Method for measuring corrosion amount and method for selecting metal materials

Abstract

An electrical resistance type corrosion sensor (1) is mounted on the metal part (16) of a moving body (15). The corrosion sensor (1) is equipped with a sensor part (2) exposed to any environment and a reference part (3) isolated from any environment, and the conductors constituting the sensor part (2) and the reference part (3) are made of the same metal material as the metal material constituting the metal part (16). Based on the electrical resistance value of the reference part (3) and the electrical resistance value of the sensor part (2), the amount of corrosion of the sensor part (2) is measured. In this way, the amount of corrosion of the metal part (16) of the moving body (15) can be determined with good precision.

Description

Technology Field

[0001] The present invention relates to a method for measuring the amount of corrosion and a method for selecting a metal material. Background Technology

[0002] Moving bodies, such as automobiles, ships, aircraft, and heavy machinery, have a metal part composed of a metal material in at least a part thereof. The concept of a moving body also includes movable bodies such as cranes and belt conveyors (hereinafter the same).

[0003] The metal parts of a moving body are damaged or deteriorate over time. One of the causes of damage and deterioration is corrosion.

[0004] In order to use the mobile device safely and for a long period of time, it is important to determine the amount of corrosion (corrosion rate) of the metal parts of the mobile device under actual usage conditions.

[0005] As the moving body moves, the way sunlight reaches the metal parts of the moving body changes.

[0006] Due to this, the state of dryness and humidity, and the attachment and detachment of corrosive substances such as airborne salt, change in the metal parts of the moving body.

[0007] For this reason, the amount of corrosion on the metal parts of the moving body varies significantly depending on the movement of the moving body, the position of the metal parts on the moving body, etc.

[0008] As a technique for determining the amount of corrosion in the metal part of a moving body, for example, Patent Document 1 discloses: “a method for measuring the corrosion environment of a moving body, wherein at least one part of the moving body, at least a portion thereof is composed of a metal material, has two types of metal electrodes having different components and / or compositions, one of which is a metal material to be selected as a constituent component of the moving body material, and the other is made of the same metal different from the above and is also made of a metal having a noble electrochemical series with respect to the above, and at least one corrosion sensor is installed such that the gap between at least one set of electrodes is 0.1 to 5 mm separated by an insulator, and the current or potential difference between the electrodes caused by the electrodes being electrically short-circuited in a corrosive environment is measured continuously or intermittently, including during movement, and the installation location of the corrosion sensor includes the interior isolated from the outside of the moving body or the interior of a constituent part of the moving body” ([Claim 1]).

[0009] In Patent Document 1, an ACM type corrosion sensor (Non-patent Documents 1 to 2) is used. Prior art literature

[0010] Japanese Patent Publication No. 2009-53205

[0011] Zairyo-to-Kankyo, The Society of Corrosion Control, 2005, Vol. 54, No. 8, pp. 375-382 Zairyo-to-Kankyo, The Society of Corrosion Control, 2002, Vol. 51, No. 9, pp. 398-403 The problem to be solved

[0012] In an ACM (Atmospheric Corrosion Monitor) type corrosion sensor, the galvanic current flowing between two dissimilar metals exposed to a corrosive environment while insulated from each other is measured, and the amount of corrosion is calculated based on an experimental formula.

[0013] However, since corrosion proceeds due to the intertwining of various factors, the amount of corrosion obtained by an ACM-type corrosion sensor may not necessarily match the actual amount of corrosion sufficiently.

[0014] The present invention is made in consideration of the above points and aims to provide a method for measuring the amount of corrosion that can determine the amount of corrosion of a metal part of a moving body with good precision. means of solving the problem

[0015] The inventors, after careful consideration, discovered that the above objective is achieved by adopting the following configuration, and thus completed the present invention.

[0016] That is, the present invention provides the following [1] to

[10] .

[0017] [1] A corrosion sensor is mounted on the metal part of a moving body having a metal part made of a metal material, and the corrosion sensor is an electrical resistance type corrosion sensor having a sensor part made of a conductor that is exposed to any environment and a reference part made of a conductor that is shielded from the any environment, and the conductor is made of the same metal material as the metal material constituting the metal part, and the amount of corrosion of the sensor part is measured based on the electrical resistance value of the reference part and the electrical resistance value of the sensor part.

[0018] [2] The corrosion sensor described in [1] has an insulating sheet, and the reference portion contacts the metal portion with only the insulating sheet.

[0019] [3] A method for measuring the amount of corrosion described in [2] above, wherein the thermal transmittance of the insulation sheet is 25 kW / (m²·K) or higher.

[0020] [4] A method for measuring the amount of corrosion described in any one of [1] to [3], wherein the sensor part and the reference part are laminated with an insulator interposed therebetween.

[0021] [5] A method for measuring the amount of corrosion described in any one of [1] to [3], wherein the amount of corrosion of the sensor unit measured is obtained at a location away from the moving body by means of communication using a communication device.

[0022] [6] A method for measuring the amount of corrosion described in [4], wherein the amount of corrosion of the sensor unit measured is obtained at a location away from the moving body by means of communication using a communication device.

