Long term Corrosion Behavior of Copper in Yunnan Tropical Rainforest Soil

Abstract:

The corrosion behavior of copper pipes buried in tropical rain forest soil environment for a long time was studied by weight-loss method, morphology analysis, composition analysis and electrochemical test in this paper. The results show that the average corrosion rate of the copper pipe after 16 years of burial is 2.5 μm/y, the law of corrosion weight loss conforms to the power function model, and its fitting equation is C=0.4273t_^-0.246. The corrosion products on the surface of the copper tube show a light green dense scale structure, which is well combined with the metal matrix. XPS、EDS and FTIR analysis results show that the main component of the corrosion product is copper green (Cu₂ (OH) ₂CO₃). The electrical test results show that after 16 years of burial, the corrosion rate of the copper tube decreases and the impedance value increases significantly, indicating that the corrosion product film has a good protective effect on the substrate and can effectively slow down the continuous development of the corrosion process.