Influence of RF sputtering power during RFMS on the electrochemical behavior of zirconia thin films in a Hanks solution

Zirconia (ZrO₂) is a ceramic oxide known for its properties such as inertness and biocompatibility, making it attractive for biomedical and protective coating applications.

In this study, Zirconia (ZrO₂) thin films were deposited using a radio-frequency magnetron sputtering (RFMS) system. A pure zirconium target was sputtered in an Ar–O₂ gas mixture. The sputtering power was systematically varied from 100 W to 400 W in order to investigate its influence on the film’s properties.

The structural, morphological and surface characteristics of the deposited films were analyzed using X-ray Diffraction, contact angle measurements and Atomic Force Microscopy. XRD results show that the monoclinic phase is predominant in lower sputtering power, and the increase in the power induces a notable change in the films' crystallinity and the preferred orientation. Higher sputtering power also led to a significance increase in the surface roughness (from 0.46 nm at 100 W to 14.77 nm at 400 W). In line with our previous work [1], in this study, the contact angle measurement showed that a sputtering power of 250 W produced the most hydrophobic films. In addition. The electrochemical behavior of the films was assessed trough potentiodynamic polarization tests in Hank’s solution. Compare to the uncoated sample, the films presented a better corrosion resistance. The results also showed that the Zirconia films exhibited a protective anti-corrosion performance.

In conclusion, the results demonstrate that the sputtering power is a key deposing parameter for tailoring different properties of zirconia thin films, confirming their potential as a protective coating for biomedical metals.

[1] H.Zegtouf et al , Influence of oxygen percentage on in vitro bioactivity of zirconia thin films obtained by RF magnetron sputtering, Applied Surface Science, V532, 2020, 147403, ISSN 0169-4332