Protection against rust
As explained in the beginning of this bulletin, titanium has excellent protection against rust – even better tan stainless steel.
How is this possible?
As covered in the bulletin about stainless steel, it is actually an iron alloy with a minimum of 10.50% chrome. The chrome produces a thin oxide layer on the metal’s surface, which prevent corrosion.
When the protective layer is damaged (for any reason), the damaged spot comes into contact with oxygen in the air, which “heals” and regenerates the protective layer. However, stainless steel in proximity to the sea rusts quickly.
This is how the mechanism works: drops of seawater are sprayed onto the metal by the wind. After the drops dry up, a layer of salt remains on the metal. This salt layer (however thin) damages the metal’s protective layer and prevents oxygen from reaching it and regenerating it.
Similarly to stainless steel, titanium is covered with an oxide protective layer. However, in the case of titanium the protective layer is much more resistant to seawater (reference: Titanium and its Alloys when in Contact with Seawater and in a Marine Atmosphere Compared to Stainless Steel (an essay by Eng. Nahum Nave – corrosion and cathode protection expert)).
According to the Timet® website, (Timet® is one of the leading companies in the world in manufacturing titanium products), when seawater, chlorinated water or brackish water is used as the main cooling agent (which is common in power stations), the pipes conducting the water are made of titanium and are provided with a 40 year guarantee. This serves as evidence to the degree of resistance of this metal against corrosion.
This property also makes titanium ideal for constructing ships, as they are in constant contact with seawater.