JP6623326B2 - Corrosion sensor - Google Patents

Corrosion sensor Download PDF

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JP6623326B2
JP6623326B2 JP2015132647A JP2015132647A JP6623326B2 JP 6623326 B2 JP6623326 B2 JP 6623326B2 JP 2015132647 A JP2015132647 A JP 2015132647A JP 2015132647 A JP2015132647 A JP 2015132647A JP 6623326 B2 JP6623326 B2 JP 6623326B2
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corrosion
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counter electrode
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JP2017015565A (en
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修二 石原
修二 石原
重信 貝沼
重信 貝沼
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Kyushu University NUC
Mitsui E&S Machinery Co Ltd
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Mitsui E&S Machinery Co Ltd
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この発明は、腐食センサに係り、特に、水位の変動または水の飛沫の影響を受けやすい箇所に設置される構造物の腐食環境を評価する腐食センサに関する。   The present invention relates to a corrosion sensor, and more particularly, to a corrosion sensor for evaluating a corrosion environment of a structure installed at a location susceptible to fluctuations in water level or splash of water.

水門および桟橋等の河川、海洋に設置される鋼構造物は、厳しい腐食性環境に曝されている。特に、潮位の変動に伴う干満の影響を受ける部位(干満帯)および水しぶきを浴びる部位(飛沫帯)においては、乾湿が頻繁に繰り返されるため、構造材の腐食速度が大きくなる傾向にある。
このような腐食性環境に設置される鋼構造物の防食対策として、水中に没する部位には電気防食が適用されることが多い。しかし、気相部位では電気防食が有効に機能しないため、重防食塗装等のコーティングによって対応するのが一般的である。 Steel structures installed in rivers and oceans, such as sluices and piers, are exposed to severe corrosive environments. In particular, in a part affected by ebb and flow (tidal zone) due to a change in tide level and in a part subject to splashing (splash zone), the rate of corrosion of the structural material tends to increase due to frequent repetition of wet and dry conditions.
As a countermeasure against corrosion of a steel structure installed in such a corrosive environment, a portion immersed in water is often applied with electrolytic protection. However, since the cathodic protection does not function effectively in the gas phase, it is common to use a coating such as heavy anticorrosion coating.

電気防食は、適切に管理することでほぼ腐食を抑制でき、また電位や電流をモニタすることによって防食の状態を評価することが可能であるが、重防食塗装等のコーティングでは、錆の生成に伴う変色等の外観的な観察等により評価するしか手法はない。
また、特許文献１には、モニタリング用の複数種類の金属片が固定された腐食環境センサを鋼構造物と同じ環境下に配置して腐食させ、それぞれの金属片の表面における色変化を測色計で測定することで、鋼構造物の設置箇所の腐食環境を評価する方法が開示されている。 In the case of cathodic protection, it is possible to suppress corrosion almost by properly managing it, and it is possible to evaluate the anticorrosion state by monitoring the potential and current. There is no other method but to evaluate it by observing external appearance such as accompanying discoloration.
Patent Document 1 discloses that a corrosive environment sensor in which a plurality of types of monitoring metal pieces are fixed is disposed in the same environment as a steel structure to cause corrosion, and a color change on the surface of each metal piece is measured. A method of evaluating a corrosive environment at a place where a steel structure is installed by measuring with a meter is disclosed.

特開２００６−６４４６６号公報JP 2006-64466 A

しかしながら、特許文献１に開示された方法では、複数種類の金属片の色変化を測定するため、経時的な腐食環境の変化を定量的に評価するのが難しく、また、潮位の変動等、水位が変動するような箇所に設置された構造物の水位変動方向における腐食環境の変化を評価することは困難であった。   However, in the method disclosed in Patent Document 1, since the color change of a plurality of types of metal pieces is measured, it is difficult to quantitatively evaluate a change in a corrosive environment over time, and the water level such as a change in tide level is also difficult. It was difficult to evaluate the change of the corrosive environment in the direction of the water level fluctuation of the structure installed in the place where the water fluctuated.

この発明は、このような従来の問題点を解消するためになされたもので、構造物の所定の方向における腐食環境の変化を定量的に評価することができる腐食センサを提供することを目的とする。   The present invention has been made to solve such a conventional problem, and has as its object to provide a corrosion sensor capable of quantitatively evaluating a change in a corrosion environment in a predetermined direction of a structure. I do.

この発明に係る腐食センサは、計測対象となる構造物の所定の方向における腐食速度の分布を計測するための腐食センサにおいて、所定の方向に配列され且つそれぞれ構造物の表面上に設置される複数の試料極と、所定の方向における複数の試料極の配置位置を含むように複数の試料極に並んで所定の方向に延び且つ構造物の表面上に配置された共通の対極と、複数の試料極および共通の対極に接続され且つ複数の試料極をそれぞれ共通の対極に接続することにより形成される複数の腐食回路を流れる複数の腐食電流に基づいて所定の方向における腐食速度の分布を計測する計測部とを備え、複数の試料極および共通の対極は、構造物の表面において同一面上に並んで配置されているものである。 A corrosion sensor according to the present invention is a corrosion sensor for measuring a distribution of a corrosion rate of a structure to be measured in a predetermined direction, wherein the plurality of corrosion sensors are arranged in a predetermined direction and are respectively installed on the surface of the structure. A plurality of sample electrodes, a common counter electrode extending in a predetermined direction alongside the plurality of sample electrodes so as to include the arrangement positions of the plurality of sample electrodes in the predetermined direction, and a plurality of sample electrodes. The distribution of the corrosion rate in a predetermined direction is measured based on a plurality of corrosion currents flowing through a plurality of corrosion circuits formed by connecting the electrode and the common counter electrode and connecting the plurality of sample electrodes to the common counter electrode, respectively. A plurality of sample electrodes and a common counter electrode are arranged side by side on the same surface on the surface of the structure .

