Effect of Fe and Ni nanoparticles on the structure and mechanical properties of alumina thin films

This paper discusses the synthesis and characterization of Al2O3/Fe and Al2O3/Ni nanocomposite thin films formed by embedding Fe or Ni nanoparticles into alumina matrix using pulsed laser deposition (PLD), RF and pulsed DC magnetron sputtering techniques. The effect of nanoparticle dispersion and temperature on the phase, structure and mechanical properties of the nanocomposite thin films were studied using grazing incidence X-ray diffraction (GIXRD), high resolution transmission electron microscopy (HRTEM) and nanoindentation respectively. The GIXRD and HRTEM studies revealed that dispersion of metal nanoparticles into alumina matrix promoted partial crystallization of Al2O3 at lower temperatures. The nanoindentation results showed an increase in hardness of the nanocomposite which was dependent on temperature and the metal content. The hardness of Al2O3/Fe nanocomposite thin films was observed to be in the range of 15 GPa-29 GPa for PLD thin films, 16.5 GPa-22.5 GPa for RF magnetron sputtered thin films and 11 GPa-16 GPa for pulsed DC sputtered thin films. The nanoindentation results also showed that the hardness of Al2O3/Ni deposited by PLD ranges from 15 GPa to 28 GPa.