Cathodic protection is one of the most efficient methods to prevent metal from electrochemical corrosion. It impresses certain cathodic current to the protected metals and makes them produce cathodic polarization.When their potential are lower than certain values,the anode dissolving process of corrosion will be effectively controlled. According to the different manners of providing cathodic current,cathodic protection will be divided into two types, including sacrificial anodes and impressed current system. Sacrificial anode method is to connect the protected metallic structures with a more negative potential metal or alloy, through their dissolving,the protected structures shall get the necessary current and will be protected effectively.Impressed current method is to convert the outside AC into low voltage DC and then transmit the protection current to the protected metallic structures through auxiliary anodes. The system will measure the potential with reference electrode and return the controlling signals to the auto-control rectifier to regulate the output current,thus keeping the metallic structures in excellent protection condition.

Usually, the cost of cathodic protection just takes 1%~3% of the total cost of protected metallic structures,however their life can be extended severalfolds or even several tens of folds. Since it has many advantages such as simple facility, easy engineering,and long life protection, cathodic protection has been quickly developed and extensively applied in recent years, and is an applicable technology which can get outstanding performance and remarkable economic profit with small investment.

The research and application of cathodic protection technology in SunRui and Fouling Control Company now is of a history of more than 40 years, and the company has done a lot of work on the development of cathodic protection technology, completed nearly one hundred of research projects, won several items of science and technology achievements awards of national-class, provincial or ministerial-class. In addition, the company has successively drafted over 20 items of national standards, military standards and ship industry standards concerning metal corrosion and protection, and the technology of cathodic protection leads the domestic market. The company engages the research and development, design, manufacture, engineering and project contracting of cathodic protection technology as well as products, and has undertaken about one thousand items of cathodic protection projects in areas such as ship, harbor installations, underground pipelines as well as pipe network, petrochemical plants, power plants, and offshore projects; our products and engineering achievements have been spread through all China as well as over 10 countries and regions like U.S., Japan, Thailand, Pakistan, Indonesia and Hongkong, all of them have got satisfactory anticorrosion performance.