複数の試料極は、構造物を構成する材料と同一の材料からなることが好ましい。
また、共通の対極は、複数の試料極と同一の材料から形成することができる。あるいは、共通の対極は、複数の試料極と同一の材料を主成分とし且つ複数の試料極より貴である材料からなることが好ましい。
また、複数の試料極は、絶縁性の熱伝導シートを介して構造物の表面上に貼り付けられることが好ましい。
一方、共通の対極は、絶縁性の熱伝導シートを介して構造物の表面上に貼り付けられることもでき、あるいは、共通の対極は、構造物により形成されていてもよい。
計測部は、複数の試料極のそれぞれに対して、試料極を共通の対極に接続することにより形成される腐食回路を流れる腐食電流を時間積分することにより試料極が設置された箇所における構造物の腐食速度を計測することが好ましい。 The plurality of sample electrodes are preferably made of the same material as the material constituting the structure.
Further, the common counter electrode can be formed from the same material as the plurality of sample electrodes. Alternatively, it is preferable that the common counter electrode is made of a material whose main component is the same material as the plurality of sample electrodes and which is more noble than the plurality of sample electrodes.
Further, it is preferable that the plurality of sample electrodes be attached on the surface of the structure via an insulating heat conductive sheet.
On the other hand, the common counter electrode may be stuck on the surface of the structure via an insulating heat conductive sheet, or the common counter electrode may be formed by the structure.
The measurement unit integrates the corrosion current flowing through the corrosion circuit formed by connecting the sample electrode to the common counter electrode for each of the plurality of sample electrodes, and integrates the structure at the location where the sample electrode is installed. It is preferable to measure the corrosion rate of steel.

この発明によれば、所定の方向に配列され且つそれぞれ構造物の表面上に設置される複数の試料極と、所定の方向における複数の試料極の配置位置を含むように複数の試料極に並んで所定の方向に延び且つ構造物の表面上に配置された共通の対極とを備え、計測部が、複数の試料極および共通の対極に接続され且つ複数の試料極をそれぞれ共通の対極に接続することにより形成される複数の腐食回路を流れる複数の腐食電流に基づいて所定の方向における腐食速度の分布を計測するので、構造物の所定の方向における腐食環境の変化を定量的に評価することが可能となる。   According to the present invention, a plurality of sample poles arranged in a predetermined direction and respectively installed on the surface of the structure, and aligned with the plurality of sample poles so as to include the arrangement positions of the plurality of sample poles in the predetermined direction. And a common counter electrode extending in a predetermined direction and disposed on the surface of the structure, wherein the measurement unit is connected to the plurality of sample electrodes and the common counter electrode, and connects the plurality of sample electrodes to the common counter electrode, respectively. Since the distribution of corrosion rate in a predetermined direction is measured based on a plurality of corrosion currents flowing through a plurality of corrosion circuits formed by performing the above, quantitatively evaluate changes in a corrosion environment in a predetermined direction of a structure. Becomes possible.

この発明の実施の形態１に係る腐食センサの構成を示す図である。FIG. 1 is a diagram showing a configuration of a corrosion sensor according to Embodiment 1 of the present invention. 構造物の表面上に配置された複数の試料極と共通の対極を示す断面図である。FIG. 4 is a cross-sectional view showing a plurality of sample electrodes arranged on the surface of a structure and a common counter electrode. 試料極と共通の対極が水中に没した状態を示す断面図である。It is sectional drawing which shows the state where the counter electrode common to a sample electrode was immersed in water. 水門を模式的に示す図である。It is a figure which shows a flood gate typically. 水門の扉体を示す斜視図である。It is a perspective view which shows the door body of a floodgate. 実施の形態１に係る腐食センサが設置された水門の扉体を示す図である。FIG. 3 is a diagram showing a door of a floodgate where the corrosion sensor according to the first embodiment is installed. 実施の形態２に係る腐食センサの構成を示す図である。FIG. 9 is a diagram showing a configuration of a corrosion sensor according to a second embodiment.

以下、この発明の実施の形態を添付図面に基づいて説明する。
実施の形態１
図１に実施の形態１に係る腐食センサの構成を示す。この腐食センサは、腐食環境の評価対象となる構造物１の表面上に設置される複数の試料極２と、構造物１の表面上で且つ複数の試料極２の近傍に配置された共通の対極３を有し、複数の試料極２のそれぞれと共通の対極３にケーブル４を介して計測部５が電気的に接続されている。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows a configuration of the corrosion sensor according to the first embodiment. This corrosion sensor includes a plurality of sample electrodes 2 installed on a surface of a structure 1 to be evaluated for a corrosive environment, and a common sample electrode 2 arranged on the surface of the structure 1 and in the vicinity of the plurality of sample electrodes 2. The measuring unit 5 has a counter electrode 3 and is electrically connected to the common counter electrode 3 with each of the plurality of sample electrodes 2 via a cable 4.

