JP2022063073A - Coating film evaluation system - Google Patents

Abstract

To provide a system with which it is possible to appropriately evaluate the degradation of a coating film.SOLUTION: Provided is a system for evaluating the degradation of a coating film that covers a base substance (e1). The system comprises: a sensor unit (d) having a first electrode (e1) being in contact with one surface of the test layer (p1) to be evaluated which is at least a portion of a coating film (p), and a second electrode (e2) being in contact with the other surface of the test layer; a measurement unit for applying an alternating current of specific frequency between the first and the second electrodes and finding a characteristic value that reflects the dielectric property of the test layer; and an evaluation unit for comparing the characteristic value with a prescribed value and evaluating the degradation degree of the test layer. The characteristic value is, for example, a dielectric loss tangent (tanδ). For the specific frequency, for example, a first frequency on the high frequency side and a second frequency on the low frequency side may be adopted. The degradation of the coating film which could not be grasped by the conventional AC impedance method can now be appropriately grasped.SELECTED DRAWING: Figure 2A

Description

The present invention relates to a system or the like capable of evaluating the degree of deterioration of a coating film.

Members and structures are coated with a coating film to ensure design and corrosion resistance. The coating film may change over time (so-called deterioration) from the initial state due to the influence of the external environment. In particular, the coating film exposed to the outdoors is easily deteriorated due to the influence of sunlight, wind and rain, corrosive gas and the like.

If the degree of deterioration (referred to as "deterioration degree") and deterioration tendency of the coating film can be evaluated (analyzed), it will be useful for repair and maintenance of the coating film and development research of paints and paints. Therefore, a proposal related to the deterioration evaluation of the coating film has been made, and there is a description related to the following documents.

Japanese Unexamined Patent Publication No. 3-160354 Japanese Unexamined Patent Publication No. 2004-53474 Japanese Unexamined Patent Publication No. 2007-101184

Kubota et al., "Prediction of Deterioration of Steel Surface Coating Material by AC Impedance Measurement", Taisei Corporation Bulletin, Vol.43 (2010), no.17, PP.1-5

In each document, the deterioration of the coating film is evaluated (diagnosis, monitoring, etc.) based on the change in impedance by the AC impedance method. However, the impedance of the coating film shows a remarkable change after the deterioration of the coating film has progressed considerably. For this reason, the conventional evaluation method cannot appropriately evaluate the deterioration of the coating film before the end of its life (for example, the deterioration at the stage where almost no change in appearance occurs).

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a coating film evaluation system or the like capable of evaluating deterioration of a coating film by a method different from the conventional method.

As a result of diligent research to solve this problem, the present inventor has conceived and embodied the evaluation of the degree of deterioration of the coating film using the dielectric property of the coating film or the index value related thereto. By developing this result, the present invention described below was completed.

<< Coating film evaluation system >>
(1) The present invention is a system for evaluating deterioration of a coating film covering a substrate, and is a first electrode in contact with one side of a logging object to be evaluated in at least a part of the coating film and the logging object. A sensor unit having a second electrode in contact with the other surface side and an AC of a specific frequency are energized between the first electrode and the second electrode to obtain characteristic values reflecting the dielectric characteristics of the logging. It is a coating film evaluation system including a measuring unit to be obtained and an evaluation unit for evaluating the degree of deterioration of the logging subject by comparing the characteristic value with a predetermined value.

(2) In the coating film evaluation system of the present invention (also simply referred to as "system"), the degree of deterioration of the coating film is evaluated using the characteristic value reflecting the dielectric property of the coating film. Deterioration can be evaluated appropriately. For example, according to the system of the present invention, even before the life of the coating film (before deterioration appears on the appearance and the impedance changes significantly), the state change of the coating film can be grasped and the remaining life of the coating film (“remaining life”). Also called "lifetime") can be predicted.

