Introduction of concrete corrosion inhibitor
Introduction of concrete corrosion inhibitor
Key words
corrosion inhibitor, concrete, chloride ion, reinforced concrete
Cause
In the marine environment of reinforced concrete structures, due to the infiltration of chloride ions and accumulation on the surface of steel bars, the passive film will be destroyed and the steel bars will be corroded. Therefore, to improve the service life of reinforced concrete structures in the ocean, the key is the corrosion protection of steel bars. Among them, the use of high-efficiency rust inhibitor is an important way to improve the corrosion resistance of steel bars in marine concrete.
Types of corrosion inhibitors
Types of corrosion inhibitors used in marine environments
Inorganic salt corrosion inhibitor: nitrite, chromate, phosphate, silicate, zinc salt, molybdate, etc.;
Organic corrosion inhibitors: organic carboxylic acids, organic aldehydes, organic amines, alcohols, etc.;
Natural polymer-based rust inhibitor: chitosan, cellulose, starch-based, etc.
The composite corrosion inhibitors obtained by compounding 2 or more kinds of substances often has a synergistic effect, and the rust inhibition effect is better.
Corrosion inhibitor principle
Regarding the mechanism of action of corrosion inhibitors on steel bars, it is generally believed that rust inhibitors promote the formation of a series of physical or chemical protective films on the surface of steel bars, thereby preventing harmful ions from invading.
Corrosion inhibitors can be divided into oxide film type, precipitation film type and adsorption film type according to the type of film formed on the surface of the steel bar.
The oxide film type rust inhibitor makes the metal surface have characteristic adsorption, blocks the ionization process of the metal, or oxidizes the metal surface to form an extremely thin and dense protective oxide film.
Precipitated film type rust inhibitor is to form a precipitated film on the metal surface through electrochemical reaction, blocking metal and corrosive medium.
The adsorption film type rust inhibitor generally forms a hydrophobic protective film on the metal surface through its non-polar group, which hinders the transfer of charges or substances related to the corrosion reaction.