構造物１の表面上において、複数の試料極２は、腐食環境の変化を評価しようとする所定の方向Ｄに１列に配列されており、共通の対極３は、所定の方向Ｄにおける複数の試料極２の配置位置をすべて含むように複数の試料極２に並んで所定の方向Ｄに延びている。
ここで、所定の方向Ｄは、例えば、構造物１が、桟橋、水門等、水位が時間的に変動する海水、河川水に晒されるような箇所に設置されている構造物である場合に、水位変動方向である鉛直方向に設定することができる。 On the surface of the structure 1, the plurality of sample electrodes 2 are arranged in a row in a predetermined direction D in which a change in the corrosive environment is to be evaluated. The plurality of sample electrodes 2 extend in a predetermined direction D so as to include all the arrangement positions of the sample electrodes 2.
Here, the predetermined direction D is, for example, when the structure 1 is a structure installed in a place such as a pier, a floodgate, or the like that is exposed to seawater or river water whose water level fluctuates with time, It can be set in the vertical direction which is the water level fluctuation direction.

複数の試料極２および共通の対極３は、それぞれ、構造物１を構成する材料と同一組成の材料から形成されている。例えば、構造物１がある組成の鋼材からなる場合には、それぞれの試料極２および共通の対極３を構造物１と同一組成の鋼材で形成する。
複数の試料極２は、互いに分離し独立しており、図２に示されるように、それぞれ、絶縁性の熱伝導シート６を介して構造物１の表面上に貼り付けられている。共通の対極３も、複数の試料極２と同様に、絶縁性の熱伝導シート７を介して構造物１の表面上に貼り付けられている。 The plurality of sample electrodes 2 and the common counter electrode 3 are each formed of a material having the same composition as the material constituting the structure 1. For example, when the structure 1 is made of a steel material having a certain composition, each sample electrode 2 and the common counter electrode 3 are formed of a steel material having the same composition as the structure 1.
The plurality of sample electrodes 2 are separated from each other and are independent of each other. As shown in FIG. 2, each of the plurality of sample electrodes 2 is attached to the surface of the structure 1 via an insulating heat conductive sheet 6. Similarly to the plurality of sample electrodes 2, the common counter electrode 3 is attached to the surface of the structure 1 via the insulating heat conductive sheet 7.

複数の試料極２および共通の対極３は、成膜により形成されたものではなく、バルク材料から形成されることが好ましい。
また、熱伝導シート６および７としては、両面に粘着材が付着された市販の熱伝導シートを使用することができる。熱伝導シートに付着されている粘着材を利用して、それぞれの試料極２および共通の対極３を構造物１の表面上に貼り付けることが可能となる。 The plurality of sample electrodes 2 and the common counter electrode 3 are preferably not formed by film formation but formed of a bulk material.
Further, as the heat conductive sheets 6 and 7, commercially available heat conductive sheets having an adhesive material adhered to both surfaces can be used. The sample electrode 2 and the common counter electrode 3 can be stuck on the surface of the structure 1 using the adhesive attached to the heat conductive sheet.

計測部５は、ケーブル４を介して接続された複数の試料極２をそれぞれ共通の対極３に接続することにより形成される複数の腐食回路を流れる複数の腐食電流Ｉｃを測定する。具体的には、計測部５は、複数の試料極２のうちの１つの試料極２を共通の対極３に接続することで形成される１つの腐食回路を流れる腐食電流Ｉｃを測定した後、この試料極２を共通の対極３から遮断し、次の試料極２を共通の対極３に接続することで形成される次の腐食回路を流れる腐食電流Ｉｃを測定する。このようにして、複数の試料極２が順次共通の対極３に接続され、それぞれ形成された腐食回路を流れる腐食電流Ｉｃが測定される。
計測部５は、さらに、複数の腐食回路を流れる複数の腐食電流Ｉｃをそれぞれ時間積分することにより、複数の試料極２における腐食速度をそれぞれ算出し、これらの腐食速度に基づいて所定の方向Ｄにおける腐食速度の分布を計測する。 The measurement unit 5 measures a plurality of corrosion currents Ic flowing through a plurality of corrosion circuits formed by connecting the plurality of sample electrodes 2 connected via the cable 4 to the common counter electrode 3, respectively. Specifically, the measuring unit 5 measures the corrosion current Ic flowing through one corrosion circuit formed by connecting one sample electrode 2 of the plurality of sample electrodes 2 to the common counter electrode 3, The sample electrode 2 is cut off from the common counter electrode 3 and the corrosion current Ic flowing through the next corrosion circuit formed by connecting the next sample electrode 2 to the common counter electrode 3 is measured. In this way, the plurality of sample electrodes 2 are sequentially connected to the common counter electrode 3, and the corrosion current Ic flowing through each formed corrosion circuit is measured.
The measuring unit 5 further calculates the corrosion rates at the plurality of sample electrodes 2 by time-integrating the plurality of corrosion currents Ic flowing through the plurality of corrosion circuits, respectively, and determines a predetermined direction D based on the corrosion rates. The distribution of the corrosion rate at is measured.