[0023] [7] A method for selecting a metal material that selects a metal material constituting the metal part based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in any one of [1] to [3] above.

[0024] [8] A method for selecting a metal material that selects a metal material constituting the metal part based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in [4] above.

[0025] [9] A method for selecting a metal material that selects a metal material constituting the metal part based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in [5] above.

[0026]

[10] A method for selecting a metal material that selects a metal material constituting the metal part based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in [6] above. Effects of the invention

[0027] According to the present invention, the amount of corrosion of the metal part of a moving body can be determined with good precision. Brief explanation of the drawing

[0028] FIG. 1 is a plan view schematically showing a corrosion sensor of a first embodiment. Figure 2 is a cross-sectional view of line AA of Figure 1. FIG. 3 is a plan view schematically showing a corrosion sensor of a second embodiment. Figure 4 is a cross-sectional view of the BB line of Figure 3. FIG. 5 is a cross-sectional view of a corrosion sensor to explain the connection state with a current source and a voltage measuring unit. Figure 6 is a drawing showing the state in which a corrosion sensor (1) is mounted on the metal part of the moving body. Specific details for implementing the invention

[0029] [Method for Measuring Corrosion Level]

[0030] The method for measuring the amount of corrosion according to the present invention is described below. In addition, the following description also serves as a description of the method for selecting a metal material according to the present invention.

[0031] In the method for measuring the amount of corrosion according to the present invention, first, an electrical resistance type corrosion sensor is mounted on the metal part of a moving body. Here, the corrosion sensor comprises a sensor part exposed to an arbitrary environment and a reference part isolated from the arbitrary environment, and the conductors constituting the sensor part and the reference part are made of the same metal material as the metal material constituting the metal part of the moving body. Then, the amount of corrosion of the sensor part is measured based on the electrical resistance value of the reference part and the electrical resistance value of the sensor part.

[0032] In the present invention, the conductor of the corrosion sensor is made of the same metal material as the metal part of the moving body, and the amount of corrosion is determined directly from the electrical resistance value without using an experimental formula. Therefore, the amount of corrosion of the metal part of the moving body can be determined with good precision.

[0033] <Corrosion Sensor>

[0034] First, the basic configuration of the electrical resistance type corrosion sensor used in the present invention will be explained based on FIGS. 1 to 2 (first embodiment) and FIGS. 3 to 5 (second embodiment).

[0035] However, the corrosion sensors that can be used in the present invention are not limited to the following embodiments.

[0036] 《First Embodiment》

[0037] FIG. 1 is a plan view schematically showing a corrosion sensor (1) of a first embodiment. FIG. 2 is a cross-sectional view along line AA of FIG. 1.

[0038] An electric resistance type corrosion sensor (1) has a sensor part (2) that is exposed to any environment and a reference part (3) that is blocked from any environment to which the sensor part (2) is exposed.

[0039] The sensor part (2) and the reference part (3) are both made of a conductor and are arranged in parallel on one side of a flat insulating sheet (4).

[0040] The “any environment” to which the sensor part (2) is exposed is a concept that includes various environments, including the “corrosive environment” in which the sensor part (2) is corroded.

[0041] That is, the corrosion sensor (1) can be used in a corrosive environment where the sensor part (2) is corroded, as well as in an environment where the sensor part (2) is not corroded.

[0042] As shown in FIG. 2, the cross-section of the sensor part (2) and the reference part (3) is a rectangle (including a square) having a predetermined thickness. Both sides of the sensor part (2) and the reference part (3) are covered with an insulating resin (5), and the upper surface of the reference part (3) is also covered with an insulating cover (6).

[0043] That is, as shown in FIG. 2, when the corrosion sensor (1) is viewed in cross-section, both sides and the top and bottom surfaces of the rectangular reference portion (3) are covered by each member. Because of this, even if the corrosion sensor (1) is in a corrosive environment, the reference portion (3) is shielded from this corrosive environment.

[0044] Meanwhile, the upper surface of the sensor part (2) is not covered by the cover (6).

[0045] That is, as shown in FIG. 2, when the corrosion sensor (1) is viewed in cross-section, both sides and the bottom of the rectangular sensor part (2) are covered by each member, but the top surface is exposed.

[0046] Because of this, when the corrosion sensor (1) is in a corrosive environment, the upper surface of the sensor part (2) is exposed to this corrosive environment. The sensor part (2), whose upper surface is exposed to the corrosive environment, undergoes corrosion in the thickness direction (the direction from the upper surface side to the lower surface side).

[0047] Next, each part of the corrosion sensor (1) will be described in more detail.

[0048] (Insulation sheet)

[0049] As described below, it is desirable to match the temperature of the reference portion (3) of the corrosion sensor (1) with the temperature of the metal portion (16) of the moving body (15) (see FIG. 6).

[0050] For this reason, when mounting the corrosion sensor (1) on the metal part (16), it is preferable to bring the reference part (3) (and sensor part (2)) into contact with the metal part (16) by interposing only the insulating sheet (4).

