10. Galvanic corrosion

Titanium is passive in water and, when coupled with most metals, will cause them to corrode. The ratio between the respective surface areas of the two materials will be important for the speed of corrosion: if titanium has a large surface area, corrosion of the second material will be rapid, as the anodic current density will be high. As titanium acts as a cathode, hydrogen may be released. If the temperature exceeds 77°C, this hydrogen can diffuse and cause the titanium to become brittle through hydride precipitation. To avoid any problems, it is advisable to use a single material, or to have electrical insulation between the titanium and the other material.

In seawater, materials with a higher corrosion potential than titanium are the Ni-Cr-Mo alloy, platinum and carbon; in these cases, titanium will corrode.

The use of composite materials...