Method for measuring corrosion amount and method for selecting metal material

Abstract

A corrosion sensor (1) of a resistance type is attached to a metal portion (16) of a mobile body (15). The corrosion sensor (1) has a sensor portion (2) exposed to an arbitrary environment and a reference portion (3) isolated from the arbitrary environment. Electric conductors constituting the sensor portion (2) and the reference portion (3) are made of the same metal material as that constituting the metal portion (16). The corrosion amount of the sensor portion (2) is determined based on the resistance value of the reference portion (3) and the resistance value of the sensor portion (2). Thus, the corrosion amount of the metal portion (16) of the mobile body (15) can be grasped with high accuracy.

Description

Technical Field

[0001] This invention relates to methods for determining corrosion levels and methods for selecting metallic materials. Background Technology

[0002] Mobile bodies such as automobiles, ships, aircraft, and heavy machinery have at least a portion of their parts made of metallic materials. The concept of a mobile body also includes movable bodies such as cranes and belt conveyors (the same applies hereinafter).

[0003] The metal parts of a moving object will be damaged or deteriorated over time. One of the causes of damage and deterioration is corrosion.

[0004] For safe and long-term use of mobile equipment, it is important to understand the amount (corrosion rate) of corrosion on the metal parts of the mobile equipment under actual use conditions.

[0005] As the moving object moves, the way sunlight shines on the metal parts of the moving object changes.

[0006] As a result, changes occur in the metal parts of the moving body, such as changes in dryness / wetness, and the adhesion and detachment of corrosive substances like salt.

[0007] Therefore, the amount of corrosion on the metal parts of the moving body varies greatly depending on the movement of the moving body and the position of the metal parts in the moving body.

[0008] As a technique for determining the amount of corrosion of the metal parts of a moving body, for example, Patent Document 1 discloses "a method for measuring the corrosion environment of a moving body, characterized in that, at least one part of the moving body is made of a metal material, there are two metal electrodes with different compositions and / or components, one of which is a metal material that should be selected as a constituent component of the moving body material, and the other is made of the same metal that is different from it, and is made of a metal with a higher electrochemical sequence than it, and one or more corrosion sensors are provided in such a way that the gap between at least one set of electrodes is separated by an insulator of 0.1 to 5 mm, including continuously or intermittently measuring the current or potential difference between the electrodes caused by an electrical short circuit in the corrosion environment during movement, and the location of the corrosion sensor includes the interior isolated from the exterior of the moving body or the inner side of the constituent part of the moving body" ([Claim 1]).

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

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2009-53205

[0013] Non-patent literature

[0014] Non-patent literature 1: Zairyo-to-Kankyo, Corrosion Prevention Society, 2005, Vol. 54, No. 8, pp. 375-382

[0015] Non-patent literature 2: Zairyo-to-Kankyo, Corrosion Prevention Society, 2002, Vol. 51, No. 9, pp. 398-403 Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] In ACM (Atmospheric Corrosion Monitor) type corrosion sensors, the galvanic current flowing between two different types of metals exposed to a corrosive environment in a mutually insulated state is measured, and the amount of corrosion is determined based on experimental formulas.

[0018] However, due to the complex interplay of various factors contributing to corrosion, the corrosion amount calculated by ACM-type corrosion sensors may not always be entirely consistent with the actual corrosion amount.

[0019] The present invention was made in view of the above problems, and its purpose is to provide a method for measuring the corrosion amount of a moving body's metal parts with high precision.

[0020] Methods for solving problems

[0021] The inventors conducted in-depth research and found that the above-mentioned objectives can be achieved by adopting the following configuration, thus completing the present invention.

[0022] That is, the present invention provides the following [1] to

[10] .

[0023] [1] A method for determining corrosion amount, wherein, A corrosion sensor is installed on the metal part of a movable body having a metal part. The metal part is made of a metallic material. The corrosion sensor is a resistive corrosion sensor, which includes a sensor part and a reference part. The sensor part is made of a conductor exposed to any environment, and the reference part is made of a conductor isolated from the arbitrary environment. The conductor is made of the same metallic material as the metal material constituting the metal part. The amount of corrosion of the sensor part is determined based on the resistance value of the reference part and the resistance value of the sensor part.

[0024] [2] According to the corrosion measurement method described in [1], the corrosion sensor has an insulating sheet, and the reference part is connected to the metal part only through the insulating sheet.

[0025] [3] According to the corrosion determination method described in [2], the heat transfer coefficient of the insulating sheet is 25 kW / (m²). 2 ·K) and above.

[0026] [4] The method for determining the amount of corrosion according to any one of [1] to [3], wherein the sensor portion and the reference portion are stacked with an insulator in between.

[0027] [5] The corrosion amount determination method according to any one of [1] to [3] wherein the corrosion amount of the sensor part is obtained at a location far from the moving body by means of communication using a communication device.

[0028] [6] According to the corrosion measurement method described in [4], the corrosion amount of the sensor part is measured in a location far from the moving body by using communication of a communication device.

[0029] [7] A method for selecting a metallic material, wherein the metallic material constituting the metallic part is selected based on the corrosion amount of the sensor part as determined by the corrosion amount determination method described in any one of [1] to [3].

