Project A5 examines in continuation of the results of the previous support phase, i.e the corrosion and the biocompatibility of NiTi shape memory alloys. Among others, the corrosion resistance is determined via a breakdown potential and the nickel release is analyzed by means of the robotic system developed in the previous support periods. Collaboration with other projects of the SFB arise e.g. from high throughput analysis of bone substitute material which has to be tested for biocompatibility.

In this context, the influence of different surface preparations and thermomechanical treatments of the shape memory materials are also examined.

Additionally, a high corrosion resistance depending on the pretreatment of the SMA has been noted such that further measurements should be done to clarify this phenomenon.

The possibilities regarding local corrosion studies with the newly introduced scanning droplet cell have been demonstrated and will be extended to examine the corrosion resistance of ternary nickel alloys. Here, the application as automated high throughput analysis method for sputtered thin film wafer is envisaged.

In the fourth support period, the AC-SECM technique, which has been fully evaluated in the mean time, should be used to look for corrosion points of failure on the surface of SMA (e.g. pitting corrosion points) and to visualize them with a high spatial resolution.

Furthermore, with AC-SECM joined materials (of the same and of different type) will be locally investigated with regard to their different electrochemical behaviour to make a point of their corrosion resistance and hence their operational life span.