[0051] The material of the insulating sheet (4) is not particularly limited as long as it is a material that is not electrically connected to the reference part (3) and the sensor part (2) and the metal part (16) of the moving body (15), and examples include glass, ceramics, plastic (synthetic resin), natural resin, etc.

[0052] It is preferable that the insulating sheet (4) has good thermal conductivity, that is, high thermal conductivity (high thermal conductivity).

[0053] Specifically, the thermal conductivity of the insulating sheet (4) is preferably 0.3 W / (m·K) or higher, more preferably 0.5 W / (m·K) or higher, and even more preferably 1.0 W / (m·K) or higher. The thermal conductivity of the insulating sheet (4) may be 3.0 W / (m·K) or higher.

[0054] Meanwhile, the upper limit is not specifically limited, and the thermal conductivity of the insulating sheet (4) may be, for example, 100.0 W / (m·K) or less, 50.0 W / (m·K) or less, 30.0 W / (m·K) or less, or 10.0 W / (m·K) or less.

[0055] As a material for such an insulating sheet (4), polyimide is preferably used, for example.

[0056] The thickness of the insulating sheet (4) (length in the vertical direction in FIG. 2) should be sufficient to insulate the reference part (3) and the sensor part (2) from the metal part (16), for example, 5 μm or more, and preferably 10 μm or more.

[0057] Meanwhile, in terms of obtaining good thermal conductivity, the thickness of the insulating sheet (4) is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less.

[0058] For the reason that the temperature of the reference part (3) and the temperature of the moving body (15) (metal part (16)) are likely to coincide, the thermal transmittance of the insulating sheet (4) is preferably 25 kW / (m²·K) or higher, more preferably 40 kW / (m²·K) or higher, even more preferably 70 kW / (m²·K) or higher, and most preferably 100 kW / (m²·K) or higher. The upper limit is not particularly limited, and the higher the value of the thermal transmittance, the more desirable it is.

[0059] In addition, the thermal transmittance of the insulating sheet (4) is obtained by dividing the thermal conductivity (unit: kW / (m·K)) of the insulating sheet (4) by the thickness (unit: m) of the insulating sheet (4).

[0060] (profit)

[0061] The material of the resin (5) is not particularly limited and can use conventionally known materials, such as epoxy resin, phenolic resin, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, etc.

[0062] The thickness of the resin (5) is equal to the thickness of the sensor part (2) and the reference part (3).

[0063] (sleeve)

[0064] The material of the cover (6) is not particularly limited and can use conventionally known materials, such as rubber, paint, etc., and a weather-resistant material is preferred.

[0065] The thickness of the cover (6) is not particularly limited, but, for example, 0.1 to 10 mm.

[0066] (Sensor section and reference section)

[0067] The conductors constituting the sensor part (2) and the reference part (3) are made of the same metal material as the metal material constituting the metal part (16) (see FIG. 6) of the moving body (15).

[0068] Examples of such metal materials include iron or iron alloys.

[0069] The iron content in the iron alloy is preferably 90 mass% or more. Elements other than iron contained in the iron alloy may include, for example, at least one element selected from the group consisting of carbon, silicon, manganese, phosphorus, and sulfur; and elements that improve corrosion resistance, such as copper and nickel.

[0070] The shape of the conductor constituting the sensor part (2) and the reference part (3) is preferably a long shape having a constant length, and, for example, as shown in FIG. 1, a meandering shape that bends at regular intervals can be used.

[0071] The sensor part (2) and the reference part (3) may be a continuous series of long conductors, for example, as shown in FIG. 1.

[0072] The length (total length) of the sensor part (2) is preferably 30 mm or more, and more preferably 100 mm or more. Meanwhile, the length (total length) of the sensor part (2) is preferably 500 mm or less, and more preferably 400 mm or less.

[0073] As shown in FIG. 2, when the sensor part (2) is viewed in cross-section, the width of the sensor part (2) (distance in the left-right direction in FIG. 2) is preferably 4 mm or more, and more preferably 5 mm or more, from the perspective of averaging out and mitigating the effect of a sudden increase in electrical resistance even if local deep corrosion occurs on the upper surface (surface) of the sensor part (2).

[0074] Meanwhile, the width of the sensor part (2) is preferably 15 mm or less, more preferably 12 mm or less, and even more preferably 10 mm or less, as if it is too wide, the electrical resistance becomes too small and it becomes difficult to measure with high precision.

[0075] The thickness of the sensor part (2) (distance in the vertical direction in FIG. 2) is preferably 50 μm or more and more preferably 100 μm or more from the perspective of ease of processing the conductor when processing the conductor to obtain the sensor part (2).

[0076] Meanwhile, the thickness of the sensor part (2) is preferably 1000 μm or less, and more preferably 600 μm or less, from the perspective of improving the measurement precision of the corrosion sensor (1).

[0077] The shape of the reference part (3) is preferably the same as the shape of the sensor part (2). This eliminates the need to correct for the difference in electrical resistance values ​​caused by the difference in shape with the sensor part (2).

[0078] These numerical ranges for the sensor part (2) and the reference part (3) are determined, for example, from the perspective of the measurement precision of the corrosion sensor (1), and from the perspective of the convenience of handling the corrosion sensor (1), the amount of corrosion, and the type of corrosion.

