor. In addition, since the conductor pattern part has a thin film part made of noble metal, corrosion of the metal thin film starts, and at the same time, a corrosion battery is formed on the metal thin film and the thin film part made of noble metal, and the sensor detection Sensitivity is improved. In addition, it is not necessary to newly provide a cathode portion, and wiring between the detection portion and the cathode portion is not necessary, so that work efficiency can be improved. In addition, it can be installed at a site where it is difficult to attach the cathode. Furthermore, since at least one thickness adjusting seal is provided on the back surface of the base material, the thickness of the protective coating on the metal thin film sheet can be accurately changed stepwise. Thereby, it becomes possible to detect the progress of deterioration of the protective coating in stages.

  According to the present invention, a metal thin film sheet composed of a conductor pattern portion formed of a metal thin film and a substrate holding the conductor pattern portion is affixed to the surface of the steel material, and the steel material to which the metal thin film sheet is affixed, Since the protective coating is applied so as to cover the metal thin film sheet, the metal thin film sheet can be installed between the protective coating film having a small thickness and the steel material. Moreover, since it is not necessary to connect a cable to the metal thin film sheet as a sensor, it is possible to detect the progress of deterioration of the protective paint without impairing the protective function of the protective coating film. As a result, an effective and efficient coating cycle can be set, and the life cycle cost can be reduced.

It is a figure which shows the outline | summary of the sensor which concerns on this embodiment. It is a figure which shows the mode of the sensor which provided the marking part. It is a flowchart which shows the manufacturing method of the sensor which concerns on this embodiment. It is a figure which shows typically a mode that the sensor which concerns on this embodiment was installed. It is a figure which shows the example which comprised the sensor which concerns on this embodiment to the elongate ribbon shape. It is a figure which shows a wireless sensor. It is a figure which shows a wireless sensor. It is a figure which shows a wireless sensor. It is a figure which shows a wireless sensor. It is a figure which shows the usage example of the sensor which concerns on this embodiment.

  In the sensor according to the present embodiment, the conductor pattern portion for detecting the progress of the deterioration of the protective paint is made of a metal thin film. The metal thin film that forms the conductor pattern part reacts with a factor that degrades the protective coating of the target steel material, or after the protective coating deteriorates, the corrosion reaction starts when it comes into contact with the atmospheric environment. There is no particular limitation as long as it is made of a metal whose physical characteristics change. A metal that corrodes in the atmospheric environment is preferable because detection sensitivity is improved and it is versatile. In particular, if iron or zinc is used as the constituent material of the conductor pattern part, the ionization tendency is large, so the reactivity in the air environment or the underwater environment is high, and it becomes easier to detect the deterioration of the protective coating film. preferable.

  The metal thin film is patterned on the material to be the base material. This pattern is arranged in a shape suitable for detecting the corrosion reaction of the metal thin film. The method for detecting the corrosion reaction of the metal thin film is particularly limited as long as it captures the corrosion phenomenon of the metal, such as a change in electric resistance, a change in potential, a change in current density, or a change in capacitance of the conductor pattern portion. It is not a thing.

  On the other hand, the base material holding the conductor pattern portion is made of a resin material that is electrically insulating and can be formed into a very thin film. The type of the resin material is not limited, but for example, polyethylene, polypropylene, vinyl chloride, fluororesin, or polycarbonate can be used. The selection of the base material is not particularly limited as long as the base material does not react with the organic solvent contained in the protective coating for the steel material, and has high weather resistance and water resistance.

  The metal thin film patterned on the resin film as the substrate is cut into a suitable shape and used as a sensor. When monitoring as a spot, it may have a square shape of several centimeters square, and if it detects a circular tube in the circumferential direction, it may have a long ribbon shape. In addition, when it is desired to detect three-dimensionally, the shape may be three-dimensionally formed.

  As described above, in the sensor according to the present embodiment, the entire thickness of the sensor can be made extremely thin by configuring the portion for detecting deterioration with a metal thin film and the substrate with a resin film. Specifically, the sensor according to the present embodiment has an overall thickness of 0.5 mm or less. For example, when the sensor is configured with a metal thin film having a thickness of 0.02 mm or less and a base material having a thickness of 0.2 mm or less, it is particularly suitable for embedding in a protective coating film.

