Formation of tetragonal or monoclinic ZrO2 coatings by oxygen plasma treatment of Zr74.7Cu19.7Nb5.6 glassy thin films

The authors report on the production of stable nanostructured tetragonal and/or monoclinic ZrO2 nanopillars achieved by means of oxygen plasma treatment of ternary Zr74.7Cu19.7Nb5.6 glassy films. The Zr-based metallic glass thin films were successfully deposited by magnetron sputtering and subsequently subjected to oxygen plasma for various exposure times. The compositions of the oxidized films were determined by Auger electron spectroscopy and X-Ray photoelectron spectroscopy depth profiling while the surface morphology was evaluated by means of atomic force microscopy and scanning electron microscopy. X-Ray diffraction was used for the structural analysis. Our results show that, depending on the length of time of oxygen plasma treatment, tetragonal and/or monoclinic ZrO2 films can be formed, the surface morphology of which exhibit nanopillar structures with an increased effective surface. These findings provide an easy and efficient way for growing ZrO2 coatings with a predefined structure suitable for protective and possibly for catalytic applications.