[0079] (Current source and voltage measuring section)

[0080] As described above, the sensor part (2) and the reference part (3) may be a continuous series of conductors.

[0081] In that case, a current source (7) is connected to both ends of a series of conductors constituting the sensor part (2) and the reference part (3), a voltage measuring part (8) is connected to both ends of the sensor part (2), and a voltage measuring part (9) is connected to both ends of the reference part (3).

[0082] By flowing a constant current from the current source (7) and measuring the voltage at the voltage measuring unit (8) and the voltage measuring unit (9), the respective electrical resistance values ​​of the sensor unit (2) and the reference unit (3) are obtained.

[0083] Then, as described below, the amount of corrosion of the sensor part (2) is calculated based on the obtained electrical resistance value.

[0084] (Logger)

[0085] It is preferable that the corrosion sensor (1) additionally be equipped with a logger (11) (see FIG. 6).

[0086] The logger (11) drives the current source (7) at arbitrary intervals, for example, to flow a constant current, measures the voltage in the voltage measuring unit (8) and the voltage measuring unit (9), obtains the electrical resistance values ​​of the sensor unit (2) and the reference unit (3), and calculates the amount of corrosion of the sensor unit (2) based on the obtained electrical resistance values.

[0087] And, the logger (11) can record data such as the amount of corrosion produced.

[0088] (Communication device)

[0089] It is preferable that the corrosion sensor (1) additionally be equipped with a communication device (12) (see FIG. 6).

[0090] Various data recorded in the logger (11) is uploaded to the cloud, etc. by communication using a communication device (12).

[0091] 《Second Embodiment》

[0092] Next, the corrosion sensor (21) of the second embodiment will be described based on FIGS. 3 to 5. The same reference numerals are used for parts identical to those described in FIGS. 1 to 2 of the first embodiment, and descriptions are omitted.

[0093] FIG. 3 is a schematic plan view showing a corrosion sensor (21) of a second embodiment. FIG. 4 is a cross-sectional view along the BB line of FIG. 3, showing an enlarged view of the vicinity of the sensor part (2) and the reference part (3).

[0094] As shown in FIG. 4, a reference portion (3) made of a conductor is placed on an insulating sheet (4). On one side opposite to the insulating sheet (4) in the reference portion (3), a sensor portion (2) made of a conductor is placed with an insulator (10) interposed therebetween. That is, the sensor portion (2) and the reference portion (3) are laminated with an insulator (10) interposed therebetween.

[0095] The material of the insulator (10) is not particularly limited as long as it is a material that does not electrically connect the sensor part (2) and the reference part (3), and examples include glass, ceramics, plastic (synthetic resin), natural resin, etc.

[0096] Since a temperature difference is likely to occur between the sensor part (2) and the reference part (3) if the thermal conductivity of the insulator (10) is poor, it is desirable to select a material with as high a thermal conductivity as possible.

[0097] If the insulator (10) is too thick, its thermal conductivity is likely to be poor, and if it is too thin, it is likely to be electrically short-circuited.

[0098] The preferred thickness of the insulator (10) varies depending on the material, for example, when the insulator (10) is a plastic film such as polyvinyl chloride, polyethylene, or polypropylene, 5 to 200 μm is preferred.

[0099] It is desirable to ensure that the insulator (10), the sensor part (2), and the reference part (3) are in close contact so that no gap occurs between them. This is because if a gap occurs, thermal conductivity is likely to be impaired.

[0100] For this reason, it is desirable to compress the insulator (10), the sensor part (2), and the reference part (3) with sufficient force, or to bond them using a thermally conductive adhesive. When bonding, it is desirable to clean the bonding surface thoroughly so that no contaminants or dust remain.

[0101] FIG. 5 is a cross-sectional view of a corrosion sensor (21) to explain the connection state with a current source (7) and a voltage measuring unit (8).

[0102] As shown in FIG. 5, a voltage measuring unit (8) is connected to terminal (2a) at one end and terminal (2b) at the other end of the sensor unit (2), and a voltage measuring unit (9) is connected to terminal (3a) at one end and terminal (3b) at the other end of the reference unit (3).

[0103] Along with the terminal (2b) of the sensor part (2) and the terminal (3b) of the reference part (3) being electrically connected, a current source (7) is connected to the terminal (2a) of the sensor part (2) and the terminal (3a) of the reference part (3).

[0104] In the following description, unless otherwise specifically mentioned, "corrosion sensor (21)" is also referred to as "corrosion sensor (1)" for convenience.

[0105] A corrosion sensor (1) of this type is mounted on the metal part (16) of the moving body (15).

[0106] <Moving Object (Installation of Corrosion Sensor on Moving Object)>

[0107] FIG. 6 is a drawing showing a state in which a corrosion sensor (1) is mounted on a metal part (16) of a moving body (15). FIG. 6 shows the case where the moving body (15) is a vehicle. However, the moving body (15) is not limited to a vehicle, and may include, for example, a ship, an aircraft, heavy equipment, etc. Additionally, the moving body (15) includes movable bodies such as a crane, a belt conveyor, etc.

