The CrAlN/SiO2 nanomultilayered films were prepared by reactive magnetron sputtering.
Effects of SiO2 layer thickness on structure and mechanical properties were studied.
The amorphous SiO2 could be crystallized and grow epitaxially with CrAlN layers.
The film shows an evident superhardness effect with maximal hardness of 38.9 GPa.
The hardening can be explained by modulus-difference and alternating-stress theories.