What causes electrochemical corrosion of metals? How to apply sacrificial anode protection technology

Corrosion has always been a headache in the pipeline transportation of oil and natural gas, once the pipeline corrosion phenomenon, will lead to oil (natural gas) leakage, in the waste of resources at the same time also pollute our living environment, so we must do a good job of pipeline anticorrosion work. Nowadays, the most used anticorrosive technology is the sacrificial anode protection technology. This chapter will give you a detailed introduction to this problem. I hope it can be helpful for you to use magnesium alloy sacrificial anode!

Knowledge point 1: Causes of electrochemical corrosion of metals

As we know, pipelines are usually buried in the land, and the physical and chemical properties of each part of the soil are different. The metallographic structure of each part of the pipeline itself (quality defects, impurities, rough surface, etc.) will undergo physical and chemical reactions with the underground media. When the electrochemical reaction occurs between the pipeline and the land, a part of the metal in the pipeline is easily ionized, and the positively charged metal ions leave the metal and transfer to the soil. The electrons in this part of the pipe section are more and more excessive, and the potential is more and more negative, and the oxidation reduction reaction occurs, resulting in electrochemical corrosion.

Knowledge point 2: Application of sacrificial anode protection technology

The sacrifical anode protection technology can protect the buried metal pipe from electrochemical corrosion. When magnesium metal material with negative potential compared with steel pipe is connected to the steel pipe, the metal pipe will play an anti-corrosion role. The protected steel pipe forms a galvanic battery in the soil, which serves as a protection power source. The metal with a negative potential becomes the anode and is damaged in the process of output current, so as to achieve the function of protecting the steel pipe.