[0108] At least part of the moving body (15) is a metal part (16) made of a metal material. If the moving body (15) is a car, the metal part (16) is, for example, the body of the car.

[0109] Here, consider the case where there is a heat source other than the atmosphere (e.g., direct sunlight) as a heat source that imparts a temperature change to the metal part (16) of the moving body (15).

[0110] The heat capacity of the metal part (16) affects the temperature change of the metal part (16). Because of this, the temperature change of the corrosion sensor (1), which is smaller than the moving body (15) (metal part (16)), is different from that of the metal part (16). The temperature affects the speed of the corrosion reaction and the wetting and drying of the water film required for the corrosion reaction.

[0111] For this reason, in order to improve the measurement precision of the corrosion sensor (1), it is desirable to match the temperature of the corrosion sensor (1) with the temperature of the moving body (15).

[0112] Specifically, it is desirable to match the temperature of the reference part (3) of the corrosion sensor (1) with the temperature of the metal part (16) of the moving body (15).

[0113] Therefore, when mounting the corrosion sensor (1) on the metal part (16), it is preferable to bring the reference part (3) into contact with the metal part (16) by interposing only the insulating sheet (4).

[0114] In this case, in reality, the insulating sheet (4) and the metal part (16) are bonded using an adhesive, or the insulating sheet (4) and the metal part (16) are bonded together with grease and then the surrounding area is hardened with a sealant. In this way, the corrosion sensor (1) is fixed to the metal part (16).

[0115] In other words, in reality, an adhesive or grease may also be interposed between the reference part (3) and the metal part (16), in addition to the insulating sheet (4).

[0116] However, even so, in the present invention, the reference portion (3) of the corrosion sensor (1) is considered to be in contact with the metal portion (16) of the moving body (15) through only the insulating sheet (4).

[0117] The thermal conductivity of the adhesive and grease is preferably 1.0 W / (m·K) or higher.

[0118] In addition, when bonding parts of the corrosion sensor (1) together (for example, bonding the reference part (3) and the insulating sheet (4)), it is preferable to use the same adhesive.

[0119] The number of corrosion sensors (1) mounted on the moving body (15) is at least one, and may be two or more.

[0120] For example, even if the same moving body (15) is used, the amount of corrosion may vary depending on the location of the metal part (16). In that case, a plurality of corrosion sensors (1) are installed on one moving body (15).

[0121] In addition, to increase measurement precision, a plurality of corrosion sensors (1) may be mounted on one moving body (15).

[0122] Depending on the shape of the moving body (15), the range in which the corrosion sensor (1) can be installed may be narrow.

[0123] In that case, compared to the corrosion sensor (1) of the first embodiment in which the sensor part (2) and the reference part (3) are arranged in parallel (Figs. 1 to 2), the corrosion sensor (21) of the second embodiment in which the sensor part (2) and the reference part (3) are stacked is preferred because the contact area with the metal part (16) is smaller.

[0124] <Measurement of Corrosion Level>

[0125] In a corrosion sensor (1) mounted on a moving body (15), a constant current is flowed from a current source (7), and the voltage is measured at a voltage measuring unit (8) and a voltage measuring unit (9), thereby obtaining the respective electrical resistance values ​​of the sensor unit (2) and the reference unit (3). The magnitude of the constant current can be arbitrarily set, for example, from the required measurement precision and power amount.

[0126] As corrosion of the sensor part (2) progresses, the electrical resistance value of the sensor part (2) gradually increases from the original value.

[0127] On the other hand, corrosion of the reference part (3) does not progress, and the electrical resistance value of the reference part (3) basically remains unchanged from the original value.

[0128] The reason why the progression of corrosion of the sensor part (2) and the increase in electrical resistance value are related is generally thought to be as follows.

[0129] The conductor constituting the sensor part (2) is thinned in the thickness direction as corrosion progresses. The thinned conductor is either lost from the surface or replaced by corrosion products and remains on the surface.

[0130] This corrosion product is an insulator, or even if it is a conductor, its conductivity is very low compared to the original conductor.

[0131] Consequently, the increase in electrical resistance value due to corrosion is considered to be due to thinning of the conductor constituting the sensor part (2).

[0132] The electrical resistance values ​​of the sensor part (2) and the reference part (3) are obtained at arbitrary intervals, and the amount of corrosion (corrosion depth) of the sensor part (2) is calculated (converted) based on the obtained electrical resistance values. The conversion formula for the amount of corrosion is represented by the following formula (1).

[0133] CD = t i {(R ri / R si ) - (R r / R s )} … (1)

[0134] CD : Amount of corrosion (deepest corrosion) [㎛]

[0135] t i : Original thickness of the sensor part [㎛]

[0136] R ri : Original electrical resistance value of the reference section [Ω]

[0137] Rsi : Initial electrical resistance value of the sensor [Ω]

[0138] R r : Electrical resistance value [Ω] when measuring the reference part

[0139] R s : Electrical resistance value [Ω] during measurement of the sensor part

[0140] Based on the above equation (1), the amount of corrosion is calculated under assumption.