次に、実施の形態１に係る腐食センサの作用について説明する。
例えば、構造物１が、海水、河川水等に晒される箇所に設置された鋼構造物であり、所定の方向Ｄが水位変動方向である鉛直方向に設定されているものとする。共通の対極３は、所定の方向Ｄにおける複数の試料極２の配置位置をすべて含むように所定の方向Ｄに延びているので、構造物１の表面上に配置された複数の試料極２のうち最も下方に位置する試料極２が水中に没したときには、この試料極２の配置位置に対応する部分の共通の対極３も水中に没することとなる。 Next, the operation of the corrosion sensor according to the first embodiment will be described.
For example, it is assumed that the structure 1 is a steel structure installed at a location exposed to seawater, river water, or the like, and the predetermined direction D is set to a vertical direction which is a water level fluctuation direction. Since the common counter electrode 3 extends in the predetermined direction D so as to include all of the arrangement positions of the plurality of sample electrodes 2 in the predetermined direction D, the common counter electrode 3 has a plurality of sample electrodes 2 arranged on the surface of the structure 1. When the lowest sample electrode 2 is immersed in water, the common counter electrode 3 corresponding to the position where the sample electrode 2 is arranged is also immersed in water.

このとき、図３に示されるように、試料極２の表面と共通の対極３の表面とが水Ｗを介して電気的に接続され、計測部５がケーブル４を介して試料極２と共通の対極３とを接続することで、計測部５から試料極２、水Ｗおよび共通の対極３を経由して計測部５に戻る腐食回路が形成される。
ここで、試料極２に腐食反応（アノード反応）が生じ、試料極２の表面から鉄イオンＦｅ２＋が水Ｗに溶解して拡散すると、試料極２中に生成された電子ｅ−が計測部５を介して共通の対極３に供給され、共通の対極３の表面上に水Ｗを構成する水分子Ｈ２Ｏと水中に溶存している酸素分子Ｏ２と電子ｅ−が反応（カソード反応）して水酸化物イオンＯＨ−を生じる。 At this time, as shown in FIG. 3, the surface of the sample electrode 2 and the surface of the common counter electrode 3 are electrically connected via the water W, and the measuring unit 5 is connected to the sample electrode 2 via the cable 4. By connecting the counter electrode 3 to the counter electrode 3, a corrosion circuit returning from the measuring section 5 to the measuring section 5 via the sample electrode 2, the water W and the common counter electrode 3 is formed.
Here, when a corrosion reaction (anode reaction) occurs in the sample electrode 2 and iron ions Fe 2+ are dissolved and diffused in the water W from the surface of the sample electrode 2, electrons e − generated in the sample electrode 2 are measured by the measuring unit. 5, water molecules H 2 O, which are supplied to the common counter electrode 3 and constitute water W on the surface of the common counter electrode 3, oxygen molecules O 2 dissolved in the water, and electrons e − react (cathode reaction). ) To form hydroxide ions OH − .

このように、アノード反応とカソード反応が試料極２と共通の対極３においてそれぞれ生じることで、共通の対極３から計測部５を通って試料極２へ腐食電流Ｉｃが流れる。この腐食電流Ｉｃは、アノード反応とカソード反応の反応速度に依存したもの、すなわち、これらの反応に関与した鉄原子Ｆｅおよび酸素分子Ｏ２等の成分の量に依存したものとなる。 In this way, the anodic reaction and the cathodic reaction occur at the sample electrode 2 and the common counter electrode 3 respectively, so that the corrosion current Ic flows from the common counter electrode 3 to the sample electrode 2 through the measuring unit 5. The corrosion current Ic are those that depend on the reaction rate of the anodic reaction and the cathodic reaction, i.e., becomes dependent on the amount of components such as iron atoms Fe and molecular oxygen O 2 involved in these reactions.

同様にして、計測部５により複数の試料極２を順次共通の対極３に接続することで形成される複数の腐食回路を流れる腐食電流Ｉｃがそれぞれ測定される。
頻繁に水中に没したり、水の飛沫の影響を受けやすい位置に配置されている試料極２においては、アノード反応およびカソード反応の速度が速くなり、大きな腐食電流Ｉｃが流れる。一方、水位が上昇しても水中に没することがなく、また、水の飛沫の影響が及ばないような高い位置に配置されている試料極２においては、アノード反応およびカソード反応の速度が遅くなり、腐食電流Ｉｃは小さくなる。
このように、複数の試料極２には、それぞれ、配置位置の腐食環境性に応じた腐食電流Ｉｃが流れ、この腐食電流Ｉｃが計測部５により測定される。 Similarly, the corrosion current Ic flowing through the plurality of corrosion circuits formed by sequentially connecting the plurality of sample electrodes 2 to the common counter electrode 3 is measured by the measurement unit 5.
In the sample electrode 2 which is frequently submerged in water or arranged in a position susceptible to water splash, the speeds of the anodic reaction and the cathodic reaction are increased, and a large corrosion current Ic flows. On the other hand, in the sample electrode 2 which is not immersed in water even when the water level rises and is located at a high position where the influence of water splash does not affect, the speeds of the anode reaction and the cathode reaction are slow. And the corrosion current Ic becomes smaller.
As described above, the corrosion current Ic corresponding to the corrosive environment of the arrangement position flows through each of the plurality of sample electrodes 2, and the corrosion current Ic is measured by the measuring unit 5.

