Titanium-Polymer joint

Project PolyTitan

Titanium and its alloys are used today in many applications. The field of application covers various areas, from medical technology, where titanium is an indispensable implant material, to aviation, where titanium components offer huge advantages due to their low weight.

Another important aspect in this context is the combination of titanium and plastics, which is becoming increasingly important. In medical technology, for example, implants are coated with silicones; in aviation, the adhesion between titanium components and other materials plays a major role. However, this bonding is the weak point of such systems, because titanium represents a poor primer for plastics due to its inert surface. The purely chemical bonding of these materials is insufficient, resulting in early failure. This can lead to serious consequences, especially in medical technology, since detached plastic coatings represent an enormous risk.

In order to increase the adhesion between titanium and plastic, a new adhesive mechanism is being developed. For this, the weak chemical bond should be replaced by a strong physical adhesion. This is done by specific structuring of the titanium surface, whereby the creation of a barb structure on the surface serves as a basis for strong adhesion.

The development of the etching process is the essential part of the project. By varying the etching parameters such as electrolyte composition, temperature and mixing an optimal barb structure should be obtained. Furthermore, it must be ensured that the mechanical properties of the components themselves are not affected by the etching process.

Comparison of an untreated (left) and structured (right) titanium surface
Comparison of an untreated (left) and structured (right) titanium surface

In cooperation with the Technical Faculty of the Christian-Albrechts-University of Kiel and the project partner Element 22, Phi-Stone AG is developing an etching system for titanium components as well as the associated polymer coating technology as part of the Polytitan project.

In order to utilize the etching process for a variety of applications, it must be designed in such a way that there is no dependence on the component geometry. Furthermore, a uniform structuring of the surfaces must be obtained, since a uniform adhesion is needed for industrial application. For this purpose, the many years of experience and know-how of the technical faculty can be used.

After structuring, the polymer coating is applied by Phi-Stone AG. In this case, it is important not to damage the etched structure during handling. Furthermore, a uniform coating of different component geometries must be ensured.