[0030] [8] A method for selecting a metallic material, wherein the metallic material constituting the metallic part is selected based on the corrosion amount of the sensor part as determined by the corrosion amount determination method described in [4].

[0031] [9] A method for selecting a metallic material, wherein the metallic material constituting the metallic part is selected based on the corrosion amount of the sensor part as determined by the corrosion amount determination method described in [5].

[0032]

[10] A method for selecting a metallic material, wherein the metallic material constituting the metallic part is selected based on the corrosion amount of the sensor part as determined by the corrosion amount determination method described in [6].

[0033] Invention Effects

[0034] According to the present invention, the corrosion amount of the metal part of the moving body can be measured with high precision. Attached Figure Description

[0035] Figure 1 This is a schematic top view of the corrosion sensor according to the first embodiment.

[0036] Figure 2 yes Figure 1 A sectional view along line AA.

[0037] Figure 3 This is a schematic top view of the corrosion sensor according to the second embodiment.

[0038] Figure 4 yes Figure 3 BB line section view.

[0039] Figure 5 This is a cross-sectional view of a corrosion sensor used to illustrate its connection status with the current source and voltage measuring unit.

[0040] Figure 6 This diagram shows the state in which a corrosion sensor 1 is installed on the metal part of the moving body. Detailed Implementation

[0041] [Methods for determining corrosion levels]

[0042] The following describes the method for determining the corrosion amount of the present invention. Furthermore, the following description also serves as an explanation of the method for selecting the metallic material of the present invention.

[0043] In the corrosion measurement method of the present invention, firstly, a resistive corrosion sensor is installed on the metal part of a moving body. Here, the corrosion sensor includes a sensor part exposed to any environment and a reference part isolated from any environment. 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 corrosion amount of the sensor part is measured based on the resistance value of the reference part and the resistance value of the sensor part.

[0044] In this invention, the conductive element of the corrosion sensor is made of the same metallic material as the metal part of the moving body, and the corrosion amount is directly determined from the resistance value without using experimental formulas. Therefore, the corrosion amount of the metal part of the moving body can be accurately measured.

[0045] <Corrosion Sensor>

[0046] First, based on Figures 1-2 (First Implementation) and Figures 3-5 (Second Embodiment) The basic structure of the resistive corrosion sensor used in this invention is described.

[0047] However, the corrosion sensors that can be used in this invention are not limited to the following embodiments.

[0048] First Implementation Method

[0049] Figure 1 This is a schematic top view of the corrosion sensor 1 according to the first embodiment. Figure 2 yes Figure 1 A sectional view along line AA.

[0050] The resistive corrosion sensor 1 has a sensor part 2 that is exposed to any environment and a reference part 3 that is isolated from the arbitrary environment exposed to the sensor part 2.

[0051] Both the sensor part 2 and the reference part 3 are made of conductive materials and are arranged side by side on one side of the flat insulating sheet 4.

[0052] The “any environment” exposed to the sensor unit 2 is a concept that includes various environments, including environments such as corrosion of the sensor unit 2, i.e., “corrosive environments”.

[0053] That is, the corrosion sensor 1 can be used in a corrosive environment where the sensor part 2 is corrosive, or in an environment where the sensor part 2 is not corrosive.

[0054] like Figure 2 As shown, the cross-sections of the sensor part 2 and the reference part 3 are rectangles (including squares) with a specified thickness. Both sides of the sensor part 2 and the reference part 3 are covered with insulating resin 5, and the upper surface of the reference part 3 is covered with an insulating cover 6.

[0055] That is, such as Figure 2 As shown, in a cross-sectional view of the corrosion sensor 1, the two sides and the top and bottom surfaces of the rectangular reference portion 3 are covered by various components. Therefore, even when the corrosion sensor 1 is in a corrosive environment, the reference portion 3 is isolated from that environment.

[0056] On the other hand, the upper surface of the sensor unit 2 is not covered by the cover 6.

[0057] That is, such as Figure 2 As shown, when the corrosion sensor 1 is viewed in cross-section, the two sides and the lower surface of the rectangular sensor part 2 are covered by various components, but the upper surface is exposed.

[0058] Therefore, when the corrosion sensor 1 is in a corrosive environment, the upper surface of the sensor unit 2 is exposed to this corrosive environment. The sensor unit 2, whose upper surface is exposed to the corrosive environment, undergoes corrosion in its thickness direction (from the upper surface side to the lower surface side).

[0059] Next, the various parts of corrosion sensor 1 will be described in more detail.

[0060] (Insulating sheet)

[0061] As will be described later, it is preferable to make the temperature of the reference part 3 of the corrosion sensor 1 equal to the temperature of the metal part 16 of the moving body 15 (reference part 3). Figure 6 The temperature is consistent.

[0062] Therefore, when the corrosion sensor 1 is mounted on the metal part 16, it is preferable to make the reference part 3 (and the sensor part 2) contact the metal part 16 only through the insulating sheet 4.

