JP2519786B2 - Method for detecting the degree of coating film deterioration of painted metal parts - Google Patents
Method for detecting the degree of coating film deterioration of painted metal partsInfo
- Publication number
- JP2519786B2 JP2519786B2 JP63277126A JP27712688A JP2519786B2 JP 2519786 B2 JP2519786 B2 JP 2519786B2 JP 63277126 A JP63277126 A JP 63277126A JP 27712688 A JP27712688 A JP 27712688A JP 2519786 B2 JP2519786 B2 JP 2519786B2
- Authority
- JP
- Japan
- Prior art keywords
- coating film
- metal member
- coated metal
- degree
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の目的】 （産業上の利用分野） この発明は、塗膜を有する塗装金属部材、例えば自動
車のボディ外板において、ピンホール等の塗膜欠陥部分
や塗膜はく離部分の発生による塗膜の劣化の程度を検出
してその防錆能力を評価するのに利用される塗装金属部
材の塗膜劣化度検出方法に関するものである。 （従来の技術） 塗装金属部材の塗膜の劣化度を検出してその防錆能力
を評価するのに利用される従来の方法としては、例え
ば、コロージョンレートメータ法，タンジェストデルタ
法，インピーダンス測定法などがある。 これらのうち、コロージョンレートメータ法は、第５
図に示すように、金属板31の表面に塗膜32を形成させた
塗装金属部材33の塗膜防錆能力を評価するに際し、塗装
金属部材33の塗膜32に、容器34内に収容した電解液35を
接触させた状態とし、電解液35中に基準極36と対極37と
を設け、基準極（Ｒ）36と対極（Ｃ）37と塗装金属部材
（Ｗ）33との間にメインユニット38より通電して塗装金
属部材33を分極させ、このときに流れる電流や一定時間
に流れる電気量を測定することによって、塗膜32の劣化
度を推定する方法である。 また、タンジェントデルタ法は、電解液に浸漬させた
対極と前記電解液と接触させた状態の塗装金属部材との
間に例えば400Hz程度の交流を印加してそのときの位相
差のタンジェントを測定することにより塗膜の劣化の程
度を推定する方法である。 さらに、インピーダンス法は、塗装金属部材に電解液
を接触させた状態にして、前記電解液に浸漬した電極と
塗装金属部材との間に広い周波数範囲で交流を印加し、
位相が45゜となる周波数の値によって塗膜のはく離の程
度を測定し、この周波数の値がはく離面積に比例するも
のとしてはく離の量を推定する方法である（「防食技
術」Vol.36,No.3,1976 第134頁〜141頁）。 （発明が解決しようとする課題） しかしながら、このような従来の塗装金属部材の塗膜
劣化度検出方法において、前二者のコロージョンレート
メータ法、およびタンジェントデルタ法では、塗装金属
部材が電解液と接触している状態において等価な電気回
路についての考察がなされておらず、単なる経験により
得られた方法に従って塗装金属部材の塗膜の劣化を評価
するようにしていたため、塗膜の劣化を定量的に評価す
ることができないという課題を有していた。 また、後者のインピーダンス測定法では、塗装金属部
材の塗膜のはく離面積を定量的に評価することが可能で
あるものの、塗膜にピンホール等の塗膜欠陥部分がある
場合には測定に誤差を生じやすく、塗膜の劣化を正しく
評価することができないことがあるという課題があっ
た。 （発明の目的） この発明は、上述した従来の課題にかんがみてなされ
たもので、塗膜を有する塗装金属部材において、ピンホ
ール等の塗膜欠陥部分や塗膜はく離部分を生じて劣化し
た塗膜について、ピンホール等の塗膜欠陥部分の面積お
よび塗膜はく離部分の面積を別々にそして各々定量的に
検出して、塗膜の劣化度合を定量的に評価することが可
能である塗装金属部材の塗膜劣化度検出方法を提供する
ことを目的としている。An object of the present invention is to provide a coating metal member having a coating film, for example, an automobile body outer panel, which has a coating film defect portion such as a pinhole or a coating peeling portion. The present invention relates to a method for detecting the degree of deterioration of a coating film of a coated metal member used to detect the degree of deterioration of the coated metal member and evaluate its rust preventive ability. (Prior Art) Conventional methods used to detect the degree of deterioration of a coating film of a coated metal member and evaluate its rust preventive ability include, for example, a corrosion rate meter method, a Tangest delta method, and impedance measurement. There is a law. Of these, the corrosion rate meter method is the fifth one.