  Furthermore, about the thickness of a base material, since it can comprise in arbitrary thickness if a material is selected in the case of manufacture, the thickness of the protective coating film which coat | covers a conductor pattern part can be changed. Moreover, if the method of sticking a film sheet (thickness adjustment seal) is used for the purpose of adjusting the thickness of the protective coating film on the back surface of the base material of the metal thin film sheet after manufacture, it can be configured to an arbitrary thickness. Is possible. For this reason, it becomes possible to grasp | ascertain the danger of corrosion earlier than the protective coating film of the metal structure used as object deteriorates. Furthermore, by changing the thickness of the base material in stages and arranging multiple sensors with multiple types of thickness, it is possible to grasp the progress of deterioration over time, and the durability of the coating film Preventive maintenance maintenance such as prediction, planned and efficient repainting of the coating can be made possible. For example, the thickness of the iron foil material of the conductor pattern portion is 0.005 mm, the thickness of the base material is 0.05 mm, 0.1 mm, and 0.15 mm. By disposing on the surface of the steel structure, it is possible to detect the progress of deterioration of the protective coating film in stages.

  When applying protective paint to metal structures to be measured, such as steel bridges, plant equipment, street lamps, underground pipes, tanks, ships, etc., the surface of the metal material before application according to this embodiment Affix the sensor. Then, a protective paint is applied. According to the present embodiment, the sensor is embedded under the coating film as it is without taking the cable out of the protective coating film.

  Thus, the sensor can be installed without causing a coating film defect that occurs when the cable is pulled out. When measuring, the coating film covering the sensor is peeled off, and a measuring instrument is directly connected to measure an electrical signal accompanying corrosion. In this case, the measurement may be performed electromagnetically using a wireless method.

  FIG. 1 is a diagram showing an outline of a sensor according to the present embodiment. The sensor 100 according to the present embodiment is a sensor for detecting the progress of deterioration of a protective coating applied to a steel material, and is a conductor pattern formed of a metal thin film (for example, an iron foil material produced by rolling iron). Part 101, base material 102 holding conductor pattern part 101, and thin film part 103 provided in a part of conductor pattern part 101 and formed of a noble metal (for example, gold). A measuring terminal 101 a is provided at the end of the conductor pattern portion 101. In this sensor 100, the protective paint deteriorates and deteriorates due to penetration of corrosion factors, ultraviolet rays, etc., and the electrical characteristics of the conductor pattern portion 101 change.

  Here, a battery in which a metal anode and cathode can be clearly distinguished is called a macro cell, and a current flowing between both electrodes is called a corrosion current (macro cell current). When a reaction in which the metal thin film is ionized (oxidation reaction: anode reaction) proceeds, a reaction in which oxygen is reduced (reduction reaction: cathode reaction) proceeds on the surface of the metal thin film. These reactions proceed simultaneously, resulting in a potential difference in which the anode part has a base potential and the cathode part has a noble potential. At the same time, a current (corrosion current) flows from the anode part to the cathode part, and corrosion of the metal thin film proceeds. By utilizing such a principle and arranging the thin film portion 103 (cathode member) made of a noble metal, the conductor pattern portion 101 can be corroded and the deterioration of the protective coating (protective coating film) is progressed. It becomes possible to grasp the situation more quickly.

  As a sensor for detecting the progress of deterioration of the protective coating applied to the steel material, a more preferable thickness of the metal thin film is 50 nm or more and less than 0.05 mm. When the thickness of the metal thin film is 0.05 mm or more, the responsiveness of the change in the electrical characteristics of the metal thin film caused by the corrosion reaction may be lowered. On the other hand, the thickness of the metal thin film is preferably 50 nm or more. If it is thinner than 50 nm, the physical strength may be insufficient and the wire may be disconnected. Considering the physical strength and the sensitivity of deterioration detection, it is more preferable that the thickness is 100 nm or more and 25 μm or less. In addition, regarding the line width of the metal thin film, if the line width is less than 0.01 mm, disconnection may occur during manufacture. On the other hand, the adhesion with the base material is weak, and damage is caused during manufacture or installation. It becomes easy to receive. From the viewpoint of installation and protection by a film, the thickness is preferably 0.01 mm or more, and when the line width is large, the sensitivity due to corrosion disconnection is lowered, so the line width is preferably 2.0 mm or less.