[0063] The material used for the insulating sheet 4 is not particularly limited as long as it does not electrically connect the reference part 3 and the sensor part 2 to the metal part 16 of the moving body 15. Examples include glass, ceramics, plastics (synthetic resins), and natural resins.

[0064] The insulating sheet 4 is preferably one with good thermal conductivity, i.e., high thermal conductivity (high thermal conductivity ratio).

[0065] Specifically, the thermal conductivity of the insulating sheet 4 is preferably 0.3 W / (m²). K) or higher, more preferably 0.5W / (m K) or higher, more preferably 1.0 W / (m K) or above. The thermal conductivity of insulating sheet 4 can also be 3.0 W / (m). K) and above.

[0066] On the other hand, there is no specific upper limit; for example, the thermal conductivity of the insulating sheet 4 is 100.0 W / (m²). Below K), it can be 50.0 W / (m³). Below K), it can be 30.0 W / (m³). Below K), it can also be 10.0 W / (m³). K) and below.

[0067] Polyimide is a preferred material for such insulating sheet 4.

[0068] The thickness of insulating sheet 4 ( Figure 2 The length in the vertical direction is sufficient to insulate the reference part 3 and the sensor part 2 from the metal part 16. For example, it is 5 μm or more, and preferably 10 μm or more.

[0069] On the other hand, from the viewpoint 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.

[0070] Based on the reason that the temperature of the reference part 3 and the temperature of the moving body 15 (metal part 16) are easily synchronized, the heat transfer coefficient of the insulating sheet 4 is preferably 25 kW / (m²). 2 K) or above, more preferably 40kW / (m²) 2 K) or above, more preferably 70kW / (m²) 2 K) or above, the optimal value is 100kW / (m²)2 K) and above. There is no specific upper limit, but the higher the value of the heat transfer coefficient, the better.

[0071] Furthermore, the heat transfer coefficient of insulating sheet 4 is the thermal conductivity of insulating sheet 4 (unit: kW / (m²)). The result is obtained by dividing K by the thickness of the insulating sheet 4 (in meters).

[0072] (Resin)

[0073] There are no particular limitations on the material of resin 5, and conventionally known materials can be used, such as epoxy resin, phenolic resin, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, etc.

[0074] The thickness of resin 5 is based on the thickness of sensor part 2 and reference part 3.

[0075] (cover)

[0076] There are no particular limitations on the material of the cover 6. Commonly known materials can be used, such as rubber and coatings. Materials with weather resistance are preferred.

[0077] The thickness of the cover 6 is not particularly limited; for example, it can be 0.1 to 10 mm.

[0078] (Sensor section and reference section)

[0079] The conductors constituting the sensor section 2 and the reference section 3 are connected to the metal section 16 constituting the moving body 15 (reference section 16). Figure 6 It is composed of the same metallic material as the metal material.

[0080] Examples of such metallic materials include iron or iron alloys.

[0081] The iron content in the ferroalloy is preferably 90% by mass or more. Other elements besides iron in the ferroalloy include, for example, at least one element selected from the group consisting of carbon, silicon, manganese, phosphorus, and sulfur; elements that improve corrosion resistance, such as copper and nickel; and other elements.

[0082] The shape of the conductive body constituting the sensor section 2 and the reference section 3 is preferably a long strip with a certain length, for example, such as... Figure 1 As shown, examples of folded shapes that bend at certain intervals can be listed.

[0083] For example, such as Figure 1 As shown, the sensor unit 2 and the reference unit 3 can also be a continuous series of elongated conductive bodies.

[0084] The length (overall length) of the sensor section 2 is preferably 30 mm or more, more preferably 100 mm or more. On the other hand, the length (overall length) of the sensor section 2 is preferably 500 mm or less, more preferably 400 mm or less.

[0085] like Figure 2 As shown, when the sensor section 2 is viewed in cross-section, from the viewpoint that even if localized deep corrosion occurs on the upper surface (surface) of the sensor section 2, the effect of a sharp increase in resistance is mitigated by averaging it as a whole, the width of the sensor section 2 ( Figure 2 The distance in the left and right directions is preferably 4mm or more, and more preferably 5mm or more.

[0086] On the other hand, if the width of the sensor section 2 is too wide, the resistance will be too small, and it will be difficult to perform high-precision measurements. Therefore, the width of the sensor section 2 is preferably 15 mm or less, more preferably 12 mm or less, and even more preferably 10 mm or less.

[0087] From the viewpoint of the ease of processing the conductor when obtaining the sensor part 2 by processing the conductor, the thickness of the sensor part 2 ( Figure 2 The distance in the vertical direction is preferably 50 μm or more, and more preferably 100 μm or more.

[0088] On the other hand, from the viewpoint of ensuring good measurement accuracy of corrosion sensor 1, the thickness of sensor part 2 is preferably 1000 μm or less, and more preferably 600 μm or less.

[0089] The shape of the reference part 3 is preferably the same as that of the sensor part 2. Therefore, it is not necessary to correct for the difference in resistance value caused by the difference in shape between the reference part 3 and the sensor part 2.