As shown in the figure, in evaluating the coating film rust preventive ability of the coating metal member 33 having the coating film 32 formed on the surface of the metal plate 31, the coating film 32 of the coating metal member 33 was housed in the container 34. The electrolytic solution 35 is kept in contact with the reference electrode 36 and the counter electrode 37 in the electrolytic solution 35, and a main electrode is provided between the reference electrode (R) 36, the counter electrode (C) 37 and the coated metal member (W) 33. This is a method of estimating the degree of deterioration of the coating film 32 by energizing from the unit 38 to polarize the coated metal member 33 and measuring the current flowing at this time and the amount of electricity flowing for a certain period of time. Further, the tangent delta method applies an alternating current of, for example, about 400 Hz between the counter electrode immersed in an electrolytic solution and the coated metal member in a state of being in contact with the electrolytic solution, and measures the tangent of the phase difference at that time. This is a method of estimating the degree of deterioration of the coating film. Furthermore, the impedance method, in a state of contacting the electrolytic solution to the coating metal member, applying an alternating current in a wide frequency range between the electrode immersed in the electrolytic solution and the coating metal member,
It is a method of measuring the degree of peeling of the coating film by the value of the frequency at which the phase is 45 °, and estimating the amount of peeling as the value of this frequency is proportional to the peeling area ("Corrosion prevention technology" Vol. 36, No. 3, 1976, pp. 134-141). (Problems to be Solved by the Invention) However, in such a conventional coating film deterioration detection method for a coated metal member, in the former two cases of the corrosion rate meter method and the tangent delta method, the coated metal member is an electrolytic solution. No consideration was given to an equivalent electric circuit in the state of contact, and the deterioration of the coating film of the coated metal member was evaluated quantitatively because the deterioration of the coating film of the coated metal member was evaluated according to the method obtained by mere experience. It had a problem that it could not be evaluated. Also, in the latter impedance measurement method, it is possible to quantitatively evaluate the peeled area of the coating film of the coated metal member, but if the coating film has a defective portion such as a pinhole, the measurement error will occur. However, there is a problem that the deterioration of the coating film may not be evaluated correctly in some cases. (Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and in a coated metal member having a coating film, a coating film defective portion such as a pinhole or a coating peeling portion is generated and deteriorated. It is possible to quantitatively evaluate the degree of deterioration of the coating film by detecting the area of the coating film defect portion such as pinhole and the area of the coating film peeling portion separately and quantitatively. An object is to provide a method for detecting the degree of coating film deterioration of a member.
