Diamond-like carbon coatings with zirconium-containing interlayers for orthopedic implants
N-doped diamond-like carbon, orthopedic implant, squeaking noise, tribocorrosion, wear resistance, zirconium
Six types of diamond-like carbon (DLC) coatings with zirconium (Zr)-containing interlayers on titanium alloy (Ti-6Al-4V) were investigated for improving the biotribological performance of orthopedic implants. The coatings consist of three layers: above the substrate a layer stack of 32 alternating Zr and ZrN sublayers (Zr:ZrN), followed by a layer comprised of Zr and DLC (Zr:DLC), and finally a N-doped DLC layer. The Zr:ZrN layer is designed for increasing load carrying capacity and corrosion resistance; the Zr:DLC layer is for gradual transition of stress, thus enhancing layer adhesion; and the N-doped DLC layer is for decreasing friction, squeaking noises and wear. Biotribological experiments were performed in simulated body fluid employing a ball-on-disc contact with a Si3N4 ball and a rotational oscillating motion to mimic hip motion in terms of gait angle, dynamic contact pressures, speed and body temperature. The results showed that the Zr:DLC layer has a substantial influence on eliminating delamination of the DLC from the substrates. The DLC/Si3N4 pairs significantly reduced friction coefficient, squeaking noise and wear of both the Si3N4 balls and the discs compared to those of the Ti-6Al-4V/Si3N4 pair after testing for a duration that is equivalent to one year of hip motion in vivo.
Choudhury, D., Lackner, J., Fleming, R. A., Goss, J., Chen, J., & Zou, M. (2017). Diamond-like carbon coatings with zirconium-containing interlayers for orthopedic implants. Mechanical Engineering Faculty Publications and Presentations., 68, 51-61. https://doi.org/https://doi.org/10.1016/j.jmbbm.2017.01.023