金屬罐內(nèi)涂層破損區(qū)氣相定位檢測局部電化學探頭技術(shù)的研究.pdf

1、i金屬罐內(nèi)涂層破損區(qū)氣相定位檢測局部電化學探頭技術(shù)的研究摘 要金屬包裝罐在食品包裝行業(yè)有著廣泛的應(yīng)用。 不同種類和厚度的涂層表現(xiàn)出差異性的防腐蝕性能， 涂層的選擇尤為重要。 金屬罐內(nèi)涂層的破損會顯著縮短食品保質(zhì)期，從而降低產(chǎn)品的質(zhì)量。針對金屬包裝罐內(nèi)涂層破損的現(xiàn)象，定位涂層破損區(qū)域位置，檢測涂層破損程度，有助于改善金屬罐的生產(chǎn)工藝，提高產(chǎn)品的質(zhì)量。 因此， 需要開發(fā)能夠在金屬包裝罐的圓柱空間內(nèi)定位和檢測罐內(nèi)涂層局部破損區(qū)域的裝置， 使之

2、能夠應(yīng)用于金屬包裝罐內(nèi)涂層的缺陷定位檢測， 能夠掃描測量罐內(nèi)圓柱區(qū)側(cè)壁以及罐底平面區(qū)域的涂層表面電化學狀態(tài)， 快速、 準確地定位和評價涂層破損區(qū)域。基于包裝罐內(nèi)涂層局部區(qū)域缺陷的定位和檢測的目的， 本論文制備了用作涂層局部缺陷檢測的銀/氯化銀固體參比電極，該電極在 3.5%的氯化鈉溶液中具有良好的電位穩(wěn)定性和較長的壽命，滿足測量要求。利用自制的銀/氯化銀固體參比電極， 本文開發(fā)了能夠在圓柱空間內(nèi)定位檢測涂層破損區(qū)的氣相局部電化學檢測探頭

3、裝置，并且構(gòu)建了 XYZθ四維掃描坐標體系。結(jié)合開路電位法和電化學阻抗法， 采用該裝置掃描測量金屬罐內(nèi)涂層表面的電化學狀態(tài)， 定位和評價涂層破損區(qū)。 在檢測中首先需要在溶液體系中， 運用該探頭檢測金屬包裝罐的整體性平均電化學阻抗譜的低頻阻抗模值， 用以判斷金屬罐內(nèi)涂層是否存在較為明顯的破損； 因缺陷處的開路電位值和電化學阻抗值會明顯不同于非缺陷區(qū)域處， 針對具有缺陷的金屬包裝罐， 通過在氣相環(huán)境中測量其開路電位數(shù)值， 精確定位出破損區(qū)的

4、位置， 并通過電化學阻抗譜的測量， 進一步分析破損區(qū)涂層的電化學腐蝕信息。本論文采用該氣相局部電化學檢測探頭裝置定位檢測了金屬罐內(nèi)底縮區(qū)、 焊縫區(qū)、底面區(qū)、罐體區(qū)的開路電位和電化學阻抗響應(yīng)，并根據(jù)其相應(yīng)的變化判斷涂層破損區(qū)的位置和程度。 結(jié)果表明， 該裝置能夠在氣相環(huán)境中準確定位檢測金屬罐內(nèi)底縮區(qū)、焊縫區(qū)、底面區(qū)、罐體區(qū)的涂層破損位置和破損狀態(tài)，具有較高的分辨率和測試精度。 此外， 本論文還對不同缺陷大小的破損涂層做了討論研究，iiiL

5、ocal Local Electrochemical Electrochemical Probe Probe for for Detecting Detecting Inner InnerCoating Coating Defects Defects in in Metal Metal can can in in Atmosphere AtmosphereAbstract AbstractMetal can in the food pa

6、ckaging industry has a wide range of applications.Different kinds and thickness of coating exhibit different performance. Coatingselection is particularly important. Coating defects in metal can would significantlyshorte

7、n shelf life of food and lower its quality. In order to solve the problem of innercoating defects in metal can, locating and detecting defect area are helpful toimprove metal cans’ production process and products’ qualit

8、y. To this end, a localelectrochemical probe for detecting inner coating defects in metal can in cylindricalspace is needed. This device is going to locate and detect inner coating defects. Itshould be able to scan elect

9、rochemical information in planar and cylindrical area inmetal can, and quickly and accurately locate and evaluate defect area.For the purpose of locating and detecting inner coating defects in metal can, asolid Ag/AgCl r

10、eference electrode was prepared in this paper. The solid Ag/AgClreference electrode had good potential stability in 3.5% NaCl solution. It could meetthe requirements for open-circuit potential and electrochemical impedan

11、cespectroscopy test in metal can. Using the homemade solid Ag/AgCl referenceelectrode, a local electrochemical probe for detecting inner coating defects in metalcan in atmosphere was developed in this paper, and XYZθ sca

12、n coordinate system infour-dimensional was also constructed. It could get the electrochemical informationof metal can’s inner coating, locating and evaluating coating defects by using OCPand EIS measurements. In this tes

13、t, firstly detecting of average EIS of metal can in5%NaCl solution was needed to determine whether there is coating damage. Formetal can which has coating defects, the value of OCP and EIS at defect area aresignificantly

14、 different from the non-defect region. By measuring OCP value inatmosphere, it could pinpoint the location of the damaged area, and by measuringEIS, it could further analysis electrochemical information.In this paper the