この発明は、塗膜を有する塗装金属部材のピンホール
等の塗膜欠陥部分や塗膜はく離部分の発生による塗膜の
劣化度を検出するに際し、塗装金属部材の塗膜表面に電
解液を接触させた状態にして、前記電解液に接する電極
と前記塗装金属部材との間に所定の間隔で周波数を変化
させた交流電圧を印加し、前記交流電圧の印加により前
記塗装金属部材の電気化学的インピーダンスの周波数変
化を生じさせ、前記電気化学的インピーダンスの周波数
変化における複数の変曲点のうち異なる変曲点によりそ
れぞれ前記塗膜のピンホール等の塗膜欠陥部分や塗膜は
く離部分の発生度合を別々に検出する構成としたことを
特徴としており、このような塗装金属部材の塗膜劣化度
検出方法の構成を上述した従来の課題を解決するための
手段としており、実施態様においては、電解液に接する
電極と塗装金属部材との間に一定の間隔で周波数を変化
させた交流電圧を印加することにより、４つの変曲点を
もつ塗装金属部材の電気化学的インピーダンス変化を前
記交流の周波数変化により発生させ、この４つの変曲点
をもつインピーダンスの周波数変化において第２の変曲
点の値によりピンホール等の塗膜欠陥部分の面積を検出
し、第２の変曲点の値と第４の変曲点の値とにより塗膜
はく離部分の面積を検出するというように、塗膜欠陥部
分の面積と塗膜はく離部分の面積とを並列の検出回路に
より分離して検出する。 この発明に係る塗装金属部材の塗膜劣化度検出方法の
実施に用いられる検出装置としては、電解液を収容して
いると共に前記電解液に接する電極をそなえ且つ塗膜を
有する塗装金属部材の前記塗膜に前記電解液の接触を可
能としたプローブと、前記プローブの電極と前記塗装金
属部材との間に所定の間隔で周波数を変化させた交流電
圧を印加する電源供給手段と、前記プローブの電解液と
前記塗装金属部材の塗膜とが接触した状態で前記プロー
ブの電極と前記塗装金属部材との間に前記電源供給手段
により所定の間隔で周波数を変化させた交流電圧を印加
することにより発生する複数の変曲点をもつインピーダ
ンスの周波数変化を測定して前記複数の変曲点のうち選
択された変曲点により前記塗膜のピンホール等の塗膜欠
陥部分や塗膜はく離部分の発生度合をそれぞれ別々に分
離して検出する検出手段と、を備えた構成のものとする
ことができる。 （発明の作用） この発明に係る塗装金属部材の塗膜劣化度検出方法で
は、上記の構成を有しているものであるから、所定の間
隔で周波数を変化させた交流電圧を印加することにより
発生する複数の変曲点をもつインピーダンスを測定して
当該インピーダンスの周波数変化において特定された変
曲点をとらえるようにし、塗装金属部材が電解液と接触
している状態で表わされる等価回路においてピンホール
等の塗膜欠陥部分と塗膜はく離部分との並列回路が形成
されるようにしているので、塗膜欠陥部分の面積と塗膜
はく離部分の面積とがそれぞれ別々に分離して演算され
うるものとなり、ピンホール等の塗膜欠陥部分および塗
膜はく離部分の発生度合がそれぞれ別々にそして各々定
量的に検出されて、塗装金属部材の塗膜の劣化度合が評
価される。 （実施例） 第１図はこの発明の実施例を示している。 第１図に示すように、塗装金属部材１は、金属板２の
例えば片面に塗膜３を有しているものであり、この塗膜
３側には、電解液４を収容すると共に前記電解液４と接
する電極５をそなえ且つ前記塗膜３に前記電解液４の接
触を可能とした筒状の容器６をそなえたプローブ７を固
定具8,8により固定してあり、塗膜３と容器５（プロー
ブ７）との間にシールリング９を介在させることによっ
て電解液４の漏れを防ぐようにしている。この場合、電
解液４としては、想定する腐食環境によっても異なる
が、通常の場合、0.5mol/（約３％）のNaCl水溶液が
用いられる。 このプローブ７の電極５と塗装金属部材１との間に
は、それぞれ通電線5a,1aを介して、定電圧電源11が接
続してあり、この定電圧電源11には、任意の周波数を発
生することができる発振器12が接続してあり、この定電
圧電源11と発振器12とで電源供給手段13を構成してい
る。 この電源供給手段13の定電圧電源11および発振器12に
は、前記電源供給手段13によって所定の間隔で周波数を
変化させた交流電圧を印加させた際に発生する複数の変
曲点をもつインピーダンスの周波数変化を測定して前記
複数の変曲点により塗膜のピンホール等の塗膜欠陥部分
の面積や塗膜はく離部分の面積をそれぞれ別々に算出す
る演算器（CPU）14が接続してあり、こららの演算結果
は表示器15で表示されるようにしてあって、この演算器
14と表示器15で検出手段16を構成している。 第２図は塗膜３が劣化していない部分の塗装金属部材
１とプローブ７との当接部分における電気的な等価回路
を示すものであって、Rsolは電解液４の抵抗、Cfは塗膜
３の測定面全体における静電容量、Rfは塗膜３の抵抗を
示している。 また、第３図は塗膜３が劣化している部分の塗装金属
部材１とプローブ７との当接部分における電気的な等価
回路を示すものであって、Rsolは電解液４の抵抗、Cfは
塗膜３の測定面全体における静電容量、Rfは塗膜３の抵
抗であってはく離面積に反比例する値、Cdlは塗膜３の
はく離部分における電気二重層容量、Rcは塗膜３のはく
離部分における反応抵抗を示し、この回路によって塗膜
３のはく離部分の面積を定量的に測定する電気回路が構
成されるようにしている。 また、同じく第３図に示す等価回路において、Rpはピ
ンホール内の溶液抵抗、Cdlpはピンホールの底部におけ
る電気二重層容量、Rcpはピンホールの底部における反
応抵抗を示し、この回路によって塗膜３のピンホール部
分（塗膜欠陥部分）の面積を定量的に測定する電気回路
が構成されるようにしている。 この実施例においては、塗装金属部材１として亜鉛め
っき鋼板を選び、金属板２（鋼板）の表面に塗膜３とし
てエポキシを25μｍの厚さで塗装した亜鉛めっき鋼板を
塩水噴霧試験に３ケ月供したのち、亜鉛めっき鋼板の電
気化学的インピーダンスを測定した。この結果を第４図
に示す。 第４図において、曲線１は前述した従来のインピーダ
ンス法によって評価できるが、曲線２では位相が45゜と
なる周波数が４個所現われるため評価することができな
い。なお、第４図の点線は第３図に示した等価回路を用
いてシミュレートしたものであり、実際の測定結果とよ
く対応している。 そこで、第４図において、曲線２のインピーダンスの
変曲点を高い方からf1,f2,f3,f4とすると、第３図に示
した等価回路について検討した結果、次のことが判明し
た。 まず、f2は回路定数と以下に示す関係がある。 f2＝1/（２πRpCf） …（１） また、等価回路あたりのRpをRpoとし、ピンホールの
面積をS1とすると、 f2＝1/（２πCfRfo/S1） …（２） S1＝f2×２πCfRpo …（３） f3＝1/（２πRpo/S1×Cdlpo×S1） ＝1/（２πRpoCdlpo） …（４） となり、（４）式からf3の値は常に一定であることがわ
かる。さらに、 Cdlp＝1/（２πRpo/S1f3） …（５） f4＝1/（２πCdlpR′） …（６） Ｒ′＝1/（２πf4Cdlp） …（７） ここで、Rfoは単位面積あたりのRfであり、S2ははく
離面積である。 したがって、（３）式でS1を求めることによりS2の値
