A laboratory study of the failure analysis of copper tube used in the air conditioning heat exchanger

• Published in: Materials and corrosion 2024-07, Vol.75 (7), p.924-931
• Main Authors: Wang, Zhongqi, Li, Haihong, Cheng, Dayong, Qin, Shiteng, Li, Deshan, Zhang, Xintao
• Format: Article
• Language: English
• Subjects: Air conditioning; air conditioning heat exchanger; Carboxylic acids; Chemical composition; Copper; copper tube; corrosion; Corrosion mechanisms; Corrosion products; Electrochemical corrosion; Exhaust gases; Failure analysis; Failure mechanisms; Heat exchangers; Industrial wastes; Macrostructure; microstructure
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202314214

The failure behavior and the failure mechanisms of the copper tube used in the air conditioning heat exchanger were analyzed using macrostructure and microstructure examination and the chemical composition analysis of the corrosion products. Results showed that the corrosion of the exterior surface of the copper tube should be responsible for the failure of the air conditioning heat exchanger. The chemical compositions of the corrosion products mainly included Cu, O, C, P, S, Cl, and so forth. The corrosion mechanisms were electrochemical corrosion under the circumstances of a humid environment, oxygen, and some corrosive medium. The corrosive media were organic carboxylic acids, Cl−, H2S, and SO2, which came from air pollutants, the combustion of fuels, the automobile exhaust, and the industrial waste gas. One or more electrochemical corrosion destroyed the integrity of the copper tube and led to the failure of the air conditioning heat exchanger in advance. This study investigates the failure behavior and the failure mechanisms of copper tubes used in the air conditioning heat exchanger. Results showed that one or more electrochemical corrosions destroyed the integrity of the copper tube and brought about the failure of the air conditioning heat exchanger in advance.