ここで、上述したように、複数の試料極２と共通の対極３は、互いに同一組成の材料から形成されており、電位差に起因した電子の加速が生じないように構成されている。
このため、それぞれの試料極２に対応して測定された腐食電流Ｉｃは、生成された電子の量に対応する。そこで、腐食電流Ｉｃから電子量を求め、腐食の反応式
Ｆｅ→Ｆｅ２＋＋２ｅ−
に入力することで、消費したＦｅのモル数すなわち重量を演算することができる。さらに、消費したＦｅの重量を時間で割れば、腐食速度を得ることができる。 Here, as described above, the plurality of sample electrodes 2 and the common counter electrode 3 are formed of materials having the same composition as each other, and are configured so that acceleration of electrons due to a potential difference does not occur.
Therefore, the corrosion current Ic measured for each sample electrode 2 corresponds to the amount of generated electrons. Then, the amount of electrons is calculated from the corrosion current Ic, and the corrosion reaction formula Fe → Fe 2 ++ 2e −
, The number of moles of consumed Fe, that is, the weight can be calculated. Further, the corrosion rate can be obtained by dividing the weight of consumed Fe by time.

このようにして、計測部５により、複数の試料極２のそれぞれにおける腐食速度が算出され、所定の方向Ｄにおける腐食速度の分布が計測される。
複数の試料極２は、それぞれ、構造物１を構成する材料と同一組成の材料から形成されているため、それぞれの試料極２に対して算出される腐食速度は、その試料極２と同じ高さに位置する部位の構造物１の腐食速度とみなすことができる。
従って、構造物１における腐食速度の分布が得られ、構造物１の所定の方向Ｄにおける腐食環境の変化を定量的に評価することが可能となる。 In this way, the measuring section 5 calculates the corrosion rate in each of the plurality of sample electrodes 2 and measures the distribution of the corrosion rate in the predetermined direction D.
Since each of the plurality of sample electrodes 2 is formed from a material having the same composition as the material constituting the structure 1, the corrosion rate calculated for each sample electrode 2 is the same as that of the sample electrode 2. It can be regarded as the corrosion rate of the structure 1 at the site located at the position.
Therefore, the distribution of the corrosion rate in the structure 1 is obtained, and it becomes possible to quantitatively evaluate the change in the corrosion environment in the predetermined direction D of the structure 1.

一般に、腐食速度は、対象物の温度により大きく変化することが知られている。しかし、実施の形態１に係る腐食センサでは、複数の試料極２は熱伝導シート６を介して構造物１の表面上に貼り付けられ、共通の対極３も熱伝導シート７を介して構造物１の表面上に貼り付けられるため、複数の試料極２および共通の対極３と構造物１の間に大きな温度差が発生することが抑制され、腐食速度を高精度に得ることができる。   In general, it is known that the corrosion rate greatly changes depending on the temperature of an object. However, in the corrosion sensor according to the first embodiment, the plurality of sample electrodes 2 are attached to the surface of the structure 1 via the heat conductive sheet 6, and the common counter electrode 3 is also connected to the structure via the heat conductive sheet 7. Since it is attached to the surface of the structure 1, a large temperature difference between the plurality of sample electrodes 2 and the common counter electrode 3 and the structure 1 is suppressed, and the corrosion rate can be obtained with high accuracy.

計測部５は、例えば、降雨時における腐食速度、１週間または１ケ月の腐食速度の平均等、種々の条件での腐食速度の分布を得ることができ、それらを比較・評価することにより、構造物１の腐食寿命の評価、メンテナンス計画の策定等に活用することが可能となる。   The measuring unit 5 can obtain a distribution of corrosion rates under various conditions, for example, a corrosion rate during rainfall, an average of the corrosion rates during one week or one month, and compare and evaluate the distribution to evaluate the structure. It can be used for evaluation of the corrosion life of the object 1 and formulation of a maintenance plan.

なお、上記の実施の形態１においては、複数の試料極２と共通の対極３とが互いに同一組成の材料から形成されていたが、計測部５で算出される腐食速度の値に影響を与えない程度の電位差を、複数の試料極２と共通の対極３との間に形成することもできる。このようにすれば、共通の対極３が単独で腐食する、試料極２と共通の対極３とでアノード反応とカソード反応が逆転する、等のおそれを回避することができる。
この場合、試料極２に対して共通の対極３を貴な材料で構成することが好ましい。具体的には、共通の対極３は、複数の試料極２と同一の材料を主成分とし且つ複数の試料極２より貴である材料から形成することができる。 In the first embodiment, the plurality of sample electrodes 2 and the common counter electrode 3 are formed of materials having the same composition as each other. However, this influences the value of the corrosion rate calculated by the measuring unit 5. An insignificant potential difference can be formed between the plurality of sample electrodes 2 and the common counter electrode 3. In this way, it is possible to avoid the possibility that the common counter electrode 3 is corroded by itself and that the anode reaction and the cathode reaction are reversed between the sample electrode 2 and the common counter electrode 3.
In this case, the common counter electrode 3 for the sample electrode 2 is preferably made of a noble material. Specifically, the common counter electrode 3 can be formed from a material containing the same material as the plurality of sample electrodes 2 as a main component and more noble than the plurality of sample electrodes 2.

