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 MSA  Vol.11 No.7 , July 2020
A Study of Water Treatment Chemical Effects on Type I” Pitting Corrosion of Copper Tubes
Abstract: It is known that one of the causes of pitting corrosion of copper tubes is residual carbon on the inner surface. It was confirmed that type I” pitting corrosion of the copper tube is suppressed by keeping the residual carbon amount at 2 mg/m2 or less, which is lower than that of the type I’ pitting corrosion, or by removing the fine particles that are the corrosion product of galvanized steel pipes. The developed water treatment chemical was evaluated using three types of copper tubes with residual carbon amounts of 0 mg/m2, 0.5 mg/m2, and 6.1 mg/m2. The evaluation was conducted for three months in an open-circulation cooling water system and compared with the current water treatment chemical. Under the current water treatment chemical conditions, only the copper tube with a residual carbon amount of 6.1 mg/m2 showed a significant increase in the natural corrosion potential after two weeks, and pitting corrosion occurred. No pitting corrosion and no increase in the natural corrosion potential were observed in any of the copper tubes that were treated with the developed water treatment chemical. In addition, the polarization curve was measured using the cooling water from this field test, and the anodic polarization of two cooling waters was compared. For copper tubes with a large amount of residual carbon, the current density near 0 mV vs. Ag/AgCl electrode (SSE) increased when the developed water treatment chemical was added.
Cite this paper: Iyasu, T. , Kuratani, M. , Ikeda, I. , Tanaka, N. , Yamada, Y. and Sakurada, O. (2020) A Study of Water Treatment Chemical Effects on Type I” Pitting Corrosion of Copper Tubes. Materials Sciences and Applications, 11, 494-504. doi: 10.4236/msa.2020.117034.
References

[1]   Cornwall, F.J., Wildsmith, G. and Gilbert, P.T. (1976) Pitting Corrosion in Copper Tubes in Cold Water Service. ASTM STP-576, 155-179.
https://doi.org/10.1520/STP41404S

[2]   Seri, O., Jimbo, Y. and Sakai, M. (2006) Effects of Debris and Residual Carbon Film in Circulated Water Containing a Corrosion Inhibiter on Pitting Attack of Copper Tubes for Air Conditioning System. Zairyo-to-Kankyo, 55, 505-510.
https://doi.org/10.3323/jcorr.55.505

[3]   Mitamura, Y., Ninomiya, M., Daikuhara, T., Inoue, Y. and Yamada, Y. (2013) Effect of Residual Free Carbon on Localized Corrosion of Copper Pipe Filled with Cooling Water during Winter Season. Journal of Japan Institute of Copper, 52, 153-157.

[4]   Yamanaka, H., Nagai, T., Nonaka., H,. Tsuchiya, H. and Fujimoto, S. (2020) Effects of Deposits on Corrosion of Copper Tubes in a Circulating Cooling Water System. Zairyo-to-Kankyo, 69, 17-25.
https://doi.org/10.3323/jcorr.69.17

[5]   Yamada, Y., Mizutani, K. and Inoue, Y. (2014) Development of Corrosion Protection Research for Copper Tube over the Last Few Decades and Future Prospects. Zairyo-to-Kankyo, 63, 158-162.

[6]   Yamada, Y., Kawano, K., Suzuki, S. and Atsumi, T. (1999) Pitting Corrosion of Copper Soft Tubes in Well Water. Zairyo-to-Kankyo, 48, 647-653.
https://doi.org/10.3323/jcorr1991.48.647

[7]   Yamada, Y., Mori, A., Hatanaka, R., Atsumi, T. and Nakao, N. (1998) Pitting Corrosion of Copper Coiled Tubes in the Air Conditioning System having the Open Heat Storage Water Tank. Zairyo-to-Kankyo, 47, 723-728.
https://doi.org/10.3323/jcorr1991.47.723

[8]   Yamada, Y. (2019) Development of Corrosion Protection Research for Copper Tube in Recent Years and Future Prospects. Refrigeration, 94, 73-77.

[9]   Mitamura, Y., Ninomiya, M., Daikuhara, T., Inoue, Y., Komukai, S. and Yamada, Y. (2012) Effect of Residual Free Carbon on Pitting Corrosion of Copper Pipe in Open Circulating Cooling Water. Journal of Japan Institute of Copper, 51, 186-190.

[10]   Sakai, M., Seri, O., Yamada, Y., Toda, I. and Iitsuka, M. (2002) Effect of Residual Carbon Deposits on Corrosion Behavior of Copper Tube Filled with Water. Zairyo-to-Kankyo, 51, 12-16.
https://doi.org/10.3323/jcorr1991.51.12

[11]   Yamada, Y., Nagata, K. and Tagashira, K. (1992) Pitting Corrosion of Copper Tube in a Phosphonic Acid Solution. Sumitomo Light Metal Technical Reports, 33, 223-229.

 
 
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