も決定される。 次に、第４図の曲線２について計算を行うと、 f2＝3.3×103（Hz） Cf＝3.98×10-9（Ｆ） Rpo＝10（Ω・cm2） から、（３）式より、 S1＝8.3×10-4（cm2） f3＝1.5×103（Hz） であり、（５）式より、 Cdlp＝8.84×10-8（Ｆ） F4＝1.0×101 であり、（７）式より、 Ｒ′＝1.8×105 Rfo＝1.3×105（Ω・cm2） Rcpo＝1.6×104（Ω・cm2） であり、（８）式より、 S2＝7.2×101（cm2） となる。 したがって、ピンホールの面積は8.3×10-4cm2,はく
離面積は7.1×101cm2を得ることができ、塗膜３の劣化
度を検出することが可能である。 なお、定数項であるRpo,Rfo,RcpoCdlpo,Cfoの値は被
測定系である塗膜の種類に固有の量であり、あらかじめ
データセットとして適切な値を演算器（CPU）14に入力
しておく。This invention, when detecting the degree of deterioration of the coating film due to the occurrence of coating film defects such as pinholes and the like on the coated metal member having a coating film, the electrolytic solution is brought into contact with the coating surface of the coated metal member. In such a state, an alternating voltage whose frequency is changed at a predetermined interval is applied between the electrode in contact with the electrolytic solution and the coated metal member, and the electrochemical application of the coated metal member is performed by applying the alternating voltage. The frequency change of the impedance is caused, and the degree of occurrence of the coating film defect portion such as a pinhole of the coating film or the coating film peeling portion is caused by different inflection points among a plurality of inflection points in the frequency change of the electrochemical impedance. It is characterized in that it is configured to detect separately, the configuration of such a coating film deterioration detection method of the coating metal member is a means for solving the above-mentioned conventional problems, In the embodiment, by applying an alternating voltage with a frequency changed at a constant interval between the electrode in contact with the electrolytic solution and the coated metal member, the electrochemical impedance change of the coated metal member having four inflection points is applied. Is generated by the frequency change of the alternating current, and the area of the coating film defect portion such as a pinhole is detected by the value of the second inflection point in the frequency change of the impedance having the four inflection points, and the second inflection is detected. The area of the coating film peeling portion is detected by the parallel detection circuit such that the area of the coating film peeling portion is detected by the value of the bending point and the value of the fourth inflection point. To detect. As a detection device used for carrying out the method for detecting the degree of coating film deterioration of a coated metal member according to the present invention, the coating metal member containing an electrolytic solution and having an electrode in contact with the electrolytic solution, and having a coating film is used. A probe capable of contacting the coating solution with the electrolytic solution, a power supply means for applying an alternating voltage with a frequency changed at a predetermined interval between the electrode of the probe and the coated metal member, and the probe. By applying an alternating voltage whose frequency is changed at predetermined intervals by the power supply means between the electrode of the probe and the coating metal member in a