例えば、鉄にクロムまたはニッケルを添加した合金鋼は、クロムまたはニッケルの添加量を増加するほど自然電位が貴になるため、構造物１が普通鋼からなる場合に、複数の試料極２を普通鋼から形成すると共に、共通の対極３をクロムまたはニッケルが添加された合金鋼から形成することで、試料極２に対して共通の対極３を貴な材料とすることができる。   For example, in the case of alloy steel in which chromium or nickel is added to iron, the spontaneous potential increases as the amount of chromium or nickel added increases. Therefore, when the structure 1 is made of ordinary steel, a plurality of sample electrodes 2 are commonly used. By forming the common counter electrode 3 from alloy steel to which chromium or nickel is added while forming the common counter electrode 3 from steel, the common counter electrode 3 with respect to the sample electrode 2 can be a noble material.

日本工業規格（ＪＩＳ）には、機械構造用合金鋼として、クロムモリブデン鋼（ＳＣＭ）のクロムの最大添加量は１．５％、ニッケルクロムモリブデン鋼（ＳＮＣＭ）のクロムの最大添加量は３．５％、ニッケルの最大添加量も３．５％と記載されている。そこで、最大添加量３．５％の範囲内でクロムまたはニッケルが添加された合金鋼あるいは最大添加量３．５％の範囲内でクロムが添加されると共に最大添加量３．５％の範囲内でニッケルが添加された合金鋼を用いて共通の対極３を形成すれば、計測部５で算出される腐食速度の値に影響を与えない程度の電位差を、複数の試料極２と共通の対極３との間に形成することが可能になる。   According to Japanese Industrial Standards (JIS), the maximum amount of chromium added to chromium molybdenum steel (SCM) is 1.5%, and the maximum amount of chromium added to nickel chromium molybdenum steel (SNCM) is 3. 5%, and the maximum addition amount of nickel is also described as 3.5%. Therefore, alloy steel to which chromium or nickel is added within the maximum addition amount of 3.5% or chromium is added within the maximum addition amount of 3.5% and the maximum addition amount is within the range of 3.5%. When the common counter electrode 3 is formed by using an alloy steel to which nickel is added by the above method, a potential difference that does not affect the value of the corrosion rate calculated by the measuring unit 5 is set to a common counter electrode with the plurality of sample electrodes 2. 3 can be formed.

構造物１としては、桟橋等の海洋構造物、水門または樋門等の河川構造物、橋梁等、水位が時間的に変動する海水、河川水に晒されたり、水の飛沫の影響を受けやすい構造物を好適に挙げることができる。
例えば、図４に示されるような水門施設１１の扉体１２を構造物１として、扉体１２に実施の形態１に係る腐食センサを設置することができる。
扉体１２は、図５に示されるように、一対のワイヤ１３で吊り下げられて昇降するが、昇降に伴って水中または水上に位置するため、乾湿が繰り返されることが多く、水門施設１１の他の部位に比較して腐食速度が大きくなる傾向にある。 The structure 1 is exposed to seawater or river water whose water level fluctuates with time, or is susceptible to water droplets, such as a marine structure such as a pier, a river structure such as a sluice gate or a gutter, or a bridge. Structures can be suitably mentioned.
For example, the door 12 of the floodgate facility 11 as shown in FIG. 4 may be used as the structure 1, and the corrosion sensor according to the first embodiment may be installed on the door 12.
As shown in FIG. 5, the door body 12 is suspended by a pair of wires 13 and moves up and down. However, since the door body 12 is located underwater or above the water as it moves up and down, it often repeats wet and dry. Corrosion rates tend to be higher than at other sites.

そこで、図６に示されるように、所定の方向Ｄを鉛直方向に設定して、扉体１２の表面上に複数の試料極２と共通の対極３を貼り付け、これら複数の試料極２および共通の対極３にケーブル４を介して計測部５を電気的に接続することで腐食センサを形成する。
このように、実施の形態１に係る腐食センサを扉体１２に設置し、計測部５で複数の試料極２に対応する腐食電流Ｉｃを測定して、それぞれの試料極２における腐食速度を算出することにより、鉛直方向の腐食速度の分布を得ることができる。 Therefore, as shown in FIG. 6, the predetermined direction D is set to the vertical direction, a plurality of sample electrodes 2 and a common counter electrode 3 are attached on the surface of the door body 12, and the plurality of sample electrodes 2 and The corrosion sensor is formed by electrically connecting the measuring unit 5 to the common counter electrode 3 via the cable 4.
As described above, the corrosion sensor according to the first embodiment is installed on the door body 12, the corrosion current Ic corresponding to the plurality of sample electrodes 2 is measured by the measurement unit 5, and the corrosion rate at each sample electrode 2 is calculated. By doing so, a distribution of the corrosion rate in the vertical direction can be obtained.

