JP3678406B2 - In-situ measurement method for corrosion rate of steel structures. - Google Patents
In-situ measurement method for corrosion rate of steel structures. Download PDFInfo
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【０００１】
【発明の属する技術分野】
この出願の発明は、鋼構造物の腐食速度のその場測定方法に関し、橋梁、ビルディングに代表される鋼構造物の腐食速度、特に環境因子の変化に伴い時々刻々と変化する腐食速度を連続的にかつリアルタイムに測定することのできる測定方法に関するものである。
【０００２】
【従来の技術とその解決課題】
鋼構造物の大気環境中における腐食は様々な環境因子の影響を受けており、非常に複雑で時々刻々と変化する。そのため、腐食の状況を連続的にかつリアルタイムに測定することは、橋梁、ビルディングに代表される鋼構造物の腐食性や寿命を評価する上で非常に重要である。大気環境中における金属材料の耐食性評価は、ＪＩＳ−Ｚ２３８１に規定された切板試験片の大気暴露による評価が主流であるが、大気暴露試験は、年単位のような長期での耐食性の比較はできるものの、その間での腐食現象の変化を捉えることはできず、また、通常は暴露試験場で行うため、どこでもできるという試験ではなかった。
【０００３】
一方、構造物を考えた場合、その形状は様々であり、各部位によってミクロな環境が異なるため、その腐食も部位ごとによって異なり、従来の切り板試験片を用いた暴露試験では、構造物のすべての部位の腐食状況を把握することは不可能である。
【０００４】
腐食性の変化を捉える方法としては、例えば、特開平７−１１３７４０号公報に開示されているが、この方法はコンピュータ室などの非常に緩やかな腐食現象での腐食性を調べるものであり、屋外のような環境によっては大きく腐食するような場所における腐食を評価することは不可能である。
【０００５】
また、構造物の各部位を考慮して腐食現象をモニタリングする方法としては、たとえば、特開昭５９−１４５６９８号公報に示されているものがある。この方法は実際の使用環境に同じ材料の試験片を設置し、実使用後に評価するという方法であり、従来の暴露試験と同様に時々刻々と変化する腐食現象を捉えることはできなかった。
【０００６】
これに対し、この出願の発明は、鋼構造物の様々な部位に絶縁層を介して、鋼製ピンとの間で交流測定を行うことにより、鋼構造物の部位別の腐食状況を連続的にかつリアルタイムに測定することを可能とする測定方法である。
【０００７】
【課題を解決するための手段】
この出願の発明は、鋼構造物の一部にセンサー電極を挿入することにより２電極式で連続測定を行う鋼構造物の腐食速度のその場測定方法において、鋼構造物の一部に挿入するセンサー電極として、狭い幅の絶縁層を挟んで鋼構造物と電気化学的性質の類似する鋼材料で製造されたピンを挿入し、鋼構造物本体と鋼製ピンとの間に電圧１０ｍＶ以上５０ｍＶ未満の交流を印加し、周波数０．０１Ｈｚ以下及び１０ＫＨｚ以上の２点の交流抵抗値を測定することを特徴とする鋼構造物の腐食速度のその場測定方法を提供する。
を提供する。
【０００８】
そして、この出願の発明は、鋼製のピンの形状が直径１ｍｍ以上５０ｍｍ未満の円筒状である上記の鋼構造物の腐食速度のその場測定方法を、さらに、狭い絶縁層の幅が１０μｍ以上１００μｍ以下である上記の鋼構造物の腐食速度のその場測定方法を提供する。
【０００９】
また、この出願の発明は、電気化学的性質が類似し、３％食塩水中における浸漬電位の差異が５０ｍＶ未満である上記の鋼構造物の腐食速度のその場測定方法をも提供する。
【００１０】
【実施の形態】
この出願の発明における鋼構造物は、鋼製の橋梁、鉄骨構造を有する建造物など、広く鋼を使用する人工構造物で、とりわけ腐食による劣化が危惧されるものを包含する。
【００１１】
この出願の発明は、鋼構造物の一部にセンサー電極を挿入することにより、２電極式で腐食速度を連続的に測定を行うことを特徴とする。
【００１２】
さらに、この出願の発明は、これらの鋼構造物の腐食速度を測定するために電気化学的性質の類似したピンを絶縁層を挟んで挿入することが特徴である。この際の絶縁層の材質は特に規定するものではないが、電気抵抗が１０6 Ω以上が望ましい。
【００１３】