state where the electrolytic solution and the coating film of the coating metal member are in contact with each other. The frequency change of the impedance having a plurality of inflection points generated is measured, and a coating defect portion such as a pinhole of the coating film or the coating peeling is performed by the selected inflection point among the plurality of inflection points. Min occurrence rate and detection means for detecting separated respectively separately, may be of a configuration with. (Operation of the Invention) Since the coating film deterioration detection method for a coated metal member according to the present invention has the above-mentioned configuration, it is possible to apply an AC voltage with a frequency changed at predetermined intervals. The impedance with multiple inflection points that occur is measured so that the inflection point specified by the frequency change of the impedance can be captured, and the pin in the equivalent circuit represented when the coated metal member is in contact with the electrolyte Since a parallel circuit of a coating film defective portion such as a hole and a coating film peeling portion is formed, the area of the coating film defective portion and the area of the coating peeling portion can be separately calculated. The degree of occurrence of coating film defects such as pinholes and coating peeling portions are detected separately and quantitatively, and the degree of deterioration of the coating film of the coated metal member is evaluated. Be done. (Embodiment) FIG. 1 shows an embodiment of the present invention. As shown in FIG. 1, the coated metal member 1 has a coating film 3 on one surface of a metal plate 2, for example. A probe 7 having an electrode 5 in contact with the liquid 4 and a cylindrical container 6 capable of contacting the electrolytic solution 4 with the coating film 3 is fixed by fixing tools 8 and 8. By interposing a seal ring 9 between the container 5 (probe 7), leakage of the electrolytic solution 4 is prevented. In this case, as the electrolytic solution 4, a 0.5 mol / (about 3%) NaCl aqueous solution is usually used, although it varies depending on the assumed corrosive environment. A constant voltage power source 11 is connected between the electrode 5 of the probe 7 and the coated metal member 1 via conducting wires 5a and 1a, respectively, and the constant voltage power source 11 generates an arbitrary frequency. Is connected to the oscillator 12, and the constant voltage power source 11 and the oscillator 12 constitute the power supply means 13. The constant voltage power supply 11 and the oscillator 12 of the power supply means 13 are impedances having a plurality of inflection points which are generated when an AC voltage whose frequency is changed at predetermined intervals by the power supply means 13 is applied. An arithmetic unit (CPU) 14 for measuring the frequency change and separately calculating the area of the coating film defect portion such as the pinhole of the coating film and the area of the coating film peeling portion by the plurality of inflection points is connected. The calculation results of these are displayed on the display unit 15.
