types of corrosion inhibitors
There are many types of corrosion inhibitors with complex corrosion inhibition mechanisms. There is no unified method that can reasonably classify them and reflect the relationship between their molecular structure and mechanism of action. For the convenience of research and use, corrosion inhibitors are often classified from various perspectives.
Determine the types of corrosion inhibitor based on its chemical composition
It can be divided into inorganic corrosion inhibitors, organic corrosion inhibitors and polymer corrosion inhibitors.
Inorganic types of corrosion inhibitors
Inorganic corrosion inhibitors mainly include chromates, nitrites, silicates, molybdates, tungstates, polyphosphates, zinc salts, etc.
Organic corrosion inhibitor
Organic corrosion inhibitors mainly include phosphonic acid (salt), phosphine carboxylic acid, mercaptobenzothiazole, benzotriazole, sulfonated lignin and other heterocyclic compounds containing nitrogen and oxygen compounds.
Polymer corrosion inhibitor
Polymer corrosion inhibitors mainly include polyethylene, POCA, polyaspartic acid and other oligomer polymer chemicals.
Classified by physical state
According to the physical state of corrosion inhibitors, corrosion inhibitors can be divided into oil-soluble corrosion inhibitors, water-soluble corrosion inhibitors and gas phase corrosion inhibitors.
Oil-soluble corrosion inhibitors are a type of corrosion inhibitor with poor water solubility and good oil solubility. They are basically composed of organic corrosion inhibitors. Its mechanism of action is generally believed to be due to the presence of polar groups. This type of corrosion inhibitor molecules are adsorbed on the metal surface, thus isolating the corrosive medium at the interface between metal and oil. Water-soluble corrosion inhibitors are corrosion inhibitors with good water solubility and poor oil solubility. Generally speaking, both inorganic and organic types can be used as water-soluble corrosion inhibitors.
Vapor phase corrosion inhibitor (volatile corrosion inhibitor or vapor rust inhibitor) is a corrosion inhibitor that can volatilize into gas at normal temperature. Therefore, if it is a solid, it must have sublimability; if it is a liquid, it must have a vapor partial pressure greater than a certain value. People can distinguish it from other water-soluble corrosion inhibitors based on whether it has this characteristic.