The prospect of using cathodic protection to solve anticorrosion of metal components

The cathodic protection of reinforced concrete water supply pipe is a kind of construction technology to protect the reinforced concrete pipe installed in corrosive section from corrosion. The cathodic protection of reinforced concrete water pipeline has been widely used in the world, but it is rarely seen in China. It may be because most areas of our country are located in arid or semi-arid areas, the groundwater level is relatively deep, and the phenomenon of soil salinization is not very serious. In addition, the pipeline water transmission project is not common at present.

However, in the long run, due to the uneven distribution of water resources in China, the state has begun to implement the plan of transferring water from rivers in rich water areas to rivers in arid areas. In order to develop water-saving irrigation, water pipes, sprinkler irrigation and drip irrigation will become the direction of agricultural development. However, it is inevitable for water pipelines to cross rivers, swamps and saline alkali soil areas. In hazardous geological areas, cathodic protection of water transmission concrete pipelines will have great development.

The so-called cathodic protection is to select two kinds of metals with large potential difference in the same electrolyte. The electrons of the metal with greater negative charge will pass through the wire and lead to the metal with higher positive electricity, so as to produce anti-corrosion effect and get protection. In this way, the metal structure that loses electrons is called anode, and the metal structure that gains electrons is called cathodic protection.

In order to reduce the potential difference between iron and electrolyte, a kind of metal with negative charge can be introduced into the same medium and connected with iron to form a circuit, so that the iron can be protected and the metal with higher negative electricity will be corroded.

In order to protect each pipe, the shunt cable must be connected with the reinforcement mesh of each pipe (generally, the pipe with cathodic protection has reserved terminal). Two points must be paid attention to when connecting: one is that the shunt cable can not be disconnected in the protection section. To maintain the continuity of the shunt cable, the terminals of each pipe can only be connected in parallel with the shunt cable; the other is that the shunt cable should be insulated from the medium. In order to avoid too much current in the shunt cable and make the whole pipeline well protected, it is necessary to segment protection. The length of the section is designed according to the resistivity value of the soil in the protected area and the pipe diameter is too small. The shunt cable is connected to the terminal on one side of the regulating terminal.

In addition, in China's water conservancy projects, metal structures are not rare, especially the corrosion protection of underwater metal components has not been effectively solved. It has a broad prospect to solve the problem of anticorrosion of metal components by using the principle of cathodic protection.

The anticorrosion method of cathodic protection has the advantages of long-term anti-corrosion. Even if the magnesium anode is replaced regularly, there is no complicated process. The operation is simple and the transparency is high. As long as the circuit current strength, voltage resistance and the loss of magnesium anode are measured, the corrosion of metal components can be found. It avoids the technical and construction problems brought by underwater anti-corrosion operation, and also avoids the loss caused by the falling off of protective layer of metal components and the need to shut off the water supply and repair again. Therefore, it is a simple and effective way to prevent corrosion by cathodic protection, and its popularization and application is only a matter of time.

Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services.