Galling not only causes excessive wear on titanium but may also result in accelerated corrosion through fretting action. Simple lubrication, using graphite or molybdenum disulfide, is often sufficient to overcome galling. It is, therefore, possible to use titanium for moving parts or for parts in sliding contact with itself or other metals with light to moderate loads. Heavier loads, on the other hand, require hardened titanium surfaces. Commercially available case hardening techniques, such as plasma spraying, ion implantation, anodising or nitriding, or coating techniques such as hard chromium electroplating or flame spraying of tungsten carbide and other hard, wear-resistant materials, are used.
Such surface treatments possess the required qualities of good adherence plus wear and scuff resistance. However, careful consideration has to be given to the compatibility of the treated surface with the corrosive environment to which it will be exposed.
