Laser-clad YSZ@Ni (core-shell nanoparticle) composites coatings

YSZ@Ni core shell nanoparticles were used to prepare a composite coating on an Fe-based alloy by laser cladding. Samples were sintered layer-by-layer with a laser power P in the range of 800-2000 W, scanning velocity V in the range of 240-600 mm/min, and the laser beam diameter D=5 mm. The microstructures, phase constituents, and microhardness of a monolayer coating were investigated and compared with those of a multilayer coating. The results showed that the existing forms of core-YSZ in the monolayer coating comprised of four types: flower-like YSZ aggregates, few nanoscale YSZ particles at the grain boundaries, proeutectic YSZ phases, and YSZ/FeCr2O4 eutectic structure. Moreover, the multilayer coating structure was more homogeneous than the monolayer one. Interestingly, the YSZ@Ni core shell nanoparticles were separated into core-YSZ and shell-Ni layer with a stratification feature during the laser cladding process. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.