Abstract: TiN/Al2O3 nanomultilayers with various Al2O3 layer thicknesses were prepared by multi_target magnetron sputtering. The chemical composition, microstructure and mechanical properties of these multilayers were characterized by energy dispersive X_ray spectrometry, X_ray diffraction, high_resolution transmission electron microscopy and nanoindentation. The result raveals that under the sputtering conditions, normally amorphous Al2O3 is forced to crystallize at very small layer thicknesses (2O3 layers form an amorphous structure and block the coherent growth of the multilayers, and thus the hardness decreases gradually.

Keywords: 
• TiN/Al2O3 nanomultilayers /
• epitaxial growth /
• template_induced crystallization /
• superhardness effect