<< Coating film evaluation method, etc. >>
(1) The present invention can also be grasped as a coating film evaluation method. For example, the present invention is a measurement in which a logging subject to be evaluated, which constitutes at least a part of a coating film covering a substrate, is energized with an AC of a specific frequency to obtain a characteristic value reflecting the dielectric characteristics of the logging subject. A coating film evaluation method comprising a step (step) and an evaluation step (step) for evaluating the degree of deterioration of the logging subject by comparing the characteristic value with a predetermined value may be used.

(2) The present invention is also understood as a sensor that can be used in a system or method for evaluating deterioration of a coating film. For example, the present invention comprises an electrode pair (first electrode and second electrode) in contact with a logging object to be evaluated at least a part of the coating film, and the logging subject is subjected to alternating current of a specific frequency. It may be a sensor that can be used to detect or measure the dielectric properties or characteristic values of logging.

As one of the electrodes (first electrode), a substrate on which a coating film is formed may be used. The coating film may be directly formed on a substrate (a part of a member, a structure, or the like), or may be formed on a substrate (first electrode) dedicated to the sensor. In the former case, the coating film (simply referred to as "actual coating film") actually formed on a member or a structure can be evaluated. In the latter case, deterioration of the coating film can be evaluated with a high degree of freedom in the same environment as the actual coating film by retrofitting a sensor or the like. In any case, in-situ observation / measurement is possible.

"others"
(1) The "-part", "-means", "-process" or "-step" referred to in the present specification can be interchangeably read. Thereby, the present invention can be grasped as both an invention of a product (coating film evaluation system, a coating film evaluation program, a coating film evaluation device (including a sensor), etc.) and an invention of a method (coating film evaluation method, etc.). .. In the program, each means and each step is executed by a computer.

(2) Unless otherwise specified, "x to y" in the present specification includes a lower limit value x and an upper limit value y. A range such as "a to b" may be newly established by using any numerical value included in the various numerical values or numerical ranges described in the present specification as a new lower limit value or upper limit value.

This is a database (example) showing changes in the dielectric loss tangent of a coating film over time. It is a schematic diagram which shows the structural example of the evaluation system of a coating film. It is a top view which shows typically the 2nd electrode (one example) in contact with a coating film. It is a processing flow (example) which constitutes the data group which concerns on the deterioration of a coating film. It is a schematic diagram which shows the application example of the evaluation system of a coating film. It is a scatter diagram which shows the frequency characteristic (example) of the dielectric loss tangent of the coating film formed on the steel sheet. It is a scatter diagram which shows the frequency characteristic (example) of the impedance of the coating film. It is a scatter diagram which shows the frequency characteristic (example) of the dielectric loss tangent of the coating film formed on the galvanized steel sheet. It is a scatter diagram which shows the frequency characteristic (example) of the impedance of the coating film.

One or more components arbitrarily selected from the present specification may be added to the components of the present invention described above. The contents described in the present specification may be appropriately applied not only to the coating film evaluation system but also to the coating film evaluation method, the coating film evaluation sensor and the like. Which embodiment is the best depends on the target, required performance, and the like.

<< Hypokeimenon >>
The substrate coated with the coating film (logger) may be made of metal or non-metal. The metal may be, for example, iron-based, aluminum-based, magnesium-based, titanium-based, or the like. As used herein, the term "~ system" means a pure metal or alloy. Typical examples of the substrate are steel plates (including plated steel plates) and aluminum alloy plates that constitute members and structures.

《Painting film》
The coating film is mainly composed of a non-conductive material (insulating material, dielectric material, etc.). The non-conductive material is, for example, a resin, an oil or fat, a ceramic or the like. The coating film may contain a particulate or fibrous filler (including pigments, additives, etc.). The type of paint that forms the coating film (presence or absence of solvent, type of solvent, etc.) does not matter.

The coating film may be a single layer or a plurality of layers (multilayer). The multi-layer is usually formed by applying paints of different types or components. For example, the coating film that covers the body of an automobile usually consists of at least three layers. Specifically, the panel (base) formed from a steel plate or the like is electrodeposited to ensure corrosion resistance, intermediate coating to ensure pitching resistance, light shielding, smoothness, etc., and designability. Topcoating and the like for ensuring weather resistance and the like are applied in order to form a multi-layered coating film. Incidentally, the panel before electrodeposition coating may be subjected to pretreatment such as chemical conversion treatment. In addition, the topcoat coating is usually a colored base coating and a transparent clear coating.