[0090] These numerical ranges related to the sensor unit 2 and the reference unit 3 are determined, for example, from the viewpoint of the measurement accuracy of the corrosion sensor 1, the ease of processing the corrosion sensor 1, the amount of corrosion, and the corrosion morphology.

[0091] (Current source and voltage measurement section)

[0092] As described above, the sensor unit 2 and the reference unit 3 can also be a continuous series of conductors.

[0093] In this case, a current source 7 is connected to both ends of a series of conductors constituting the sensor section 2 and the reference section 3, a voltage measuring section 8 is connected to both ends of the sensor section 2, and a voltage measuring section 9 is connected to both ends of the reference section 3.

[0094] A constant current flows through the current source 7, and the voltage is measured by the voltage measuring unit 8 and the voltage measuring unit 9, thereby determining the resistance values ​​of the sensor unit 2 and the reference unit 3.

[0095] Then, as described later, the amount of corrosion of sensor unit 2 is calculated based on the obtained resistance value.

[0096] (Recorder)

[0097] The corrosion sensor 1 preferably also includes a recorder 11 (see reference). Figure 6 ).

[0098] The recorder 11 drives the current source 7 at arbitrary intervals to make a constant current flow, and makes the voltage measuring unit 8 and voltage measuring unit 9 measure the voltage, calculate the resistance value of the sensor unit 2 and the reference unit 3, and calculate the corrosion amount of the sensor unit 2 based on the calculated resistance value.

[0099] Furthermore, the recorder 11 can record data such as the calculated amount of corrosion.

[0100] (Communication equipment)

[0101] The corrosion sensor 1 preferably also includes a communication device 12 (see reference). Figure 6 ).

[0102] The various data recorded in the recorder 11 are uploaded to the cloud, etc., through communication using the communication device 12.

[0103] Second Implementation Method

[0104] Next, based on Figures 3-5 The corrosion sensor 21 of the second embodiment will be described. Regarding the corrosion sensor based on... Figures 1-2 The same reference numerals are used for the same parts as in the first embodiment described, and the description is omitted.

[0105] Figure 3 This is a schematic top view of the corrosion sensor 21 according to the second embodiment. Figure 4 yes Figure 3 The BB-line cross-sectional view is enlarged to show the vicinity of the sensor section 2 and the reference section 3.

[0106] like Figure 4 As shown, a reference portion 3 made of a conductor is disposed on an insulating sheet 4. On one side of the reference portion 3 opposite to the insulating sheet 4, a sensor portion 2 made of a conductor is disposed with respect to the insulator 10. That is, the sensor portion 2 and the reference portion 3 are stacked with respect to the insulator 10.

[0107] The material used as insulator 10 can be any material that does not electrically connect the sensor part 2 and the reference part 3, and there are no particular limitations. Examples include glass, ceramics, plastics (synthetic resins), and natural resins.

[0108] If the thermal conductivity of the insulator 10 is poor, a temperature difference will easily occur between the sensor part 2 and the reference part 3. Therefore, it is preferable to select a material with high thermal conductivity.

[0109] When the insulator 10 is too thick, its thermal conductivity is likely to deteriorate. On the other hand, when it is too thin, it is prone to short circuits.

[0110] The preferred thickness of the insulator 10 varies depending on its material. For example, when the insulator 10 is a plastic film such as polyvinyl chloride, polyethylene, or polypropylene, it is preferably 5 to 200 μm.

[0111] Preferably, the insulator 10 is tightly attached to the sensor part 2 and the reference part 3 without creating gaps. This is because if gaps are created, thermal conductivity is easily impaired.

[0112] Therefore, it is preferable to press the insulator 10 against the sensor part 2 and the reference part 3 with sufficient force, or to use a thermally conductive adhesive for bonding. During bonding, it is preferable to thoroughly clean the bonding surface so that no dirt, dust, or other contaminants remain.

[0113] Figure 5 This is a cross-sectional view of the corrosion sensor 21 used to illustrate its connection status with the current source 7 and the voltage measuring unit 8.

[0114] like Figure 5 As shown, a voltage measuring unit 8 is connected to one end of the sensor unit 2, namely terminal 2a, and the other end, namely terminal 2b, and a voltage measuring unit 9 is connected to one end of the reference unit 3, namely terminal 3a, and the other end, namely terminal 3b.

[0115] Terminal 2b of sensor unit 2 is electrically connected to terminal 3b of reference unit 3, and current source 7 is connected to terminal 2a of sensor unit 2 and terminal 3a of reference unit 3.

[0116] Unless otherwise specified, "corrosion sensor 21" will be referred to as "corrosion sensor 1" in the following description for convenience.

[0117] Such a corrosion sensor 1 is mounted on the metal part 16 of the moving body 15.

[0118] <Moving body (mounting of corrosion sensor relative to moving body)>

[0119] Figure 6 This diagram shows the state in which a corrosion sensor 1 is installed on the metal part 16 of the moving body 15. Figure 6 The diagram shows a case where the moving body 15 is a car. However, the moving body 15 is not limited to a car; other examples include ships, aircraft, and heavy machinery. Furthermore, the moving body 15 also includes movable bodies such as cranes and belt conveyors.

