Si_3N_4/CrN nanostructured multilayers grown by RF reactive magnetron sputtering

The amorphous/polycrystalline Si3N4/CrN nano-structured multilayer films ha ve been prepared by radio frequency （RF） reactive magnetron sputtering. The comp osition,microstructure and mechanical properties of these films were characteri zed by X-ray photoelectron spectroscopy （XPS）,X-ray diffraction （XRD）,high- resolution transmission electron microscopy （HRTEM） and nano-indentation. The C rN and （Si3N4） single layer films are polycrystalline face centered-cubic and amorphous structures,respectively. The CrN and Si3N4 layers are nearly stoichiometric. The HRTEM image indicates that the interfaces are planar and m odulation structure is clear in multilayers. The hardness values of Si3N4/Cr N multilayers are between those of the constituent CrN and Si3N4 films at a substrate temperature of 20 ℃,and are somewhat higher than those of Si3N4 films at a deposition temperature of 500 ℃. There is no superhardness effect in the Si3N4/CrN multilayers. Based on the experimental results,the hardeni ng mechanisms in the multilayers have been discussed.