  The conductor pattern portion 101 has a two-dimensional circuit pattern formed on the substrate 102. Formation of a two-dimensional uneven shape or spiral circuit on the substrate improves the probability of contact with a corrosion factor. The line length is desirably 50 mm or more from the viewpoint of the contact probability with the corrosion factor. In this embodiment, for example, the thickness of the metal thin film is 5 μm, the line width of the conductor pattern portion 101 is 1.0 mm, and the total line length is 250 mm.

  FIG. 2 is a diagram illustrating a state of the sensor 100-1 in which the marking unit M is provided in the sensor 100 illustrated in FIG. The marking portion M is formed of a material having a specific heat different from that of iron, such as ethylene propylene resin. That is, since this sensor is embedded under the protective paint, the position of the sensor may not be known during measurement. For this reason, the marking part M is provided in the sensor 100-1, and marking is discriminate | determined with the nondestructive inspection machine etc. which used infrared rays from the exterior of the protective coating film. Thereby, it becomes possible to specify the position where the sensor is buried and the position of the connection terminal, and to measure the portion by peeling the coating film locally. For example, when the sensor target metal is iron or an iron alloy, the specific heat is 400 to 600 (J / kg ° C.), but the specific heat of the resin material is more than 1000 (J / kg ° C.). In particular, the specific heat of chloroprene rubber and ethylene propylene rubber is 2000 (J / kg ° C.) or more. These can be used for the material of the marking portion M. Here, an example in which the marking portion M is provided on the base member 102 is shown, but the base member 102 itself may be made of the same material as the marking portion M. In this case, since the base material 102 itself has a specific heat different from that of iron or an iron alloy, it is possible to grasp the embedded position of the sensor.

  FIG. 3 is a flowchart showing a method for manufacturing the sensor according to the present embodiment. Here, a method for manufacturing a sensor having the marking portion M shown in FIG. 2 will be described. First, a metal thin film and a base material are integrated, and a metal thin film sheet is produced (step S1). Here, an adhesive is applied to a resin film (for example, a resin film such as PET or polyimide material) serving as a base material, and the iron foil material and the base material are bonded together using a roller or the like. Thereby, an iron foil sheet is produced.

  Next, a resist film having a conductor pattern is formed on the iron foil of the produced metal thin film sheet (step S2). That is, a resist film in the shape of a sensor (conductor pattern portion) and a circuit is formed on the metal thin film of the metal thin film sheet by screen printing, photo printing, or the like. Along with this, a guide or the like for individually cutting and separating the sensor with a die after printing is printed.

  Next, etching is performed (step S3). Here, the resist-printed metal thin film sheet is etched in an etching tank. As a result, the exposed metal thin film not provided with the resist film is dissolved by the etching solution (for example, ferric chloride solution). After the etching is completed, the metal thin film sheet is taken out from the etching tank and the adhering liquid is washed.

  Next, the resist film is removed with a solvent or the like to complete the conductor pattern portion and the circuit outline (step S4). Next, masking is performed on a part of the detection portion of the sheet that has been etched (step S5), put into a film forming apparatus (for example, vacuum deposition, sputtering), and time adjustment is performed so as to obtain a predetermined film thickness. By forming a noble metal (eg, gold or platinum) film on the entire surface, a cathode metal film is formed (step S6).

  Here, the noble metal is not particularly limited as long as the natural potential is noble, has a large potential difference from the metal forming the conductor pattern portion, and is stable in an environment where the metal forming the conductor pattern portion corrodes. . In the present embodiment, for example, a noble metal typified by gold or platinum, or an alloy thereof is preferable. Next, regarding the configuration of the cathode, if it is gold or platinum, the film thickness is in the range of 10 nm to 10 μm. If the film thickness is thinner than 10 nm, pinholes and the like may occur, and it is difficult to coat uniformly, which is not preferable. When the film thickness is thicker than 10 μm, the flexibility is lowered, bending peeling may occur, and the cost increases.

