In Part 1 of this feature, "Corrosion — What it is and what can be done to prevent it: Part 1," GlobalSpec looked at the solutions being undertaken to prevent corrosion, ranging from robots capable of cleaning corrosion-inducing fouling from ships to a collar that detects corrosion development on pipelines.

Part 2 of this feature will look at the many coating technologies in development to prevent corrosion of various materials.

Self-cleaning coating

Nanoveu, an Australian nanotechnology company, has developed a self-cleaning coating solution for solar panels. According to the company, the E series hard coat is an antimicrobial, transparent coating that is anti-fouling, self-maintaining, anti-static and hydrophilic. The coating reportedly inhibits the formation of biofilm and algae growth on solar panels that hinders their energy output and promotes corrosion.

Further, Nanoveu’s coating prevents sand, dirt and all other surface contaminants from clinging to panels. This, according to Nanoveu, eliminates the need for manually cleaning solar panels, which can be expensive. Instead, thanks to the coating’s hydrophilic properties, dirt and sand easily slide off the panels and the degradation of the solar panels is subsequently avoided.

Anti-soiling coating

Like the solar panel coating solution developed by Nanoveu, Rads Global Business, a Netherlands-based company, has also developed an anti-soiling coating for solar panels.

Source: Rads Global Business

The anti-soiling and anti-reflective nanocoating for solar panel glass is called HP+ and it is composed of four different nanomaterials: three compounds called NanoClean, Vetra clean and Vtranova, which are used to ready solar panel surfaces for the deposition of a fourth compound called HydroPlus.

According to the developers of the coating, HydroPlus forms a 120 nm thick layer of coating on the glass, resulting in the anti-soiling, anti-corrosion, anti-abrasion, self-cleaning and anti-reflective behaviors of the coated solar panels.

Silicon (Si) and magnesium (Mg) coating

A team led by researchers from the National Korea Maritime and Ocean University has developed an anti-corrosive coating for steel used in maritime applications.

A common method used for improving the corrosion resistance of steel is to coat it with other metals including aluminum (AI). Yet, Al can only be used sparingly in marine applications because it reacts with chloride ions in sea water, thus leading to corrosion.

As such, the researchers added silicon (Si) and magnesium (Mg) to the steel to form an alloyed coating. To overcome the challenge of not being able to easily deposit Mg as a coating using the method of dipping the steel into a hot bath of metal salts, the researchers plated aluminized steel (Al and Si) with Mg using a physical vapor deposition technique.

Scientists develop new anti-corrosion coating to increase the economic life and durability of steel machinery in an environment-friendly manner. Source: Korea Maritime and Ocean University

The coating was then exposed to a temperature of 375° C and subjected to corrosion testing via salt spray testing. According to the researchers, the combination of AI-Mg-Si resulted in a material with anti-corrosive properties. Once further developed, the coating could potentially be used to protect ship hulls or marine and coastal facilities from corrosion.

Sulfur and selenium coating

Scientists from Rice University have developed a flexible and self-healing anti-corrosion coating that also protects steel.

Composed of a sulfur and selenium compound, the coating could be used to protect steel components of buildings, bridges and other infrastructure against the elements.

Source: Rice University

The Rice University team tested the compound on slabs of steel that were submerged in seawater alongside non-treated steel. After one month submerged in seawater, the researchers determined that once retrieved the slabs of steel coated in the sulfur and selenium compound were unchanged while untreated slabs of steel had rusted.

When tested against sulfate-reducing bacteria, such as biofilms and plankton, the coated steel also outperformed the untreated steel after one month.

Additionally, when portions of the sulfur and selenium film were cut in half, they reconnected when exposed to heat and continued to successfully protect the steel.

Conclusion

These are a just a few examples of the anti-corrosion solutions being undertaken to prevent the development of corrosion on assorted material surfaces. This feature hardly scratches the surface on this topic, so check back with GlobalSpec for its ongoing coverage of this and other surface engineering topics.