The logging subject to be evaluated may be a single layer or a plurality of layers. The coating film may be a plurality of layers, or the logging may be only one layer thereof, or two or more layers (including all layers). Logging is selected according to the purpose of evaluation.

"electrode"
Electrodes are provided on each surface side of the logging layer. The substrate (part) made of a conductive material may also serve as one electrode (first electrode). In the present specification, the substrate side is referred to as "first" and the opposite side (external environment side) is referred to as "second" with respect to the logging subject.

The electrode should be made of a material that has little effect on the dielectric properties and conductivity (impedance, etc.) of the logging subject. For example, the electrode may be made of a conductive material that is highly corrosion resistant (insoluble, sparingly soluble) or has a noble standard electrode potential. Specific electrode materials include stainless steel, Ti-based materials, noble metals (Pt, Au, Ag), oxide semiconductors, nictide conductive materials (Ti 3P _, FeTiP, XTiP (X: metal element), etc.).

However, the electrodes not exposed to the external environment may be iron-based, aluminum-based, or the like. This is the case where the substrate covered with the coating film (logger) is used as the first electrode, or the topcoat (upper layer) is formed on the second electrode arranged on the logging (lower layer).

The electrode may be in any form, but may be, for example, foil-shaped or thin plate-shaped. The second electrode on the external environment side is preferably breathable or liquid-permeable. As a result, the action (effect) of the external environment on the logging layer is suppressed from being blocked by the second electrode. That is, the deterioration of the logging under the second electrode can be appropriately evaluated. Such a second electrode may be, for example, porous (punching metal (foil), sintered body, etc.), mesh-like, or the like.

"measurement"
An alternating current of a specific frequency is applied between the electrodes, and the dielectric characteristics of the logging subject or the characteristic values that reflect the characteristics are measured (including when calculated or analyzed) according to the specific frequency.

(1) Dielectric characteristics include the permittivity (ε) when the logging object is regarded as a dielectric, and the capacitance (C) when the logging object and the electrode pairs on both sides thereof are regarded as a capacitor. The permittivity, capacitance, and the like usually have frequency characteristics (dependency) and may fluctuate depending on the frequency of the alternating current (electric field) to be energized. This is due to the delay in orientation (polarization) of the molecules constituting the dielectric, thermal vibration, leakage current (dielectric loss) generated between the electrodes of the capacitor, and the like.

Focusing on the permittivity, which is a typical example of the permittivity, the permittivity (ε) under AC energization is generally a complex permittivity (ε = ε'-iε ", i: imaginary unit, ε': real part, It is expressed by ε ": imaginary part). In addition, as characteristic values that reflect the dielectric characteristics, for example, dielectric loss tangent (tanδ), electrical modulus (M ^* = jwCo · Z ^* / M ^* and Z ^* : complex number, Z ^* : complex impedance, Co: vacuum Electric capacity) etc.

The dielectric loss tangent is obtained as the ratio (ε "/ ε') of the imaginary part (ε") to the real part (ε'). Here, the imaginary part (ε ") indicates the dielectric loss rate due to the polarization delay or the like. When viewed as a capacitor, the current flowing through the capacitor (capacitance: C) is Ic, and the current flows through the parasitic resistance (resistance value: r). The current: Ir, the angular frequency: ω = 2πf (f: AC frequency), and tan δ = Ir / Ic = 1 / ωrC can also be obtained. Thus, the dielectric positive contact is the heat lost with respect to the supplied electric energy. It indicates the ratio of energy. In other words, the dielectric density can be said to be an index of the deterioration of the insulating property of the dielectric and the deterioration of the coating film.

Incidentally, the measurement of the dielectric constant includes a (parallel electrode) capacitance method, a reflection transmission method, a resonance method and the like. A measuring method according to the frequency is appropriately selected, but in the case of the present invention, the capacitive method is usually sufficient.

