Effects of deposition parameters on microstructure of CrN/Si3N4 nanolayered coatings and their thermal stability

Polycrystalline CrN/Si3N4 multilayer films were deposited by using two reactive magnetron sputtering targets, Cr and Si, respectively, and the as-deposited multilayer coatings were annealed at 900 degrees C for 2-4h in vacuum. We investigated the effects of mixed discharge gas pressure, bias voltage, substrate temperature and annealing temperature on the microstructural and interfacial properties of polycrystalline CrN/Si3N4 multilayer films. X-ray diffraction and x-ray reflectivity measurements showed that the layer structure of the coatings is maintained even after annealing at 900 degrees C for 4 h when the Si3N4 layer thickness is 0.3 nm, which meant that with proper control of the Si3N4 thickness CrN/Si3N4 multilayer coatings had an excellent thermal stability and were potential candidates for high-temperature tribological applications.