Smart Anti-Corrosion Nano Coatings

The use of nanoparticles in the manufacture of anti-corrosion coatings is one of the most important achievements of nanotechnology. Important functions of nanoparticles in corrosion control include improving barrier properties, cathodic protection, anodic protection, and increasing adhesion properties of the coating.

The use of nanoparticles as carriers of corrosion inhibitors is also an indirect protective function of nanoparticles in the manufacture of smart coatings. The most important reasons for the development and expansion of smart coatings are their stability, elegance, and environmental properties.

Nanoparticles, due to their characteristics such as lateral surface and high chemical reactivity, are able to carry a high percentage of corrosion inhibitor particles on them. The important principle in using nanoparticles for smart coatings is to choose a type of nanoparticle that can create some kind of temporary or inhibitory connections. As soon as there is a sign of the presence of corrosion products, these connections are broken and the inhibitor is released into the environment.

In a class of smart anti-corrosion nanocoatings, the bonds formed between the nanoparticles and the inhibitor are sensitive to hydroxide ions (which are major by-products of metal corrosion processes) and as soon as they are released into the environment, the bonds are broken and the inhibitor moves towards the damaged area. Under the influence of corrosive agents, the inhibitor is reduced and creates insoluble oxides. These insoluble oxides are deposited on the metal surface and prevent the electrolyte from penetrating the metal surface and cause the metal surface to be deactivated.

One of the most important advantages of this class of coatings is the lack of use of some chemical inhibitors such as chromates, which are highly carcinogenic.

When choosing the type of nanoparticles, it is very important to consider the high lateral surface area, low price and creating an accessible surface through good dispersion of nanoparticles. Smart nanocoatings produced using a small percentage of inhibitor (less than 5%) are able to compete well with coatings containing high levels of inhibitor (30 to 40%) and even show better corrosion resistance. Smart anti-corrosion nanocoatings are particularly useful for use inside aircraft fuel storage tanks, where access to the inner surface is difficult.