実施の形態１に係る腐食センサでは、複数の試料極２が、互いに分離し独立し、それぞれ、絶縁性の熱伝導シート６を介して構造物１の表面上に貼り付けられ、共通の対極３も、複数の試料極２から独立し、絶縁性の熱伝導シート７を介して構造物１の表面上に貼り付けられるため、構造物１の構造および形状に関わらずに、複数の試料極２および共通の対極３を容易に構造物１の表面上に配置することができる。   In the corrosion sensor according to the first embodiment, the plurality of sample electrodes 2 are separated and independent from each other, are respectively attached to the surface of the structure 1 via the insulating heat conductive sheet 6, and the common counter electrode 3 is provided. Is also attached to the surface of the structure 1 via the insulating heat conductive sheet 7 independently of the plurality of sample electrodes 2, regardless of the structure and shape of the structure 1. And the common counter electrode 3 can be easily arranged on the surface of the structure 1.

例えば、図５に示したように、水門施設１１の扉体１２は、一般に、複数の桁または梁により複数部分に区切られた裏面構造を有しているので、桁または梁の上に水が残り、腐食しやすい環境になるおそれがあるが、実施の形態１に係る腐食センサを用いれば、区切られた部分に個別に試料極２を配置して、腐食速度の分布を評価することが可能となる。ただし、共通の対極３は、所定の方向Ｄにおける複数の試料極２の配置位置をすべて含むように所定の方向Ｄに延びている必要がある。   For example, as shown in FIG. 5, the door body 12 of the floodgate facility 11 generally has a back surface structure divided into a plurality of parts by a plurality of girders or beams. There is a possibility that the environment is likely to remain susceptible to corrosion. However, if the corrosion sensor according to the first embodiment is used, it is possible to arrange the sample electrodes 2 individually in the divided portions and evaluate the distribution of the corrosion rate. It becomes. However, the common counter electrode 3 needs to extend in the predetermined direction D so as to include all the arrangement positions of the plurality of sample electrodes 2 in the predetermined direction D.

実施の形態２
上記の実施の形態１においては、所定の方向Ｄに配列された複数の試料極２の配置位置をすべて含むように所定の方向Ｄに延びる共通の対極３が構造物１の表面上に貼り付けられていたが、これに限るものではなく、共通の対極を構造物によって形成することもできる。
図７に示される実施の形態２の腐食センサは、実施の形態１の腐食センサにおいて、構造物１の表面上に配置されていた共通の対極３を省略し、計測部５にケーブル４を介して構造物１を電気的に接続したものである。 Embodiment 2
In the first embodiment, the common counter electrode 3 extending in the predetermined direction D is attached on the surface of the structure 1 so as to include all the arrangement positions of the plurality of sample electrodes 2 arranged in the predetermined direction D. However, the present invention is not limited to this, and a common counter electrode can be formed by a structure.
The corrosion sensor according to the second embodiment shown in FIG. 7 differs from the corrosion sensor according to the first embodiment in that the common counter electrode 3 arranged on the surface of the structure 1 is omitted, and the measurement unit 5 is connected to the measurement unit 5 via the cable 4. The structures 1 are electrically connected to each other.

このような構成としても、計測部５が、複数の試料極２を順次共通の対極としての構造物１に接続することにより形成される腐食回路を流れる腐食電流Ｉｃを測定することで、実施の形態１と同様にして、それぞれの試料極２における腐食速度を算出し、所定の方向Ｄの腐食速度の分布を得ることが可能となる。
この実施の形態２では、構造物１の表面上に共通の対極を貼り付ける必要がなくなり、構造物１への腐食センサの設置がさらに容易となる。 Even in such a configuration, the measuring unit 5 measures the corrosion current Ic flowing through the corrosion circuit formed by sequentially connecting the plurality of sample electrodes 2 to the structure 1 as a common counter electrode, thereby realizing the implementation. In the same manner as in Embodiment 1, it is possible to calculate the corrosion rate in each sample electrode 2 and obtain the distribution of the corrosion rate in the predetermined direction D.
In the second embodiment, it is not necessary to attach a common counter electrode on the surface of the structure 1, and the installation of the corrosion sensor on the structure 1 is further facilitated.

例えば、構造物１が、図５に示した扉体１２のように、複数の桁または梁により複数部分に区切られた構造を有していても、複数の試料極２を互いに分離して構造物１の表面上に貼り付け、これら複数の試料極２と構造物１を計測部５に電気的に接続するだけで、腐食センサを設置することができ、容易に構造物１における腐食速度の分布を評価することが可能となる。   For example, even if the structure 1 has a structure divided into a plurality of portions by a plurality of beams or beams as in the door body 12 shown in FIG. 5, a plurality of sample electrodes 2 are separated from each other. The corrosion sensor can be installed simply by sticking on the surface of the object 1 and electrically connecting the plurality of sample electrodes 2 and the structure 1 to the measuring unit 5, and the corrosion rate of the structure 1 can be easily determined. The distribution can be evaluated.