[0120] At least a portion of the movable body 15 is a metal part 16 made of metallic material. In the case that the movable body 15 is a car, the metal part 16 is, for example, the car body.

[0121] Here, as a heat source that imparts temperature changes to the metal part 16 of the moving body 15, we consider the case where there is a heat source other than the atmosphere (such as direct sunlight).

[0122] The heat capacity of the metal part 16 affects its temperature change. Therefore, the temperature change of the corrosion sensor 1, which is smaller than the moving body 15 (metal part 16), differs from that of the metal part 16. Temperature affects the rate of corrosion reaction and the wetting and drying of the water film required for the corrosion reaction.

[0123] Therefore, in order to ensure good measurement accuracy of corrosion sensor 1, it is preferable to make the temperature of corrosion sensor 1 the same as the temperature of moving body 15.

[0124] Specifically, it is preferable to make the temperature of the reference part 3 of the corrosion sensor 1 the same as the temperature of the metal part 16 of the moving body 15.

[0125] Therefore, when the corrosion sensor 1 is installed on the metal part 16, it is preferable to make the reference part 3 contact the metal part 16 only through the insulating sheet 4.

[0126] At this point, an adhesive is used to bond the insulating sheet 4 to the metal part 16, or the insulating sheet 4 is pressed tightly against the metal part 16 through grease and then fixed around it with a sealant. In this way, the corrosion sensor 1 is fixed to the metal part 16.

[0127] That is, in fact, in addition to the insulating sheet 4, adhesives, greases, etc. can be sandwiched between the reference part 3 and the metal part 16.

[0128] However, even so, in this invention, the reference part 3 of the corrosion sensor 1 is considered to be in contact with the metal part 16 of the moving body 15 only through the insulating sheet 4.

[0129] The thermal conductivity of the adhesive and grease is preferably 1.0 W / (m²). K) and above.

[0130] Furthermore, when bonding the various parts of the corrosion sensor 1 to each other (for example, when bonding the reference part 3 to the insulating sheet 4), it is preferable to use the same adhesive.

[0131] The number of corrosion sensors 1 installed on a moving body 15 is at least one, and may also be two or more.

[0132] For example, even with the same moving body 15, the amount of corrosion can vary depending on the location of the metal part 16. In this case, multiple corrosion sensors 1 are installed on one moving body 15.

[0133] In addition, to improve measurement accuracy, multiple corrosion sensors 1 can be installed on a single moving body 15.

[0134] Depending on the shape of the moving body 15, the range of the corrosion sensor 1 can sometimes be narrow.

[0135] In this case, the corrosion sensor 1 of the first embodiment, which has a sensor unit 2 and a reference unit 3 arranged side by side, is compared with the sensor unit 2 and the reference unit 3. Figures 1-2 In contrast, the corrosion sensor 21 of the second embodiment, which has a sensor section 2 and a reference section 3 stacked on top of each other, is... Figures 3-5 The area where it contacts the metal part 16 is small, therefore it is preferred.

[0136] <Determination of Corrosion Level>

[0137] In the corrosion sensor 1 installed on the movable body 15, a constant current flows through the current source 7, and the voltage is measured by the voltage measuring unit 8 and the voltage measuring unit 9, thereby determining the resistance values ​​of the sensor unit 2 and the reference unit 3. The magnitude of the constant current can be arbitrarily set, for example, according to the required measurement accuracy and electric force.

[0138] As corrosion of sensor 2 progresses, the resistance value of sensor 2 gradually increases from its initial value.

[0139] On the other hand, the corrosion of reference part 3 does not progress, and the resistance value of reference part 3 remains basically unchanged from the initial value.

[0140] The reason why the corrosion cross-sectional view of sensor part 2 is related to the increase in resistance value is generally believed to be as follows.

[0141] As corrosion progresses, the conductive material constituting sensor section 2 thins in the thickness direction. The conductive material that has thinned out by a certain amount disappears from the surface or is replaced by corrosion products and remains on the surface.

[0142] The corrosion product is non-conductive, or even if it is conductive, its conductivity is very low compared to the original conductive material.

[0143] As a result, the increase in resistance caused by corrosion is considered to be caused by the thinning of the wall thickness of the conductor constituting the sensor part 2.

[0144] The resistance values ​​of sensor section 2 and reference section 3 are determined at arbitrary intervals, and the corrosion amount (corrosion depth) of sensor section 2 is calculated (converted) based on the determined resistance values. The conversion formula for corrosion amount is expressed by the following formula (1).

[0145] CD=t i {(R ri / R si )-(R r / R s )}…(1)

[0146] CD: Corrosion depth (corrosion amount) [μm]

[0147] t i Initial thickness of the sensor section [μm]

[0148] R ri The initial resistance value [Ω] of the reference section.

[0149] R si The initial resistance value of the sensor section [Ω]

[0150] R r The resistance value [Ω] measured at the reference section.

[0151] R s The resistance value [Ω] measured by the sensor section.

[0152] Based on the above equation (1), the corrosion amount is calculated based on the assumptions.