[0141] For example, the initial thickness of both the reference part (3) and the sensor part (2) is “100 μm”, and the initial electrical resistance value (R) of the reference part (3) ri The original electrical resistance value (R) of the ) and the sensor part (2) si All of these are "0.1 Ω", and also the electrical resistance value (R) at the time of measurement of the reference part (3) r ) is an unchanging “0.1 Ω” from the beginning, but on the other hand, as corrosion of the sensor part (2) progresses, the electrical resistance value (R s When this is increased to “0.11 Ω”, the amount of corrosion is calculated as “9.1 μm” from the above equation (1) as 100 × {(0.1 / 0.1) - (0.1 / 0.11)}.

[0142] <Temperature compensation, etc.>

[0143] In the corrosion sensor (1), it is also desirable to compensate for the temperature.

[0144] That is, when the electrical resistance value of the reference part (3) changes, it is desirable to correct the amount of corrosion measured based on this change, assuming that this change is caused by a change in temperature.

[0145] Generally, the electrical resistivity of metals increases as the temperature rises.

[0146] For example, in the above assumption, the temperature has risen compared to the original, and the electrical resistance value (R) of the sensor part (2) at the time of measurement s) It is assumed that this is not "0.11 Ω", but "0.121 Ω", which is a 10% increase.

[0147] In this case, if calculated from the above equation (1) as 100 × {(0.1 / 0.1) - (0.1 / 0.121)}, the amount of corrosion becomes “17 μm”, which is significantly different from the original amount of corrosion “9.1 μm”.

[0148] However, at this time, for example, the electrical resistance value (R) of the reference part (3) r Likewise, if the value changes from "0.1 Ω" to "0.11 Ω" (a 10% increase) due to a rise in temperature, the amount of corrosion can be corrected based on this change.

[0149] That is, the amount of corrosion is calculated as “9.1 μm” from the above equation (1) as 100 × {(0.1 / 0.1) - (0.11 / 0.121)}, and the same result as in the case where there is no change in temperature is obtained.

[0150] As described above, by matching the temperature of the reference part (3) with the temperature of the metal part (16), the effectiveness of the temperature compensation is further increased.

[0151] The entity responsible for measuring the amount of corrosion and performing temperature compensation described above is not specifically limited, but, for example, a logger (11) can be cited.

[0152] The logger (11), for example, calculates the amount of corrosion of the sensor unit (2) while compensating for the temperature, and records data such as the calculated amount of corrosion.

[0153] Various data, such as the amount of corrosion recorded in the logger (11), are uploaded to the cloud, etc., by communication using a communication device (12).

[0154] The user of the corrosion sensor (1) can determine the amount of corrosion of the sensor part (2), etc., at any time, even if they are at any location away from the moving object (15), by downloading the uploaded data.

[0155] The user of the corrosion sensor (1) can use the detected amount of corrosion for various purposes.

[0156] For example, the moving body (15) can be maintained so that during the assumed usage period of the moving body (15), the amount of corrosion does not exceed the corrosion zone of the metal part (16) (the amount of corrosion that is permissible in the metal part (16)).

[0157] In addition, based on the amount of corrosion identified, the metal material of the metal part (16) may be selected so that the amount of corrosion does not exceed the corrosion zone of the metal part (16) during the assumed usage period of the movable body (15).

[0158] Examples

[0159] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples described below.

[0160] Tests were conducted under the conditions shown in Table 1 below. Specifically, as described below, a corrosion sensor was mounted on a moving body to measure the amount of corrosion.

[0161] <Moving Body>

[0162] First, four types of moving bodies (including movable bodies) having metal parts were selected: automobiles, heavy machinery, cranes, and belt conveyors. The types of selected moving bodies are shown in Table 1 below.

[0163] In addition, the metal parts of automobiles, heavy machinery, and cranes are their respective bodies. The metal part of a belt conveyor is the belt (conveyor belt).

[0164] <Corrosion Sensor>

[0165] A corrosion sensor was installed on the metal part of the selected mobile body. One corrosion sensor was installed for each mobile body.

[0166] 《No. 1 ~ 20: Electric Resistance Corrosion Sensors》

[0167] In No. 1 to 20, an electric resistance type corrosion sensor (21) of the second embodiment (Figs. 3 to 5) was used as a corrosion sensor.

[0168] (No. 1 ~ 5 and 7 ~ 20)

[0169] More specifically, referring to FIGS. 3 to 5, a reference portion (3) is placed on an insulating sheet (4) made of polyimide (thickness: 25 μm, thermal conductivity: 1.0 W / (m·K), thermal transmittance: 40 kW / (m²·K)).

[0170] On the insulating sheet (4), a resin (5), which is an epoxy resin, was spread evenly and completely over the thickness of the reference portion (3), covering both sides of the reference portion (3).

[0171] On top of that, an insulator (10) (polyvinyl chloride, thickness: 100 μm), which is a plastic film, is placed, and a sensor part (2) is placed so as to overlap with a reference part (3) by interposing the insulator (10).

[0172] On the insulator (10), a resin (5), which is an epoxy resin, was spread evenly and completely without gaps to the thickness of the sensor part (2), covering both sides of the sensor part (2).