この出願の発明では、鋼構造物本体と鋼製ピンとの間に電圧１０ｍＶ以上５０ｍＶ未満の交流を印加し、周波数０．０１Ｈｚ以下及び１０ＫＨｚ以上の２点の交流抵抗値を測定することを特徴とするが、これは実施例２に示したように、周波数０．０１Ｈｚ以下と１０ＫＨｚ以上での交流抵抗値の差と腐食速度との間に相関があるという発見に基づいている。
【００１４】
この際に電圧１０ｍＶ未満では測定値の精度が劣り、５０ｍＶ以上では鋼構造物と鋼製ピンのどちらかを分極することになり、それぞれの表面状態が変化してしまうため、腐食速度とは異なる別の反応に起因する抵抗値が得られる。
【００１５】
この出願の発明のピンの形状については、方形や楕円形など特に規定するものではないが、円筒形の場合、腐食速度の測定において電極形状による異方性がなく、より正確な測定が行えるという特徴がある。
【００１６】
直径の大きさは電極の相対する部分（周の長さ）に比例するが、直径１ｍｍ未満の場合、測定する面積が小さくなるため、交流抵抗値が不安定で測定値の精度が劣り、５０ｍｍ以上では、電極表面での電流の分布が生じるため、腐食速度に対応する正確な抵抗値を得ることができない。
【００１７】
また、この出願の発明では、絶縁層の幅の下限は特に規定するものではないが、１０μｍ未満の場合、加工上の問題から電極間の絶縁が非常に困難であり、また１００μｍより大きい場合では、実施例３に示したように測定値に絶縁層の抵抗値の影響が生じるため、１００μｍ以下と規定した。
【００１８】
さらに、この出願の発明では、インピーダンスの測定において２電極式手法を採るため、鋼構造物もしくはピン電極のどちらか一方が腐食進行する場合、腐食速度に対応しない抵抗値が得られる。そのため、本手法ではピンの材質について鋼構造物の腐食挙動と同一なものとすることが特徴である。
【００１９】
電気化学的性質としては、３％食塩水中における浸漬電位の差異が５０ｍＶ未満の場合、ほぼ類似した腐食挙動をとることから、ピンの材質について電気化学的性質を規定する。
【００２０】
以下、実施例にしたがい、この出願の発明をさらに詳細に説明する。
【００２１】
【実施例】
（実施例１）
この出願の発明における測定システムが図１、図２に示される。
【００２２】
鋼構造物の各部位（１）（１）の中央部にセンサー電極（２）を４フッ化エチレンを重合した合成樹脂製の絶縁層（３）を挟んで挿入し、電流電圧測定装置（４）によりセンサー電極（２）と鋼構造物（１）との間に電圧１０ｍＶ以上５０ｍＶ未満の正弦交流電圧を印加する。
【００２３】
電圧と２電極間で流れる電流を周波数応答解析装置（５）で各周波数に対する電圧と電流の振幅と位相差を求め、高周波数側（例えば１０ＫＨｚ）及び低周波数側（例えば０．０１ＫＨｚ）のインピーダンスを求め、その差の逆数からコンピュータを用いて鋼構造物の腐食速度を連続的にかつリアルタイムに得ることができる。
【００２４】
測定する周波数については、図３に示すように、硫酸ナトリウム水溶液中におけるインピーダンスの周波数特性から１０ＫＨｚ以上及び０．０１ＫＨｚ以下では周波数依存性が殆どないことがわかる。
【００２５】
サンプルセンサーを用いてこの測定システムにより実際の屋外環境で測定した結果の一部を表１に示す。システムの測定条件は正弦交流電圧１０ｍＶ、測定周波数は１０ＫＨｚ及び０．０１Ｈｚである。このシステムにより時間に対する腐食速度の変化がリアルタイムに測定可能であることがわかる。
【００２６】
【表１】
（実施例２）
図４に、実測した腐食深さと腐食速度から計算した腐食深さについて比較したグラフを示す。実施例１で用いたサンプルセンサーにより、恒温恒湿槽内で３％ＮａＣｌ水溶液による腐食試験を行いながら図１のシステムにより腐食速度のその場測定を行ったときの結果である。システムの測定条件は正弦交流電圧１０ｍＶ、測定周波数は１０ｋＨｚ及び０．０１ｋＨｚである。
【００２８】
計算による腐食深さは得られた腐食速度について測定時間の積分により計算した値であり、実測した腐食深さは腐食試験後に表面の凹凸を光学的に測定したときの値である。両者の値は比例関係にあり、実測した腐食量と本発明の測定方法により得られた腐食量とが非常によく一致することが判る。
（実施例３）
挿入したピン（２）の形状及び絶縁層の幅に付いては、サンプルセンサーを用いて決定した。その結果を表２に示す。ピン（２）の直径が１ｍｍ未満の場合、測定電極の大きさが非常に小さいため、正弦交流電圧に対する測定電流が非常に小さくなり、測定値の精度が劣り、また、５０ｍｍ以上では、大気腐食がμｍオーダーの水膜上で進行することから、鋼構造物とピン電極間に流れる電流分布が不均一になりやすくなる。そのため、本発明のようにピン（２）の直径を１ｍｍ以上、５０ｍｍ未満にする必要がある。