The detection means 16 is composed of 14 and the display 15. FIG. 2 shows an electrical equivalent circuit of the contact portion between the coating metal member 1 and the probe 7 where the coating film 3 is not deteriorated, where Rsol is the resistance of the electrolytic solution 4 and Cf is the coating solution. The capacitance Rf of the entire measurement surface of the film 3 represents the resistance of the coating film 3. Further, FIG. 3 shows an electrical equivalent circuit in the contact portion between the coated metal member 1 and the probe 7 in the portion where the coating film 3 is deteriorated, where Rsol is the resistance of the electrolytic solution 4, Cf Is the capacitance of the coating 3 over the entire measuring surface, Rf is the resistance of the coating 3 and is inversely proportional to the peeling area, Cdl is the electric double layer capacitance at the peeling portion of the coating 3, and Rc is the coating 3 The circuit shows the reaction resistance in the peeled portion, and this circuit constitutes an electric circuit for quantitatively measuring the area of the peeled portion of the coating film 3. Also, in the equivalent circuit shown in FIG. 3, Rp is the solution resistance in the pinhole, Cdlp is the electric double layer capacitance at the bottom of the pinhole, and Rcp is the reaction resistance at the bottom of the pinhole. An electric circuit for quantitatively measuring the area of the pinhole portion (coating film defective portion) of No. 3 is configured. In this example, a galvanized steel sheet was selected as the coated metal member 1, and a galvanized steel sheet coated with epoxy as a coating film 3 at a thickness of 25 μm on the surface of the metal sheet 2 (steel sheet) was subjected to a salt spray test for 3 months. Then, the electrochemical impedance of the galvanized steel sheet was measured. The results are shown in FIG. In FIG. 4, the curve 1 can be evaluated by the conventional impedance method described above, but the curve 2 cannot be evaluated because four frequencies having a phase of 45 ° appear. The dotted line in FIG. 4 is simulated using the equivalent circuit shown in FIG. 3, and corresponds well with the actual measurement result. Therefore, in FIG. 4, assuming that the inflection points of the impedance of the curve 2 are f 1 , f 2 , f 3 , and f 4 from the highest point, the equivalent circuit shown in FIG. found. First, f 2 has the following relationship with the circuit constant. f 2 = 1 / (2πRpCf) (1) Also, if Rp per equivalent circuit is Rp o and the area of the pinhole is S 1 , then f 2 = 1 / (2πCfRf o / S 1 ) (2) S 1 = f 2 × 2πCfRp o (3) f 3 = 1 / (2πRp o / S 1 × Cdlp o × S 1 ) = 1 / (2πRp o Cdlp o ) (4) It can be seen that the value of f 3 is always constant. Furthermore, Cdlp = 1 / (2πRp o / S 1 f 3) ... (5) f 4 = 1 / (2πCdlpR ') ... (6) R' = 1 / (2πf 4 Cdlp) ... (7) Here, Rf o is Rf per unit area, and S 2 is a peeling area. Therefore, the value of S 2 is also determined by obtaining S 1 by the equation (3). Next, when the curve 2 in FIG. 4 is calculated, from f 2 = 3.3 × 10 3 (Hz) Cf = 3.98 × 10 -9 (F) Rp o = 10 (Ω · cm 2 ), (3) From the formula, S 1 = 8.3 × 10 −4 (cm 2 ) f 3 = 1.5 × 10 3 (Hz), and from the formula (5), Cdlp = 8.84 × 10 −8 (F) F 4 = 1.0 × 10 1 and from the formula (7), R ′ = 1.8 × 10 5 Rf o = 1.3 × 10 5 (Ω · cm 2 ) Rcp o = 1.6 × 10 4 (Ω · cm 2 ) and the formula (8) Therefore, S 2 = 7.2 × 10 1 (cm 2 ). Therefore, the area of the pinhole can be 8.3 × 10 −4 cm 2 and the peeling area can be 7.1 × 10 1 cm 2, and the degree of deterioration of the coating film 3 can be detected. Incidentally, a constant term Rp o, Rf o, the values of Rcp o Cdlp o, Cf o is the specific amount of the type of coating to be measured based arithmetic unit (CPU an appropriate value in advance as a data set ) Enter it in 14.
