Superhard V-Si-N coatings (>50GPa) with the cell-like nanostructure prepared by magnetron sputtering

By using reactive magnetron co-sputtering deposition, we prepared V-Si-N coatings from a pulsed-DC-excited vanadium source and an RF-DC-coupled Si source. The process was run at 773K under a relatively high partial pressure of nitrogen (0.3Pa) and generated intense ion bombardment at the substrate (Ji/JMe ~4.5). These favorable process conditions led to the formation of dense and smooth V-Si-N coatings with high hardness values (>33GPa). We performed high-resolution transmission electron microscopy (HRTEM) studies for the coating with 5.5at.% Si and identified a cell-like nanostructure, in which nanocrystalline VN grains were encapsulated by 50GPa nanoindentation hardness and >80% elastic recovery. The purposes of this study were as follows:•to develop a sputtering process with a high ion flux under a high PN2,•to provide an HRTEM image for the cell-like nanostructure,•to deposit >50GPaV-Si-N coatings using the sputtering process,•to report the first study on magnetron-sputtered V-Si-N hard coatings.