【００２９】
絶縁層（３）については、４フッ化エチレンを重合した合成樹脂を用いた。これは、実施例１で用いたサンプルセンサーにおいて、絶縁層の幅を１００μｍ、５００μｍ、１０００μｍにしたときのインピーダンスの値である。
【００３０】
測定条件は正弦交流電圧１０ｍＶ、測定周波数は１０ｋＨｚ及び０．０１ｋＨｚであり、恒温恒湿槽内を温度２５°Ｃ、相対湿度９５％に保った状態で５％ＮａＣｌ水溶液で測定した。この恒温恒湿槽内の条件では、サンプルセンサー上に形成される水膜は肉眼で確認できるほど非常に厚い。１０ｋＨｚのときのインピーダンス値において、絶縁層の幅が５００μｍ、１０００μｍのときの値は、１００μｍのときの値よりも大きくなっており、絶縁層の幅に起因する抵抗が生じている。
【００３１】
一方、０．０１Ｈｚのときのインピーダンス値においては、腐食速度が０．０１Ｈｚのときのインピーダンス値と１０ｋＨｚのときのインピーダンス値との差の逆数に比例することから、１０ｋＨｚのときのインピーダンス値と比較して十分大きい必要がある。
【００３２】
【表２】
表２において、その差は絶縁層の幅が１００μｍの場合、約５５０Ωを示したが、その他の腐食センサでは殆ど差がなかった。
【００３４】
絶縁層の幅の下限値については、１０μｍ未満の場合、両電極間の抵抗が１ＫΩ以下になり絶縁が不十分であるため、腐食速度に対応しない抵抗値が得られる。
（実施例４）
挿入したピンの材質については、本測定システムにおいて市販の炭素鋼製のピン及び市販のステンレス鋼製のピンを電極としたときの測定データを表３に示す。
【００３５】
市販の炭素鋼製のピンは用いた鋼構造物と同一の材質であり、ステンレス鋼製のピンとは３％食塩水中における浸漬電位の差異が５０ｍＶ以上である。用いたピン電極は直径２５ｍｍ、幅１００μｍとし、測定条件は正弦交流電圧１０ｍＶ、測定周波数は１０ｋＨｚ及び０．０１Ｈｚとした。
【００３６】
【表３】
ステンレス鋼製のピン電極を用いた場合、１０ｋＨｚのときのインピーダンス値はほとんど変わらないが、 ０．０１Ｈｚでは、ほぼステンレス鋼製ピン電極自体のインピーダンス値が測定されており、実際の鋼構造物の腐食速度より非常に小さい値が測定される。
【００３８】
一方、鋼構造物と類似した電気化学的性質をもつ市販の炭素鋼製のピン電極では、鋼構造物の正確な腐食速度が得られている
【００３９】
【発明の効果】
この出願の発明によれば、構造物の様々な部位における腐食状況について、構造物を破壊することなく常にモニターすることができるので、従来型の暴露試験とは異なる新しい腐食性及び寿命評価法として期待できる。
【００４０】
従来、構造物の腐食を調査する場合、破壊した後に評価するという手法や部分的な採取により評価するという手法などをとるため、非常に莫大な労力と費用が掛かっていた。この出願の発明によれば、非破壊で構造物の腐食状況を連続的にモニタすることが可能であり、また、コンピュータを用いることにより、遠隔操作も可能であるから、従来と比較して非常に簡便にかつ最小限の労力で測定が可能となり、その経済的効果は極めて大きい。
【図面の簡単な説明】
【図１】この出願の発明の鋼構造物にピン電極を挿入したときの断面模式図である。
【図２】この出願の発明の測定システムを示す図である。
【図３】この出願の発明の測定方法により、硫酸ナトリウム水溶液中で測定したインピーダンスの周波数特性を示す図である。
【図４】この出願の発明の測定方法により、測定した腐食速度から計算した腐食量と光学的に実測した腐食深さを比較したグラフである。
【符号の説明】
１ 鋼構造物
２ ピン電極
３ 絶縁層
４ 電流電圧測定装置
５ 周波数応答解析装置
６ 計算機[0001]
BACKGROUND OF THE INVENTION
The invention of this application relates to a method for in-situ measurement of the corrosion rate of steel structures. The corrosion rate of steel structures represented by bridges and buildings, in particular, the corrosion rate that changes every moment with changes in environmental factors is continuously measured. In particular, the present invention relates to a measurement method capable of measuring in real time.