この発明に係る塗装金属部材の塗膜劣化度検出方法で
は、塗装金属部材の塗膜表面に電解液を接触させた状態
にして、前記電解液に接する電極と前記塗装金属部材と
の間に所定の間隔で周波数を変化させた交流電圧を印加
し、前記交流電圧の印加により前記塗装金属部材の電気
化学的インピーダンスの周波数変化を生じさせ、前記電
気化学的インピーダンスの周波数変化における複数の変
曲点のうち異なる変曲点によりそれぞれ前記塗膜のピン
ホール等の塗膜欠陥部分や塗膜はく離部分の発生度合を
別々に検出するようにしたから、ピンホール等の塗膜欠
陥部分と塗膜はく離部分の両方を有する劣化した塗膜を
もつ塗装金属部材において、塗膜欠陥部分の面積と塗膜
はく離部分の面積の両方を別々にそして各々定量的に検
出して、塗膜の劣化度合を定量的に評価することが可能
であるという著しく優れた効果がもたらされる。In the method for detecting the degree of coating film deterioration of a coated metal member according to the present invention, an electrolytic solution is brought into contact with the coating film surface of the coated metal member, and a predetermined amount is provided between the electrode in contact with the electrolytic solution and the coated metal member. An alternating voltage of which frequency is changed at intervals is applied to cause a frequency change of the electrochemical impedance of the coated metal member by the application of the alternating voltage, and a plurality of inflection points in the frequency change of the electrochemical impedance. Among them, different inflection points are used to detect the degree of occurrence of coating film defects such as pinholes and coating peeling portions of the coating film separately. Deterioration of the coating film on a coated metal member having a deteriorated coating film having both parts by detecting both the area of the coating film defect portion and the area of the coating film peeling portion separately and quantitatively. Significantly excellent effect that it is possible to quantitatively evaluate the case is provided.
第１図はこの発明に係る塗装金属部材の塗膜劣化度検出
方法の実施例を示す要部説明図、第２図は塗膜が劣化し
ていない部分の塗装金属部材とプローブとの当接部分に
おける電気的な等価回路を示す説明図、第３図は塗膜が
劣化している部分の塗装金属部材とプローブとの当接部
分における電気的な等価回路を示す説明図、第４図は亜
鉛めっき鋼板の塩水噴霧試験後における電気化学的イン
ピーダンスの周波数による変化を測定した結果を示すグ
ラフ、第５図は従来の塗装金属部材の塗膜劣化度検出方
法のうちのインピーダンス法の要部構成を示す説明図で
ある。 １……塗装金属部材、３……塗膜、４……電解液、５…
…電極、７……プローブ、13……電源供給段、16……検
出手段。FIG. 1 is an explanatory view of essential parts showing an embodiment of a method for detecting the degree of coating film deterioration of a coated metal member according to the present invention, and FIG. 2 is a contact between a coated metal member and a probe where the coating film is not deteriorated. FIG. 3 is an explanatory diagram showing an electrical equivalent circuit in a portion, FIG. 3 is an explanatory diagram showing an electrical equivalent circuit in a portion where the coating metal member and the probe are in contact with each other in a portion where the coating film is deteriorated, and FIG. FIG. 5 is a graph showing the results of measuring the change in the electrochemical impedance of a galvanized steel sheet after a salt spray test with frequency, and FIG. 5 is a main configuration of the impedance method in the conventional method for detecting the degree of deterioration of a coated metal member. FIG. 1 ... Painted metal member, 3 ... Coating film, 4 ... Electrolyte solution, 5 ...
... electrode, 7 ... probe, 13 ... power supply stage, 16 ... detection means.
