How do corrosion and scale inhibitors form a protective film on the cathode to inhibit corrosion?
Publish Time: 2025-07-02
In industrial circulating water systems, metal pipes and equipment are in contact with water for a long time, which is prone to corrosion problems. This not only affects the stable operation of the system, but may also cause serious economic losses. In order to effectively meet this challenge, corrosion and scale inhibitors are widely used in various cooling water, boiler water and central air-conditioning systems.The key to the ability of corrosion and scale inhibitors to form a protective film on the cathode surface is that their molecular structure has good adsorption and film-forming ability. When the agent enters the circulating water system, it will be evenly distributed throughout the system with the water flow. In specific areas on the metal surface (such as the cathode), the active ingredients in corrosion and scale inhibitors can be quickly adsorbed on the metal surface and gradually form a dense and stable film.Although this film is invisible to the naked eye, it can act as a "barrier" to isolate the metal from corrosive ions in the water (such as chloride ions, dissolved oxygen, etc.). In this way, the probability of electrochemical reactions is greatly reduced, thereby effectively slowing down or even preventing the corrosion process.Not only that, corrosion and scale inhibitors can also work synergistically with other water quality regulators to further enhance the anti-corrosion effect. For example, in water with a certain hardness, corrosion and scale inhibitors can not only inhibit corrosion, but also prevent calcium and magnesium ions from depositing into scale through complexation or dispersion, achieving the function of "one dose, multiple effects".In practical applications, the protective film formed by corrosion and scale inhibitors has a certain self-repairing ability. Even in the case of water flow impact or slight wear, the agent components can continue to be replenished to the damaged area to maintain the integrity of the protective film. This feature makes it perform well in long-term circulating water systems, reducing the frequency of frequent addition or replacement of agents and improving the operating efficiency of the system.In addition, most modern corrosion and scale inhibitor products use environmentally friendly formulas, do not contain heavy metals or high-phosphorus components, and are in line with the current trend of green development. They can provide continuous and reliable protection for metal materials without affecting water quality safety.In terms of selection, different systems also have different requirements for corrosion and scale inhibitors. For example, for systems containing stainless steel materials, products with stress corrosion resistance for austenitic stainless steel should be selected; while for copper alloy materials, the control effect of the agent on copper ions should be considered. Therefore, before use, the appropriate type of corrosion and scale inhibitors should be selected in combination with specific water quality parameters and system materials to ensure the best protection effect.In general, corrosion and scale inhibitors significantly improve the corrosion resistance of circulating water systems by forming an effective protective film on the cathode surface. It not only extends the service life of the equipment, but also reduces maintenance costs. It is one of the important means to ensure the safe and stable operation of industrial water systems.In the future, with the continuous advancement of water treatment technology, the functions of corrosion and scale inhibitors will be more comprehensive and are expected to play an important role in a wider range of industrial fields. Whether it is a new project or the transformation and upgrading of an old system, the rational use of corrosion and scale inhibitors is one of the key measures to improve system reliability and achieve energy conservation and emission reduction goals.
