Development of ALD system with Joule heating for preparing biocompatible protective coating on NiTi


In our previous research, platinum coating on NiTi alloy was grown in order to improve biocompatibility of NiTi alloys used as implants. NiTi has useful functional properties applicable in medicine but in long-term perspective, the alloy surface may leak poisonous Ni ions. The aim of the presently proposed research is to reach an essential improvement in platinum deposition on NiTi surface using atomic layer deposition (ALD). Compared with traditional methods, ALD is particularly suitable for the protective coating of NiTi due to its relatively low process temperature, excellent coating conformity on complex structures and good thickness control. In this project, the main challenges are as follows: (i) a reduction of organic material in ALD Pt layer and (ii) a choice of a suitable under-layer to reduce the initial island-like growth mode. Besides the improved biocompatibility of NiTi the other benefits of platinum coating are an excellent chemical stability and enhanced visibility under X-ray fluoroscopy.