フロントページの続き (56)参考文献 特開 昭59−34143（ＪＰ，Ａ) 特開 昭63−259456（ＪＰ，Ａ) 特開 昭61−57849（ＪＰ，Ａ) ”Ｐｒｏｃ．ｏｆ Ｓｙｍｐｏｓｉｕ ｍ ｏｎ Ｃｏｒｒｏｓｉｏｎ Ｐｒｏ ｔｅｃｔｉｏｎ ｂｙ Ｏｒｇａｎｉｃ Ｃｏａｔｉｎｇ”．Ｔｈｅ Ｅｌｅｃ ｔｒｏｃｈｅｍｉｃａｌ Ｓｏｃｉｅｔ ｙ．（1987）Ｐ．197〜207Continuation of the front page (56) Reference JP-A-59-34143 (JP, A) JP-A-63-259456 (JP, A) JP-A-61-57849 (JP, A) "Proc. Of Symposium on Corrosion" Protection by Organic Coating ". The Electrochemical Societ y. (1987) P. 197 ~ 207
Claims (1)
の塗膜欠陥部分や塗膜はく離部分の発生による塗膜の劣
化度を検出するに際し、塗装金属部材の塗膜表面に電解
液を接触させた状態にして、前記電解液に接する電極と
前記塗装金属部材との間に所定の間隔で周波数を変化さ
せた交流電圧を印加し、前記交流電圧の印加により前記
塗装金属部材の電気化学的インピーダンスの周波数変化
を生じさせ、前記電気化学的インピーダンスの周波数変
化における複数の変曲点のうち異なる変曲点によりそれ
ぞれ前記塗膜のピンホール等の塗膜欠陥部分や塗膜はく
離部分の発生度合を別々に検出することを特徴とする塗
装金属部材の塗膜劣化度検出方法。1. When detecting the degree of deterioration of a coating film due to the occurrence of coating film defects such as pinholes and the like on a coated metal member having a coating film, an electrolytic solution is applied to the coating surface of the coated metal member. In the contacted state, an alternating voltage with a frequency changed at a predetermined interval is applied between the electrode in contact with the electrolytic solution and the coated metal member, and the electrochemistry of the coated metal member is applied by applying the alternating voltage. Changes in the frequency of the electrochemical impedance, and different inflection points among a plurality of inflection points in the frequency change of the electrochemical impedance cause a film defect portion such as a pinhole of the film and a film peeling portion. A method for detecting the degree of coating film deterioration of a coated metal member, which is characterized in that the degree of detection is detected separately.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63277126A JP2519786B2 (en) | 1988-11-01 | 1988-11-01 | Method for detecting the degree of coating film deterioration of painted metal parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63277126A JP2519786B2 (en) | 1988-11-01 | 1988-11-01 | Method for detecting the degree of coating film deterioration of painted metal parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02122248A JPH02122248A (en) | 1990-05-09 |
| JP2519786B2 true JP2519786B2 (en) | 1996-07-31 |
Family
ID=17579156
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63277126A Expired - Lifetime JP2519786B2 (en) | 1988-11-01 | 1988-11-01 | Method for detecting the degree of coating film deterioration of painted metal parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2519786B2 (en) |
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|---|---|---|---|---|
| RU2520164C2 (en) * | 2012-07-20 | 2014-06-20 | Федеральное государственное бюджетное учреждение Научно-исследовательский институт проблем хранения Федерального агенства по государственным резервам | Forecast method of durability of industrial corrosion-protection paint coatings for metal surfaces |
| EP4354116A3 (en) * | 2022-10-12 | 2024-06-19 | Mazda Motor Corporation | Measurement apparatus for corrosion inspection |
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-
1988
- 1988-11-01 JP JP63277126A patent/JP2519786B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| "Ｐｒｏｃ．ｏｆＳｙｍｐｏｓｉｕｍｏｎＣｏｒｒｏｓｉｏｎＰｒｏｔｅｃｔｉｏｎｂｙＯｒｇａｎｉｃＣｏａｔｉｎｇ"．ＴｈｅＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＳｏｃｉｅｔｙ．（１９８７）Ｐ．１９７〜２０７ |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2520164C2 (en) * | 2012-07-20 | 2014-06-20 | Федеральное государственное бюджетное учреждение Научно-исследовательский институт проблем хранения Федерального агенства по государственным резервам | Forecast method of durability of industrial corrosion-protection paint coatings for metal surfaces |
| EP4354116A3 (en) * | 2022-10-12 | 2024-06-19 | Mazda Motor Corporation | Measurement apparatus for corrosion inspection |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02122248A (en) | 1990-05-09 |
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