[0002]
[Prior art and solutions]
Corrosion of steel structures in the atmospheric environment is influenced by various environmental factors, and is very complex and changes from moment to moment. Therefore, continuous and real-time measurement of the corrosion state is very important in evaluating the corrosivity and life of steel structures represented by bridges and buildings. Corrosion resistance of metal materials in the atmospheric environment is mainly evaluated by atmospheric exposure of the test piece specimen specified in JIS-Z2381, but the atmospheric exposure test is a comparison of long-term corrosion resistance such as annual units. Although it was possible, the change in the corrosion phenomenon during that time could not be captured, and because it was normally performed at an exposure test site, it was not a test that could be done anywhere.
[0003]
On the other hand, when considering a structure, the shape varies, and the microenvironment varies depending on each part. Therefore, the corrosion also varies depending on the part. In the exposure test using a conventional cut plate test piece, It is impossible to grasp the corrosion status of all parts.
[0004]
As a method for capturing the change in corrosivity, for example, disclosed in Japanese Patent Application Laid-Open No. 7-113740, this method is for investigating the corrosivity in a very slow corrosive phenomenon such as a computer room. Depending on the environment, it is impossible to evaluate the corrosion in a place that corrodes greatly.
[0005]
Further, as a method of monitoring the corrosion phenomenon in consideration of each part of the structure, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 59-145698. This method is a method in which a test piece of the same material is installed in an actual use environment and evaluated after the actual use, and a corrosion phenomenon that changes every moment as in the conventional exposure test cannot be captured.