(2) The evaluation index of the logging subject may be the dielectric property (dielectric constant, capacitance, etc.) itself, or the characteristic value (dielectric loss tangent, etc.) reflecting the dielectric property. That is, the "characteristic value" referred to in the present specification includes the dielectric property itself.

The molecular structure, morphology (for example, thickness), etc. of the logging test layer, which is at least a part of the coating film, changes (deteriorates) with time (aging), and the characteristic values of the logging test layer may also change reflecting this. .. If the characteristic value is used as an index, it is possible to grasp the change with time of the logging layer (and thus the coating film) from an early stage, as compared with the case where only the impedance is used as an index as in the conventional case.

At this time, if each characteristic value obtained by alternating current energization of at least two frequencies is used as an evaluation index, changes in the logging layer can be grasped more accurately. For example, the specific frequency includes the first frequency on the high frequency side and the second frequency on the low frequency side, and by the first characteristic value corresponding to the first frequency and the second characteristic value corresponding to the second frequency, or. Deterioration of the logging subject should be evaluated by the third characteristic value reflecting them.

The specific frequency may be selected in consideration of the composition, thickness, coating method, etc. of the logging object. If the specific frequency is too small, it takes a long time for each measurement. If the specific frequency is excessive, the change in characteristic values with respect to changes in logging can be small. The specific frequency may be selected, for example, in the range of 0.01 to 10000 Hz, 0.1 to 1000 Hz, and even 0.5 to 500 Hz.

The first frequency may be selected, for example, in the range of 10 to 1000 Hz, 30 to 500 Hz, and further 50 to 200 Hz. The second frequency may be selected, for example, in the range of 0.1 to 100 Hz, 1 to 50 Hz, and further 5 to 30 Hz.

The ratio (f1 / f2) of the first frequency (f1) to the second frequency (f2) may be, for example, about 1 to 100 or even about 5 to 50. Further, the difference (| f1-f2 |) between the first frequency (f1) and the second frequency (f2) may be, for example, about 10 to 1000 or even about 50 to 500.

"evaluation"
(1) The degree of deterioration of a logging subject is evaluated, for example, by comparing a characteristic value obtained for a specific frequency with a predetermined value. The comparison with the predetermined value may be made for each acquisition (measurement) of the characteristic value, or may be made as an average value of a plurality of characteristic values.

The degree of deterioration may be, for example, the degree of change in the state or morphology of the logging subject, or the remaining life (remaining life) in which the logging subject (and thus the coating film) can function.

(2) FIG. 1 schematically illustrates a case where the degree of deterioration of a logging is evaluated based on the dielectric loss tangent (tan δ / characteristic value) obtained corresponding to a specific frequency. In FIG. 1, a (t) indicates, for example, the change with time of the first characteristic value on the high frequency (first frequency) side, and b (t) indicates, for example, the second on the low frequency (second frequency) side. The change over time of the characteristic value is shown. Further, c (t) is a function c (a, b) derived from a (t) and b (t), and shows the change with time of the third characteristic value in which both are integrated. c (t) can be obtained, for example, as k · a (t) × b (t), m · a (t) + n · b (t) (k, m, n: coefficient).

It is considered that such a (t) and b (t) reflect the following changes with time of the coating film. As an example, considering a coating film exposed to the atmosphere, the coating film gradually absorbs moisture over time and then increases ionic conductivity in the coating film. Examples of ions conducted when energized include coating film components, H ⁺ , OH ⁻ , components taken in from the outside world (Cl, etc.) and the like.

Since a (t) monotonically increases until a certain point in time (t1) and then becomes saturated, it is considered that a (t) reflects the amount of water (moisture content) absorbed by the logging. .. The reason why such a tendency can be seen in the characteristic values on the high frequency side is considered to be an increase in the free volume of the resin due to the intrusion of water into the resin. Incidentally, usually, there is almost no change in appearance or impedance of the logging layer (coating film) near t1.