なお、図１、図６および図７では、５個の試料極２が所定の方向Ｄに配列されていたが、試料極２の個数は５個に限るものではなく、複数の任意の個数の試料極２を所定の方向Ｄに沿って配列し、これらの試料極２を計測部５に接続して腐食速度の分布を計測することができる。
また、複数の試料極２が配列される所定の方向Ｄは、鉛直方向に限らず、腐食環境の変化を評価しようとする任意の方向に設定することができる。 In FIGS. 1, 6 and 7, five sample electrodes 2 are arranged in the predetermined direction D. However, the number of sample electrodes 2 is not limited to five, and a plurality of arbitrary number The sample electrodes 2 are arranged in a predetermined direction D, and these sample electrodes 2 are connected to the measuring unit 5 to measure the distribution of the corrosion rate.
The predetermined direction D in which the plurality of sample electrodes 2 are arranged is not limited to the vertical direction, and may be set to any direction in which a change in the corrosive environment is to be evaluated.

１ 構造物、２ 試料極、３ 共通の対極、４ ケーブル、５ 計測部、６，７ 熱伝導シート、１１ 水門施設、１２ 扉体、１３ ワイヤ、Ｄ 所定の方向、Ｗ 水、Ｉｃ 腐食電流。   1 structure, 2 sample electrodes, 3 common counter electrodes, 4 cables, 5 measuring units, 6,7 heat conductive sheet, 11 sluice facility, 12 door body, 13 wires, D predetermined direction, W water, Ic corrosion current.

Claims (8)

計測対象となる構造物の所定の方向における腐食速度の分布を計測するための腐食センサにおいて、
前記所定の方向に配列され且つそれぞれ前記構造物の表面上に設置される複数の試料極と、
前記所定の方向における前記複数の試料極の配置位置を含むように前記複数の試料極に並んで前記所定の方向に延び且つ前記構造物の表面上に配置された共通の対極と、
前記複数の試料極および前記共通の対極に接続され且つ前記複数の試料極をそれぞれ前記共通の対極に接続することにより形成される複数の腐食回路を流れる複数の腐食電流に基づいて前記所定の方向における腐食速度の分布を計測する計測部と
を備え、
前記複数の試料極および前記共通の対極は、前記構造物の表面において同一面上に並んで配置されていることを特徴とする腐食センサ。 In a corrosion sensor for measuring the distribution of corrosion rate in a predetermined direction of the structure to be measured,
A plurality of sample poles arranged in the predetermined direction and each placed on the surface of the structure,
A common counter electrode that extends in the predetermined direction along with the plurality of sample electrodes so as to include the arrangement position of the plurality of sample electrodes in the predetermined direction, and is disposed on the surface of the structure;
The predetermined direction based on a plurality of corrosion currents flowing through a plurality of corrosion circuits connected to the plurality of sample electrodes and the common counter electrode and formed by connecting the plurality of sample electrodes to the common counter electrode, respectively. and a measuring unit for measuring the distribution of the corrosion rate in,
The corrosion sensor according to claim 1, wherein the plurality of sample electrodes and the common counter electrode are arranged on the same surface on the surface of the structure . 前記複数の試料極は、前記構造物を構成する材料と同一の材料からなる請求項１に記載の腐食センサ。   The corrosion sensor according to claim 1, wherein the plurality of sample electrodes are made of the same material as a material constituting the structure. 前記共通の対極は、前記複数の試料極と同一の材料からなる請求項２に記載の腐食センサ。   The corrosion sensor according to claim 2, wherein the common counter electrode is made of the same material as the plurality of sample electrodes. 前記共通の対極は、前記複数の試料極と同一の材料を主成分とし且つ前記複数の試料極より貴である材料からなる請求項２に記載の腐食センサ。   3. The corrosion sensor according to claim 2, wherein the common counter electrode is mainly composed of the same material as the plurality of sample electrodes and is made of a material which is more noble than the plurality of sample electrodes. 4. 前記複数の試料極は、絶縁性の熱伝導シートを介して前記構造物の表面上に貼り付けられる請求項１〜４のいずれか一項に記載の腐食センサ。   The corrosion sensor according to claim 1, wherein the plurality of sample electrodes are attached to a surface of the structure via an insulating heat conductive sheet. 前記共通の対極は、絶縁性の熱伝導シートを介して前記構造物の表面上に貼り付けられる請求項１〜５のいずれか一項に記載の腐食センサ。   The corrosion sensor according to any one of claims 1 to 5, wherein the common counter electrode is attached to a surface of the structure via an insulating heat conductive sheet. 前記共通の対極は、前記構造物により形成されている請求項１〜５のいずれか一項に記載の腐食センサ。   The corrosion sensor according to claim 1, wherein the common counter electrode is formed by the structure. 前記計測部は、前記複数の試料極のそれぞれに対して、前記試料極を前記共通の対極に接続することにより形成される腐食回路を流れる腐食電流を時間積分することにより前記試料極が設置された箇所における前記構造物の腐食速度を計測する請求項１〜７のいずれか一項に記載の腐食センサ。   The measurement unit is provided with the sample electrode by time-integrating a corrosion current flowing through a corrosion circuit formed by connecting the sample electrode to the common counter electrode for each of the plurality of sample electrodes. The corrosion sensor according to any one of claims 1 to 7, wherein a corrosion rate of the structure at a location where the corrosion has occurred is measured.
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