Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly

2009   Vol. 10   No. 4   p. 613~618

Atmospheric corrosion mapping of copper surfaces from diffuse light scattering measurements by an optoelectronic sensor system

Marimuthu PAULVANNA NAYAKI^†1, Arunachalam P. KABILAN²

(¹Department of Electronics and Communication Engineering, PSNA College of Engineering and Technology, Dindigul 624622, India)
(²Department of Electronics and Communication Engineering, Chettinad College of Engineering and Technology, Karur 639114, India)
^†E-mail: paulmn5@yahoo.com
Received Feb. 18, 2008; revision accepted July 28, 2008; Crosschecked Feb. 9, 2009

Abstract: A novel light scattering technique for mapping metal surface corrosion is presented and its results on copper exposed to atmosphere are reported. The front end of the instrument is made up of a sensor module comprising a thin beam light emitting diode (LED) illuminating a small spot on the metal surface, and a matched pair of photodetectors, one for capturing the reflected light and the other for sampling the scattered light. The analog photocurrent signals are digitized and processed online by a personal computer (PC) to determine the corrosion factor defined in terms of the two current values. By scanning the sample surface using the light beam and by computing the corrosion factor values simultaneously, a three dimensional graph and a two dimensional contour map are generated in the PC using Matlab tools. The values of the corrosion factor measured in different durations of exposure to atmosphere, which obey a bilogarithmic law, testify to the validity of our mathematical model.

Key words: Light scattering, Optoelectronic sensor, Atmospheric corrosion mapping
doi:10.1631/jzus.A0820107             CLC number: TP212; TG172

References:

[1] Cramer, S.D., Covino, B.S.Jr. (Eds.), 2003. Corrosion Fundamentals, Testing and Protection. ASM Handbook, Volume 13A. ASM International, New York.

[2] Degueldre, C., Prey, S.O., Francioni, W., 1996. An inline diffuse reflection spectroscopy study of the oxidation of stainless steel under boiling water reactor conditions. Corr. Sci., 38:1763-1782.

[3] El-Mahdy, G.A., 2005. Atmospheric corrosion of copper under wet/dry cyclic conditions. Corr. Sci., 47(6):1370-1383.

[4] Fitzgerald, K.P., Nairn, J., Atrens, A., 1998. The chemistry of copper patination. Corr. Sci., 40(12):2029-2050.

[5] Fonseca, I.T.E., Picciochi, R., Mendonca, M.H., Ramos, A.C., 2004. The atmospheric corrosion of copper at two sites in Portugal: a comparative study. Corr. Sci., 46(3):547-556.

[6] Franey, J.P., Davis, M.E., 1987. Metallographic studies of the copper patina formed in the atmosphere. Corr. Sci., 27(7):659-668.

[7] Mansfeld, F., Tsai, S., 1980. Laboratory studies of atmosphere corrosion—weight loss and electro chemical measurements. Corr. Sci., 20(7):853-872.

[8] Marcus, P., 2002. Corrosion Mechanisms in Theory and Practice. Marcel Dekker Inc., New York.

[9] Roberge, P.R., 1999. Hand Book of Corrosion Engineering. McGraw Hill Professional, New York, p.10-55.

[10] Salnick, A., Faubel, W., Klewe-Nebenius, H., Vendl, A., Ache, H.J., 1995. Photothermal studies of copper patina formed in the atmosphere. Corr. Sci., 37(5):741-767.

[11] Shanly, C.W., Hummel R.E., Verink, E.D.Jr., 1980. Differential reflectometry of corrosion products of copper. Corr. Sci., 20(4):481-487.

[12] Urban, F.K.III, Hummel, R.E., Verink, E.D.Jr., 1982. Differential reflectometry of thin film metal oxides on copper, tungsten, molybdenum and chromium. Corr. Sci., 22(7):647-660.

[13] Veleva, L., Tomas, S.A., Marin, E., Cruz-Orea, A., Delgadillo, I., Alvarado-Gil, J.J., Quintana, P., Pomes, R., Sanchez, F., Vargas, H., et al., 1997. On the use of the photoacoustic technique for corrosion monitoring of metals: Cu and Zn oxides formed in tropical environments. Corr. Sci., 39(9):1641-1655.