Since b (t) reaches its maximum (peak) at a certain point in time (t2), it is considered that it reflects the ionic conductivity in the logging. This is because the ion conductivity has water in the logging layer, and the binding (constraint) of the ions in the logging test layer decreases and increases with time. The reason why such a tendency can be seen in the characteristic values on the low frequency side is considered to be that the water content and the free volume in the resin are above a certain level, and the mobility of ions is increased. By the way, usually, the decrease in the impedance of the logging body begins to be remarkable in the vicinity of t2. For example, the impedance of the logging layer can be about 1/10 to 1/100 of the initial value, or ¹⁰⁹ Ω or less, and even ¹⁰⁸ Ω or less. It is considered that such a coating film not only has a deteriorated design (change in appearance) but also has a limit (that is, a life) in its environmental blocking ability (corrosion resistance, etc.). After that, it is considered that erosion (for example, rust and pitting corrosion) will occur on the substrate of the coating film.

As shown in FIG. 1, comparing a predetermined value obtained based on one or both of a (t) and b (t) prepared in advance, or c (t) derived from them, and an actually measured characteristic value. , The degree of deterioration of the logging (coating film) can be evaluated. For example, when the time (tx) corresponding to the actually measured characteristic value (x) is obtained from a database (c (t) or the like), the remaining life of the coating film can be obtained with t2-tx = J.

The selection of a (t), b (t), and c (t) to be used as a database may be made according to the purpose of evaluating the coating film. Further, depending on the components, morphology, etc. of the logging subject, a (t) described above indicates a change over time in the second characteristic value on the low frequency (second frequency) side, and b (t) indicates a high frequency (first frequency). It may show a change with time of the first characteristic value on the frequency) side.

"Data processing"
It is preferable that the characteristic value constitutes a data group together with the measurement time (time), the degree of deterioration, the environmental information indicating the measurement environment, and the like. This makes it possible to analyze the deterioration tendency of the coating film. Therefore, the system of the present invention may further include an analysis unit that analyzes the deterioration tendency of the logging subject based on the data group. The deterioration tendency is, for example, a change over time in the rate of progress of deterioration.

The environmental information may include information on the atmosphere (temperature, humidity, etc.) to which the coating film is exposed, as well as location information indicating the place or area to be measured. The position information is obtained from, for example, a Global Positioning System (GPS) or the like. When evaluating the deterioration of the coating film provided on a moving body (automobile or the like), the locus information of the car navigation may be used as the position information.

The storage and analysis of the data group may be performed on the substrate side where the sensor unit is located, or may be performed at a remote location with respect to the substrate. Therefore, the system of the present invention may further include a transmission unit that wirelessly transmits a data group to a remote location. The analysis result based on the data group may be utilized for the development research of the coating film, or may be returned to the substrate side as the remaining life of the coating film or the repair guidance.

The relationship between the dielectric properties of the coating film measured by applying alternating current and the deterioration of the coating film was clarified. The present invention will be described in more detail based on such a specific example.

"Constitution"
An outline of the coating film evaluation system S (simply referred to as “system S”) is shown in FIG. 2A. The system S includes a sensor unit d, a measuring device (measuring unit) connected to the sensor unit d, and an evaluation device (evaluation unit) for analyzing data obtained from the measuring device.

(1) The sensor unit d includes a logging layer p1 coated on the entire upper surface of the substrate e1 (first electrode), an electrode e2 (second electrode) provided on the opposite surface side thereof, a logging layer p1 and a logging layer p1. It has an upper layer p2 coated on the entire upper surface of the electrode e2 (the opposite surface side of the substrate e1). The substrate e1 and the electrode e2 are connected to the measuring device by wirings w1 and w2, respectively. The logging layer p1 and the upper layer p2 are collectively referred to as a coating film p. The electrode e2 is made of, for example, a metal foil in which a large number of penetrating small holes h are formed, as schematically shown in FIG. 2B.

