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ZrO2 thin films were deposited on 316L stainless steel substrate by a radio-frequency magnetron sputtering system. The substrate bias voltage, the working gas rate and the reactive gas fraction in the gas mixture were varied. These variations produce a variation in the deferent properties of the obtained films. The deposited films were characterized by X-Rays Diffraction, Atomic Force Microscopy, nano-indentation and potentiodynamic polarization. The experimental results show that the film thickness and the roughness of the films are highly influenced by the plasma parameters. XRD results show that the monoclinic phase is predominant in unbiased deposited films. The best anti-corrosion performance and hardness were obtained for ZrO2 deposited with a substrate bias voltage of −75 V, Ar rate of 6 sccm and oxygen fraction of 25%. [ABSTRACT FROM AUTHOR]

• ZrO 2 films were deposited on stainless steel 316L by RF magnetron sputtering. • The ZrO 2 coated 316L are hydrophobic. • Bioactivity tests in vitro demonstrate the formation of a hydroxyapatite layer on the films surface. The zirconia (ZrO 2) films were deposited using radio-frequency magnetron sputtering (RFMS) from a pure zirconium target in Ar-O 2 gas mixture with different percentage of the oxygen. The effect of Oxygen percentage on the film's characteristics was investigated by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and tribology test. Also, the contact angle of the films was measured in order to evaluate their hydrophobicity. Additionally, in vitro test in artificial blood plasma and further SEM observations were performed to study bioactivity of the films. The experimental results showed that the roughness, the porosity and the thickness of the films depend on the oxygen percentage. According to XRD and Raman spectroscopy results, the films present a polymorph phase of monoclinic and tetragonal. Zirconia films at low oxygen percentage showed better hydrophobic behavior with 114.5° at 15% of oxygen. These films also exhibit a lower friction coefficient and wear rate (0.22 and 6 × 10−07 mm3/m respectively). However the best bioactive behavior was exhibited by the films deposited at 25% of oxygen due to their higher roughness and porosity. In fact, it was found that the bioactivity of the films is highly dependent on the porosity and roughness of the films. [ABSTRACT FROM AUTHOR]

Zirconium oxide (ZrO 2) thin films were grown onto 316L stainless steel by radio frequency magnetron sputtering (RFMS), at different substrate D.C. bias voltages (from 0 to −100 V). The deposition was performed using a pure zirconium target in the presence of an Ar-O 2 gas mixture. The characterization of the deposited films was performed using scanning Electron Microscope, atomic Force Microscopy, X-rays diffraction, Raman spectroscopy, nanoindentation and potentiodynamic polarization. The structures of all ZrO 2 films are crystalline. The monoclinic phase is predominant in the grounded films (0 V). However, the application of bias voltage depicts a tetragonal phase. Nanoindentation results reveal promoted values of the hardness of the ZrO 2 films. Corrosion behavior of the films was studied in Hank's solution using the potentiodynamic polarization method. The comparison between the uncoated samples and the coated ones showed a reduction in corrosion current density for coated samples. The minimum corrosion rate of the film deposited at −100 V was 0.04992 mpy, which is about 18 times less than that of the uncoated steel (0.88135 mpy). The optimum anti-corrosion performance and hardness were obtained for ZrO 2 deposited at a bias voltage of −100 V. • ZrO 2 films were deposited by magnetron sputtering from a metallic Zr target using oxygen as reactive gas. • ZrO 2 films with high hardness and high protective efficiency (94%) are demonstrated. • The hardness increases with the bias voltage applied to substrate. • Corrosion resistance is affected by negative bias voltage of ZrO 2 film. [ABSTRACT FROM AUTHOR]