Progress at Month 9

Technical development started at month 2 within three work packages in parallel. Laboratory-scale surface treatment equipment design started in work package 2 focusing on development the mechanical and the electrical parts. The laboratory equipment was intended to be used for surface treatment procedure optimization in order to see how the system behaves and to validate the proper
behavior of the planned small-scale system. As the surface modification steps are performed in separate liquid tanks, the mechanical setup was developed accordingly. The CAD design for mechanical elements and holding parts were prepared and a solid structure was fabricated. Special scalable sample holder units were designed and fabricated providing adequate electrical connection while maintaining proper sealing in order to protect the connection points from unwanted oxidation.
The electrical system including the control units and high-performance, programmable power supplies were designed and fabricated as a standalone unit having all components installed into an electrical cabinet providing a simple user interface in the front and electrical connections on the backside. The electrical and mechanical parts were integrated and tested.
Surface treatment procedure development started in work package 3 with sample preparation. Due to the high number of optimization steps and experiments the project requires a significant amount of samples made from different base materials with different geometries. Samples are prepared continuously in the course of the project according to the need of the actual development steps. The preparation of the first batch was also followed by optical and SEM (scanning electron microscope) investigations in order to reveal the mechanical effects of the machining processes. The whole surface treatment procedure comprises three separate steps, out of which chemical etching was optimized first; defining the proper technical parameters such as etchant composition, etchant temperature and etching time. Weight measurement, stereomicroscopic examination, SEM and
EDS-analysis, surface roughness measurements were performed before and after the etching process. The second surface modification method involved in the project is electrochemical polishing which aims to produce a smooth, mirror-like surface creating an oxide layer on the surface. Several parameter combinations (including electrical, chemical, mechanical and thermal ones) were investigated in order to find the optimal settings for producing high-quality, reproducible results. The task was successfully accomplished providing valuable input for the upcoming tasks. The third surface treatment method in the line of NanoTi Project is anodic oxidation which aims to create proper nanosurfaces on titanium discs. The pattern and surface energy of the created nanosurfaces have key roles in the behavior of the implants in microbiology and biocompatibility tests. The properties depend on the applied anodizing parameters. Type of electrolyte, treatment time, voltage and current characteristics, stirring velocity and cathode material can significantly influence the morphology, structure and chemical composition of the TiO2 layer. Intermediate samples were also biologically characterized. Due to technical problems, the optimization of this process has not been finished yet causing delay into the project. The revision of the time plan has been started and
corrective actions together with a modified project schedule is under finalization.
As the equipment development proceeded, the technical bottlenecks and features to be updated were continuously monitored in Work package 4. The aim of this activity was to collect as much information as possible that can effectively contribute to the development of the prototype device which is due to M12. As a result, several electrical and mechanical features were modified. In parallel, the development of the final, automated prototype is also progressing. The final prototype is based on an industrial programmable logic controller providing a modern LCD interface to the end-user to set parameters. Besides, it also enables all parameters to be continuously monitored and logged, which is important for quality control issues (i.e. batch-to-batch control).
As the development of the surface modification procedure proceeds, treated samples are continuously examined in WP5. Non-destructive investigations have been started but the destructive examinations are in delay due to the abovementioned technical problems. Both destructive and non-destructive investigations are meant to better understand the mechanical stability and physical properties of the new surfaces. Professional surface tension measurement system will be also involved into the investigation in February.