Fracture-resistant TiO2 / Metal composite protective coating on NiTi stent by ALD nanolamination (ALD)

The aim of the research is to improve the biocompatibility of NiTi alloys used as implants. NiTi has useful functional properties useful in medicine, but in the long run, toxic Ni can leak from the alloy surface. A promising solution is the preparation of a conformal and protective crack-resistant coating for NiTi. In our previous research, we applied atomic layer deposition (ALD) for the growth of conformal Al2O3 and TiO2 layers with excellent electrochemical but inferior mechanical properties. Compared to traditional methods, ALD is particularly suitable for a protective coating on NiTi due to its low process temperature, excellent coating conformity on the complex structure and good thickness control. In this project, TiO2 / metal nanolaminate will be applied using ALD as a protective coating for NiTi stents in order to improve the electrochemical and mechanical properties. The addition of metal layers between the TiO2 layers could prevent delamination of the coating on NiTi due to its better plastic and elastic properties. Platinum is chosen as a metal layer due to its chemical stability.