[0006]
On the other hand, the invention of this application continuously measures the corrosion status of each part of the steel structure by performing alternating current measurement with the steel pin through the insulating layer at various parts of the steel structure. It is a measurement method that enables measurement in real time.
[0007]
[Means for Solving the Problems]
The invention of this application is a method for in-situ measurement of corrosion rate of a steel structure in which a sensor electrode is inserted into a part of the steel structure to perform continuous measurement with a two-electrode type, and is inserted into a part of the steel structure. As a sensor electrode, a pin made of a steel material having an electrochemical property similar to that of a steel structure is inserted with a narrow-width insulating layer interposed therebetween, and a voltage of 10 mV or more and less than 50 mV between the steel structure body and the steel pin. AC was applied, provides situ measurements how the corrosion rate of the steel structure, characterized by measuring the AC resistance value of the frequency 0.01Hz below and 10KHz least two points.
I will provide a.
[0008]
The invention of this application relates to a method for in-situ measurement of the corrosion rate of the steel structure in which the shape of the steel pin is a cylindrical shape having a diameter of 1 mm or more and less than 50 mm, and the width of the narrow insulating layer is 10 μm or more. that provides in situ method of measuring the corrosion rate of the steel structures is 100μm or less.
[0009]
The invention of this application, electrical chemical properties similar, the difference in immersion potential in a 3% saline solution is also provides situ measurements how the corrosion rate of the steel structures is less than 50 mV.
[0010]
Embodiment
The steel structure in the invention of this application includes artificial structures using a wide range of steel, such as steel bridges and structures having a steel frame structure, especially those that are likely to be deteriorated due to corrosion.
[0011]
The invention of this application is characterized in that the corrosion rate is continuously measured by a two-electrode type by inserting a sensor electrode into a part of a steel structure.
[0012]
Further, the invention of this application is characterized in that pins having similar electrochemical properties are inserted with an insulating layer interposed therebetween in order to measure the corrosion rate of these steel structures. The material of the insulating layer at this time is not particularly specified, but it is desirable that the electric resistance is 10 6 Ω or more.
[0013]
In the invention of this application, an alternating current having a voltage of 10 mV or more and less than 50 mV is applied between the steel structure main body and the steel pin, and two points of AC resistance values of a frequency of 0.01 Hz or less and 10 KHz or more are measured. However, as shown in Example 2, this is based on the discovery that there is a correlation between the difference between the AC resistance values at frequencies of 0.01 Hz or less and 10 KHz or more and the corrosion rate.
[0014]
At this time, if the voltage is less than 10 mV, the accuracy of the measured value is inferior, and if it is 50 mV or more, either the steel structure or the steel pin will be polarized, and the respective surface conditions will change, which is different from the corrosion rate. A resistance value resulting from another reaction is obtained.
[0015]
The pin shape of the invention of this application is not particularly specified as a square or an ellipse, but in the case of a cylindrical shape, there is no anisotropy due to the electrode shape in the measurement of the corrosion rate, and more accurate measurement can be performed. There are features.
[0016]
The size of the diameter is proportional to the opposite part (peripheral length) of the electrode, but when the diameter is less than 1 mm, the area to be measured is small, so that the AC resistance value is unstable and the measurement value accuracy is inferior, 50 mm As described above, since current distribution occurs on the electrode surface, an accurate resistance value corresponding to the corrosion rate cannot be obtained.
[0017]
In the invention of this application, the lower limit of the width of the insulating layer is not particularly specified, but if it is less than 10 μm, it is very difficult to insulate the electrodes due to processing problems. As shown in Example 3, the measurement value was influenced by the resistance value of the insulating layer, so that it was defined as 100 μm or less.
[0018]
Furthermore, in the invention of this application, since the two-electrode method is employed in the impedance measurement, when either the steel structure or the pin electrode undergoes corrosion, a resistance value that does not correspond to the corrosion rate is obtained. Therefore, this method is characterized in that the pin material is the same as the corrosion behavior of the steel structure.
