Figure 4. The arrow indicates a Ni
rich particle in the SEM image (a), which was identified by the EDS
mapping (b).
Figure 5 is a representative optical image demonstrating the formation
of ferrite and perlite microstructure of the steel substrate and the
coating thickness irregularity. Alumina was identified by EDS analysis
adhered to the substrate due to the blasting, and it appears as the dark
grey phase on the optical microscopy. There is no good resolution of
coating splats in optical microscopy.