Saltwater corrosion happens faster than freshwater because of the increased presence of dissolved ions.
This causes metals closer towards the ocean to rust and corrode faster than those more inland.
Water in our oceans is recorded at an average 3.5% salinity. This means that salts, such as sodium chloride (NaCl), comprise roughly 35 parts per thousand (ppt) of seawater. While this may sound like a low-level density, chlorides exhibit an extremely aggressive affinity to metals and can rapidly penetrate steel grades that are not suitably corrosion resistant. Chlorides eat into the material causing spots and pits in the component surface, which can propagate through the material and rapidly cause complete mechanical failure. This phenomenon is known as pitting corrosion.
Metals like stainless steel and titanium are often exposed to seawater corrosion. Rust can be prevented with a process called galvanisation. This process adds a protective layer of zinc to the surface of metal.
Galvanising protects from rust in several ways:
- It forms a barrier that prevents corrosive substances from reaching the underlying steel or iron.
- The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
- The zinc protects its base metal by corroding before iron.
- The zinc surface reacts with the atmosphere to form a compact, adherent patina that is insoluble in rainwater.
Lazenby Group have a vast amount of experience designing and installing kiosks into all kinds of environments; whether that be near the coast, sub-zero temperatures, or desert-like conditions. As such we can offer our expert knowledge to help design products which are fit for your purpose.