Coating SiC on Zircaloy-4 by magnetron sputtering at room temperature

Coating refractory ceramics onto alloys has been considered to be a feasible way to enhance the mechanical properties along with the corrosion and radiation resistance of the cladding materials. Here, we report a room-temperature magnetron sputtering method to deposit SiC films onto Zircaloy-4 substrate. By optimizing variety of processing parameters including target-substrate distance, sputtering power and deposition pressure, we finally obtained a dense SiC film with high values of hardness (25.61 GPa), elastic modulus (214.9 GPa) and critical load (8.24 N). Structural characterization indicates nanocrystalline (∼10 nm) structures of the SiC films, which is expected to show better radiation resistance than bulk SiC. Effects of processing parameters especially the deposition pressure on film microstructures and mechanical properties have been investigated in depth, which involve difference in energy of sputtering particles, nucleation and growth of grains, and stress states of the deposited films.