Synthesis and Characterization of Metal-Ceramic Thin Film Nanocomposites With Improved Mechanical Properties

Thin films composite materials consisting of metallic nanocrystals embedded in an insulator host have been synthesized using alternating-target pulsed laser deposition of Fe/Ni and Al₂O₃. The evaluation of structural quality of the thin film composites using high resolution transmission electron microscopy and scanning transmission electron microscopy with atomic number contrast has revealed the formation of a biphase system with thermodynamically driven segregation of Ni and alumina during pulsed laser deposition. The best hardness values of the thin film composites, measured using nanoindentation techniques, was found to 20–30% larger than pure alumina films fabricated under identical conditions. The improvement in values of hardness of Al₂O₃ thin films by embedding metal nanocrystals is related to the evolution of a microstructure which efficiently hinders the manipulation and movement of dislocation and the growth of microcracks, which in turn, is achieved by grain boundary hardening.