Microstructural and tribological studies of Al2O3/ZrO2 nano multilayer thin films prepared by pulsed laser deposition

Abstract

Nanostructured single layer aluminium oxide (Al2O3), single layer zirconium oxide (ZrO2) and the (Al2O3/ZrO2) nano multilayer films were deposited on Si (100) substrates at an optimized oxygen pressure of 3×10 -2 mbar at room temperature by pulsed laser deposition. The Al2O3 layer was kept constant at 5 nm, while ZrO2 layer thickness was varied from 5 nm to 20 nm. The X-ray diffraction (XRD) studies of single layer of Al2O3 film indicated the cubic γ-Al2O3, while the single layer of ZrO2 indicated both the monoclinic and tetragonal phases. The Al2O3/ZrO2 multilayer films of 5/5 nm and 5/10 nm indicated the tetragonal phase of ZrO2 with nanocrystalline nature. The FESEM and AFM studies showed the dense and smooth morphology of the films. The pin-on disc revealed that the 5/10 nm multilayer film has low friction coefficient ~ 0.10. The wear rate of multilayers film is half of the wear rate of the single layer films and 5/10 nm multilayer film showed a reduced wear rate when it is compared to other single and multilayers. The Al2O3-ZrO2 ceramics find wide applications in wear and corrosion resistance components, high temperature applications and bio-implant materials.