In this embodiment, a cold-rolled steel sheet (SPCC) or a hot-dip galvanized steel sheet (SGCC) used for an automobile body was used as the substrate e1. The substrate e1 was 10 cm × 10 cm × t3 mm. The lower surface of the substrate e1 (the side opposite to the logging layer p1) was left unpainted after the wiring w1 was soldered.

A punching metal foil made of platinum (Pt) was used for the electrode e2. The electrode e2 has, for example, a width of 1 to 2 cm, a length of 15 to 20 cm, a thickness of 0.1 to 5 μm, a hole diameter of 0.2 to 0.5 cm, and a hole density of 3 to 9 pieces / cm ² . ..

The logging test layer p1 was formed by baking and painting an electrodeposition paint used for anticorrosion coating of an automobile body. A resin-based (epoxy) was used as the electrodeposition paint. The film thickness of logging p1 was 15 to 25 μm.

The upper layer p2 was formed by overcoating with a clear paint of an automobile body. A resin-based (acrylic) was used as the clear paint. The film thickness of the upper layer p2 was 50 to 100 μm.

(2) As a measuring device, an LCR meter (ModuLab manufactured by Solartron Analytical Co., Ltd.) capable of measuring the dielectric loss tangent (tan δ) of logging p1 and the impedance (Z) of logging p1 for each frequency was used.

In this example, the frequency characteristic of tan δ was measured in the range of 1 Hz to 103 Hz, and the frequency characteristic of | Z | was measured in the range of ^10-2 Hz to ¹⁰ Hz.

As an example of the specific frequency at the time of deterioration evaluation, f1: 100Hz (first frequency) and f2: 10Hz (second frequency) were selected. The reasons for selecting these frequencies will be described later. Measured value of tan δ obtained at f1 (first characteristic value): α (t), measured value of tan δ obtained at f2 (second characteristic value): β (t) at the elapsed time t from the start of measurement. And. The measurement was performed after a certain period of time.

(3) The evaluation device consists of a computer (personal computer, in-vehicle control device (ECU), etc.), and α (t) and β (t) acquired from the measuring device are compared with the databases a (t) and b (t). do. a (t) and b (t) are databases (functions) showing changes over time in tan δ at f1 and f2, respectively, for a coating film similar to logging p1. a (t) and b (t) were prepared in advance by the same measurement as α (t) and β (t). As shown in FIG. 1, the characteristic value γ (t) determined from α (t) and β (t) is compared with the database c (t) determined from a (t) and b (t). May be good.

The elapsed life (tx) at the time of actual measurement can be predicted by comparing the actually measured value with a predetermined value obtained from the database. The remaining life (J = t2-tx) is calculated from the difference between the elapsed life (tx) and the critical life (t2) on the database. In this way, deterioration evaluation of logging p1 becomes possible.

(4) FIG. 3 shows an example of a series of processing flows constituting the data group including the remaining life (J). In step S1, α (t) and β (t) at a certain time point (t) are measured. In step S2, the deterioration parameter γ (t) is further calculated from α (t) and β (t). In step S3, the remaining life (J) of the coating film is calculated by comparing γ (t) with the database c (t) prepared in advance corresponding to the deterioration parameter thereof. In step S4, a data group corresponding to the measurement time point (t) and the remaining life (J) is configured. In addition to the measurement time point (t) and remaining life (J), the data group includes characteristic values or deterioration parameters γ (t), environmental information indicating the measurement environment (temperature, humidity, light intensity, wet / dry state, etc.), and position. Information etc. should be included.

(5) An example of a coating film evaluation system in which a sensor unit is attached to an automobile (moving body) is schematically shown in FIG. The data group configured on the automobile side is transmitted from the automobile to a storage unit (cloud storage or the like) in a remote place, for example. An analysis unit (analysis center, etc.) in a remote location analyzes a series of data groups (big data) read from the storage unit to clarify the correlation between the usage environment of the automobile and the deterioration tendency of the coating film, and paints. Information on membrane life and repair is sent wirelessly to the car.

