Microstructure and mechanical properties of TiAlN/SiO2 nanomultilayers synthesized by reactive magnetron sputtering

TiAlN/SiO2 nanomultilayers with different SiO2 layer thickness were synthesized by reactive magnetron sputtering. The microstructure and mechanical properties were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and nano-indentation. The results indicated that, under the template effect of Bl-NaCl structural TiAlN layers, amorphous SiO2 was forced to crystallize and grew epitaxially with TiAlN layers when SiO2 layer thickness was below 0.6 nm, resulting in the enhancement of hardness and elastic modulus. The maximum hardness and elastic modulus could respectively reach 37 GPa and 393 GPa when SiO2 layer thickness was 0.6 nm. As SiO2 layer thickness further increased, SiO2 transformed back into amorphous state and broken the coherent growth of nanomultilayers, leading to the decrease of hardness and elastic modulus. (C) 2010 Elsevier B.V. All rights reserved.