  In forming the cathode coating, the adhesion between the metal forming the conductor pattern portion and the noble metal is not necessarily good. Therefore, in the present embodiment, in order to improve the adhesion, a buffer layer (buffer metal) of another metal can be provided between the metal forming the conductor pattern portion and the noble metal. This buffer metal is a metal that is more noble than the metal that forms the conductor pattern portion, and has good adhesion to the noble metal on the surface and the metal that forms the conductor pattern portion, and forms the conductor pattern portion. The metal is not particularly limited as long as it is a metal that is more stable in the atmosphere than the metal to be used. For example, metals, such as copper, titanium, chromium, nickel, are mentioned. In particular, titanium and chromium are preferable because they have excellent adhesion between a base metal and a noble metal as a potential. By providing this buffer layer (buffer metal), the adhesion of each layer can be improved, and a stable thin film cathode can be formed on the sensor.

  The thickness of the buffer layer is preferably in the range of 5 nm to 5 μm, and is preferably formed thinner than the noble metal on the upper surface. This has the effect of preventing the influence of the metal of the buffer layer from becoming strong when subjected to a thermal shock or the like, and avoiding the occurrence of fine cracks in the noble metal of the surface coating. When the thickness of the buffer layer is thinner than 5 nm, the effect as the buffer layer is reduced, which is not preferable. When the thickness of the buffer layer is thicker than 5 μm, the flexibility decreases, and physical properties such as the thermal expansion coefficient and elastic coefficient of the buffer metal may affect the noble metal of the cathode part, and may cause fine cracks. This is not preferable.

  As a method for coating a noble metal on the surface portion of the conductor pattern portion of the metal thin film and the buffer layer, for example, vacuum deposition or sputtering is suitable. Further, as a dry coating method, a vacuum plating method (PVD) or a chemical vapor deposition method (CVD) may be used. Alternatively, the metal may be formed into a powder paint and formed into a film using screen printing. Further, as wet plating, a film may be formed using electrolytic plating or chemical plating.

  Next, a marking resin as the marking portion M is formed on the base material of the sensor using silk screen printing (step S7). Next, the sheet is divided (step S8). After the division, the masking is peeled off to complete the conductor pattern portion. After completion, the sensors subjected to the protection treatment are then cut and separated individually using a punching die.

  FIG. 4 is a diagram schematically illustrating a state in which the sensor according to the present embodiment is installed. The left side of the drawing is a plan view, and the right side is a cross-sectional view. A sensor 100 is affixed to the steel material S, and a protective coating is applied thereon to form a protective coating T. When the base material is made of a resin material having a high specific heat, the sensor 100 can easily detect the position from the difference in thermal characteristics between the steel material and the base material using infrared thermography. Further, when the sensor 100 has a wireless antenna, the position of the sensor 100 can be easily specified by using wireless from the outside. In order to detect the progress of deterioration of the protective coating film T, for example, the electrical resistance of the conductor pattern portion is measured for the sensor installed as shown in FIG. The electrical resistance is measured by, for example, extending a measurement terminal of the conductor pattern portion and connecting a measuring instrument. Further, it may be measured electromagnetically by a wireless method.

  In this case, according to the present embodiment, the thickness of the protective coating film can be changed by changing the thickness of the base material. By arranging a plurality of types of sensors having different substrate thicknesses, the thickness of the protective coating can be accurately changed, and stepwise deterioration detection can be performed. In this case, at the same time, it is possible to grasp the protective performance of the coating film in the actual local environment. Moreover, since the coating film is applied thinner than the other locations at the location where the sensor is affixed, it is also possible to grasp the soundness of the steel material of the frame.

  Since the sensor according to the present embodiment is very thin and flexible, it can cope with curved surfaces such as pipes and tanks in a chemical factory plant or a spherical gas tank. In addition, when the shape of the conductor pattern portion is changed so as to increase the number of corrosion products when the metal thin film corrodes, the coating film on the sensor surface can be peeled off. By combining with the method of installing by changing the thickness of the base material, the coating directly above the sensor at the installation site can be peeled off and visually confirmed without damaging the steel of the housing, and the remaining coating can be easily confirmed. The film thickness and danger can be grasped.

