Physicochemical and mechanical properties of crystalline/amorphous CrN/Si3N4 multilayers

We investigated the mechanical and physicochemical properties of CrN/Si3N4 multilayered coatings in the bilayer period interval from 2 to 10 nm, produced by depositing the thin film multilayer structure by reactive sputtering at 300 °C, a temperature superior to those used in previously reported works on this specific structure. This resulted in an appreciable increase in hardness for a bilayer period around 4 nm, as well as a corresponding increase in the resistance to plastic deformation of the coating for bilayer periods around 4 to 6 nm. Various physicochemical characterization techniques used here indicated that the individual CrN and Si3N4 layers were stoichiometric and the interfaces of the multilayer structures were abrupt. The Si3N4 layers were amorphous while the CrN ones were polycrystalline. Furthermore, Si was mainly bonded to N as Si3N4, whereas Cr was bonded as CrN and chromium oxides.