[0019]
As the electrochemical properties, when the difference in immersion potential in 3% saline is less than 50 mV, the corrosion behavior is almost similar, so the electrochemical properties are defined for the pin material.
[0020]
Hereinafter, the invention of this application will be described in more detail in accordance with examples.
[0021]
【Example】
(Example 1)
The measurement system in the invention of this application is shown in FIGS.
[0022]
A sensor electrode (2) is inserted into the central part of each part (1) (1) of the steel structure with a synthetic resin insulating layer (3) polymerized with tetrafluoroethylene interposed therebetween, and a current-voltage measuring device (4 ), A sine AC voltage of 10 mV or more and less than 50 mV is applied between the sensor electrode (2) and the steel structure (1).
[0023]
The frequency and current difference between the voltage and the current flowing between the two electrodes is obtained with a frequency response analyzer (5), and the impedance on the high frequency side (for example, 10 KHz) and low frequency side (for example, 0.01 KHz) is obtained. The corrosion rate of the steel structure can be obtained continuously and in real time using a computer from the reciprocal of the difference.
[0024]
As shown in FIG. 3, the frequency to be measured shows that there is almost no frequency dependence at 10 KHz or more and 0.01 KHz or less from the frequency characteristics of impedance in a sodium sulfate aqueous solution.
[0025]
Table 1 shows a part of the result of measurement in an actual outdoor environment using this measurement system using a sample sensor. The measurement conditions of the system are a sinusoidal AC voltage of 10 mV, and the measurement frequencies are 10 KHz and 0.01 Hz. It can be seen that the change in corrosion rate with time can be measured in real time with this system.
[0026]
[Table 1]
(Example 2)
FIG. 4 shows a graph comparing the actually measured corrosion depth and the corrosion depth calculated from the corrosion rate. It is a result when the in-situ measurement of the corrosion rate is performed by the system of FIG. 1 while performing the corrosion test with the 3% NaCl aqueous solution in the thermo-hygrostat by the sample sensor used in Example 1. The measurement conditions of the system are a sinusoidal AC voltage of 10 mV, and the measurement frequencies are 10 kHz and 0.01 kHz.
[0028]
The calculated corrosion depth is a value calculated by integrating the measurement time with respect to the obtained corrosion rate, and the actually measured corrosion depth is a value when the surface irregularities are optically measured after the corrosion test. Both values are in a proportional relationship, and it can be seen that the actually measured corrosion amount and the corrosion amount obtained by the measurement method of the present invention agree very well.
(Example 3)
The shape of the inserted pin (2) and the width of the insulating layer were determined using a sample sensor. The results are shown in Table 2. When the diameter of the pin (2) is less than 1 mm, the size of the measurement electrode is very small, so the measurement current with respect to the sine AC voltage is very small and the measurement accuracy is inferior. Proceeds on a water film of the order of μm, so that the current distribution flowing between the steel structure and the pin electrode tends to be non-uniform. Therefore, it is necessary to make the diameter of the pin (2) 1 mm or more and less than 50 mm as in the present invention.
[0029]
For the insulating layer (3), a synthetic resin obtained by polymerizing ethylene tetrafluoride was used. This is the impedance value when the width of the insulating layer is 100 μm, 500 μm, and 1000 μm in the sample sensor used in Example 1.
[0030]
The measurement conditions were a sinusoidal AC voltage of 10 mV, the measurement frequencies were 10 kHz and 0.01 kHz, and the measurement was performed with a 5% NaCl aqueous solution in a state where the temperature and humidity chamber was maintained at 25 ° C. and relative humidity of 95%. Under the conditions in this constant temperature and humidity chamber, the water film formed on the sample sensor is so thick that it can be confirmed with the naked eye. In the impedance value at 10 kHz, the values when the width of the insulating layer is 500 μm and 1000 μm are larger than the values when the width is 100 μm, and resistance due to the width of the insulating layer is generated.
