The effect of relative humidity on the corrosion-resisting property of fluorocarbon coating

Yang Lixia1,2,3, Li Xiaogang1, Zhang Sanping2, Deng Hongda2, Lin An4
1School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, China
2Wuhan Institution of Materials Protection, Wuhan, China
3School of Material Science and Chemistry Engineering, China University of Geosciences, Wuhan, China
4College of Resources and Environmental Science, Wuhan University, Wuhan, China

Tóm tắt

The effect of relative humidity on the corrosion-resisting property of fluorocarbon coating was investigated by water vapor transmission technique and electrochemical impedance spectroscopy technique. Measurements were carried out on samples, which were tested in an accelerated corrosion environment for the same time (300, 500, 800 and 1000 h). The experimental results were obtained as follows: (i) The water absorption, coating resistance and corrosion rate of metal under the coating changed with relative humidity and aging time, the results obtained by EIS are good consistent with those by water vapor transmission technique; (ii) when the subject investigated presented two time constant, the goodness of fit by EEC R(C(R(CR))) was inferior to that by EEC R(C(R(QR))), but the error of parameters acquired from the former was smaller, by which we could analyze the experiment result quantitatively. With the appearance of diffusion layer on the metal, the difference of metal capacitance was aggravated, the error of parameters acquired from EEC R(C(R(C(RW)))) was bigger than that from EEC R(C(R(Q(RW)))).

Tài liệu tham khảo

Padget J C, Moreland P J. Use of AC Impedance in the Study of the Anti-corrosive Properties of Chlorine-containing Vinyl Acrylic Latex Co-polymers [J].Coating Technology, 1983, 55: 39–40 Leidheiser H, Granata R D. Ion Transport through Protective Polymeric Coatings Exposed to an Aqueous Phase [J].IBM Journal of Research and Development, 1988, 32(5): 582–590 Yaseen M, Funke W. Effect of Temperature on Water-absorption and Permeation Properties of Coatings [J].The Oil & colour Chemists Association, 1978, 61(88): 284–291 MARGARETA, HULDËN. Water Permeation in Coatings [J].Progress in Organic Coatings, 1985, 13: 171–194 Conde A. Electrochemical Impedance Spectroscopy for Studying the Degradation of Enamel Coatings [J].Corrosion Science, 2002, 44: 1555–1567 é Fréchette. Evaluation of the Corrosion Resistance of Painted Steels by Impedance Measurements [J].Corrision Science, 1992, 33(7): 1067–1081 Ursula Rammelt. Characterization of Active Pigments in Damage of Organic Coatings on Steel by means of Electrochemical Impedance Spectroscopy [J].Progress in Organic Coatings Organic Coatings, 1994, 24: 309–322 Catela A S L. EIS Evaluation of Attached and Free Polymer Films [J].Progress in Organic Coatings, 2000, 38: 1–7 Reinhard G. Application of Electrochemical Impedance Spectroscopy (EIS) for Characterizing the Corrosion-protective Performance of Organic Coatings on Metals [J].Progress in Organic Coatings, 1992, 21: 205–266 T Monetta. Protective Properties of Epoxy-based Organic Coatings on Mild Steel [J].Progress in Organic Coatings, 1993, 21: 353–369 Bonora P L, Deflorian F, Fedrizzi L. Electrochemical Impedance Spectroscopy as a Tool for Investigating under Paint Corrosion [J].Electrochemical Acta, 1996, 41 (7–8): 1073–1082 Dehri I, Erbil M. The Effect of Relative Humidity on the Atmospheric Corrosion of Defective Organic Coating Materials: an EIS Study with a New Approach [J].Corrosion Science, 2000, 42: 969–978