Brittle SiC coatings have been successfully applied on Ni-Cr-based superalloy substrates to improve their oxidation resistance at high temperatures. The coating has been formed through the plastic deformation of the substrate with particle segmentation. The overlaid SiC layer shows the ability to slow down the outward chromium diffusion and hence sustaining the elemental content of the substrate. The formation of MoSi 2 and SiO 2 layers beneath SiC layer plays an important role in the oxidation rate reduction at elevated temperature environment. Scratch adhesion test result shows an excellent adhesion of SiC coating, as the coating delamination did not happen up to a 3.7N load. Four-point bending tests also pointed out the strong adhesion of oxide scales, which is necessary for further oxidation prevention.
- Cold spray
- Silicon carbide