Titanium and its alloys are the most commonly used metal materials for medical implants in orthopedics and dental applications because of their low density, high strength, non-toxicity and excellent corrosion resistance. Compared with traditional stainless steel and cobalt-based alloys, titanium alloys have a lower elastic modulus, and the low elastic modulus has been proven to reduce the stress shielding effect, thereby better inducing and promoting osseointegration. These advantages make it More suitable for clinical medical applications.
However, titanium and its alloys cannot meet the clinical requirements of biomedical implants. Long-term clinical studies have found that titanium implants have poor wear resistance. The wear debris generated by the friction of titanium implants can cause inflammation and have toxic effects on the human body. .
In order to improve the biological and tribological properties of titanium alloys, the introduction of surface modification technology to enhance the biological activity, wear resistance and antibacterial properties of titanium and titanium alloys is to improve existing conventional biological materials to meet current and evolving clinical needs The more economical and effective method.
At present, a variety of physical and chemical methods have been used to improve the wear performance of the titanium alloy surface, by depositing a ceramic coating with excellent wear resistance on the titanium surface to improve its wear and corrosion performance. Commonly used wear-resistant coatings include diamond-like carbon (DLC) and titanium nitride (TiN) coatings.
Diamond-like carbon film (DLC)
Diamond-like carbon film is often used as a wear-resistant coating on medical metal implants due to its high hardness, excellent wear resistance, low friction coefficient and good biocompatibility. Part of the implant device treated with the surface modification of the diamond-like carbon film has achieved clinical application, and has broad application prospects in improving the wear resistance and corrosion resistance of artificial joint metal components.
Titanium Nitride (TiN)
TiN has good wear resistance and corrosion resistance. It was first used in cutting tools to extend its service life. Later, it was discovered that titanium nitride has biocompatibility and began to be used in medical implants, such as orthopedics and dentures. At present, the main methods for preparing titanium nitride are physical vapor deposition (PVD), chemical vapor deposition (CVD) and thermal spraying.