[0153] For example, the initial thickness of both the reference section 3 and the sensor section 2 is "100 μm", and the initial resistance value (R) of the reference section 3 is... ri ) and the initial resistance value (R) of sensor unit 2. si All values ​​are "0.1Ω", and the resistance value (R) measured by the reference unit 3 is... r The resistance value (R) remains constant at 0.1Ω from the beginning. On the other hand, the resistance value (R) changes as corrosion progresses in sensor section 2. s When the Ω is increased to “0.11Ω”, the corrosion amount is calculated as “9.1μm” according to the above formula (1) with 100×{(0.1 / 0.1)-(0.1 / 0.11)}.

[0154] <Temperature compensation, etc.>

[0155] Temperature compensation is also preferably performed in corrosion sensor 1.

[0156] That is, when the resistance value of the reference part 3 changes, the change is caused by a temperature change, and the measured corrosion amount is preferably corrected based on this change.

[0157] Generally speaking, the higher the temperature of a metal, the higher its resistivity.

[0158] For example, in the above assumption, the temperature rises compared to the initial value, and the resistance value (R) of sensor section 2 at the time of measurement... s It is not “0.11Ω”, but “0.121Ω” with an increase of 10%.

[0159] In this case, assuming that the corrosion amount is calculated according to the above formula (1) with 100×{(0.1 / 0.1)-(0.1 / 0.121)}, the corrosion amount is "17μm", which is very different from the original corrosion amount "9.1μm".

[0160] However, at this time, for example, if the resistance value (R) of the reference part 3... r Similarly, due to the increase in temperature, the value changes from "0.1Ω" to "0.11Ω" by 10%, and the amount of corrosion can be corrected based on this change.

[0161] That is, the corrosion amount is calculated as “9.1μm” according to the above formula (1) with 100×{(0.1 / 0.1)-(0.11 / 0.121)}, which is the same result as the case without temperature change.

[0162] As described above, by aligning the temperature of the reference section 3 with the temperature of the metal section 16, the effectiveness of temperature compensation is further increased.

[0163] There is no particular limitation on the subject that performs the above-mentioned measurement of corrosion and temperature compensation; for example, recorder 11 can be cited.

[0164] For example, the recorder 11 performs temperature compensation while calculating the corrosion amount of the sensor unit 2 and records the calculated corrosion amount and other data.

[0165] The corrosion amount and other data recorded in the recorder 11 are uploaded to the cloud via communication using the communication device 12.

[0166] By downloading the uploaded data, the user of corrosion sensor 1 can monitor the corrosion level of sensor 2 at any time, even if they are located in any place far away from the moving body 15.

[0167] Users of corrosion sensor 1 can use the measured corrosion levels for various purposes.

[0168] For example, during the intended use of the mobile body 15, the mobile body 15 can be maintained in a manner that the amount of corrosion does not exceed the amount of corrosion of the metal part 16 (the amount of corrosion that is permissible in the metal part 16).

[0169] In addition, the metal material of the metal part 16 can be selected based on the known corrosion amount, so that the corrosion amount does not exceed the corrosion amount of the metal part 16 during the intended use of the moving body 15.

[0170] Example

[0171] The present invention will now be specifically described by way of examples. However, the present invention is not limited to the examples described below.

[0172] The tests were conducted under the conditions shown in Table 1 below. Specifically, as described below, corrosion sensors were installed on the moving body, and tests were conducted to determine the amount of corrosion.

[0173] <Moving Body>

[0174] First, four types of moving bodies (including movable bodies) with metal parts are selected: automobiles, heavy machinery, cranes, and belt conveyors. The selected types of moving bodies are shown in Table 1 below.

[0175] In addition, the metal parts of automobiles, heavy machinery, and cranes are their respective bodies. The metal parts of belt conveyors are the belts (conveyor belts).

[0176] <Corrosion Sensor>

[0177] Install corrosion sensors on the metal parts of the selected moving parts. Install one corrosion sensor on each moving part.

[0178] No. 1~20: Resistive Corrosion Sensors

[0179] In Nos. 1 to 20, the resistive corrosion sensor 21 of the second embodiment is used as the corrosion sensor. Figures 3-5 ).

[0180] (No.1~5 and 7~20)

[0181] In more detail, refer to Figures 3-5 To illustrate, the insulating sheet 4 is made of polyimide (thickness: 25 μm, thermal conductivity: 1.0 W / (m²)). K), heat transfer coefficient: 40kW / (m²) 2 A reference unit 3 is configured on K).

[0182] On the insulating sheet 4, the epoxy resin 5 is evenly spread to cover the thickness of the reference part 3, covering both sides of the reference part 3.

[0183] An insulator 10 (polyvinyl chloride, thickness: 100μm) as a plastic film is disposed on it, and then the sensor part 2 is disposed in a manner that overlaps with the reference part 3 through the insulator 10.

[0184] On the insulator 10, the resin 5, which is an epoxy resin, is evenly spread to cover the thickness of the sensor part 2, covering both sides of the sensor part 2.

[0185] As the conductor (metallic material) constituting the sensor part 2 and the reference part 3, a strip-shaped conductor (total length: 200mm, width: 10mm, thickness: 200μm) is used, and the same metallic material as the metal part of the moving body (such as the body of a car) is used.