[0173] For the conductor (metal material) constituting the sensor part (2) and the reference part (3), a long conductor (total length: 200 mm, width: 10 mm, thickness: 200 μm) was used, and the same metal material as the metal part of the target moving body (body of a car, etc.) was used.

[0174] The insulating sheet (4) of such a corrosion sensor (21) was bonded to the metal part of the target moving body (such as the body of a car) using a high thermal conductivity adhesive (thermal conductivity: 2.1 W / (m·K)).

[0175] (No.6)

[0176] A corrosion sensor (21) (Figs. 3 to 5) was manufactured in the same manner as No. 1 to 5 and 7 to 20, except that an insulating sheet (4) (thickness: 25 μm, thermal transmittance: 12 kW / (m²·K)) with a thermal conductivity of 0.3 W / (m·K) was used, and the sensor was attached to the metal part of the moving body.

[0177] In addition, in the column for “thermal conductivity of insulation sheet” in Table 1 below, “low” was written for No. 6, and “-” was written for other examples.

[0178] No. 21 ~ 30

[0179] As a corrosion sensor, one of the following was used: an ACM type corrosion sensor, a corrosion sensor based on the electrochemical impedance method (EIS), and a quartz crystal microbalance (QCM) type corrosion sensor.

[0180] For the measurement of the amount of corrosion using an ACM type corrosion sensor, refer to non-patent literature 1 to 2.

[0181] Direct sunlight

[0182] The metal part of the moving body has a part that is exposed to direct sunlight, which is a heat source other than the atmosphere, and a part that is not exposed to it. If the corrosion sensor is mounted in the part exposed to direct sunlight, "Yes" is indicated, and if the corrosion sensor is mounted in the part not exposed to direct sunlight, "-" is indicated in the "Heat Source" column of Table 1 below.

[0183] Temperature Synchronization

[0184] In the case where an electric resistance type corrosion sensor is used, if the reference part of the corrosion sensor is mounted by contacting the metal part of the moving body with only an insulating sheet interposed, "Yes" is indicated in the "Temperature Synchronization" column of Table 1 below.

[0185] Meanwhile, if a spacer (stainless steel plate “SUS304”, thickness: 2 mm) is placed between the insulating sheet and the metal part of the moving body, “-” is indicated in the “Temperature Synchronization” column of Table 1 below.

[0186] In addition, "-" was indicated for cases where a corrosion sensor other than an electric resistance type was used.

[0187] <environment>

[0188] The corrosive environment of the mobile body was set to the atmosphere in all cases. However, the usage area of ​​the mobile body was varied in each example.

[0189] In the case where the mobile body was used in area A with low flying salt content, "low flying salt" was indicated; in the case where it was used in area B with higher flying salt content than area A, "high flying salt" was indicated; and in the case where it was used in a cold snowy area where melting salt is dispersed, "melting salt" was indicated in the "Environment" column of Table 1 below.

[0190] In addition, "+ soil" was added to the "Environment" column in Table 1 below when the mobile body was used in a situation where it came into contact with soil, and "+ coal" was added when it came into contact with coal.

[0191] <period>

[0192] The test period was set to approximately 3 months (between 89 and 105 days).

[0193] <Corrosion Amount (Sensor)>

[0194] After the test period, the amount of corrosion (unit: μm) was measured by a corrosion sensor mounted on the metal part of the moving body. When an electrical resistance type corrosion sensor was used, the amount of corrosion of the sensor part was measured. The measured amount of corrosion was recorded in the “Sensor” column of “Amount of Corrosion” in Table 1 below.

[0195] <Corrosion Amount (Test Specimen)>

[0196] To compare with the amount of corrosion from the corrosion sensor, a test specimen described below was mounted on the metal part of the moving body in close proximity to the corrosion sensor and subjected to corrosion during the test period. After the test period had elapsed, the amount of corrosion of the test specimen was determined.

[0197] Ideally, the amount of corrosion on the metal parts of the moving body should be measured in person; however, since it is difficult to determine this non-destructively, a test specimen was used instead to determine the amount of corrosion.

[0198] A cold-rolled steel sheet (SPC material) measuring 150 mm × 70 mm × 0.8 mm was fitted to the automobile as a test specimen.

[0199] As test specimens, 150 mm × 70 mm × 0.8 mm welded structural rolled steel (SM material) was fitted to the heavy equipment, crane, and belt conveyor.

[0200] The amount of corrosion of the test specimen was determined in accordance with ISO 8407.

[0201] Specifically, after the test period, rust on the test specimen was removed using a pickling solution prepared by adding 3.5 g of hexamethylenetetramine to 500 mL of hydrochloric acid and mixing it to 1000 mL, and the amount of corrosion (unit: μm) was calculated from the difference in mass before and after the test.

[0202] The calculated amount of corrosion was recorded in the “Test Specimen” column of “Amount of Corrosion” in Table 1 below.

[0203] <error>

[0204] The amount of corrosion obtained using a corrosion sensor and the error (unit: %) of the amount of corrosion of the test specimen were calculated.