FIG. 5 is a diagram showing an example in which the sensor according to the present embodiment is formed in an elongated ribbon shape. The sensor 50 has a conductor pattern portion 51 that detects the progress of deterioration of the protective paint. As shown in FIG. 5, it is installed so as to surround the sensor 50 in the cylindrical steel T _1. Then, a protective paint is applied from above the sensor 50. When measuring the electrical characteristics of the conductor pattern portion 51, the measurement is performed by connecting a measuring instrument to the terminal 52. Thus, by installing the sensor 50 so as to go around the steel material T1, it is possible to detect the deterioration of the protective paint regardless of the direction in which the corrosion factor enters.

  FIG. 6 is a diagram illustrating a wireless sensor. In the sensor 62, a conductor pattern portion 61 is formed on the base material 60. The conductor pattern part 61 is connected to a circuit part 63 including an IC chip. The circuit unit 63 is connected to the antenna coil 64 and the wiring unit 65. In addition, by placing a radio wave absorbing paint (for example, ferrite-containing paint) or a radio wave absorbing sheet (for example, a ferrite sheet) between the antenna coil and the steel material to be adhered, the influence of the steel material is reduced and stable. Wireless communication is possible. According to this sensor 62, a passive type sensor can be configured while the conductor pattern portion 61 remains thin. That is, it is possible to acquire the electrical characteristics of the conductor pattern portion 61 by irradiating the antenna coil 64 with electromagnetic waves from the reader device. The circuit portion 63 has a thickness larger than that of the conductor pattern portion 61, but can be disposed separately from the conductor pattern portion, and thus can be installed on a steel material without affecting corrosion detection. is there.

  7A and 7B are diagrams showing other wireless sensors. Here, the conductor pattern portion and the power feeding portion are integrated. That is, as shown in FIG. 7, the conductor pattern portion 74 is exposed from the opening 71, and the conductor pattern portion 74 is connected to the circuit portion 72. The circuit unit 72 is connected to the antenna coil 70 via the wiring unit 73. In addition, by placing a radio wave absorbing paint (for example, ferrite-containing paint) or a radio wave absorbing sheet (for example, a ferrite sheet) between the antenna coil and the steel material to be adhered, the influence of the steel material is reduced and stable. Wireless communication is possible. As shown in FIG. 7B, a laminate is applied to a portion other than the opening 71. Thereby, the conductor pattern part 74 is exposed from the opening part 71, and the others are protected by the laminate. Such a sensor is affixed to a steel material, and a protective coating is applied thereon.

  FIG. 8 is a diagram illustrating another wireless sensor. The sensor 80 is an active type sensor equipped with a battery. A plurality of conductor pattern portions 81 are connected to the changeover switch 89 in parallel. This makes it possible to cover a wide range. Each conductor pattern portion 81 is connected to the circuit portion 88 via the changeover switch 89. The circuit unit 88 includes an IC (not shown), and transmits and receives signals to and from the microcomputer 87. The circuit unit 88 receives power from the battery 85 and operates. The circuit unit 88 performs wireless communication with the reader device via the antenna coil 83. Thus, since the circuit part 88 and the conductor pattern part 81 are separated, the active pattern sensor can be configured regardless of the shape of the conductor pattern part 81 while the conductor pattern part 81 remains thin. it can. In addition, since the changeover switch 89 is provided, a large number of conductor pattern portions can be connected. Thereby, even if a corrosion factor intrudes from any installation location and the paint deteriorates, the position can be specified.

  FIG. 9 is a diagram illustrating a usage example of the sensor according to the present embodiment. In a state where the sensor 90 is affixed to the steel material and embedded in the protective coating film, measurement is performed by irradiating a radio signal from the reader device 91.

  Thereby, it becomes possible to detect the progress of deterioration of the protective coating locally. As a result, an effective and efficient coating cycle can be set, and the life cycle cost can be reduced.

