The new achievements of Anhui University of Technology improve the surface protection effect of medical titanium alloys

Recently, the team of Zhang Shihong, professor of the Key Laboratory of Green Preparation and Surface Technology of Advanced Metal Materials of the Ministry of Education, Anhui University of Technology, published the latest research results of medical titanium alloy surface protection in the international authoritative journal “Corrosion Science”.

Medical titanium alloy has become the preferred material for human implants due to its advantages of light weight, high specific strength, excellent biocompatibility and corrosion resistance, but its long-term service in the human environment produces easy corrosion and wear, which in turn affects the function of titanium alloy implants. Zirconium nitride (ZrN) coatings prepared by physical vapor deposition (PVD) technology have excellent wear resistance and biocompatibility, making them an important protective coating for bone implants. However, the columnar grain boundaries and growth defects in ZrN coatings are easy to provide a “channel” for the penetration of corrosive media, reduce its corrosion and corrosion wear properties, and limit its further application in bone implants.

By introducing a zirconium metal (Zr) layer into the ZrN coating, the research team formed a Zr/ZrN multilayer coating, which reduced the columnar grain boundaries and growth defects of the coating, thereby improving the corrosion resistance and corrosion resistance of the coating in the simulated human body solution.

a Schematic diagram of Zr/ZrN multilayer coating structure, b Schematic diagram of corrosion and wear experiment. Photo courtesy of Anhui University of Technology

The results show that the Zr layer in the multi-layer coating can preferentially form a zirconium dioxide (ZrO2) passivation film and the multilayer structure can effectively inhibit the penetration of the corrosive medium and make it have good corrosion resistance. At the same time, the introduction of Zr metal layer inhibits crack propagation during the wear process, and further improves the corrosion and wear performance of Zr/ZrN multilayer coating.

According to reports, the research work reveals the penetration law of corrosive medium in multi-layer coating and the formation mechanism of passivation film, clarifies the interaction mechanism between corrosive medium and crack during corrosion and wear, and can provide a theoretical basis for the further application of Zr/ZrN multilayer coating in the surface protection of medical titanium alloy.

Anhui University of Technology is the first unit of the paper, the team member Associate Professor Cai Fei is the first author and corresponding author of the paper, 2019 master’s student Zhou Qi is the co-first author of the paper, and Zhang Shihong is the co-corresponding author of the paper. The above research results have been supported by the Natural Science Foundation of Anhui Province and the Natural Science Research Project of Anhui Universities. (Source: China Science News, Zheng Cai, Chen Bin)

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