[0205] The smaller the absolute value of the error, the better the precision of the corrosion amount obtained using the corrosion sensor can be evaluated. In particular, if the absolute value of the error is 10% or less, the precision can be evaluated as even better.

[0206] [Table 1]

[0207]

[0208] [Table 1 continued]

[0209]

[0210] <Summary of Evaluation Results>

[0211] As shown in Table 1 above, No. 1 to 20 (Inventive Examples) using an electric resistance type corrosion sensor had a smaller absolute value of error than No. 21 to 30 (Comparative Examples) using other corrosion sensors, so it can be said that the amount of corrosion of the metal part of the moving body could be determined with good precision.

[0212] Among No. 1 to 20, No. 11 to 12 (an example where "direct sunlight" is "yes" but "temperature synchronization" is "-") had an absolute value of error exceeding 10%.

[0213] In this regard, No. 1 to 10 and 13 to 20 had better precision, with an absolute value of error of 10% or less.

[0214] In addition, when comparing No. 5 and No. 6 among No. 1 to 20, in which only the thermal conductivity of the insulating sheet differs, No. 5, which has a higher thermal conductivity of the insulating sheet, had a smaller absolute value of error than No. 6, which has a lower thermal conductivity of the insulating sheet, and thus had better precision.

[0215] The corrosion amount of No. 21 to 25, using an ACM type corrosion sensor, showed a tendency to be larger overall than the corrosion amount of the test specimen.

[0216] In particular, the corrosion amount of No. 23 to 24, which was tested under conditions of contact with coal, deviated significantly from the corrosion amount of the test specimen. This is thought to be due to the fact that the coal dust accumulated on the ACM-type corrosion sensor retained moisture caused by rainfall, etc., resulting in a high output throughout the test period.

[0217] Similar to Nos. 26 to 28, which used an EIS-based corrosion sensor, and Nos. 21 to 25, which used an ACM-type corrosion sensor, the absolute value of the error was large, so the precision was insufficient.

[0218] No. 29 to 30, which used QCM type corrosion sensors, were practically unable to measure the amount of corrosion. Since QCM type corrosion sensors are based on the principle of using a thin film for measurement, it is thought that under the test conditions, the amount of corrosion exceeded the thickness of this thin film.

[0219] <Chusi : No.5b>

[0220] A test to measure the amount of corrosion was conducted in the same manner as No. 5, except that 10 corrosion sensors were installed on one mobile body (heavy-duty machine) (for convenience, it is referred to as “No. 5b”).

[0221] Similar to No. 5, 10 corrosion sensors were installed on the parts of the moving body exposed to direct sunlight.

[0222] As a result, the error between the amount of corrosion obtained using the corrosion sensor and the amount of corrosion of the test specimen became 1.8%, which is more accurate than No. 5. Explanation of the symbols

[0223] 1: Corrosion sensor (First embodiment) 2 : Sensor section 2a: Terminal of the sensor part 2b : Terminal of the sensor part 3 : Reference 3a : Terminal of the reference section 3b : Terminal of the reference section 4: Insulation sheet 5 : Suzy 6 : Cover 7 : Current source 8: Voltage measuring section 9: Voltage measuring section 10: Insulator 11 : Logger 12: Communication devices 15 : Mobile body 16 : Metal part 21: Corrosion sensor (Second embodiment)

Claims

Claim 1 A method for measuring the amount of corrosion, wherein a corrosion sensor is mounted on the metal part of a movable body having a metal part composed of a metal material, and the corrosion sensor is an electrical resistance type corrosion sensor comprising a sensor part composed of a conductor exposed to any environment and a reference part composed of a conductor isolated from said any environment, wherein the conductor is made of the same metal material as the metal material constituting the metal part, and the amount of corrosion of the sensor part is measured based on the electrical resistance value of the reference part and the electrical resistance value of the sensor part. Claim 2 A method for measuring the amount of corrosion according to claim 1, wherein the corrosion sensor has an insulating sheet, and the reference portion contacts the metal portion with only the insulating sheet interposed therebetween. Claim 3 A method for measuring the amount of corrosion according to claim 2, wherein the thermal transmittance of the insulation sheet is 25 kW / (㎡·K) or higher. Claim 4 A method for measuring the amount of corrosion according to any one of claims 1 to 3, wherein the sensor part and the reference part are laminated with an insulator interposed therebetween. Claim 5 A method for measuring the amount of corrosion according to any one of claims 1 to 3, wherein the amount of corrosion of the sensor part measured is obtained at a location away from the moving body by communication using a communication device. Claim 6 A method for measuring the amount of corrosion according to claim 4, wherein the amount of corrosion of the sensor part measured is obtained at a location away from the moving body by communication using a communication device. Claim 7 A method for selecting a metal material, based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in any one of claims 1 to 3, and selecting a metal material constituting the metal part. Claim 8 A method for selecting a metal material, based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in claim 4, and selecting a metal material constituting the metal part. Claim 9 A method for selecting a metal material, based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in claim 5, and selecting a metal material constituting the metal part. Claim 10 A method for selecting a metal material, based on the amount of corrosion of the sensor part measured by the method for measuring the amount of corrosion described in claim 6, and selecting a metal material constituting the metal part.

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