50 sensor 51 conductor pattern part 52 terminal 60 base material 61 conductor pattern part 62 sensor 63 circuit part 64 antenna coil 65 wiring part 70 antenna coil 71 opening 72 circuit part 73 wiring part 74 conductor pattern part 80 sensor 81 conductor pattern part 83 antenna coil 85 battery 87 microcomputer 88 circuit section 89 selector switch 90 sensor 91 the reader device 100 sensor 101 conductor pattern portion 101a measuring terminal 102 substrate 103 thin section M marking unit S steel T protective coating T ₁ steel

Claims (11)

A deterioration detection method for detecting the progress of deterioration of a protective coating applied to a steel material,
A step of attaching a metal thin film sheet composed of a conductive pattern portion formed of a metal thin film and a base material holding the conductive pattern portion to the surface of the steel material;
A step of applying a protective coating so that the metal thin film sheet is coated on the steel material to which the metal thin film sheet is attached,
Connecting a measuring instrument electrically or magnetically to the conductor pattern portion of the metal thin film sheet, and measuring the electrical characteristics of the conductor pattern portion, at least,
A deterioration detection method, comprising: detecting a progress of deterioration of the protective coating applied to the steel material based on the measured electrical characteristics of the conductor pattern portion.   The deterioration detection method according to claim 1, wherein a plurality of types of metal thin film sheets having different substrate thicknesses are attached to a surface of a steel material. Before affixing the metal thin film sheet to the surface of the steel material, including a step of affixing at least one thickness adjustment seal to the back surface of the metal thin film sheet or the surface of the steel material;
The metal thin film sheet with the thickness adjustment seal attached to the back surface is attached to the surface of the steel material, or the metal thin film sheet is attached to the thickness adjustment seal attached to the surface of the steel material. The deterioration detection method according to claim 1. The metal thin film sheet includes a marking portion formed of a material having a specific heat different from that of the metal,
The method further comprises the step of specifying the position of the metal thin film sheet coated with the protective paint by non-destructively detecting the heat radiation characteristic or / and the heat receiving characteristic of the marking part using an infrared thermography. The deterioration detection method according to claim 1. A detection circuit for measuring a change in electrical characteristics of the conductor pattern portion is connected to the conductor pattern portion of the metal thin film sheet according to claim 1, a control IC chip is connected to the detection circuit, and the IC chip is connected to the detection circuit. Connecting an antenna pattern for wireless communication to form a measurement unit;
The method further comprises the step of identifying the position of the sensor covered with the protective coating and the electrical characteristics of the pattern part by nondestructively detecting the measurement unit using radio waves. Item 2. The deterioration detection method according to Item 1. A method of manufacturing a sensor for detecting the progress of deterioration of a protective coating applied to a steel material,
A step of producing a metal thin film sheet by integrating the metal thin film and the substrate;
Forming a resist film of a circuit pattern on the metal thin film of the metal thin film sheet;
Etching the metal thin film sheet on which the resist film is formed;
Removing the resist film of the metal thin film sheet after the etching;
A method of manufacturing a sensor, comprising: masking a part of a circuit pattern of the metal thin film sheet and coating a noble metal or a noble metal and a buffer metal on another part. A method of manufacturing a sensor for detecting the progress of deterioration of a protective coating applied to a steel material,
Masking a portion other than the pattern portion formed on the substrate; and
Forming a conductive pattern portion on the substrate by forming a thin film on the pattern portion by any one of vapor deposition, sputtering, or ion plating. A method for manufacturing a sensor.   8. The method of manufacturing a sensor according to claim 6, further comprising a step of forming the base material with a material having a specific heat different from that of the metal.   8. The method for manufacturing a sensor according to claim 6, further comprising a step of forming a marking portion on the base material using a material having a specific heat different from that of the metal. A sensor that detects the progress of deterioration of the protective coating applied to steel,
A conductor pattern formed of a metal thin film;
A base material for holding the conductor pattern portion;
A thin film portion formed of a noble metal and provided in a part of the conductor pattern portion;
A marking portion formed of a material having a specific heat different from that of the metal,
A sensor characterized in that the electrical characteristics of the conductor pattern portion change in a state where it is affixed to a steel material and covered with a protective paint. A sensor that detects the progress of deterioration of the protective coating applied to steel,
A conductor pattern formed of a metal thin film;
A base material for holding the conductor pattern portion;
A thin film portion formed of a noble metal and provided in a part of the conductor pattern portion;
And at least one thickness adjustment seal provided on the back surface of the base material,
A sensor characterized in that the electrical characteristics of the conductor pattern portion change in a state where it is affixed to a steel material and covered with a protective paint.

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