Surface modifications transform titanium alloys into biomaterials
Implanted biomaterials can act as a powerful tool to address damage in hard tissues, like bones and teeth. In order to do so, the inserted material must have a low elastic modulus and density, as well as good biocompatibility and strength.
Many titanium alloys possess these beneficial properties but have not been used in clinical applications because certain qualities, such as hardness, wearability, corrosion resistance, and cellular activity, are still lacking or have not been systematically investigated.
Liang et al. discussed how surface modification techniques can transform titanium alloys into viable hard tissue implants. The group focused on four categories of methods based on physical, chemical, electrochemical, and surface plastic deformation technologies.
For example, these techniques can improve metal properties via deposition of thin film layers or coatings, surface quenching or heating, ion doping, etching, and mechanical impacts.
“This work aims to summarize the main and commonly used surface modification methods for titanium alloys for engineers and new researchers in this field,” said author Shun-Xing Liang. “Through this review, they can learn and understand the characteristics of each surface modification method, helping them select a suitable method that can meet their requirements.”
Compared to electrochemical methods, chemical techniques require high temperature and long duration. Mechanical methods do not change the chemical composition and maintain plasticity and ductility, but the improvement in surface hardness, anti-wear, and corrosion resistance is weaker than other methods.
“Developing surface modification technologies for clinical applications instead of lab-only ones should be an important next step,” said Liang. “Better and more suitable surface performance is always the focus.”
Source: “Review on major technologies improving surface performances of Ti alloys for implant biomaterials,” by S. X. Liang, K. Y. Liu, L. X. Yin, G. W. Huang, Y. D. Shi, L. Y. Zheng, and Z. G. Xing, JVST: A (2022). The article can be accessed at https://doi.org/10.1116/6.0001801 .