Titanium has a tendency to gall when in rubbing contact with itself and other surfaces. A number of techniques have been developed to engineer the titanium surface and overcome this problem:
• Ion Implantation
• Shot Peening
The Ion Implantation Process
In the ion implantation process, ions, (usually nitrogen) are implanted into the surface of the components to modify the surface structure and composition. The ions are projected towards the surface in a high energy beam which penetrates the surface leaving a nitrogen rich zone. The process does not require heating the component as the ions penetrate using the kinetic energy of the beam.
Surfaces after Ion Implantation
The end result is a surface which is visually almost unchanged but contains an extremely fine dispersion of titanium nitrides. The surface is forced into compression and the hard nitrides provide a substantial improvement in the wear properties by increasing surface hardness and reducing galling.
The Advantages of Ion Implantation
The advantages of the process are that there is no distinct coating layer of the risk of delamination. No change in dimensions and none of the risks of carrying out elevated temperature treatments. The process is performed under high vacuum and can be carried out selectively on the wear surfaces of components.
Applications of Ion Implanted Titanium
Ion implantation is used in biomedical applications for replacement joints and other titanium prostheses. In the food processing, chemicals and engineering sectors the unique benefits of ion implantation are used for the enhancement of a wide range of precision components.