Influence of substrate bias voltage on structure, mechanical and corrosion properties of ZrO2 thin films deposited by Reactive Magnetron Sputter Deposition

• Published in: Surface & coatings technology 2020-07, Vol.393, p.125821, Article 125821
• Main Authors: Zegtouf, Hind, Saoula, Nadia, Azibi, Mourad, Bait, Larbi, Madaoui, Noureddine, Khelladi, Mohamed Redha, Kechouane, Mohamed
• Format: Article
• Language: English
• Subjects: 316L stainless steel; AFM; Atomic force microscopy; Austenitic stainless steels; Bias; Corrosion; Corrosion currents; Corrosion prevention; Corrosion rate; Corrosion resistance; Deposition; Direct current; Electric potential; Gas mixtures; Hardness; Magnetic properties; Magnetron sputtering; Nanoindentation; Polarization; Raman spectroscopy; Substrates; Thin films; Voltage; XRD; Zirconium dioxide; Zirconium oxides; ZrO2 thin films
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.125821

Zirconium oxide (ZrO2) 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-O2 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 ZrO2 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 ZrO2 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 ZrO2 deposited at a bias voltage of −100 V. •ZrO2 films were deposited by magnetron sputtering from a metallic Zr target using oxygen as reactive gas.•ZrO2 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 ZrO2 film.