[0186] Use a high thermal conductivity adhesive (thermal conductivity: 2.1 W / (m²)). K), the insulating sheet 4 of such corrosion sensor 21 is bonded to the metal part of the moving body (such as the body of a car).

[0187] (No.6)

[0188] In addition to using a thermal conductivity of 0.3 W / (m Insulating sheet 4 (thickness: 25μm, heat transfer coefficient: 12kW / (m²)) of K) 2 In addition to K), corrosion sensors 21 were manufactured in the same manner as No.1~5 and 7~20. Figures 3-5 ), and is bonded to the metal part of the moving body.

[0189] It should be noted that in the "thermal conductivity of insulating sheet" column of Table 1 below, No. 6 is marked "low", while the other examples are marked "-".

[0190] Nos. 21-30

[0191] As a corrosion sensor, any one of the following can be used: an ACM-type corrosion sensor, an electrochemical impedance spectroscopy (EIS)-based corrosion sensor, and a quartz oscillator microbalance (QCM)-type corrosion sensor.

[0192] The determination of corrosion using an ACM-type corrosion sensor is based on non-patent literature 1-2.

[0193] Direct sunlight

[0194] The metal parts of the moving body have areas that are directly exposed to sunlight, which is a heat source other than the atmosphere, and areas that are not exposed to sunlight. In the "Heat Source" column of Table 1 below, "Yes" is recorded when a corrosion sensor is installed on the area directly exposed to sunlight, and "-" is recorded when a corrosion sensor is installed on the area not exposed to direct sunlight.

[0195] <Temperature Synchronization>

[0196] When using a resistive corrosion sensor, if the reference part of the corrosion sensor is installed in contact with the metal part of the moving body only through an insulating sheet, the "Temperature Synchronization" column in Table 1 below will be marked as "Yes".

[0197] On the other hand, if a spacer (stainless steel plate "SUS304", thickness: 2mm) is provided between the insulating sheet and the metal part of the moving body, "-" is recorded in the "Temperature Synchronization" column of Table 1 below.

[0198] In addition, when using a corrosion sensor that is not resistive, it is also recorded as "-".

[0199] <Environment>

[0200] The corrosive environment of the mobile devices was set to the atmosphere. However, the geographical locations where the mobile devices were used varied in each case.

[0201] In the “Environment” column of Table 1 below, “Low Drift Salt” is recorded when using a mobile vehicle in region A where the drift salt content is low, “High Drift Salt” is recorded when using a mobile vehicle in region B where the drift salt content is higher than that in region A, and “Snow Melting Salt” is recorded when using a mobile vehicle in a cold snow-covered area where snow melting salt is distributed.

[0202] Furthermore, when the mobile body is used in contact with soil, "+soil" will be added to the "Environment" column of Table 1 below, and when it is used in contact with coal, "+coal" will be added to the "Environment" column of Table 1 below.

[0203] <period>

[0204] The trial period was set at approximately 3 months (between 89 and 105 days).

[0205] <Corrosion Measurement (Sensor)>

[0206] After the test period, the corrosion amount (unit: μm) was measured using a corrosion sensor installed on the metal part of the moving body. When using a resistive corrosion sensor, the corrosion amount of the sensor part was measured. The measured corrosion amount was recorded in the "Sensor" column of "Corrosion Amount" in Table 1 below.

[0207] Corrosion Measurement (Test Piece)

[0208] To compare the corrosion amount with that of the corrosion sensor, a test piece (described later) is mounted adjacent to the corrosion sensor on the metal part of the moving body and subjected to corrosion during the test. Then, after the test period, the corrosion amount of the test piece is determined.

[0209] This is because, instead of measuring the corrosion of the metal parts of the moving body, it is difficult to determine the corrosion amount non-destructively. Therefore, test pieces are used to determine the corrosion amount.

[0210] A 150mm×70mm×0.8mm cold-rolled steel sheet (SPC material) was installed on a car as a test piece.

[0211] 150mm×70mm×0.8mm welded structural rolled steel (SM material) was installed as test pieces on heavy machinery, cranes and belt conveyors.

[0212] The corrosion amount of the test piece was determined according to ISO 8407.

[0213] Specifically, after the test period, the rust on the test piece was removed by adding 3.5g of hexamethylenetetramine to 500mL of hydrochloric acid and making up to 1000mL. The corrosion amount (unit: μm) was calculated from the mass difference before and after the test.

[0214] Record the calculated corrosion amount in the "Test Piece" column of "Corrosion Amount" in Table 1 below.

[0215] <Error>

[0216] Calculate the error (in %) between the corrosion amount obtained using the corrosion sensor and the corrosion amount of the test piece.

[0217] The smaller the absolute value of the error, the better the accuracy of the corrosion amount determined using the corrosion sensor. In particular, the accuracy is considered even better when the absolute value of the error is below 10%.