"Frequency characteristic"
(1) Measurement Using the sensor unit d described above, the frequency characteristics of the dielectric loss tangent (tan δ) and impedance (| Z |) of the logging layer p1 were measured. The measurement was carried out in a state where the upper layer p2 was in contact with a saline solution (concentration 1 mol / L), and the measurement was carried out at the initial stage (elapsed days 0 days), after 42 days, and after 84 days, respectively. When the substrate e1 also serving as the first electrode is a cold-rolled steel sheet (SPCC), tan δ and | Z | are shown in FIGS. 5A and 5B, respectively. When the substrate e1 is a hot-dip galvanized steel sheet (SGCC), tan δ and | Z | are shown in FIGS. 6A and 6B, respectively.

(2) Evaluation As can be seen from FIGS. 5A and 6A, it was found that there was a peak (extreme value) of tan δ between 10 and 100 Hz when 42 days had passed. This peak is not seen early. It was also found that when 84 days had passed, the peak declined and disappeared, and tan δ became saturated near 100 Hz (first frequency) on the high frequency side.

Considering the deterioration process of the coating film, tan δ near 100 Hz is considered to reflect the degree of water absorption (moisture content) into the logging layer p1.

Next, looking at tan δ after 84 days, tan δ rapidly increases on the low frequency side. Such a tendency is not seen at the beginning or after 42 days. Considering the deterioration process of the coating film, the increase in tan δ on the low frequency side is considered to reflect the increase in ionic conductivity after water content. Such a state is considered to be a stage where the deterioration of the coating film (logger p1) has progressed considerably. This is supported by the fact that the decrease in | Z | becomes remarkable after 84 days, as shown in FIGS. 5B and 6B.

Further, the rapid increase in tan δ due to the deterioration of the coating film occurs, for example, around 10 Hz (second frequency). By observing the tan δ near that frequency, the influence of the material of the substrate e1 that cannot be grasped from | Z | can be grasped. Therefore, in the case of this embodiment, 10 Hz can be mentioned as an index value in the low frequency range in which the ionic conductivity has a dominant influence on the characteristics of the coating film.

As described above, according to the present invention, it was found that the degree of deterioration (remaining life, etc.) of the coating film, which could not be grasped by the conventional AC impedance method, can be appropriately grasped.

S coating film evaluation system d sensor part p coating film p1 logging layer p2 upper layer e1 substrate (first electrode)
e2 2nd electrode

Claims (9)

A system that evaluates the deterioration of the coating film that covers the substrate.
A sensor unit having a first electrode in contact with one surface side of the logging object to be evaluated in at least a part of the coating film and a second electrode in contact with the other surface side of the logging object.
A measuring unit that applies an alternating current of a specific frequency between the first electrode and the second electrode to obtain a characteristic value that reflects the dielectric characteristics of the logging subject.
An evaluation unit that evaluates the degree of deterioration of the logging by comparing the characteristic value with a predetermined value,
A coating film evaluation system. The specific frequency includes at least a first frequency on the high frequency side and a second frequency on the low frequency side.
The coating film evaluation system according to claim 1, wherein the characteristic value reflects a first characteristic value corresponding to the first frequency and a second characteristic value corresponding to the second frequency. The coating film evaluation system according to claim 1 or 2, wherein the characteristic value is a dielectric loss tangent. The substrate is made of a conductive material and is made of a conductive material.
The coating film evaluation system according to any one of claims 1 to 3, wherein the first electrode is made of the base material. The coating film evaluation system according to any one of claims 1 to 4, wherein the second electrode has air permeability or liquid permeability. The coating film evaluation system according to any one of claims 1 to 5, wherein the logging test layer and the second electrode are overcoated. The coating film evaluation system according to any one of claims 1 to 6, wherein a data group including the characteristic value and / or the deterioration degree and environmental information indicating the measurement environment of the characteristic value is configured. The coating film evaluation system according to claim 7, further comprising a transmission unit that wirelessly transmits the data group. The coating film evaluation system according to claim 7 or 8, further comprising an analysis unit for analyzing the deterioration tendency of the logging subject based on the data group.

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