Application of electrochemical corrosion protection

The application of electrochemical corrosion protection, at present, the laboratory mainly uses leaching method and electrochemical test method to study the electrochemical corrosion performance of cemented carbide. The polarization curves of cemented carbide samples were obtained by potential dynamic scanning. The corrosion potential, corrosion current density, critical current density and minimum current density in the passivation range were obtained, and the corrosion performance of cemented carbide was evaluated.


The corrosion potential reflects the thermodynamic trend of corrosion. The more negative the corrosion potential is, the easier the sample will be corroded. The parameters related to current density reflect the dynamic characteristics of corrosion process. Generally speaking, the higher the anodic polarization current density, the faster the corrosion rate.


Electrochemical corrosion also exists in the low temperature section of each unit in the refinery. Due to the particularity of refining process and the poor quality of crude oil, the electrochemical corrosion medium in refinery is complex and changeable, which brings difficulties to the electrochemical corrosion protection of refinery. The electrochemical corrosion protection measures of refinery mainly include raw material control, process corrosion protection, coating protection, etc. Cathodic protection is a common electrochemical protection measure in refinery. According to the protection mode, it can be divided into sacrificial anode protection and forced current cathodic protection. Cathodic protection scheme should be made according to the characteristics of medium and equipment. In the electrochemical corrosion environment of refinery, cathodic protection is mainly used for the internal and external corrosion protection of large oil tanks and the water cooler of heat exchanger.


According to the characteristics of electrochemical corrosion behavior of materials, metal materials can be divided into active metal materials dissolved in corrosion medium and passive metal materials with protective film on the surface. The influence of nano surface on electrochemical corrosion behavior of materials in acidic medium was discussed by using electrochemical testing technology and surface analysis technology. The results show that the surface activity of the material is improved and the dissolution rate of the active metal material is increased, and the passivation film on the surface of the passivated metal material is easier to form. Therefore, surface nanocrystals can be used to prevent the corrosion of some metals.


Among all ship systems, seawater system is the worst system in the working environment. Its circulating medium is seawater, which is one of the most corrosive natural corrosives. Therefore, the pipeline, valve and equipment in seawater system are most vulnerable to electrochemical corrosion. The common anti-corrosion methods include: adding sacrificial flange or sacrificial pipe at the contact of different metals to weaken the effect of electrolyte solution and neutralize the effect of negative ion solution in seawater; using non-metallic materials or metal materials with the same potential, which are not easy to be corroded; the most commonly used method on board is to cut off the connection between different metals.


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.