[0218] [Table 1]

[0219] <Summary of Evaluation Results>

[0220] As shown in Table 1 above, the absolute values ​​of the errors of No. 1 to 20 (inventive examples) which use resistive corrosion sensors are smaller than those of No. 21 to 30 (comparative examples) which use other corrosion sensors, and it can be said that they can accurately measure the amount of corrosion on the metal parts of the moving body.

[0221] Among No.1 to 20, the absolute value of the error in No.11 to 12 ("direct sunlight", but "temperature synchronization" is "-") exceeds 10%.

[0222] In contrast, the absolute values ​​of the errors for No.1~10 and 13~20 are less than 10%, indicating better accuracy.

[0223] Furthermore, if we compare No.5 and No.6, which differ only in the thermal conductivity of their insulating sheets among No.1 to No.20, the absolute value of the error of No.5, which has a higher thermal conductivity of its insulating sheet, is smaller and the accuracy is better than that of No.6, which has a lower thermal conductivity of its insulating sheet.

[0224] It was observed that the corrosion amount of No. 21~25, which used ACM-type corrosion sensors, tended to be greater than that of the test pieces.

[0225] In particular, the corrosion amounts of samples No. 23-24, which were tested under conditions of contact with coal, deviated significantly from those of the test pieces. This is believed to be because the coal dust accumulated in the ACM-type corrosion sensor retained moisture caused by rainfall, resulting in high output throughout the test.

[0226] Corrosion sensors No. 26-28, which use EIS-based corrosion sensors, also exhibit large absolute errors and insufficient accuracy, similar to corrosion sensors No. 21-25, which use ACM-type corrosion sensors.

[0227] The corrosion measurements in samples No. 29-30, which used the QCM type corrosion sensor, were essentially unable to determine the amount of corrosion. The QCM type corrosion sensor is based on the principle of thin-film measurement; therefore, it is assumed that under the conditions of this experiment, the amount of corrosion exceeded the thickness of the thin film.

[0228] Additional Experiment: No. 5b

[0229] In addition to installing ten corrosion sensors on a moving body (heavy machinery), the same test to determine the amount of corrosion was carried out as No.5 (for convenience, it is referred to as "No.5b").

[0230] Similar to No.5, ten corrosion sensors were installed on the parts of the moving body that were exposed to direct sunlight.

[0231] As a result, the error between the corrosion amount calculated using the corrosion sensor and the corrosion amount of the test piece was 1.8%, which is more accurate than No.5.

[0232] Label Explanation

[0233] 1: Corrosion sensor (first embodiment)

[0234] 2: Sensor Department

[0235] 2a: Terminal of the sensor section

[0236] 2b: Terminals of the sensor section

[0237] 3: Reference Section

[0238] 3a: Terminal of the reference section

[0239] 3b: Terminal of the reference section

[0240] 4: Insulating sheet

[0241] 5: Resin

[0242] 6: Cover

[0243] 7: Current source

[0244] 8: Voltage Measurement Section

[0245] 9: Voltage Measurement Section

[0246] 10: Insulator

[0247] 11: Recorder

[0248] 12: Communication equipment

[0249] 15: Moving body

[0250] 16: Metal Department

[0251] 21: Corrosion sensor (second embodiment).

Claims

1. A method for determining corrosion amount, wherein, A corrosion sensor is mounted on the metal part of a movable body having a metal section, the metal section being made of a metallic material. The corrosion sensor is a resistive corrosion sensor, comprising a sensor part and a reference part. The sensor part is composed of a conductor exposed to any environment, and the reference part is composed of a conductor isolated from the arbitrary environment. The conductor is made of the same metal material as the metal material constituting the metal part. The corrosion amount of the sensor part is determined based on the resistance value of the reference part and the resistance value of the sensor part.

2. The method for determining corrosion amount according to claim 1, wherein, The corrosion sensor has an insulating sheet. The reference portion is connected to the metal portion only through the insulating sheet.

3. The method for determining corrosion amount according to claim 2, wherein, The heat transfer coefficient of the insulating sheet is 25 kW / (m²). 2 ·K) and above.

4. The method for determining the amount of corrosion according to any one of claims 1 to 3, wherein, The sensor section and the reference section are stacked together with an insulator in between.

5. The method for determining the amount of corrosion according to any one of claims 1 to 3, wherein, The corrosion level of the sensor was measured at a location far from the moving body by using communication equipment.

6. The method for determining corrosion amount according to claim 4, wherein, The corrosion level of the sensor was measured at a location far from the moving body by using communication equipment.

7. A method for selecting a metallic material, wherein, The metal material constituting the metal part is selected based on the corrosion amount of the sensor part as determined by the corrosion amount measurement method according to any one of claims 1 to 3.

8. A method for selecting a metallic material, wherein, The metal material constituting the metal part is selected based on the corrosion amount of the sensor part measured by the corrosion amount measurement method described in claim 4.

9. A method for selecting a metallic material, wherein, The metal material constituting the metal part is selected based on the corrosion amount of the sensor part measured by the corrosion amount measurement method described in claim 5.

10. A method for selecting a metallic material, wherein, The metal material constituting the metal part is selected based on the corrosion amount of the sensor part measured by the corrosion amount measurement method described in claim 6.

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