[0031]
On the other hand, the impedance value at 0.01 Hz is proportional to the reciprocal of the difference between the impedance value at the corrosion rate of 0.01 Hz and the impedance value at 10 kHz, so it is compared with the impedance value at 10 kHz. And it needs to be big enough.
[0032]
[Table 2]
In Table 2, the difference was about 550Ω when the width of the insulating layer was 100 μm, but there was almost no difference in other corrosion sensors.
[0034]
As for the lower limit value of the width of the insulating layer, when it is less than 10 μm, the resistance between the two electrodes is 1 KΩ or less and the insulation is insufficient, so that a resistance value not corresponding to the corrosion rate is obtained.
(Example 4)
As for the material of the inserted pin, Table 3 shows measurement data when a commercially available carbon steel pin and a commercially available stainless steel pin are used as electrodes in this measurement system.
[0035]
A commercially available carbon steel pin is made of the same material as the steel structure used, and the difference in immersion potential in 3% saline is 50 mV or more from the stainless steel pin. The pin electrode used had a diameter of 25 mm and a width of 100 μm, the measurement conditions were a sine AC voltage of 10 mV, and the measurement frequencies were 10 kHz and 0.01 Hz.
[0036]
[Table 3]
When a stainless steel pin electrode is used, the impedance value at 10 kHz is almost the same, but at 0.01 Hz, the impedance value of the stainless steel pin electrode itself is measured, and the actual steel structure A value much smaller than the corrosion rate is measured.
[0038]
On the other hand, with a commercially available carbon steel pin electrode having electrochemical properties similar to those of a steel structure, an accurate corrosion rate of the steel structure can be obtained.
【The invention's effect】
According to the invention of this application, the corrosion status at various parts of the structure can be constantly monitored without destroying the structure. Therefore, as a new corrosiveness and life evaluation method different from the conventional exposure test, I can expect.
[0040]
Conventionally, when investigating the corrosion of a structure, it takes a tremendous amount of labor and cost because it takes a method of evaluating after destruction or a method of evaluating by partial sampling. According to the invention of this application, it is possible to continuously monitor the corrosion state of the structure without destruction, and remote control is possible by using a computer. Therefore, the measurement can be performed easily and with minimum labor, and the economic effect is extremely large.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view when a pin electrode is inserted into a steel structure of the invention of this application.
FIG. 2 is a diagram showing a measurement system of the invention of this application.
FIG. 3 is a diagram showing frequency characteristics of impedance measured in a sodium sulfate aqueous solution by the measurement method of the invention of this application.
FIG. 4 is a graph comparing the corrosion amount calculated from the measured corrosion rate and the optically measured corrosion depth by the measurement method of the invention of this application.
[Explanation of symbols]
DESCRIPTION OF
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| CN103808647A (en) * | 2012-11-05 | 2014-05-21 | 金祖权 | Cement based corrosion current sensor |
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| JP4895886B2 (en) * | 2006-03-29 | 2012-03-14 | 新日本製鐵株式会社 | Corrosion measurement sensor |
| JP4886577B2 (en) * | 2007-04-06 | 2012-02-29 | 新日本製鐵株式会社 | Corrosion rate measuring sensor, apparatus, and corrosion rate measuring method |
| JP5066160B2 (en) * | 2009-11-25 | 2012-11-07 | 株式会社神戸製鋼所 | Method for predicting steel sheet thickness reduction |
| US10401319B2 (en) * | 2017-01-16 | 2019-09-03 | The Boeing Company | Structural health monitoring system |
| JP7144203B2 (en) * | 2018-06-13 | 2022-09-29 | 三菱重工業株式会社 | Corrosion sensor and manufacturing method of corrosion sensor |
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| CN103808647A (en) * | 2012-11-05 | 2014-05-21 | 金祖权 | Cement based corrosion current sensor |
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